Overview
The cat has seven lumbar vertebrae (L1–L7). They are the largest vertebrae of the column, and their bodies lengthen caudally up to the mid-lumbar region. The region is very flexible: flexion and extension of the lumbar spine lengthen the stride at the gallop and power the jump.
Key features
- Bodies: long and slightly flattened dorsoventrally.
- Transverse processes: long, flat and directed cranioventrally. They give attachment to the hypaxial muscles (psoas, quadratus lumborum) and to the aponeurosis of the abdominal muscles.
- Spinous processes: lower and wider than the thoracic ones, sloping cranially.
- Mammillary and accessory processes: the mammillary processes sit on the cranial articular processes, and the accessory processes project caudally from the pedicle and overlap the next vertebra; both anchor bundles of the epaxial muscles.
- L7: shorter, with a wide caudal end that articulates with the sacrum at the lumbosacral joint.
- Spinal cord: in the cat it ends further caudally than in the dog, at about the level of L7, and the dural sac can continue into the sacrum.
Clinical relevance
- Epidural anaesthesia: the needle is placed in the lumbosacral space. Because the spinal cord and dural sac reach further back than in the dog, accidental intrathecal injection is more likely in the cat.
- Disc disease and lumbosacral stenosis: less common than in the dog but described in older cats; they cause lumbar pain, reluctance to jump and pelvic limb deficits.
- Spinal lymphoma and trauma (road accidents) are other causes of lumbar spinal cord injury.