Anatomy of Cervical Vertebra

Overview

• Focus on cervical vertebra, specifically cervical vertebra #4 of the horse.
• Comparison with cervical vertebra of different animal species.

Cervical Vertebra #4 in Horses

Structure

• Body:

  • Long body located ventrally.
  • Cranial Extremity:
    • Convex shape.
  • Caudal Extremity:
    • Concave shape, articulates with cranial extremity of cervical vertebra #5.

• Ventral Crest: Present on the ventral surface of the body.

Arch

• Vertebral Arch:
  • Composed of left and right pedicles and dorsal plate.
  • Forms vertebral foramen (contains spinal cord), leading to the vertebral canal when combined with other vertebrae.

Notches

• Cranial Vertebral Notch: Opening on the cranial surface of the arch.
• Caudal Vertebral Notch: Located at the adjacent vertebra.
  • These notches together form the intervertebral foramen, which allows exit for cervical spinal nerves.

Processes

• Spinous Process:
  • One spinous process, less developed in horses.
• Articular Processes:
  • Cranial Articular Processes: Face upward for articulation with cervical vertebra #5.
  • Caudal Articular Processes: Face downward for articulation with cervical vertebra #4.
• Transverse Processes:
  • Two transverse processes, divided into ventral and dorsal parts (ventral tubercle and dorsal tubercle).

Transverse Foramen

• Found at the root of the transverse processes (left and right).
• Forms transverse canal that contains the vertebral artery, vein, and nerve, unique to cervical vertebrae.

Comparative Anatomy of Cervical Vertebrae

Camel

• Spinous Process: More developed than in horses.
• Body: Longer than that of horses.
• Ventral Crest: Absent or sharp.
• Transverse Processes: Ventral tubercle more developed.

Ox

• Body: Shorter compared to camel and horse.
• Spinous Process: More developed, finger-shaped.
• Transverse Processes:
  • Similar structure to horses, with ventral and dorsal parts.

Sheep, Dog, and Cat

• Spinous Process: More developed in sheep and dog compared to horse.
• Transverse Foramen: Present at the base of transverse processes.

Cervical Vertebrae #1 (Atlas) and #2 (Axis)

• Have unique shapes differing from cervical vertebrae #3 to #7.

Cervical Vertebrae #6 and #7

• Cervical Vertebrae #6 (in Ox):
  • Spinous process is prominent. Ventral blade formation in transverse process.
• Cervical Vertebrae #7:
  • No transverse foramen observed.
  • Articular surfaces for the first rib present (fovea costales).
  • Identifying features of C7 include the absence of transverse foramen and short body.

Summary of Key Features

• All cervical vertebrae share transverse processes, but C7 is distinct with no transverse foramen.
• Unique articular surfaces for rib attachment on C7 are a key identification feature.