What is the spinal level for the subcostal nerve?

What is the spinal level for the subcostal nerve?

• A. L1
• B. T12
• C. L2, L3
• D. L4, L5

Answer: (B)

The subcostal nerve is the ventral ramus of the 12th thoracic spinal nerve (T12). It travels just beneath the last rib and supplies the lower part of the anterior abdominal wall (the external oblique, and parts of the internal oblique and transversus abdominis) as well as sensation to the corresponding skin area. This makes T12 the correct spinal level. It’s not from L1, which mainly contributes the iliohypogastric and ilioinguinal nerves, nor from L2–L3 or L4–L5, which are involved with other lumbar region nerves and pathways. The naming “subcostal” itself reflects its position below the last rib, aligning with the T12 level.

The subcostal nerve is the ventral ramus of the 12th thoracic spinal nerve (T12). It travels just beneath the last rib and supplies the lower part of the anterior abdominal wall (the external oblique, and parts of the internal oblique and transversus abdominis) as well as sensation to the corresponding skin area. This makes T12 the correct spinal level.

It’s not from L1, which mainly contributes the iliohypogastric and ilioinguinal nerves, nor from L2–L3 or L4–L5, which are involved with other lumbar region nerves and pathways. The naming “subcostal” itself reflects its position below the last rib, aligning with the T12 level.