Search results
Results From The WOW.Com Content Network
The anterior divisions of the lumbar nerves, sacral nerves, and coccygeal nerve form the lumbosacral plexus, the first lumbar nerve being frequently joined by a branch from the twelfth thoracic. For descriptive purposes this plexus is usually divided into three parts: lumbar plexus; sacral plexus; pudendal plexus
In human anatomy, the sacral plexus is a nerve plexus which provides motor and sensory nerves for the posterior thigh, most of the lower leg and foot, and part of the pelvis. It is part of the lumbosacral plexus and emerges from the lumbar vertebrae and sacral vertebrae (L4-S4). [ 1 ]
The lumbar plexus is a web of nerves (a nerve plexus) in the lumbar region of the body which forms part of the larger lumbosacral plexus. It is formed by the divisions of the first four lumbar nerves (L1-L4) and from contributions of the subcostal nerve (T12), which is the last thoracic nerve .
The ventral rami of L1–L5 spinal nerves with a contribution of T12 form lumbar plexus. This plexus lies within the psoas major muscle. Nervi of the plexus serve the skin and the muscles of the lower abdominal wall, the thigh and external genitals. The largest nerve of the plexus is the femoral nerve.
The first three lumbar nerves, and the greater part of the fourth together form the lumbar plexus. The smaller part of the fourth joins with the fifth to form the lumbosacral trunk, which assists in the formation of the sacral plexus. The fourth nerve is named the furcal nerve, from the fact that it is subdivided between the two plexuses.
The lumbosacral trunk from the L4 and L5 roots descends between the sacral promontory and ala, and the S1 to S3 roots emerge from the ventral sacral foramina. These nerve roots unite to form a single nerve in front of the piriformis muscle. The nerve passes beneath the piriformis and through the greater sciatic foramen, exiting the pelvis.
The alae support the psoas major muscles and the lumbosacral trunk which connects the lumbar plexus with the sacral plexus. In the articulated pelvis, the alae are continuous with the iliac fossa. Each ala is slightly concave from side to side, and convex from the back and gives attachment to a few of the fibers of the iliacus muscle. The ...
The lateral cutaneous branch ("iliac branch") pierces the internal oblique muscles and the external oblique muscles immediately above the iliac crest. [4] It is distributed to the skin of the gluteal region, behind the lateral cutaneous branch of the subcostal nerve; the size of this branch bears an inverse proportion to that of the lateral cutaneous branch of the subcostal nerve.