Clinical Signs
Gross Lesions
Histopath
Normals
0 of 0 
Sort Results
This Image
Clinical Sign:
Tissue:
Etiology:
Species:
DESCRIPTION
DISEASE PROFILE
DIFFERENTIALS
MD-022A.jpg
gross image
- firm swelling: subcutaneous
Leg, subcutaneous tissue
Marek's Disease
chicken (Gallus gallus)
Clinical Description
In some cases of Marek's disease, large subcutaneous lymphomas may be observed throughout the body (shown here in the leg on the left). A normal leg is shown on the right for comparison.
MD-004A.jpg
clinical sign
paralysis (legs), dyspnea
- dyspnea
- paralysis: whole body
Leg
Marek's Disease
chicken (Gallus gallus)
Clinical Description
The most common form of Marek’s disease is the lymphoproliferative syndrome, wherein mononuclear infiltrates develop in peripheral nerves and organs. The clinical signs associated with this condition are non-specific and relate to the location of the lesions. A variety of neurologic signs can develop including spastic paralysis of the limbs, exhibited here. This chicken is also gasping, a sign associated with the paralysis of the respiratory and digestive systems.
MD-021A.jpg
gross image
- crusts, skin
- hyperemia: skin
- ulcer: skin
Leg, skin
Marek's Disease
chicken (Gallus gallus)
Clinical Description
“Alabama red leg†is a Marek's disease syndrome associated with tumors in broiler breeders and roosters. Lesions consist of severe hyperemia of the skin of the shanks that can eventually become ulcerated and have brown crusts.
MD-003A.jpg
clinical sign
Paralysis, paresis (legs)
- paralysis: whole body
- paraparesis
Leg
Marek's Disease
chicken (Gallus gallus)
Clinical Description
Paresis and paralysis are usually asymmetrical, reflecting the asymmetrical peripheral nerve involvement of Marek’s disease. This clinical sign often manifests itself with the bird stretching one leg forward and one leg backward, as seen here.
MD-114A.jpg
gross image
- enlarged feather follicles: skin
skin
Marek's Disease
Unknown
Clinical Description
In Marek's disease, the skin around the feather follicles may become raised and roughened (shown here), due to epithelial cell proliferation.
pullet2close
clinical sign
Paralysis (legs)
- paralysis: whole body
Leg
Marek's Disease
chicken (Gallus gallus)
Clinical Description
Spastic paralysis of the legs associated with peripheral nerve involvement in Marek's disease.
MD-016A.jpg
gross image
- enlarged feather follicles: skin
skin
Marek's Disease
chicken (Gallus gallus)
Clinical Description
In some cases of Marek’s disease, only a few feather tracts may be affected, as shown here. In advanced cases, most of the feather follicles of the entire body may be affected due to lymphoid infiltration.
MD-005A.jpg
clinical sign
opisthotonus
- opisthotonus
head, neck
Marek's Disease
chicken (Gallus gallus)
Clinical Description
In Marek's disease, opisthotonus (backwards extension of the head and neck), torticollis (lateral twisting of the head and neck), and other nervous signs are sometimes observed.
MD-116A.jpg
gross image
- enlarged feather follicles: skin
skin
Marek's Disease
Unknown
Clinical Description
Detailed view of the lymphoproliferative skin lesions associated with Marek’s disease.
Copy of LAYER
clinical sign
Torticollis (head and neck)
- torticollis
head, neck
Marek's Disease
chicken (Gallus gallus)
Clinical Description
Neurologic signs in Marek's disease may include torticollis, shown here.
MD-120A.jpg
gross image
- enlarged feather follicles: skin
skin
Marek's Disease
Unknown
Clinical Description
Detailed view of the lymphoproliferative skin lesions associated with Marek’s disease.
Broilertorticolis
clinical sign
torticollis (head and neck)
- torticollis
head, neck
Marek's Disease
chicken (Gallus gallus)
Clinical Description
This chicken, infected with Marek's disease virus, is exhibiting torticollis, a lateral twisting of the head and neck.
MD-020A.jpg
gross image
- enlarged feather follicles: skin
skin
Marek's Disease
chicken (Gallus gallus)
Clinical Description
Marek's disease may involve individual feather follicles, as observed in this chicken exhibiting swelling of the follicles.
MD-221A.jpg
clinical sign
paralysis (neck)
- paralysis: whole body
neck
Marek's Disease
chicken (Gallus gallus)
Clinical Description
Other nervous signs associated with Marek’s disease may include neck paralysis, shown here.
MD-019A.jpg
gross image
- nodules: skin
skin
Marek's Disease
Unknown
Clinical Description
In Marek's disease, skin lesions may coalesce into large patches of tumors.
MD-108A.jpg
clinical sign
paralysis
- paralysis: whole body
Marek's Disease
chicken (Gallus gallus)
Clinical Description
In Marek's disease, transient paralysis can occur and is caused by temporary vasculitis and edema in the brain. The condition typically persists for 1-2 days, after which time the chickens will experience a rapid and total recovery. Later, infected chickens may develop MD lymphomas with clinical signs reflecting tissue involvement.
MD-006A.jpg
clinical sign
Paralysis (legs, neck), ataxia
- ataxia
- paralysis: whole body
Leg, neck
Marek's Disease
chicken (Gallus gallus)
Clinical Description
In transient paralysis syndrome, a form of Marek’s disease, chickens may exhibit ataxia and flaccid paralysis of the neck and limbs.
MD-012A.jpg
gross image
- abnormal iris pigmentation
- abnormal pupillary shape
eye, iris, pupil
Marek's Disease
chicken (Gallus gallus)
Clinical Description
Ocular lesions, sometimes associated with Marek's disease, is usually due to lymphoid infiltration of iris that causes white discoloration. The pupil is often irregular (as shown here) and does not respond to changes of light. A normal eye is on the left.
MD-024A.jpg
gross image
- abnormal iris pigmentation
- abnormal pupillary shape
eye, iris, pupil
Marek's Disease
Unknown
Clinical Description
Marek's disease infiltration of the eyes. A normal eye is shown in the center for comparison. Note, the eyes on the left and right have lighter colored irises and the iris/pupil shape is irregular. Both findings are related to lymphoid infiltration of the iris.
SILKY2
clinical sign
wings, legs
- paralysis: whole body
Leg, Wing
Marek's Disease
chicken (Gallus gallus)
Clinical Description
Paralysis of the legs and wings caused by lymphomas involving the peripheral nerves, resulting from Marek's disease infection.
MD-031A.jpg
gross image
- white infiltrates: peripheral nerves
peripheral nerves
Marek's Disease
Unknown
Clinical Description
In Marek's disease, lymphomatous infiltrates may occur in any peripheral nerves. These infiltrations can be somewhat subtle at times and comparing the right and left sides of the paired nerves is often helpful.
MD-109A.jpg
clinical sign
Paralysis, paresis (legs)
- paralysis: whole body
- paraparesis
Leg
Marek's Disease
chicken (Gallus gallus)
Clinical Description
Paresis and paralysis are usually asymmetrical, reflecting the asymmetrical peripheral nerve involvement of Marek’s disease. This clinical sign often manifests itself with the bird stretching one leg forward and one leg backward, as seen here.
MD-105A.jpg
clinical sign
depression, diarrhea
- diarrhea
- generalized depression
Marek's Disease
chicken (Gallus gallus)
Clinical Description
Some chickens with Marek's disease may exhibit vague clinical signs such as depression, anorexia, weight loss, and diarrhea, as shown here. These signs are often related to visceral infiltrations of neoplastic cells.
MD-026A.jpg
gross image
- enlargements: peripheral nerves
peripheral nerves
Marek's Disease
chicken (Gallus gallus)
Clinical Description
Often the nerve plexi are involved in lymphoid infiltration in Marek's disease. Look for lesions in the ischiadic/sciatic and brachial nerve plexi. Here the left ischadic plexus is asymmetrically enlarged. Comparing the symmetry of the paired right and left nerves is often the best way to distinguish such abnormalities.
MD-018A.jpg
clinical sign
nodules and ulcers (skin)
- enlarged feather follicles: skin
- ulcer: skin
skin
Marek's Disease
chicken (Gallus gallus)
Clinical Description
In Marek's disease, affected feather follicles can become roughened and develop ulcers. These ulcers may develop secondary infections, exacerbated by the immunosuppressive nature of Marek’s disease.
MD-071A.jpg
gross image
- white infiltrates: peripheral nerves
peripheral nerves
Marek's Disease
chicken (Gallus gallus)
Clinical Description
On post-mortem examination, gross lesions may be found in peripheral nerves. Here, the vagus nerve on the bottom (black arrow) has a grossly evident focal enlargement caused by Marek’s disease virus.
MD-027A.jpg
gross image
- enlargements: peripheral nerves
- yellow discoloration, peripheral nerves
peripheral nerves
Marek's Disease
chicken (Gallus gallus)
Clinical Description
Peripheral nerves with Marek’s lesions may have edema, loss of cross-striation, and a grey or yellow discoloration. Compare the affected nerve on the left with the glistening white unaffected nerve on the right.
MD-013A.jpg
clinical sign
swelling (wattles)
- swelling: wattles
wattles
Marek's Disease
chicken (Gallus gallus)
Clinical Description
Swelling of the wattles (shown here) and combs can also occur in Marek's disease if the lymphomas infiltrate the subcutaneous tissue of these nonfeathered areas.
silkysciaticnervesmd
gross image
- enlargements: peripheral nerves
- yellow discoloration, peripheral nerves
peripheral nerves
Marek's Disease
chicken (Gallus gallus)
Clinical Description
The sciatic nerve on top is enlarged and has a yellow discoloration, while the nerve on the bottom is normal and is shown for comparison.
MD-008A.jpg
clinical sign
abnormal pupil shape, abnormal iris color
- abnormal iris pigmentation
- abnormal pupillary shape
eye, iris
Marek's Disease
chicken (Gallus gallus)
Clinical Description
A comparison between a normal chicken on the right and a chicken infected with Marek's disease on the left. The eye on the left shows how neoplastic cellular infiltration of the iris can produce an abnormal iris shape and color.
MD-025A.jpg
gross image
- enlargements: peripheral nerves
- yellow discoloration, peripheral nerves
peripheral nerves
Marek's Disease
chicken (Gallus gallus)
Clinical Description
The sciatic nerve of a bird infected with Marek's disease has been removed and shown on top with a normal nerve on the bottom for comparison. The affected nerve is enlarged, yellowish, translucent and has a loss of cross-striations.
MD-007A.jpg
clinical sign
abnormal pupil shape, abnormal iris color
- abnormal iris pigmentation
- abnormal pupillary shape
eye, iris, pupil
Marek's Disease
chicken (Gallus gallus)
Clinical Description
Marek’s disease may be associated with unilateral or bilateral ocular abnormalities. The most common signs observed are changes in iris color and shape of iris/pupil (shown here), caused by lymphoid infiltration.
silkybraquialplexus
gross image
- white infiltrates: peripheral nerves
peripheral nerves
Marek's Disease
Unknown
Clinical Description
The sciatic (ischiadic) nerve on the left has an enlarged sciatic plexus, while the corresponding nerve on the right is normal.
MD-009A.jpg
clinical sign
miosis (pupil)
- miosis
eye, pupil
Marek's Disease
chicken (Gallus gallus)
Clinical Description
Lymphoid infiltration of the iris may interfere with normal pupil dilation and constriction. The miotic pupil, shown here, prevents accommodation to changes in lighting conditions.
MD-033A.jpg
gross image
- white infiltrates: peripheral nerves
peripheral nerves
Marek's Disease
chicken (Gallus gallus)
Clinical Description
The peripheral nerves have been fully removed to allow a comparison between normal (top) and nerves (bottom) in a chicken infected with Marek's disease.
MD-034A.jpg
gross image
- enlargement: spinal cord
spinal cord
Marek's Disease
chicken (Gallus gallus)
Clinical Description
The dorsal root ganglia from bird with Marek's disease may be enlarged, but examination requires careful dissection of the spinal cord and its nerve trunks.
SILKY1
clinical sign
paralysis
- paralysis: legs
Marek's Disease
chicken (Gallus gallus)
Clinical Description
Leg paralysis associated with peripheral nerve involvement in Marek's disease.
MD-042A.jpg
gross image
- white infiltrates: lungs
- white neoplastic infiltrates: heart
heart, lungs
Marek's Disease
chicken (Gallus gallus)
Clinical Description
The more virulent strains of Marek’s disease can be associated with lymphomas on virtually any visceral organ. Here, the heart and lung of an infected chicken is shown on top and compared to the corresponding normal organs on the bottom. When examining a flock of birds infected with the visceral form of Marek’s, usually multiple organs or tissues are involved.
Copy of LUNG1
gross image
- white infiltrates: lungs
lungs
Marek's Disease
Unknown
Clinical Description
In this photo, taken from a bird infected with Marek's disease, multiple lymphomatous lesions are visible in the lungs.
MD-154A.jpg
gross image
- white infiltrates: lungs
lungs
Marek's Disease
Unknown
Clinical Description
Marek's disease tumors in the lungs.
MD-152A.jpg
gross image
- white infiltrates: lungs
lungs
Marek's Disease
chicken (Gallus gallus)
Clinical Description
Marek's disease tumors in the lungs.
MD-036A.jpg
gross image
- white infiltrates: oropharynx
oropharynx
Marek's Disease
chicken (Gallus gallus)
Clinical Description
Marek's disease tumors in the oropharynx.
MD-044A.jpg
gross image
- white focal lesions: liver
- white infiltrates: lungs
- white infiltrates: spleen
liver, lungs, spleen
Marek's Disease
chicken (Gallus gallus)
Clinical Description
Lymphomas can develop on virtually any organ. Here the liver, lungs, and spleen all show white Marek’s lesions.
MD-230A.jpg
gross image
- pale areas in muscle wall: proventriculus
proventriculus
Marek's Disease
chicken (Gallus gallus)
Clinical Description
White Marek’s disease lesions in the wall of the proventriculus.
MD-231A.jpg
gross image
- white infiltrates: proventriculus
proventriculus
Marek's Disease
Unknown
Clinical Description
The proventriculus has been opened to show the nodular lesions in the muscle wall of a bird infected with Marek's disease.
MD-062A.jpg
gross image
- white infiltrates: proventriculus
proventriculus
Marek's Disease
chicken (Gallus gallus)
Clinical Description
In this bird infected with Marek's disease, there is a more diffuse infiltration of the mucosa of the proventriculus.
MD-047A.jpg
gross image
- proventriculus
proventriculus
Marek's Disease
chicken (Gallus gallus)
Clinical Description
A nodular lymphoma in the mucosa of the proventriculus (organ on the left).
MD-057A.jpg
gross image
- pale areas in muscle wall: gizzard
ventriculus (gizzard)
Marek's Disease
Unknown
Clinical Description
A focal lymphoma in the incised wall of the gizzard caused by Marek's disease.
MD-049A.jpg
gross image
- nodule: gizzard
ventriculus (gizzard)
Marek's Disease
Unknown
Clinical Description
A lymphoma lesion in the wall of the gizzard in a bird infected with Marek's disease.
MD-276A.jpg
gross image
- white focal lesions: liver
liver
Marek's Disease
chicken (Gallus gallus)
Clinical Description
Marek's disease tumors in the liver.
MD-065A.jpg
gross image
- enlargement: kidneys
- pale discoloration: kidneys
kidney
Marek's Disease
chicken (Gallus gallus)
Clinical Description
Marek’s disease visceral lymphoma can also produce a more diffuse lesion. Organs, such as this kidney, may become diffusely enlarged, are sometimes firm on palpation, and may have white to grey areas of discoloration, as seen here.
MD-060A.jpg
gross image
- white infiltrates: kidneys
kidney
Marek's Disease
chicken (Gallus gallus)
Clinical Description
Marek's disease tumors in the kidneys.
Copy of kidneytumor+urol
gross image
- enlargement: kidneys
- white infiltrates: kidneys
kidney
Marek's Disease
chicken (Gallus gallus)
Clinical Description
Lymphomatous lesions in the kidney caused by Marek's disease.
MD-066A.jpg
gross image
- white infiltrates: kidneys
kidney
Marek's Disease
chicken (Gallus gallus)
Clinical Description
In this photo, taken from a bird infected with Marek's disease, MD tumors are visible in the kidneys.
MD-236A.jpg
gross image
- atrophy: thymus gland
- enlargement: spleen
- premature atrophy: bursa of Fabricius
bursa of Fabricius, spleen, thymus gland
Marek's Disease
chicken (Gallus gallus)
Clinical Description
The degree of visceral tumor involvement in Marek's disease varies by virus strain and the genetic line of chicken. In this image the spleen, bursa, and thymus of 3 chickens infected with different strains of MD is shown. A normal control is shown on top for comparison. Note that the more virulent strain, presented on the bottom row, was associated with a greater degree of bursal and thymic atrophy.
MD-043A.jpg
gross image
- enlargement: spleen
- white infiltrates: spleen
spleen
Marek's Disease
chicken (Gallus gallus)
Clinical Description
Here, a comparison of a normal spleen and a spleen affected by Marek’s disease shows splenic enlargement as well as the characteristic white lymphoma lesions scattered throughout the organ.
SPLEENC2
gross image
- enlargement: spleen
- white infiltrates: spleen
spleen
Marek's Disease
chicken (Gallus gallus)
Clinical Description
Splenomegaly with lymphomatous lesions caused by Marek's disease.
MD-138A.jpg
gross image
- abnormal color: spleen
spleen
Marek's Disease
chicken (Gallus gallus)
Clinical Description
A detailed view of a spleen infiltrated by Marek's disease lymphomas, giving the organ a mottled white appearance.
MD-141A.jpg
gross image
- white infiltrates: spleen
spleen
Marek's Disease
chicken (Gallus gallus)
Clinical Description
in Marek's disease, organ infiltrates can be focal, as seen in this spleen.
MD-142A.jpg
gross image
- white infiltrates: spleen
spleen
Marek's Disease
Unknown
Clinical Description
Alternatively, organ infiltrates can be more diffuse, as seen in this spleen from a bird infected with Marek's disease.
MD-064A.jpg
gross image
- nodules: ovary
ovary
Marek's Disease
chicken (Gallus gallus)
Clinical Description
Marek's disease tumors in the ovary.
MD-054A.jpg
gross image
- white neoplastic infiltrates: heart
epicardium, heart
Marek's Disease
chicken (Gallus gallus)
Clinical Description
In this photo, taken from a bird infected with Marek's disease, MD tumors are visible in the epicardium of the heart.
MD-050A.jpg
gross image
- white infiltrates: intestines
intestine
Marek's Disease
chicken (Gallus gallus)
Clinical Description
Marek's disease tumors distributed throughout the entire gastrointestinal tract.
MD-103A.jpg
gross image
- white infiltrates: intestines
intestine, jejunum
Marek's Disease
chicken (Gallus gallus)
Clinical Description
In this photo, Marek's disease tumors have infiltrated the jejunum and surrounding mesentery.
MD-051A.jpg
gross image
- nodules: intestines
intestine
Marek's Disease
chicken (Gallus gallus)
Clinical Description
This intestinal lesion, caused by Marek’s disease, demonstrates a nodular type of lymphoma. When nodular tumors occur, their borders are firmly associated with the surrounding tissue.
Copy of Image001
gross image
- white infiltrates: pancreas
pancreas
Marek's Disease
Unknown
Clinical Description
A large number of tumors in the pancreas of a bird infected with Marek's disease.
MD-101A.jpg
gross image
- white infiltrates: intestines
intestine
Marek's Disease
chicken (Gallus gallus)
Clinical Description
Marek's disease tumors in the intestines.
MD-160A.jpg
gross image
- white infiltrates: pancreas
pancreas
Marek's Disease
chicken (Gallus gallus)
Clinical Description
In this photo, Marek's disease tumors have infiltrated the pancreas.
MD-039A.jpg
gross image
- white infiltrates: pectoral muscles
pectoral muscles
Marek's Disease
Unknown
Clinical Description
Marek's disease tumors found in the pectoral muscles.
MD-246A.jpg
gross image
- atherosclerosis: vessels
vessels
Marek's Disease
chicken (Gallus gallus)
Clinical Description
Atherosclerosis (fatty proliferation on vessels) may occur in chickens infected with some strains of Marek's disease. This image shows artherosclerosis of blood vessels on the surface of the gizzard.
MD-069A.jpg
gross image
- nodules: ovary
kidney, ovary
Marek's Disease
chicken (Gallus gallus)
Clinical Description
In Marek's disease, as the nodules on organs enlarge, as shown on this kidney and ovary, the normal architecture of the organ is destroyed and sometimes areas of tissue necrosis can occur.
MD-068A.jpg
gross image
- nodules: ovary
ovary
Marek's Disease
Unknown
Clinical Description
Marek's disease tumors in the ovary.
Bursalatrophy
gross image
- premature atrophy: bursa of Fabricius
bursa of Fabricius
Marek's Disease
chicken (Gallus gallus)
Clinical Description
There is premature atrophy of the bursa induced by Marek's disease virus.
MD-073A.jpg
gross image
- premature atrophy: bursa of Fabricius
bursa of Fabricius
Marek's Disease
chicken (Gallus gallus)
Clinical Description
In Marek’s disease, bursal atrophy is often noticeable in young birds. This finding is not pathognomonic for MD, since it may occur in many other diseases. The bursa on the right is from a normal bird while the bursa on the left is from an MD infected bird.
MD-074A.jpg
gross image
- focal infiltration: bursa of Fabricius
bursa of Fabricius
Marek's Disease
chicken (Gallus gallus)
Clinical Description
Tumors may occasionally occur in the Bursa in Marek's disease. These tumors are diffuse in nature, involving the entire plicae. The Bursa on the left has a diffuse tumor involving several plicae, with focal areas of necrosis that should not be confused with a focal tumor. The Bursa on the right is from a normal bird.
MD-196A.jpg
gross image
- enlargement: testes
testes
Marek's Disease
chicken (Gallus gallus)
Clinical Description
The teste in the bottom of this photo shows a tumor, resulting from Marek's disease, causing asymmetrical enlargement of the gonad.
MD-190A.jpg
gross image
- enlargement: testes
testes
Marek's Disease
chicken (Gallus gallus)
Clinical Description
MD tumors in the testes.
MD-083A.jpg
gross image
- pectoral muscles
pectoral muscles
Marek's Disease
chicken (Gallus gallus)
Clinical Description
Large lymphoid tumor in the deep pectoral muscle of this chicken infected with Marek's disease.
MD-070A.jpg
gross image
Marek's Disease
other
Clinical Description
Marek’s disease virus is primarily transmitted from chicken-to-chicken through inhalation of contaminated dust and dander as well as direct contact between chickens. However, darkling beetles (Alphitobius diaperinus) can be a carrier of Marek’s disease virus in the poultry house.
CoelomicCavity1
normal
heart, liver
Normal Reference
chicken (Gallus gallus)
Clinical Description
With the bird in dorsal recumbency, the walls of the right atrium and ventricle are positioned on top. After death, the atria often expand with blood and can appear quite enlarged. The great vessels can be seen entering the base of the heart. The heart muscle should be reddish-brown in color. A variable amount of fat will be present in the coronary grooves. If the bird is emaciated, this fat may be absent or have undergone serous atrophy, resulting in a gelatinous, wet appearance. Look for any external lesions on the epicardial surface of the heart or on the surrounding fat.
CoelomicCavity3
normal
heart
Normal Reference
chicken (Gallus gallus)
Clinical Description
With the bird in dorsal recumbency, the walls of the right atrium and ventricle are positioned on top. After death, the atria often expand with blood and can appear quite enlarged. The great vessels can be seen entering the base of the heart. The heart muscle should be reddish-brown in color. A variable amount of fat will be present in the coronary grooves. If the bird is emaciated, this fat may be absent or have undergone serous atrophy, resulting in a gelatinous, wet appearance. Look for any external lesions on the epicardial surface of the heart or on the surrounding fat.
Heart1
normal
heart
Normal Reference
chicken (Gallus gallus)
Clinical Description
The heart muscle should be reddish-brown in color. A variable amount of fat will be present in the coronary grooves. If the bird is emaciated, this fat may be absent or have undergone serous atrophy, resulting in a gelatinous, wet appearance. Look for any external lesions on the epicardial surface of the heart or on the surrounding fat.
Heart3
normal
heart
Normal Reference
chicken (Gallus gallus)
Clinical Description
View of the left side of the heart.
Heart7
normal
heart
Normal Reference
chicken (Gallus gallus)
Clinical Description
View of the apex of the heart.
Heart11
normal
heart
Normal Reference
chicken (Gallus gallus)
Clinical Description
The bottom 1/3 of the apex of the heart has been removed. This view allows the thickness of the ventricular walls and septum to be assessed. The right ventricular free wall should be approximately 1/3 to 1/2 the thickness of the intraventricular septum and the left ventricular free wall. In the normal heart, the lumina of the ventricles should be small and there should be negligible space between the walls of the ventriculae and the septum. In cardiac diseases, such as pulmonary hypertension or congenital defects, this space will be widened.
Heart8
normal
heart, right atrioventricular valve
Normal Reference
chicken (Gallus gallus)
Clinical Description
In this view, the chambers of the right atrium and ventricle have been opened by making a cut up the right ventricular free wall. Once opened, the right atrioventricular valve and endocardium are exposed. The septal leaf of the right valve is normally very muscular.
Heart9
normal
heart, left atrioventricular valve
Normal Reference
chicken (Gallus gallus)
Clinical Description
In this view, the chambers of the left atrium and ventricle have been opened by making a cut up the left ventricular free wall. The left atrioventricular valve is normally thin and smooth.
Heart10
normal
aortic valve, heart
Normal Reference
chicken (Gallus gallus)
Clinical Description
The aorta has been opened by inserting scissors under the left atrioventricular valve and cutting upward. The normal lumen of the aorta, as seen here, is creamy white and the leaflets of the aortic valve are uniform and very thin.
18_liver
normal
liver
Normal Reference
chicken (Gallus gallus)
Clinical Description
The liver is separated into a right and left lobe, as seen here, attached at the base. The right hepatic lobe is slightly larger than the left and the liver margins should come to a thin crisp edge.
liver2
normal
liver
Normal Reference
chicken (Gallus gallus)
Clinical Description
In domestic birds, the left lobe has a fissure running along its surface, dividing it into 2 parts.
liver1
normal
liver
Normal Reference
chicken (Gallus gallus)
Clinical Description
The liver is separated into a right and left lobe, as seen here, attached at the base. The right hepatic lobe is slightly larger than the left and the liver margins should come to a thin crisp edge.
liver3
normal
liver
Normal Reference
chicken (Gallus gallus)
Clinical Description
The overall size of the liver is variable, often extending beyond the edge of the sternum. To identify hepatomegaly, look at the liver margins. Blunted or thickened margins are a sign of an enlarged liver.
liver4
normal
liver
Normal Reference
chicken (Gallus gallus)
Clinical Description
Healthy hepatic parenchyma should be somewhat firm on palpation and have a smooth and glistening appearance. The color of the liver can vary depending on the nutritional state of the bird. Generally, the liver is reddish-brown but it can be light brown or even slightly yellow, depending on the fat content in the diet. However, a very yellow liver is an abnormal finding, except in chicks between 1 to 5 days of age.
liver5
normal
liver
Normal Reference
chicken (Gallus gallus)
Clinical Description
Healthy hepatic parenchyma should be somewhat firm on palpation and have a smooth and glistening appearance. The color of the liver can vary depending on the nutritional state of the bird. Generally, the liver is reddish-brown but it can be light brown or even slightly yellow, depending on the fat content in the diet. However, a very yellow liver is an abnormal finding, except in chicks between 1 to 5 days of age.
gallbladder1
normal
gallbladder
Normal Reference
chicken (Gallus gallus)
Clinical Description
The gallbladder is located on the visceral surface of the right hepatic lobe. It is normally dark green in color, due to the bile located within the lumen of this thin-walled structure. During autolysis, bile pigments may leak out of the gallbladder, staining the adjacent hepatic tissues yellow to green. This bile inbibition is a normal part of autolysis and should not be confused with a lesion. Similar staining can also occur in the ascending duodenum, adjacent to the area where the bile and pancreatic ducts empty. The size of the gallbladder is variable and may be enlarged in birds that are off-feed.
gallbladder2
normal
gallbladder
Normal Reference
chicken (Gallus gallus)
Clinical Description
The gallbladder is located on the visceral surface of the right hepatic lobe. It is normally dark green in color, due to the bile located within the lumen of this thin-walled structure. During autolysis, bile pigments may leak out of the gallbladder, staining the adjacent hepatic tissues yellow to green. This bile inbibition is a normal part of autolysis and should not be confused with a lesion. Similar staining can also occur in the ascending duodenum, adjacent to the area where the bile and pancreatic ducts empty. The size of the gallbladder is variable and may be enlarged in birds that are off-feed.
liver6
normal
liver
Normal Reference
chicken (Gallus gallus)
Clinical Description
View of the liver on cross section. As seen here, the color and texture should be uniform. Focal or regional changes may indicate a lesion. It’s normal for a small amount of blood to ooze from the cut surface of the liver.
39_lungs
normal
lungs
Normal Reference
chicken (Gallus gallus)
Clinical Description
The lungs are tightly adhered to the dorsal rib cage. Their color should be bright pink in a fresh bird but will become increasinly more congested, wet, and dark red with autolysis, as seen here. To assess the lungs, do not over-interpret their color but rather, use a combination of visual inspection and palpation to assess the health of this tissue.
19_air_sacs
normal
air sacs
Normal Reference
chicken (Gallus gallus)
Clinical Description
The air sacs are thin membranes distributed throughout the body. In a fresh healthy bird, air sacs should be transparent but, as seen here, the membranes will become slightly cloudy after death. In over-conditioned birds, fat may be present on the air sac membranes. Inflammation of the air sacs can result in thickened membranes, opacities, or fibrin deposition. Fluid, foam, or exudate can accumulate between the air sac membranes.
CoelomicCavity2
normal
proventriculus, ventriculus (gizzard)
Normal Reference
chicken (Gallus gallus)
Clinical Description
The proventriculus is the glandular stomach that lies between the esophagus and the gizzard. It is lined with mucosal glands that secrete digestive enzymes important in food break down. On close inspection, these glands can be seen through the serosal surface, giving it a “honeycomb-like†texture. On palpation the proventriculus should feel turgid and, its surface should be shiny tan. Look for abnormalities such as hemorrhagic lesions or neoplastic infiltrates on its surface.
Proventriculus1
normal
proventriculus, ventriculus (gizzard)
Normal Reference
chicken (Gallus gallus)
Clinical Description
The serosa of the proventriculus is normally shiny, tan, and has a fine vascular pattern. In a fresh bird, on close inspection, the glands can be visualized through the mucosa. The muscular wall of the proventriculus should feel uniformly turgid. Flaccidity or dilatation of the organ might indicate an improper diet or feeding program, infection, or neuromuscular dysfunction. The external features of the ventriculus, or gizzard, should consist of alternating bands of dark red and light red smooth muscles, forming a roughly circular shape. These muscles may be covered by a thick layer of fat, as seen here. On palpation, the gizzard should be extremely firm. Thinning or laxity in the muscles may indicate inflammation, an improper diet or feeding program, or neuromuscular problems.
Proventriculus3
normal
proventriculus
Normal Reference
chicken (Gallus gallus)
Clinical Description
The proventriculus in situ.
Pancreas3
normal
proventriculus, ventriculus (gizzard)
Normal Reference
chicken (Gallus gallus)
Clinical Description
The serosa of the proventriculus is normally shiny, tan, and has a fine vascular pattern. In a fresh bird, on close inspection, the glands can be visualized through the mucosa. The muscular wall of the proventriculus should feel uniformly turgid. Flaccidity or dilatation of the organ might indicate an improper diet or feeding program, infection, or neuromuscular dysfunction. The external features of the ventriculus, or gizzard, should consist of alternating bands of dark red and light red smooth muscles, forming a roughly circular shape. These muscles may be covered by a thick layer of fat. On palpation, the gizzard should be extremely firm. Thinning or laxity in the muscles may indicate inflammation, an improper diet or feeding program, or neuromuscular problems.
Proventriculus6
normal
proventriculus, ventriculus (gizzard)
Normal Reference
chicken (Gallus gallus)
Clinical Description
View of the serosal surface of the proventriculus and gizzard (ventriculus).
Proventriculus9
normal
proventriculus
Normal Reference
chicken (Gallus gallus)
Clinical Description
Close-up of the glands of the proventriculus as seen through the outer wall.
Proventriculus10
normal
proventriculus
Normal Reference
chicken (Gallus gallus)
Clinical Description
View of the glands of the proventriculus as seen from the mucosal surface.
Proventriculus11
normal
proventriculus
Normal Reference
chicken (Gallus gallus)
Clinical Description
Close-up view of the glands of the proventriculus as seen from the mucosal surface.
28_proventriculos
normal
proventriculus
Normal Reference
chicken (Gallus gallus)
Clinical Description
The contents of the proventriculus can vary from mucoid and creamy to more formed pieces of ingesta, depending on how recently the bird ate.
Proventriculus8
normal
proventriculus, ventriculus (gizzard)
Normal Reference
chicken (Gallus gallus)
Clinical Description
View of the serosal surface of the proventriculus and gizzard (ventriculus).
Ventriculus5
normal
ventriculus (gizzard)
Normal Reference
chicken (Gallus gallus)
Clinical Description
The external features of the ventriculus, or gizzard, should consist of alternating bands of dark red and light red smooth muscles, forming a roughly circular shape. These muscles may be covered by a thick layer of fat, as seen here.
Proventriculus7
normal
proventriculus, ventriculus (gizzard)
Normal Reference
chicken (Gallus gallus)
Clinical Description
View of the left side of the proventriculus and gizzard.
31_gizzard_contents
normal
ventriculus (gizzard)
Normal Reference
chicken (Gallus gallus)
Clinical Description
The consistency of the gizzard contents will vary depending on the stage of digestion. Generally, it contains fibers and portions of seeds. Additionally, small pebbles, ingested to facilitate the break up of food, may also be present.
Ventriculus6
normal
ventriculus (gizzard)
Normal Reference
chicken (Gallus gallus)
Clinical Description
The mucosa of the gizzard is covered by a sturdy layer of protein called koilin, which aids in food digestion. The koilin layer should be smooth and uniform. The color may vary from white, to yellow, to green depending on the diet and the degree of bile staining.
Ventriculus7
normal
ventriculus (gizzard)
Normal Reference
chicken (Gallus gallus)
Clinical Description
Close-up view of the koilin layer of the gizzard (ventriculus).
Spleen1
normal
spleen
Normal Reference
chicken (Gallus gallus)
Clinical Description
The spleen is located dorsal to the gizzard.
Spleen4
normal
spleen
Normal Reference
chicken (Gallus gallus)
Clinical Description
On very close inspection, the spleen as a slight stippled pattern.
29_spleen
normal
spleen
Normal Reference
chicken (Gallus gallus)
Clinical Description
On very close inspection, the spleen as a slight stippled pattern.
Spleen5
normal
spleen
Normal Reference
chicken (Gallus gallus)
Clinical Description
On very close inspection, the spleen as a slight stippled pattern.
Spleen6
normal
spleen
Normal Reference
chicken (Gallus gallus)
Clinical Description
View of the cut section of the spleen. On cross section, the spleen may appear slightly granular due to the variations in red and white pulp.
Duodenum1
normal
duodenum
Normal Reference
chicken (Gallus gallus)
Clinical Description
The duodenum has a descending and ascending loop, arranged in a U-shape. The loops are held together by a thin strip of mesentery and surround the pancreas. The appearance of the intestine can vary greatly depending on the post-mortem condition of the bird. In a fresh bird, the serosa of a healthy intestine is usually pink, smooth, and glistening. As the post-mortem interval increases, the intestinal walls will become congested, as seen here, and eventually, even a healthy loop of bowel may appear dark red. However, if the serosa has a dull granular appearance, this can be evidence of inflammation. The normal appearance of the pancreas is pale red or slightly yellow. On close inspection, its glandular nature is evident. Swelling of the pancreas can be recognized if the organ extends beyond its normal location between the loops of the duodenum.
Duodenum4
normal
duodenum
Normal Reference
chicken (Gallus gallus)
Clinical Description
The walls of the duodenum should be smooth and uniform and offer little resistance to incision. In the proximal duodenum, the ingesta is normally mucoid and pale tan to yellow. Distal to the bile ducts, the ingesta becomes more green in color.
Duodenum3
normal
duodenum, pancreas
Normal Reference
chicken (Gallus gallus)
Clinical Description
The duodenum has a descending and ascending loop, arranged in a U-shape. The loops are held together by a thin strip of mesentery and surround the pancreas. The appearance of the intestine can vary greatly depending on the post-mortem condition of the bird. In a fresh bird, the serosa of a healthy intestine is usually pink, smooth, and glistening. As the post-mortem interval increases, the intestinal walls will become congested, as seen here, and eventually, even a healthy loop of bowel may appear dark red. However, if the serosa has a dull granular appearance, this can be evidence of inflammation. The normal appearance of the pancreas is pale red or slightly yellow. On close inspection, its glandular nature is evident. Swelling of the pancreas can be recognized if the organ extends beyond its normal location between the loops of the duodenum.
Duodenum2
normal
duodenum
Normal Reference
chicken (Gallus gallus)
Clinical Description
The duodenum has a descending and ascending loop, arranged in a U-shape. The loops are held together by a thin strip of mesentery and surround the pancreas. The appearance of the intestine can vary greatly depending on the post-mortem condition of the bird. In a fresh bird, the serosa of a healthy intestine is usually pink, smooth, and glistening. As the post-mortem interval increases, the intestinal walls will become congested, as seen here, and eventually, even a healthy loop of bowel may appear dark red. However, if the serosa has a dull granular appearance, this can be evidence of inflammation. The normal appearance of the pancreas is pale red or slightly yellow. On close inspection, its glandular nature is evident. Swelling of the pancreas can be recognized if the organ extends beyond its normal location between the loops of the duodenum.
Pancreas4
normal
pancreas
Normal Reference
chicken (Gallus gallus)
Clinical Description
The normal appearance of the pancreas is pale red or slightly yellow. On close inspection, its glandular nature is evident. Swelling of the pancreas can be recognized if the organ extends beyond its normal location between the loops of the duodenum.
24_pancreas_texture
normal
pancreas
Normal Reference
chicken (Gallus gallus)
Clinical Description
On close inspection, the pancreas has a fine glandular texture.
MeckelsDiverticulum1
normal
Mekel's diverticulum
Normal Reference
chicken (Gallus gallus)
Clinical Description
After 10 days of age, the only remnant of the yolk sac is a small tag of scar tissue, called Meckel’s diverticulum. This tag, located on the antimesenteric side of the intestine, contains lymphoid tissue and is part of the GALT, or Gut Associated Lymphoid Tissue. Meckel’s diverticulum is also an important anatomical landmark, as it is located at the junction between the jejunum and the ileum. Being able to differentiate the jejunum from the ileum is important to generating differentials for intestinal diseases. Some infections, such as coccidiosis, have a predilection for the jejunum and other diseases target the ileum.
MeckelsDiverticulum2
normal
Mekel's diverticulum
Normal Reference
chicken (Gallus gallus)
Clinical Description
After 10 days of age, the only remnant of the yolk sac is a small tag of scar tissue, called Meckel’s diverticulum. This tag, located on the antimesenteric side of the intestine, contains lymphoid tissue and is part of the GALT, or Gut Associated Lymphoid Tissue. Meckel’s diverticulum is also an important anatomical landmark, as it is located at the junction between the jejunum and the ileum. Being able to differentiate the jejunum from the ileum is important to generating differentials for intestinal diseases. Some infections, such as coccidiosis, have a predilection for the jejunum and other diseases target the ileum.
Cecum1
normal
ceca
Normal Reference
chicken (Gallus gallus)
Clinical Description
At the junction between the ileum and the descending colon, are two blind-ended sacs known as the ceca. In domestic poultry, the cecae are large structures that bend over themselves, with their apices pointing caudally. The walls should be thin and semi-translucent, allowing the greenish-colored intestinal contents to be visualized within. If the walls are opaque, thin or irregular, infection should be suspected.
Ileum1
normal
ceca
Normal Reference
chicken (Gallus gallus)
Clinical Description
At the junction between the ileum and the descending colon, are two blind-ended sacs known as the ceca. In domestic poultry, the cecae are large structures that bend over themselves, with their apices pointing caudally. The walls should be thin and semi-translucent, allowing the greenish-colored intestinal contents to be visualized within. If the walls are opaque, thin or irregular, infection should be suspected.
CecalTonsil1
normal
cecal tonsil
Normal Reference
chicken (Gallus gallus)
Clinical Description
At the base of the ceca, near the junction of the ileum and the descending colon, are 2 important lymphoid structures called cecal tonsils. The tissue here bulges outward slightly as it is thicker and slightly more granular.
CecalTonsil2
normal
cecal tonsil
Normal Reference
chicken (Gallus gallus)
Clinical Description
At the base of the ceca, near the junction of the ileum and the descending colon, are 2 important lymphoid structures called cecal tonsils. The tissue here bulges outward slightly as it is thicker and slightly more granular.
CecalTonsil3
normal
cecal tonsil
Normal Reference
chicken (Gallus gallus)
Clinical Description
As demonstrated here, the cecal tonsils should be opened and the mucosa examined closely. This is a common location for lesions to be detected. In inflammatory or neoplastic diseases, the tonsils may be come enlarged and mottled red and tan. In some viral infections, the lymphoid tissue may become necrotic, causing the tonsils to become red.
33_cecaltonsil_mucosa
normal
cecal tonsil
Normal Reference
chicken (Gallus gallus)
Clinical Description
The cecal tonsil has been opened to show the mucosa. It’s important to examine this area closely for lesions. In inflammatory or neoplastic disease, the cecal tonsils may become enlarged and mottled red and tan. In some viral infections, this lymphoid tissue may become necrotic, causing the tonsils to become red.
CecalTonsil4
normal
cecal tonsil
Normal Reference
chicken (Gallus gallus)
Clinical Description
As demonstrated here, the cecal tonsils should be opened and the mucosa examined closely. This is a common location for lesions to be detected. In inflammatory or neoplastic diseases, the tonsils may be come enlarged and mottled red and tan. In some viral infections, the lymphoid tissue may become necrotic, causing the tonsils to become red.
Cecum2
normal
ceca, ileum
Normal Reference
chicken (Gallus gallus)
Clinical Description
The serosa of the ileum should be shiny, tan, and smooth, with no thickening or bulges. Be careful not to over-interpret the color of the intestinal walls as post-mortem congestion and autolysis can quickly turn the intestinal walls red or black. Because the intestinal walls are semi-translucent, look for areas of proliferation or mucosal exudate which can sometimes be visualized through the intestinal wall. At the junction between the ileum and the descending colon, are two blind-ended sacs known as the ceca. In domestic poultry, the cecae are large structures that bend over themselves, with their apices pointing caudally. The walls should be thin and semi-translucent, allowing the greenish-colored intestinal contents to be visualized within. If the walls are opaque, thin or irregular, infection should be suspected.
34_intestinal_lumen
normal
intestine
Normal Reference
chicken (Gallus gallus)
Clinical Description
The quality of intestinal ingesta can yield important clues about the functional status of the intestines. If the ingesta is normal, as seen here, regardless of the appearance of the intestinal wall, the intestines were likely functioning normal at the time of death. If the content is abnormal, intestinal dysfunction is present. Keep in mind that as the ingesta moves though the intestines, its color and consistency will change. In the jejunum, pictured here, the ingesta becomes slightly thicker and yellow tan in color.
colon1
normal
ceca
Normal Reference
chicken (Gallus gallus)
Clinical Description
Distal to the ceca, the intestines continue as a short straight tube known as the descending colon. These walls should be smooth and uniform. Look for any dilatations which may indicate an obstruction due to a mechanical blockage, a scar, or another disease process.
35_cloaca
normal
cloaca
Normal Reference
chicken (Gallus gallus)
Clinical Description
The cloaca is the common chamber for the gastrointestinal, urinary, and reproductive tracts. Here the cloaca has been opened. By the time ingesta enters the cloaca, it should have the normal color and consistency of feces and will be mixed with urates from the urinary system.
Cloaca1
normal
bursa of Fabricius, cloaca
Normal Reference
chicken (Gallus gallus)
Clinical Description
On the dorsal wall of the cloaca is a diverticulum called the Bursa of Fabricius. This structure is an important lymphoid organ. The shape of the bursa varies with species. In the chicken, it is roughly pear shaped. In ducks, geese and turkeys it is more spindle shaped. The size varies with the age of the bird. It typically reaches its maximum size between 4 to 12 weeks of age, at which time it can weigh up to 4 grams. Normally, the bursa begins to involute when the bird is approximately 3 months of age. By the time the bird reaches sexual maturity, it may no longer be evident on gross examination.
Cloaca2
normal
bursa of Fabricius
Normal Reference
chicken (Gallus gallus)
Clinical Description
On the dorsal wall of the cloaca is a diverticulum called the Bursa of Fabricius. This structure is an important lymphoid organ. The shape of the bursa varies with species. In the chicken, it is roughly pear shaped. In ducks, geese and turkeys it is more spindle shaped. The size varies with the age of the bird. It typically reaches its maximum size between 4 to 12 weeks of age, at which time it can weigh up to 4 grams. Normally, the bursa begins to involute when the bird is approximately 3 months of age. By the time the bird reaches sexual maturity, it may no longer be evident on gross examination.
Bursa2
normal
bursa of Fabricius
Normal Reference
chicken (Gallus gallus)
Clinical Description
On the dorsal wall of the cloaca is a diverticulum called the Bursa of Fabricius. This structure is an important lymphoid organ. The shape of the bursa varies with species. In the chicken, it is roughly pear shaped. In ducks, geese and turkeys it is more spindle shaped. The size varies with the age of the bird. It typically reaches its maximum size between 4 to 12 weeks of age, at which time it can weigh up to 4 grams. Normally, the bursa begins to involute when the bird is approximately 3 months of age. By the time the bird reaches sexual maturity, it may no longer be evident on gross examination.
Bursa1
normal
bursa of Fabricius
Normal Reference
chicken (Gallus gallus)
Clinical Description
On the dorsal wall of the cloaca is a diverticulum called the Bursa of Fabricius. This structure is an important lymphoid organ. The shape of the bursa varies with species. In the chicken, it is roughly pear shaped. In ducks, geese and turkeys it is more spindle shaped. The size varies with the age of the bird. It typically reaches its maximum size between 4 to 12 weeks of age, at which time it can weigh up to 4 grams. Normally, the bursa begins to involute when the bird is approximately 3 months of age. By the time the bird reaches sexual maturity, it may no longer be evident on gross examination.
36_bursa
normal
bursa of Fabricius
Normal Reference
chicken (Gallus gallus)
Clinical Description
The bursa of Fabricius has been opened to show its mucosal surface. The normal mucosa consists of many folds of tissue, which are pale white to pink or tan and slightly firm on palpation.
Vent1
normal
vent
Normal Reference
chicken (Gallus gallus)
Clinical Description
The vent, located just beneath the tail, is the external orifice of the urinary, genital and gastrointestinal systems. The normal vent is free of fecal and urate staining, swelling, redness, or evidence of trauma.
37_ovary
normal
ovary
Normal Reference
chicken (Gallus gallus)
Clinical Description
This image shows the normal ovary of a sexually immature female, approximately 10 weeks of age. Here, the ovary is small and inactive.
Ribs1
normal
rib bone
Normal Reference
chicken (Gallus gallus)
Clinical Description
View of the dorsal aspect of the ribs. Note that the ventral ribs have been removed from the field.
38b_kidney_chain
normal
kidney
Normal Reference
chicken (Gallus gallus)
Clinical Description
The kidneys consist of a right and left chain, with each chain being made up of 3 lobes. The lobes are tightly embedded in the bone of the synsacrum. They are normally red to dark mahogany brown in color and have a slightly granular texture.
38a_kidney_texture
normal
kidney
Normal Reference
chicken (Gallus gallus)
Clinical Description
This image shows a detailed view of the normal texture of the kidneys.
40_ishradic_nerve
normal
peripheral nerves
Normal Reference
chicken (Gallus gallus)
Clinical Description
The nerves should have a creamy-white color and a slightly striated texture on close inspection. This image shows a normal ishiadic plexus in the caudal coelomic cavity.
ThyroidGlandLeft2
normal
thyroid gland
Normal Reference
chicken (Gallus gallus)
Clinical Description
The thyroid glands should be smooth, oval, and reddish-brown in color. On very close inspection, the thyroid glands have a very fine granular appearance.
07_beak_articulation
normal
beak
Normal Reference
chicken (Gallus gallus)
Clinical Description
A properly formed beak, shown here, is bilaterally symmetrical and the upper and lower halves should form a smooth line where they articulate.
beak2
normal
beak
Normal Reference
chicken (Gallus gallus)
Clinical Description
A properly formed beak is bilaterally symmetrical and the upper and lower halves should form a smooth line where they articulate. Nutritional imbalances may result in beak malformations. The color of the beak depends on the bird’s coloration, with lighter birds typically having yellow beaks. However, beak color can also be influenced by physiologic factors. For example, yellow pigment in the beak may be lost as the chicken produces more eggs.
choana1
normal
oropharynx
Normal Reference
chicken (Gallus gallus)
Clinical Description
The oropharynx should be examined for any lesions. Note that birds do not have a soft palate or a discrete boundary between the oral cavity and the pharynx. The color of the oral mucosa will vary with lighter birds tending to have a pink mucosa while darker birds will have more pigment. Look for ulcers, erosions, opacities, diptheritic nodules, or other lesions.
tongue1
normal
tongue
Normal Reference
chicken (Gallus gallus)
Clinical Description
A bird’s tongue is supported by the hyobranchial apparatus, making it somewhat inflexible.
09_oral_mucosa
normal
oropharynx
Normal Reference
chicken (Gallus gallus)
Clinical Description
The color of the oral mucosa will vary with the overall coloration of the bird. However, the mucosa should be free of ulcers, erosions, opacities, diptheritic nodules, and other lesions.
tongue3
normal
tongue
Normal Reference
chicken (Gallus gallus)
Clinical Description
The dorsal surface of the chicken tongue should be smooth and pink. There is a row of large papillae near the caudal attachment of the tongue. Inspect the tongue for any lesions such as ulcers or nodules.
08_tongue
normal
tongue
Normal Reference
chicken (Gallus gallus)
Clinical Description
The dorsal surface of the chicken’s tongue is smooth and there is a row of large papillae near the caudal attachment. When inspecting the tongue, look for ulcers and erosions.
choana2
normal
choana
Normal Reference
chicken (Gallus gallus)
Clinical Description
On the roof of the oropharynx is a fissure, called the choana, which opens into the nasal cavity. Inspect the area around the choana for ulcers. The choana is also a good place to find respiratory exudate. Birds do not form liquid pus and inspusated exudate tends to accumulate in the choanal orifice. If exudate is present, you can collect a swab sample from the choana. The choana is surrounded by ridges and rows of sharp well-demarcated papillae that point caudally. A variety of diseases can damage the papillae, resulting in blunting.
13_infundibular_cleft
normal
infundibular cleft
Normal Reference
chicken (Gallus gallus)
Clinical Description
Just caudal to the choana is the infundibular cleft. This is the opening to the Eustachian tube and it is surrounded by ridges and rows of sharp well-demarcated papilla that point caudally.
pharynx1
normal
oropharynx, tongue
Normal Reference
chicken (Gallus gallus)
Clinical Description
The tongue, esophagus, and trachea have been removed as one unit. This view allows the structures of the structures of the caudal oral cavity and pharynx to be examined more closely.
pharynx3
normal
oropharynx
Normal Reference
chicken (Gallus gallus)
Clinical Description
The tongue, esophagus, and trachea have been removed as one unit. This view allows the structures of the caudal oral cavity and pharynx to be examined more closely.
crop1
normal
esophagus
Normal Reference
chicken (Gallus gallus)
Clinical Description
The esophagus runs down the length of the neck and, in domestic species, is interrupted by a diverticulum called the crop. The esophagus continues down the neck and empties into the proventriculus. The esophagus and crop are thin-walled and located just below the skin. Their outer surfaces should be pale tan and smooth.
crop2
normal
esophagus
Normal Reference
chicken (Gallus gallus)
Clinical Description
The esophagus runs down the length of the neck and, in domestic species, is interrupted by a diverticulum called the crop. The esophagus continues down the neck and empties into the proventriculus. The esophagus and crop are thin-walled and located just below the skin. Their outer surfaces should be pale tan and smooth.
crop3
normal
crop, esophagus
Normal Reference
chicken (Gallus gallus)
Clinical Description
The mucosal surface of the esophagus should be smooth and glistening. The cranial portion contains many glands and the caudal portion has numerous longitudinal folds. The color along the entire length should be pale tan to pink. The presence of proliferative lesions may indicate a viral infection or a dietary imbalance. You can gently wash away any food material from the walls of the crop with some water but do not scrape the mucosa. Food material should wash away easily while fibrin and exudate will stick to the mucosa. Look for ulcers and erosions, which appear as red or pale depressions in the mucosa.
26_esophagus_folds
normal
esophagus
Normal Reference
chicken (Gallus gallus)
Clinical Description
The caudal portion of the normal esophagus has numerous longitudinal folds, as seen here.
crop4
normal
crop
Normal Reference
chicken (Gallus gallus)
Clinical Description
You can gently wash away any food material from the walls of the crop with some water but do not scrape the mucosa. Food material should wash away easily while fibrin and exudate will stick to the mucosa. Look for ulcers and erosions, which appear as red or pale depressions in the mucosa.
crop5
normal
crop
Normal Reference
chicken (Gallus gallus)
Clinical Description
You can gently wash away any food material from the walls of the crop with some water but do not scrape the mucosa. Food material should wash away easily while fibrin and exudate will stick to the mucosa. Look for ulcers and erosions, which appear as red or pale depressions in the mucosa.
Trachea3
normal
trachea
Normal Reference
chicken (Gallus gallus)
Clinical Description
The trachea should be uniform in color, ranging from pale pink to tan or white and the external surface should be smooth. Upper respiratory disease may produce tracheal lesions that are sometimes visible on the outer surface. Look for discoloration, nodules, or irregularities in the tracheal cartilages.
palate2
normal
trachea
Normal Reference
chicken (Gallus gallus)
Clinical Description
The trachea is a thin tube completely encircled by small cartilagenous rings. The trachea should be uniform in color, ranging from pale tan to white and the external surface should be smooth. Look for discoloration, nodules, or irregularities in the tracheal cartilages.
21_trachea_cartilage
normal
trachea
Normal Reference
chicken (Gallus gallus)
Clinical Description
The trachea is a thin tube completely encircled by cartilagenous rings. The trachea should be uniform in color, ranging from pale pink to tan or white and the external surface should be smooth. Upper respiratory disease may produce tracheal lesions that are sometimes visible on the outer surface. Look for discoloration, nodules, or irregularities in the tracheal cartilages.
Syrinx1
normal
syrinx, trachea
Normal Reference
chicken (Gallus gallus)
Clinical Description
At the terminal end of the trachea lies the syrinx, a flattened area at the junction of the trachea and the primary bronchi. The syrinx is responsible for generating vocal sounds.
20_syrinx
normal
syrinx
Normal Reference
chicken (Gallus gallus)
Clinical Description
Since the diameter of the syrinx is significantly smaller than that of the trachea, examine this area closely for occlusions caused by exudate, fungal mats, or parasites.
Syrinx2
normal
syrinx
Normal Reference
chicken (Gallus gallus)
Clinical Description
Since the diameter of the syrinx is significantly smaller than that of the trachea, examine this area closely for occlusions caused by exudate, fungal mats, or parasites.
Trachea4
normal
trachea
Normal Reference
chicken (Gallus gallus)
Clinical Description
View of the inside lumen of the trachea.
Jugular1
normal
jugular vein
Normal Reference
chicken (Gallus gallus)
Clinical Description
The left jugular vein of the bird, seen here, is much larger than the right.
Jugular2
normal
jugular vein
Normal Reference
chicken (Gallus gallus)
Clinical Description
The left jugular vein of the bird, seen here, is much larger than the left. The vagal and glossopharyngeal nerves are closely associated with the veins.
22_jugular_and_nerve
normal
peripheral nerves
Normal Reference
chicken (Gallus gallus)
Clinical Description
The vagal and glossopharyngeal nerves run parallel with the jugular veins.
ThyroidGlandLeft1
normal
thyroid gland
Normal Reference
chicken (Gallus gallus)
Clinical Description
The thyroid glands are located on each side of the neck, medial to the jugular vein and cranial to the origin of the subclavian and common carotid arteries.
23_thyroid_parathyroid
normal
thyroid gland
Normal Reference
chicken (Gallus gallus)
Clinical Description
The glands should be smooth, oval, and reddish-brown in color. On very close inspection, the thyroid glands have a very fine granular appearance.
ThyroidGlandRight2
normal
thyroid gland
Normal Reference
chicken (Gallus gallus)
Clinical Description
Just caudal to the thyroid glands are the small pale pink parathyroid glands. The right parathyroid gland, seen here, lies directly adjacent to the right thyroid gland. The left parathyroid gland is slightly separated from the left thyroid gland.
Thymus1
normal
thymus gland
Normal Reference
chicken (Gallus gallus)
Clinical Description
The thymus is a bilateral chain of structures, located in the lateral neck region. each side is composed of 4 to 7 lobes. In chickens less than 17 weeks of age, the thymus should be visible but normally regresses around the time of sexual maturity.
Thymus2
normal
thymus gland
Normal Reference
chicken (Gallus gallus)
Clinical Description
The lobes of the thymus, normally present only in immature birds, are pale tan to pink in color.
VIT E-SELENIUM - 019A.jpg
normal
brain
Normal Reference
chicken (Gallus gallus)
Clinical Description
The avian brain has a smooth surface, with no gyri or sulci. Its cortex should appear smooth and glistening and the right and left sides should be symmetrical.
44_brain
normal
brain, cerebrum
Normal Reference
chicken (Gallus gallus)
Clinical Description
This image shows a detailed view of the surface of the normal cerebrum.
PectoralMuscles1
normal
pectoral muscles
Normal Reference
chicken (Gallus gallus)
Clinical Description
The 3 muscles involved in flight in the bird, called the pectoral muscles, lie on either side of the keel bone. These muscles are very large, making them ideal for body muscle assessment. The muscles should be smooth and have a relatively uniform texture.
PectoralMuscles2
normal
pectoral muscles
Normal Reference
chicken (Gallus gallus)
Clinical Description
The pectoral muscles can be removed from the keel and ribs in order to examine them more closely. Look for areas of necrosis, inflammation, or hemorrhage.
PectoralMuscles3
normal
pectoral muscles
Normal Reference
chicken (Gallus gallus)
Clinical Description
With the muscles removed, look for areas of necrosis, inflammation, or hemorrhage. A series of parallel cuts through the muscle bellies can facilitate this assessment.
eyes1
normal
comb, eyelid, wattles
Normal Reference
chicken (Gallus gallus)
Clinical Description
The eyelids should be free of swelling or exudate from ocular discharge.
eyes2
normal
eyelid
Normal Reference
chicken (Gallus gallus)
Clinical Description
The eyelids should be free of swelling or exudate from ocular discharge.
10_eye_insitu
normal
eye
Normal Reference
chicken (Gallus gallus)
Clinical Description
The cornea should be clear and convex and the sclera white. Iris color will vary with the breed and color of the bird however, look for abnormalities of the iris such as redness, anterior synechia, or exudate in the anterior chamber. The shape of the iris and pupil should be uniform and round.
12_conjunctiva
normal
conjunctiva
Normal Reference
chicken (Gallus gallus)
Clinical Description
The conjunctiva is a mucous membrane. It should be light pink in color and free of any redness, swelling, or exudate.
15_eye_front
normal
eye
Normal Reference
chicken (Gallus gallus)
Clinical Description
The eye has been removed from the skull showing the full extent of the orbit.
11_ear
normal
ear
Normal Reference
chicken (Gallus gallus)
Clinical Description
The ears in the bird are simple ostea, with no external pinna. The openings should be free of swelling, exudate, or other material.
beak1
normal
comb, wattles
Normal Reference
chicken (Gallus gallus)
Clinical Description
The comb and wattles are outgrowths of skin that are highly vascularized, making them a useful way to assess the bird's overall health. They are normally bright red but their color will quickly fade after death. However, they should remain firm and uniform on palpation. look for abnormalities such as edema, petechiae, necrosis, cyanosis, papules and ulcers.
14_sinus
normal
infraorbital sinus
Normal Reference
chicken (Gallus gallus)
Clinical Description
The infraorbital sinuses are triangular-shaped cavities, located rostroventral to the eyes. The sinuses are air-filled lumens, with one opening into the nasal cavity and the other into the caudal nasal cavity.
06_leg_conformation
normal
Leg
Normal Reference
chicken (Gallus gallus)
Clinical Description
As seen here, the legs bones of the should be straight and symmetrical.
limb1
normal
leg bones
Normal Reference
chicken (Gallus gallus)
Clinical Description
The leg bones should be straight and symmetrical. Palpate the bones for fractures and calluses and the joints for swelling or effusion. Flex and extend all the joints to assess range of motion, keeping in mind the effects of rigor mortis.
integument1
normal
skin
Normal Reference
chicken (Gallus gallus)
Clinical Description
The skin on the limbs is covered by scales that are normally dry, flat, and slightly overlapping. Some parasites live beneath the scales of the legs. Some infectious diseases can cause keratinous outgrowths from this skin.
integument2
normal
skin
Normal Reference
chicken (Gallus gallus)
Clinical Description
The skin on the limbs is covered by scales that are normally dry, flat, and slightly overlapping. Some parasites live beneath the scales of the legs. Some infectious diseases can cause keratinous outgrowths from this skin.
integument3
normal
digits, foot pads
Normal Reference
chicken (Gallus gallus)
Clinical Description
Digital pads cover the plantar surface of the birds’ feet. These pads are composed of thick skin and adipose tissue. In the center of the foot, there is a large central metatarsal pad. The pads should be soft, free of scabs, swellings, edema, hemorrhages, or other lesions.
pad2
normal
foot pads
Normal Reference
chicken (Gallus gallus)
Clinical Description
In the center of the foot, there is a large central metatarsal pad. The pads should be soft, free of scabs, swellings, edema, hemorrhages, or other lesions.
01_claw
normal
claws
Normal Reference
chicken (Gallus gallus)
Clinical Description
In birds housed on the floor, claws will normally come to a blunt tapered end, as seen here. Claws may be somewhat sharper in birds housed in cages. Curling or fraying claws are abnormal findings.
feathers1
normal
feathers
Normal Reference
chicken (Gallus gallus)
Clinical Description
Birds have several types of feathers distributed across various regions of their body including down, body feathers, and flight feathers. Look for abnormalities in feather conformation such as warping or malformed barbs and barbules. Make note of any body regions that are missing feathers. Feathers are normally distributed along tracks on the body, called pterylae. These tracks are interspersed with featherless tracts called apteria. Keep in mind, that not all feather loss is abnormal. Seasonal feather molting is a normal physiologic process. Additionally, females who are incubating eggs may have an area on their abdomen lacking feathers, called the brood patch. In non-pathologic feather loss, the skin will appear healthy. In cases of pathologic feather loss, such as excessive feather picking by the bird, or its cage mates, the skin will be traumatized.
04_down_feather
normal
feathers
Normal Reference
chicken (Gallus gallus)
Clinical Description
This image shows a typical “down†feather.
integument4
normal
skin
Normal Reference
chicken (Gallus gallus)
Clinical Description
The skin in the chicken is normally very thin and the amount of pigment varies from pink to black, depending on the coloration of the bird. The skin should be free of exudate and have little or no scale. Look for any lesions or evidence of ectoparasites.
05_apteria
normal
feathers
Normal Reference
chicken (Gallus gallus)
Clinical Description
Feathers are normally distributed along tracks on the body, known as pterylae, seen here. These tracks are interspersed with featherless areas called apteria. Patches of feather loss may be due to normal physiologic processes, such as seasonal molting. Pathologic feather loss can result from trauma and infection and is associated with skin lesions.
feathers2
normal
feathers
Normal Reference
chicken (Gallus gallus)
Clinical Description
Pay attention to the feather sheath, the area where the feather emerges from the follicle. Swelling in this location can be indicative of several types of infection.
feathers3
normal
feathers
Normal Reference
chicken (Gallus gallus)
Clinical Description
Pay attention to the feather sheath, the area where the feather emerges from the follicle. Swelling in this location can be indicative of several types of infection.
Uropygealgland1
normal
uropygeal gland
Normal Reference
chicken (Gallus gallus)
Clinical Description
The uropygial, or preen gland, is located dorsal to the base of the tail. This cutaneous gland secretes an oily substance that birds spread over their feathers during preening. These secretions help maintain normal healthy feathers.
Uropygealgland2
normal
uropygeal gland
Normal Reference
chicken (Gallus gallus)
Clinical Description
The body of the gland is located subcutaneously and its two lobes can sometimes be visualized beneath the skin, as seen here. The gland’s duct exits externally through a small papilla. Infected glands may result in swelling and reddening of the surrounding skin.
42_cartilage
normal
cartilage
Normal Reference
chicken (Gallus gallus)
Clinical Description
Cartilage should be smooth, shiny, and white with a slightly blue tinge, as seen here. Look for degenerative changes and roughed, discolored areas.
43_bone_marrow
normal
leg bones
Normal Reference
chicken (Gallus gallus)
Clinical Description
In a young bird, cut the long bone of the leg lengthwise to examine the epiphysis. Nutrient or mineral deficiencies can lead to poor mineralization of the bone. Look for widening of the epiphyseal plate or generalized hypoplasia of the bone.
Marek's Disease
Marek's Disease
Marek's Disease
Etiology
Marek's disease (MD) is a transmissible neoplastic disease, primarily affecting chickens. The disease is caused by a cell-associated herpesvirus, containing double-stranded DNA. There are three serotypes of MDV but oncogenicity is only associated with serotype 1 MDVs. Within this serotype however, there are many strains of MDV, whose pathogenicity varies widely. Subsequently, clinical signs in infected chickens vary from asymptomatic infection to neurologic disease, skin disease, and ocular lesions.
Host Range
Marek's disease is primarily a disease of commercial chickens, but it can also affect turkeys. MD often occurs in 2-5 month-old (sexually immature) chickens but can also occur after the onset of egg production. This form of the disease is referred to as
- Avian Encephalomyelitis
- Erythroblastosis
- Genetic Grey Eye
- Histomoniasis
- Lymphoid leukosis
- Myeloblastosis
- Myelocytomatosis
- Newcastle Disease
- Ovarian Carcinoma
- Reticuloendotheliosis
- Riboflavin Deficiency
- Tuberculosis
![[icon]](/avian-atlas/sites/all/themes/avianatlas/images/footer_help.gif){kind=small}
![[icon]](/avian-atlas/sites/all/themes/avianatlas/images/footer_tellus.gif){kind=small}
![[icon]](/avian-atlas/sites/all/themes/avianatlas/images/footer_howhelp.gif){kind=small}
