Gross Anatomy II - Avian

Gross Anatomy II - Avian

• External Exam Objectives:

  • Identify and palpate relevant musculoskeletal structures on a chicken carcass.
  • Palpate and assess anatomical links of the thoracic and pelvic limbs.
  • Visually inspect the carcass's body conformation and position of the avian skeleton.
  • Understand the avian skeleton's position (hidden under contour feathers)
  • Properly identify anatomical structures for proper restraint of the thoracic limb.
  • Identify relevant soft tissues analyzed during physical examination

• Internal Anatomy Objectives:

  • Carefully dissect the chicken carcass to identify the anatomy in situ.
  • Identify at least one intact air sac.
  • Properly identify soft tissue organs (respiratory, gastrointestinal, immune, and urogenital tracts).
  • Practice incising the avian integument and plucking body feathers.
  • Remove superficial organs to identify deeper anatomical structures.
  • Differentiate muscular masses responsible for flight and injecting parenteral drugs.

External (physical) exam

• Body Condition: Palpate the keel (entire length) and visualize any fat deposits.
• Feather Tracts (Pterylae): Contour feathers are arranged in tracts, with bare areas (apteria) between tracts, important for blood collection.
• Pectoral Muscles: Superficial muscles are preferred for intramuscular injections.
• Abdominal Space: Place fingers between the distal keel and pubic bones for proper flat/concave assessment.
• Vent: Opening of the cloaca used for measuring body temperature and collecting samples.
• Crop and Thoracic Inlet: Locate the crop on the right side of the neck and identify the L&R jugular veins by spreading feathers.
• Clavicle and Coracoid Bones: Palpable bones connecting the shoulder girdle to the sternum; assess for luxations/fractures.
• Nares (Nostrils): Exam of the nostrils.
• Infraorbital Sinus: Triangular cavity, a common infection site (hypovitaminosis A).
• Eyes and Conjunctiva: Fold lower eyelid to assess eye condition (round, clear, shiny).
• Ear Canal: Examine ear canal size (varies by species).
• Comb and Wattle: Outgrowths of skin thickened with vascularity; color change indicates low oxygen levels.

External (physical) exam - Thoracic Limb (wing)

• Humerus: Pneumatic bone; common site for venipuncture.
• Elbow Joint: Observe and palpate.
• Radius and Ulna: Ulna is larger for supporting secondary flight feathers.
• Wrist (Carpal) Joint: Contains 2 bones(ulna/radial); site for intraosseous catheters insertion.
• Primary Flight Feathers: Attached to digits (manus) and major metacarpus; grow laterally.
• Secondary Flight Feathers: Attached to the ulna; grow in a medial direction.
• Axillary Feathers: Separate primary from secondary flight feathers.
• Alula Feather: Supported by the alular digit; important for landing.
• Patagium: Feathered fold between shoulder and carpal joint; major patagium ligament.
• Major Metacarpus and digits: Site for attachment to primary flight feathers.

External (physical) exam - Pelvic Limb (leg)

• Tarsometatarsus: Covered by scales and not feathers; a common site for venipuncture.
• Digital Pad: Soft tissue that can be infected (bumblefoot).
• Intertarsal/ Hock Joint: Joint for the ankle.
• Tibiotarsus: Tibia and upper foot bones fused; numerous feather tracts.
• Stifle (Knee) Joint: Observe and palpate joint articulation space; a possible insertion point for intraosseous catheter insertion.
• Femur: Possible to palpate underneath the heavy muscle mass.
• Synsacrum: Fused vertebrae forming a framework for support.
• Notarium: Fused thoracic vertebrae, with one free vertebra between notarium and synsacrum; possible for spinal fractures.
• Last Rib: Halfway between the spine and sternum, a site for placing air sac cannulas.

Internal Anatomy - Dissection Guide (Summary)

• Plucking Feathers: Gentle plucking procedure is indispensable for proper wound management.
• Incising Skin: Longitudinal incision from the sternum to vent.
• Separating Skin: Using fingers or forceps to separate the skin.
• Cutting through abdominal body wall: Examining organs in situ.
• Incising pectoralis Muscle: Reflecting the large muscle for examination.
• Removing pectoral Muscles and Rib Section: Removing the sternum.
• Identifying organs in situ (trachea, syrinx, esophagus, crop, jugular vein, thyroid gland, heart, liver, proventriculus, ventriculus, duodenum, pancreas, intestine, spleen, ceca, rectum, cloaca, kidneys, sacrolumbar plexus, ischiadic nerve).
• Identifying the reproductive tract (female) in situ.
• Identifying the cloaca. Identify the 3 compartments (Coprodeum, Urodeum, Proctodeum).
• Identifying the male reproductive organs. (Testes, Vas Deferens).