Description
The lower limb receives its innervation from the lumbosacral plexus, which is formed by portions of the lumbar and sacral plexuses.
The lumbar plexus is formed by the anterior rami of the first to fourth lumbar nerves (L1-L4), with a contribution from the twelfth thoracic (subcostal; T12) nerve . The sacral plexus is formed by ventral communicating branches of the fourth lumbar nerve (L4), which combines with the fifth lumbar nerve (L5) to form the lumbosacral trunk. This trunk then receives contributions from the first, second, and third sacral nerves (S1-S3) forming the sacral plexus.
The lumbar plexus gives rise to the obturator and femoral nerve. The obturator nerve innervates the skin of the medial thigh and the adductor muscles of the leg. The femoral nerve divides into an anterior division (the saphenous nerve), which innervates the skin of the anterior portion of the leg and the pectineus and sartorius muscles, and a posterior division, which innervates the muscles that form the quadriceps femoris.
The sacral plexus gives rise to the sciatic nerve. The sciatic nerve is the largest nerve in the human body and divides into common fibular and tibial branches. They provide the leg, ankle, and foot with motor and sensory innervation.
Related parts of the anatomy
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Muscle Innervation
Basically they are areas of muscles, nerves, and vessels surrounded by bone and tight fascia not yielding to an increased pressure, for instance after trauma when edema occurs.
