Overview
Cattle have six lumbar vertebrae. They form the skeleton of the loin between the last rib and the sacrum, support the epaxial and sublumbar muscles and transmit the thrust of the pelvic limbs to the trunk. Their bodies are longer than those of the thoracic vertebrae.
Key features
- Transverse processes (processus transversi): very long, plate-like and horizontal, longest in the middle of the series. Their tips are palpable under the skin and form the dorsal boundary of the paralumbar fossa (flank), which is bounded cranially by the last rib. The sublumbar muscles attach to their ventral surface.
- Spinous processes: broad and sturdy; their dorsal border is palpable on the midline of the loin.
- Articular processes: the concave cranial ones embrace the convex caudal ones of the vertebra in front; this interlocking limits rotation and lateral bending. The cranial ones carry mamillary processes.
- Lumbosacral space: between the arch of L6 and the sacrum; palpable as a midline depression caudal to the spinous process of L6.
Clinical relevance
- Body condition: the tips of the transverse processes and the spinous processes are palpated or inspected to score body condition; they are prominent in a thin cow and covered with fat in a fat one.
- Paravertebral anaesthesia: anaesthetises the flank for standing laparotomy (caesarean section, abomasal surgery, rumenotomy). The proximal technique blocks the T13, L1 and L2 nerves as they leave the intervertebral foramina, using the cranial border of the transverse processes of L1, L2 and L3 as landmarks; the distal technique blocks them at the tips of the transverse processes of L1, L2 and L4.
- Lumbosacral space: puncture site for collecting cerebrospinal fluid in the standing animal and for lumbosacral epidural anaesthesia.
- Vertebral body abscesses in calves and ankylosing spondylosis in old bulls; the fused vertebrae of the latter can fracture, for example during mounting.