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Overview of lower extremity peripheral nerve syndromes

Seward B Rutkove, MD
Section Editor
Jeremy M Shefner, MD, PhD
Deputy Editor
John F Dashe, MD, PhD


This topic provides an overview of lower extremity peripheral nerve syndromes. Peripheral nerve syndromes involving the upper extremities are discussed separately. (See "Overview of upper extremity peripheral nerve syndromes".)


Nerve roots emerge from the spinal column from the L2 to S4 levels through the neural foramina and join to form a complex entity known as the lumbosacral plexus (figure 1). Unlike the brachial plexus, in which the anatomy is delineated through trunks, divisions, and cords, the lumbosacral plexus has only two main components: the lumbar plexus (made up of nerve fibers from the L2 through L5 roots) and the sacral plexus (made up of nerve fibers from the S1 through S4 roots).

The largest nerve that emerges from the lumbar plexus is the femoral nerve, which descends beneath the inguinal ligament before dividing into a number of smaller branches innervating the anterior thigh musculature and skin (figure 2). One pure sensory branch, the saphenous nerve, continues down the medial leg to the arch of the foot. Although the subject of some disagreement, the iliopsoas muscle is innervated by the femoral nerve or a small nerve of its own that travels alongside the femoral. The obturator nerve also emerges from the lumbar plexus, descending more medially than the femoral, exiting the pelvis through the obturator foramen where it innervates the thigh adductors and a small cutaneous area in the medial thigh.

A small nerve, the lateral femoral cutaneous nerve, also has its origin directly from the plexus. It travels lateral to the femoral nerve underneath the inguinal ligament to innervate the skin of the lateral thigh.

Contributions from the lower lumbar plexus and upper sacral plexus give rise to the sciatic nerve. This nerve passes through the sciatic foramen and descends the posterior aspect of the leg until it reaches the popliteal fossa, where it divides into the posterior tibial and common peroneal nerves.

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Literature review current through: Nov 2017. | This topic last updated: Aug 29, 2017.
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