Femoral Mononeuropathy Clinical Presentation

Updated: Sep 07, 2021
  • Author: Nitin Butala, MBBS, MS; Chief Editor: Nicholas Lorenzo, MD, CPE, MHCM, FAAPL  more...
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Patients with femoral neuropathy complain of difficulty with stairs and frequent falling secondary to "knee buckling." This weakness is typically of acute or subacute onset. On occasion a femoral neuropathy can be associated with an athletic injury. [17] This contrasts with a myopathic process in which the weakness is subacute to chronic in onset and bilateral in nature.

Acute, severe pain in the groin, thigh, and/or lower abdomen may occur if the neuropathy is associated with a retroperitoneal hematoma. [18] Otherwise, the associated pain is usually mild and located near the inguinal ligament.

Patients may complain of medial leg and calf numbness. Sensory symptoms in saphenous nerve distribution are rare with injury to the main trunk of the femoral nerve.


Physical Examination

Weakness of the quadriceps muscle and decreased patellar reflex are the most striking examination findings. If the neuropathy is advanced and chronic, wasting of the quadriceps may be noted. If a retroperitoneal hematoma is present, hip extension may cause pain.

In some patients, the iliopsoas muscle is involved. In such cases, the lesion must be above the inguinal ligament, as the motor branch to this muscle comes off before the inguinal ligament.

In isolated femoral neuropathies, the thigh adductors are normal. Although the thigh adductors share common lumbar roots with the muscles innervated by the femoral nerve, they are innervated by the obturator nerve along with the sciatic nerve and therefore are spared. Sensory deficits consist of numbness of the medial thigh and the anteromedial calf.