Six new cases of femoral neuropathy in hemophilic patients are described. The syndrome begins with severe pain in the groin, in the inferior aspect of the thigh, and deep in the hip region. This is followed by a pronounced contracture of the hip in flexion and external rotation. A tender swelling appears in the iliac fossa and groin with a depression in the center corresponding to the inguinal ligament. Finally, a flaccid paralysis of the quadriceps femoris and diminution or absence of sensation in the anteromedial aspect of the thigh and proximal portion of the leg, with a depressed or absent patellar reflex,is discovered.

I propose that this syndrome is the result of hemorrhage in the iliopsoas muscle at the musculotendinous junction beneath the iliacus fascia and that the femoral nerve becomes compressed beneath the unyielding inguinal ligament superiorly and the iliopectineal ligament medially.

Treatment consists in bed rest, analgesics, and fresh-frozen plasma during the acute phase. .During the convalescent phase, a Hessing long brace is used to protect the knee from hemarthrosis until functional return of the quadriceps femoris has occurred.

To date, the validity of the theory that the femoral-nerve palsy is the result of iliopsoas hemorrhage at the musculotendinous junction and compression of the femoral nerve beneath the inguinal ligament has not been verified. I anticipate someday seeing a non-hemophilic patient with a traumatic iliacus hemorrhage and femoral neuropathy. Should such an opportunity present itself, exploration beneath Poupart's ligament may show the femoral nerve to be compressed and thus confirm the proposed cause of the clinical picture.