Sacral Plexus

Ventral Branches of Sacral and Coccygeal Nerves

The ventral branches of the sacral and coccygeal spinal nerves form the sacral and coccygeal plexuses. The ventral branches of the four superior sacral nerves penetrate the pelvis through the anterior sacral foramina, the fifth sacral nerve penetrates between the sacrum and coccyx and the coccygeal below the coccyx.

Each ventral branch of the sacral nerves receives a gray communicating branch from a corresponding sympathetic ganglion. The efferent visceral branches leave the second to fourth sacral nerves as pelvic splanchnic nerves that contain the parasympathetic fibers, which reach tiny ganglia in the pelvic viscera walls.

The organization of the sacral plexus is quite elementary and simple. The sacral plexus is formed by the lumbosacral trunk, ventral branches of the first to the third sacral nerves, and part of the fourth, with the remainder of the latter joining the coccygeal plexus.

The anastomotic branch of L4 joins the L5 constituting the lumbosacral trunk. Then the lumbosacral trunk joins with S1 and then successively to S2, S3 and S4.

This nervous compact exits the pelvis through the larger sciatic foramen. Shortly after crossing this foramen, the sacral plexus emits its collateral branches and resolves into the terminal branch, which is the sciatic nerve. For the muscles of the gluteal region are the Superior Gluteal Nerves (L4, L5 and S1) and Lower Buttock (L5, S1 and S2). An important sensitive branch is the Posterior Thigh Nerve, formed by S1, S2 and S3.

For the perineum we have the Pudding Nerve formed from S2, S3 and S4.

THE Sciatic Nerve It is the longest and longest nerve in the human body because its fibers can run down to the toes. This nerve is made up of two portions, which are the Common Fibular Nerves (L4, L5, S1 and S2) and Tibial, formed by L4, L5, S1, S2 and S3. O Common Fibular Nerve already in the popliteal fossa it runs obliquely downward and laterally forking in nerves Superficial and Deep Fibular.

From the sacral plexus also nerves to the internal obturator muscle and superior twin muscle (L5, S1 and S2); for the piriformis muscle (S1 and S2); for the quadriceps thigh muscle and the inferior twin muscle (L4, L5 and S1); to the levator ani, coccygeal and external sphincter muscles of the anus (S4); and the pelvic splanchnic nerve (S2, S3 and S4).

LOMBOSACRAL PLEX
 
LOMBOSACRAL PLEX
Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.
LOMBOSACRAL PLEX
 
LOMBOSACRAL PLEX
Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.
UPPER GLUTES AND LOWER GLUTES
 
UPPER GLUTES AND LOWER GLUTES
Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.
ISCHIATIC NERVE
 
ISCHIATIC NERVE
Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.
FIBER NERVE
 
FIBER NERVE
Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.
TIBIAL NERVE
 
TIBIAL NERVE
Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.