The posterior paramedian nucleus (paramedian posterior nerve, Latin n. paramedianus posterior), or posterior paramedian branch (Latin rami posteriori paramediani) is a branch of the posterior spinal cord, part of the lumbar plexus, which begins from a branch of the sacral plexus.
The nucleus of the paramedian posterior nerve is located in the posterior part of the spinal cord at the level of the L1-L2 vertebrae. It is responsible for innervation of the skin on the back of the thigh and lower leg, and also provides sensitivity to the muscles that are located on the back of the leg.
The paramedian posterior nerve is part of the lumbar plexus and has several branches. One of them, the paramedian muscular branch, innervates the muscles on the back of the leg and thigh. The second branch, the paramedian cutaneous branch, provides innervation to the skin on the posterior surface of the body.
Damage to the paramedian posterior branch can result in loss of sensation in the back of the legs and buttocks, as well as loss of muscle function in this area. This may be due to injury, surgery, or other factors. In such cases, diagnosis and treatment are necessary to restore normal nerve function.