External Exam and Dissection Guides PDF

Gross Anatomy II - Avian External (physical) exam learning objectives: Everything 1. To conduct a physical exam on the chicken carcass identifying and palpating relevant musculoskeletal structures. 2. To palpate the anatomical landmarks of both the thoracic and pelvic limbs. 3....

Gross Anatomy II - Avian External (physical) exam learning objectives: Everything 1. To conduct a physical exam on the chicken carcass identifying and palpating relevant musculoskeletal structures. 2. To palpate the anatomical landmarks of both the thoracic and pelvic limbs. 3. To assess the body condition of the carcasses through visual inspection and palpation. 4. To understand the anatomical position of the avian skeleton (when is hidden by contour (body) and flight feathers. 5. To correctly identify anatomical structures for properly restrain the thoracic limb during an examination. to 6. To identify the relevant soft tissue external structures that are assessed during the physical examination. in Internal anatomy dissection guide learning objectives: 1. To carefully dissect the chicken carcass while identifying the anatomy in situ and being able to identify at least 1 intact air sac. 2. To correctly identify the soft tissue organs from the respiratory, gastrointestinal, immune, and urogenital tracts. 3. To practice plucking body (contour) feathers and practice incising the avian integument. 4. To remove the superficial organs to identify in situ deeper anatomical structures. 5. To differentiate the 2 muscle masses that are responsible for flight and for injecting guide parenteral (injectable) drugs.  External (physical) exam 1. Body condition: palpate the keel (entire length) and visualize any fat 6. Crop (and thoracic inlet): deposits (if present) alongside the The crop is found on the keel. right side of the neck. 7 The L & R jugular veins can be 2. Feather tracts (pterylae): 6 seen by spreading the feathers contour feathers are arranged in to the sides instead of tracts in several parts of the body. spreading the feathers up and The bare spaces between feather 1 down. tracts are called apteria. In the 3 neck region, there is an apteric 7. Clavicle & coracoid bones: 2 site over the jugular vein that these bones connect the shoulder helps in blood collection. girdle o the sternum. Both can be 4 palpated to diagnose luxations and 3. Pectoralis muscles are fractures. superficial and are the preferred site for intramuscular injections. 4. Abdominal space: place middle 5 and index fingers between the distal end of the keel and pubic bones, this space should be flat or concave. 5. Vent is the opening of the cloaca and is clinically important for measuring body temperature and collecting cloacal swabs.  External (physical) exam - Head structures 1. Nares (nostrils) 2. Infraorbital sinus: triangular cavity under the skin; this is a common site of infection as a consequence of hypovitaminosis A (malnutrition). 3. Eyes and conjunctiva; fold out gently the lower lid to expose the conjunctiva; the eyes must be round, clear of opacities and shiny (in a live bird). Almond- shaped eyes mean the bird is either dehydration and/or sick. 4. Ear canal: covered by feathers; the size of the canal varies by species, being the largest in nocturnal birds (owls for example). 5-6. Comb and wattle: these are ornamental outgrowths of skin; are usually thickened and exceptionally vascular. These structures can turn purple-blue when circulating oxygen levels are low.  External (physical) exam - Oral cavity 1. Choana: is the median fissure in the palate that connects the oropharynx to 3. Laryngeal mound: contains the the nasal cavity. Important opening of the ; note there’s site for sample collection for 1 no epiglottis and note the presence microbiology. Immediately of papillae. Tracheal intubation in caudal to the choana is birds is simple since the tracheal another slit-like opening opening (a) is readily visible. called the infundibular cleft which is the opening of the Eustachian tubes. 2. Tongue: usually does not protrude and is relatively small. At the base of the tongue, 3 a there are papillae (“spiky” soft tissue that 2 points caudally helping the caudal movement of food).  External (physical) exam - Thoracic limb (wing) 1. Humerus: pneumatic bone; wing vein is on the medial side of the wing and is a common site for venipuncture. 6 2. Elbow joint: observe and palpate. 5 3. Radius and ulna: the ulna is larger and it 4 supports the secondary flight feathers. 8 Palpate both bones. 3 7 1 4. Wrist (carpal) joint: has 2 carpal bones 2 (ulnar and radial bones) and the ulnar carpal 10 bone can be palpated as a small protuberance on the medial aspect the wing. This is a site of insertion for intraosseous catheters. 9 5. Major metacarpus and digits: site of attachments for the primary flight feathers. Restraint of the wings is done by holding onto the bony structures (joints) and not by the feathers. 6. Alula feather: supported by the alular digit (birds only have 3 digits at the level of the thoracic limb/ 8. Primary flight feathers: arranged in a lateral direction; they attached to wing) and is necessary for landing). the digits (manus) and major metacarpus. 7. Patagium: triangular fold of feathered skin 9. Secondary flight feathers: arranged in a medial direction; attached to between the shoulder and carpal joint; palpate the ulna. the major patagium ligament. 10. Axillary feather: separates the primary from secondary feathers.  External (physical) exam - Pelvic limb (legs) Tarsometarsus: covered by scales and not by feathers in most species; the medial metatarsal vein is a common site for venipuncture for chickens and waterfowl. Digital pad: soft tissue that can become infected 8 easily from inadequate perches and substrate leading 9 to a condition called bumblefoot. 7 Intertarsal joint: also called the hock joint (the 6 ankle). Tibiotarsus: this bone results from the fusion of the tibia 5 and upper bones of the foot; note the numerous feather tracts. This is the so called “drumstick”. 4 Stifle (knee) joint: flex the joint to observe and palpate the articulate space; this is another site to place an intraosseous (IO) catheter. 3 Femur: may be able to palpate underneath the heavy muscle mass. 1 Synsacrum: fused series of vertebrae from the thoracic, lumbar, sacral and caudal vertebrae; provides rigid framework from which the body is 2 supported by the limbs. Notarium: fused thoracic vertebrae; a free vertebrae is found between the notarium and 9. Last rib: palpate and visualize the last rib area half-way synsacrum and is where spinal fractures can occur. between the spine and the sternum; this is the location for placing an air sac cannula.  Internal anatomy - Dissection guide 1. Pluck the feathers: 2. Incise longitudinally the skin at the midline of the abdomen – from distal end of from cloaca to beak; be sternum to the vent. This type of incision is used when abdominal surgery is required (for gentle while plucking example when the bird is egg-bound or has a foreign object in its stomach). since this procedure is indispensable for 3. Separate the skin with your fingers or with forceps (blunt dissection) – from vent to proper wound beak. management.  4. Cut through abdominal body wall and observe in situ: 5. Incise the pectoralis muscle Liver (A) along the keel (B) reflect muscle laterally to Ventriculus (distal portion) observe the supracoracoideus muscle (C). Duodenal loop Intramuscular injections are given in the pectoral Pancreas muscles. A A A  Internal anatomy - Dissection guide 6. Remove pectoral muscles and cut through the ribs on both sides of the sternum (dotted line) to remove the sternum; cut the clavicle and coracoid bones as well. Before cutting, lift the distal end of the sternum to visualize the ribs.  Internal anatomy - Dissection guide B A A C a B E 7. Identify in situ: A. Trachea, syrinx at tracheal bifurcation (a). The left and right primary bronchi can be seen by reflecting the heart. B. Esophagus and crop. C. Jugular vein. G D. (little red circle) Left thyroid gland. F E. Heart F. Liver (note that liver covers the apex of the heart and this is important for radiographic interpretation). H G. Proventriculus (reflect liver lobe medially to visualize it). H. Ventriculus (the ventriculus is usually covered by large amounts of fat as it is shown in the image). I I. Duodenal loops: visualize the pancreas between the duodenal loops.  Internal anatomy - Dissection guide 8. Reflect the heart (A) and liver (B) medially to visualize the lungs (C) and air sacs (D) in situ. The lungs are small and tightly adhered to the spine. The air sacs are thin-walled, clear, almost transparent bags where no gas exchange occurs. In most species, there are 9 air sacs, 8 are paired and are called by their location: cervical, cranial thoracic, caudal thoracic, abdominal and 1 single air sac called interclavicular air sac. C Fat C D D B Fat covering the proventriculus  Internal anatomy - Dissection guide Ventriculus 9. Reflect the ventriculus dorsally to Liver observe the spleen (A), which is a B Ribs (cut) small, kidney-shaped organ located near the junction of the proventriculus and ventriculus. A Location of the spleen is important for radiographic interpretation as this organ increases in size with chronic and systemic infections. Intestinal loops Ventriculus The ventriculus is arranged into 4 bands of smooth muscle. Two of these muscle bands are thick and dark in color - they are caudodorsal and cranioventral ; and the 2 other muscle bands are smaller, lighter in color and are craniodorsal and caudoventral. B C The caudoventral thin muscle (B) is the site B C for surgically incise the ventriculus to retrieve foreign objects.  Internal anatomy - Dissection guide A 10. Reflect the lower intestinal loops to visualize the kidney lobes; 3 lobes are identified and are named by location: cranial or anterior lobe (A),intermediate lobe (B) and caudal or posterior lobe (C). Observe the B ureters as small, thin tubes filled with a chalky-white substance (urates which are the main nitrogenous waste). C D 11. Remove the heart and the liver to visualize the esophagus (D); the tracheal bifurcation, syrinx and L & R primary bronchi (red circle), F the proventriculus (E); lung parenchyma (F); caudal thoracic air sacs (G). G E  Internal anatomy - Dissection guide 12. Remove the gastrointestinal tract from the tongue to the cloaca and lay the organs flat to identify: (A) Tongue and laryngeal mound. (B) Esophagus and crop. (C) Proventriculus. (D) Ventriculus (both thin and both thick muscles). (E) Spleen. (F) Duodenum and pancreas. (G) Jejunum. (H) Ileum (I) Paired ceca (J) Colorectum (K) Cloaca The Meckel’s or vitelline diverticulum is the short blind remnant of the yolk sac and yolk duct and is marks the boundary between the jejunum and ileum.  Internal anatomy - Dissection guide 13. Identify the reproductive tract (female shown here): (A) Lung space (left lung has been removed) (B) Oviduct: in reproductively active birds, this organ is large and highly vascularized occupying most of the space in the lower left abdomen. (C) Rectum (portion of the large intestines). (D) Ovary with multiple follicles at different stages of maturation.  Internal anatomy - Dissection guide 14. Identify the cloaca (circled) which is a bell-shaped Male birds have paired testes that are dilation of the rectum and incise it to identify the 3 bean-shaped and symmetrically compartments: arranged on either side of the (CD) Coprodeum receives content from the GI tract. midline of the spine. The size of the (UD) Urodeum receives content from urogenital tracts. testes increase substantially during (PD) Proctodeum is a short compartment connected to the reproductive activity. bursa of Fabricius on dorsal portion of cloaca. (BF) Bursa of Fabricius is the organ that produces B cells R = Rectum  Internal anatomy - Dissection guide 15. Remove the kidneys to observe the sacrolumbar plexus (A) and dissect the muscles of the inner thigh to expose the ischiadic nerve (B). This nerve increases in size with a common pathology called Marek’s disease. B A A B  Internal anatomy - Dissection guide J 16. Image for reference of internal anatomy of the A male chicken: B D (A) Heart (B) Liver (C) Lung C (D) Intestinal loops (E) Testicle (right) (F) Vas deferens (convoluted “squiggly line”). Lateral E to the vas deferens, observe a smaller and thin tube with a white material, this is the ureter. (G) Rectum (distal segment of the large intestine). F G (H) Cloaca: note the bell-shape organ. (I) Kidney: distal or caudal lobe I (J) Gall bladder H