E1 - The skeleton of domestic birds

Question 1

Skeleton

Give the characteristics of avian bones

Answer 1

• Ø epiphysis in avian bones
  
  • Skeleton grows to full size quicker and calcificates to large extent
• Pneumatic bones: bones are arifilled
• Tendons of muscles can calcify and ossificate

Question 2

Skeleton

Skull

Answer 2

• Modified for beak
  
  • Ø os incisivum
• 3 parts of os occipitale:
  
  • ​Basi-occipital
  • Exo-occipital
  • Supra-occipital
• 3 jugular bones instead of arcus zygomaticus
• 2 parts of os ethmoidale:
  
  • ​Mes-ethomidale
  • Ect-ethmoidale
• Ossa otica
  
  • ​1 auditory ossicle: columella
• Os hyoideum → hyale
  
  • ​Urahyale
  • Paraglossum / entoglossum

Question 3

Skeleton

Vertebral column

Answer 3

Vertebrae:

• 14 cervical
  
  • S-shaped
  • Atlas has a big angle of rotation
• 7 thoracic
• 14 lumbar & sacral (fused)
• 7 coccygeal
• Notarium: fusion of thoracic vertebrae
• Synsacrum: fusion of:
  
  • Last thoracic
  • All lumbar
  • All sacral
  • 1^st coccygela
• Pygosyl: last coccygela vertebrae fuses
• Os lumbosacrale: pelvis fuses to sysacrum

Ribs:

• 7 ribs
  
  • Asternal ribs: first 2 and last 2 ribs
• Proc. uncinatus: support and stability

Pelvis:

1. Ilium
2. Ishium
3. Synsacium
4. Os pubis
   
   1. ​Ala preacetabulum
   2. Ala postacetabulum
   • Openings
     
     1. For. acetabulum
     2. For. obturatorium
     3. For. ilioischiadicum
   • Fenestra ishiopubica (nerves & vessels)

Question 4

Skeleton

Bones of the trunk

Answer 4

• Very narrow scapula on dorsal edge of ribs
• Clavicle - procoracoid
• Canalis triosseus composed of:
  
  • Clavicle
    
    • ​Furcola (fusion of 2 clavicle, “wish bone”)
  • Coracoid bone
  • Scapula
• ​​Tendon to lift the wings runs through the canalis triosseus
• Sternum:
  
  • ​Carina sterni (for attachment of pectoral muscles)
  • 3 trabeculae:
    
    • Trabeculae lateralis
    • Trabeculae intermedialis
    • Trabeculae mediana

Bones:

1. ​Clavicle
2. Coracoid bone
3. Scapula
4. Flotting ribs
5. Vertebral ribs
6. Sternal ribs
7. Sternum

Question 5

Skeleton

Forelimb (wing)

Answer 5

• Humerus
• Radius
• Ulna
• Carpus
  
  • 2 carpal bones:
    
    • Os carpi ulnare
    • Os carpi radiale
• 3 digits:
  
  • Digit 1: 1 phalanx
  • Digit 2: 2 phalanx
  • Digit 3: 1 phalanx

Question 6

Skeleton

Hindlimb

Answer 6

• Femur
• Patella
• Fibula
• Tibiotarsus (+ sesamoid bone)
  
  • ​Tarsal bones proximal row fuses to tibia
• Tarsometatarsus
  
  • ​Tarsal bones distal rowfuses tometatarsal bones
  • 2^nd, 3^rd, 4^th Mt also fused

​

• 4 digits:
  
  • Digit 1: 2 phalanx (points caudally)
  • Digit 2: 3 phalanx ​(points cranially)
  • Digit 3: 4 phalanx ​(points cranially)
  • Digit 4: 5 phalanx (points cranially)

Question 7

Skeleton

Muscles

Answer 7

• M. pectoralis
  
  • O: carina sterni
  • I: humerus
  • ​A: pull wing down
• M. supracoracoideus
  
  • O: humerus, runs through canalis triosseus
  • I: wraps around carina sterni
  • ​A: raises wing
• M. ambiens
  
  • ​O: pelvic bone
  • I: joins flexor muscles to digits
  • A: as stifle flexes it grasps with feet