Sacral spinal nerve 4 explained

Sacral spinal nerve
Latin:	nervi spinalis

The sacral spinal nerve 4 (S4) is a spinal nerve of the sacral segment.^[1]

Muscles

S4 supplies many muscles, either directly or through nerves originating from S4. They are not innervated with S4 as single origin, but partly by S4 and partly by other spinal nerves. The muscles are:

• iliococcygeus
• puborectalis
• coccygeus
• sphincter ani externus muscle
• sphincter urethrae membranaceae

Notes and References

1. http://www.ama-assn.org/ama/pub/category/7173.html American Medical Association