Which nerves are blocked by a paravertebral nerve block in the paralumbar fossa?

• A. T13, L1, L2
• B. L1, L2, L3
• C. T12, T13, L3
• D. L2, L3, L4

Answer: (A)

A paravertebral nerve block in the paralumbar fossa specifically targets the spinal nerves that emerge from the thoracic and lumbar segments of the spine. In this case, the appropriate nerves blocked are T13, L1, and L2.

These nerves are crucial for providing sensation and motor function to specific areas of the abdomen and hindquarters. The T13 nerve, being the last thoracic nerve, supplies the skin over the abdomen and parts of the thigh, while L1 and L2 contribute to the innervation of the flank and nearby structures. Blocking these nerves is an effective technique for achieving analgesia in procedures involving abdominal surgery or conditions related to the abdomen in food animals.

Other choices involve different combinations of lumbar and thoracic nerves that either miss the critical nerves for effective abdominal analgesia or include nerves that do not contribute as significantly to the targeted area for the paravertebral block. Therefore, the combination of T13, L1, and L2 in the correct answer accurately reflects the goal of the procedure, which is to block sensory input from the region being targeted for surgical intervention or pain management.