Avian Anatomy: Musculoskeletal

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Avian AnatomyMusculoskeletal

• P. T. Redig

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Objectives

• Provide details of clinically important
  anatomical aspects of avian skeleton
• Provide details of anatomical contraints imposed
  by flight on the avian skeleton

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Origins and Evolutionary Radiation

• Theropod Dinosaurs -- 85-160 million years ago
• Presently, over 9,500 species of birds compared
  to about 4,000 mammals

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Array of Avian Anatomical Diversity

• See 35 mm slides - 11

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Retained Dinosauran Features

• Egg-laying
• Feathers as modified scales (new evidence
  indicates Velociraptors may have had feathers)
• Air Sacs

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Concessions to Flight and Aerodynamics

• Center of Gravity Shift
• Reduction in weight of head -- no teeth
• Increase mobility of head and neck
• Increased mobility of mouth parts -
  craniokinesis
• Scleral Oscicles
• Pneumatization
• Trussing

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Fusion of Axial Skeletal Elements
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Additional Aspects

• Scapula
• Coracoid and Furcula
• Triosseal Canal (foramen triosseum)
• Uncinate process

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Skeletal Structure of Modern Bird

• Note keel for attachment of flight muscles
• Note position of femurs

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Unique Muscle Configurations

• Pectoralis Major
• Supracoracoideus
• Wing Mechanics

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Forelimb Anatomy

• Humeral features
• Antebrachium
• Metacarpus
• Alula
• Major and Minor Metacarpal
• Flight Feather Attachment

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Propatagial Tendon
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Musculature of Pectoral Limb Humerus

• Biceps
• Triceps
• Deltoid
• Radial Nerve

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Musculature of the Pectoral Limb Antebrachium

• Extensor carpi radialis
• Common digital extensor
• Extensor metacarpi ulnaris
• Supinator

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Osteology of the Pelvic Limb Femur

• Femur
• Synsacrum
• Acetabulum (gliding joint)

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Osteology of the Pelvic Limb Tibiotarsus

• Stifle Joint
• Hock Joint
• Fibula
• Cnemial Crest

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Osteology of the Pelvic Limb Tarsometatarsus and
Digits

• Embryonic fusion of bones to form tarsometatarsus
• Digital Formula
• Numbering
• Hallux
• Elements one more than the number of the digit

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Musculature of Pelvic LimbHip and Femur

• Quadriceps equiv.
• Iliotibialis cranialis
• Iliotibialis lateralis
• Iliofibularis
• Femerotibialus externus
• Surgical Approach to femur

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Myology of Pelvic Limb Tibiotarsal Region
(medial)
Gastrocnemius - 3 heads Fibularis longus Tibialis
cranialis Long digital extensor
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Ophthalomological Anatomy

• Afternoon Seminar