Neck Flashcards
Cervical vertebrae
-7 cervical vertebrae
-almost all mammals
Atlas and axis of cervical vertebrae
-first two: atlas and axis
-have modified movement to allow free movement of head
Cervical vertebrae shape
-body flattened dorsally, and with arch forms vertebral foramen
-body has a median crest ventrally, with a cranial convex surface and a caudal concave surface
Transverse foramina
-actually short canals and transmit vertebral vessels
Vertebral foramina
-forms the vertebral canal for the spinal cord
Spinous process
-length and angles vary
Synovial joints of cervical vertebrae
-joints between caudal and cranial articular processes of neighbours
Transverse processes
-divided into dorsal and ventral
Intervertebral foramina
-bases of arch notched and with neighbour to form hole for the spinal nerves to pass through
Intervertebral disc
-a fibrocartilagous structure between neighbouring vertebral bodies
-made of a soft gel-like center called nucleus pulposus (pulpy nucleus) and surrounded by concentric layers of dense fibrous tissue called annulus fibrosus
Where are intervertebral discs absent?
-between C1 and C2
Disc hernias
-caused by the rupture of annulus fibrosis (fibrous layer surrounding intervertebral disc)
Intervertebral disc species differences
-Thick in dogs and cats (~15-20% of columnar length)
-Thin in ungulates (~10% of columnar length)
Atlas
-C1
-has no body, no spinous process but dorsal and ventral arches
-wings of atlas (transverse process) are often visible and palpable in live animals
-caudal aspect of ventral arch has wings with excavations (fovea) for condyles
-dorsal arch has transverse foramina (absent in ox)
-lateral vertebral foramen transmits 1st spinal nerve
-alar foramen (only a notch in dog) transmits ventral branch of 1st spinal nerve
Atlas ventral arch fovea
-articulates with axis forming fovea dentis