The S2-4 nerve distribution corresponds to which anatomical area commonly referred to as the saddle area?

The S2-4 nerve distribution corresponds to which anatomical area commonly referred to as the saddle area?

• A. Thigh
• B. Perineal region
• C. Forearm
• D. Calf

Answer: (B)

Nerve roots S2 through S4 innervate the perineal region via the pudendal nerve, and this area is what clinicians refer to as the saddle region. The perineal region includes the skin around the anus and external genitalia, as well as the pelvic floor muscles and the external anal sphincter, all of which receive sensory and motor input from S2–S4. That connection is why the saddle area maps to the perineum. The other regions are supplied by different nerve roots: the thigh mainly by L2–L4 nerves, the forearm by nerves from the brachial plexus (C5–T1), and the calf by branches of the sciatic nerve (L4–S3).

Nerve roots S2 through S4 innervate the perineal region via the pudendal nerve, and this area is what clinicians refer to as the saddle region. The perineal region includes the skin around the anus and external genitalia, as well as the pelvic floor muscles and the external anal sphincter, all of which receive sensory and motor input from S2–S4. That connection is why the saddle area maps to the perineum. The other regions are supplied by different nerve roots: the thigh mainly by L2–L4 nerves, the forearm by nerves from the brachial plexus (C5–T1), and the calf by branches of the sciatic nerve (L4–S3).