Overview
The cat has seven cervical vertebrae. The atlas (C1) and the axis (C2) are very distinctive; the third to the seventh share a similar plan and are described together here. They form a short but very mobile neck, which the cat flexes and turns widely when grooming.
Key features
- Body (corpus vertebrae): with a convex cranial end (head) and a concave caudal end (fossa). The intervertebral discs lie between the bodies.
- Vertebral arch and canal: wide; in the caudal part of the neck they house the cervical intumescence of the spinal cord, which gives rise to the nerves of the brachial plexus.
- Spinous processes: low in C3 and C4, becoming progressively taller towards C7.
- Transverse processes and transverse foramen: from C3 to C6 the base of the transverse process is pierced by the transverse foramen; the series of foramina forms the canal for the vertebral artery and vein. In C6 the ventral part of the process forms a broad plate, the ventral lamina, a landmark on lateral radiographs.
- Seventh cervical (C7): the transition to the thorax. It has no transverse foramen, its spinous process is taller and the caudal edge of its body carries a costal fovea for the head of the first rib.
- Articular processes: large, with nearly horizontal surfaces that allow wide lateral and dorsoventral movement.
Clinical relevance
- Hypervitaminosis A: cats fed liver-rich diets for months develop exostoses that fuse the cervical and cranial thoracic vertebrae (deforming cervical spondylosis), with neck stiffness and pain.
- Intervertebral disc disease: much less common than in the dog; cervical disc herniation is rare in the cat.
- Ventroflexion of the neck: in the cat it is usually caused by neuromuscular weakness (hypokalaemia, thiamine deficiency, myasthenia), not by vertebral disease.
- Trauma: fractures and luxations after road accidents and falls.