Description
Nerves of the femoral region (thigh) originate from the lumbar and sacral plexuses. The muscles and tissues around the femur can be divided into three compartments, namely the anterior, medial, and posterior compartments. A major nerve is associated with each compartment.
The femoral nerve provides innervation to the anterior compartment of the thigh. It originates from the lumbar plexus and enters the thigh by passing underneath the inguinal ligament. Prior to entering the thigh, the femoral nerve innervates the iliacus and pectineus muscles. After passing underneath the inguinal ligament, the femoral nerve innervates the muscles in the anterior compartment of the thigh, including the quadriceps femoris (vastus lateralis, vastus intermedius, vastus medialis, and rectus femoris) and sartorius muscles (Ishiguro et al., 2012).
The cutaneous innervation to the anterior thigh is provided by various nerves, including the anterior femoral cutaneous nerve (a branch of femoral nerve), the lateral femoral cutaneous nerve (direct branch of the lumbar plexus), and the femoral branch of the genitofemoral nerve (direct branch of the lumbar plexus). One long cutaneous branch of the femoral nerve, called the saphenous nerve, innervates the skin as far distally as the medial side of the foot.
The obturator nerve innervates the medial compartment of the thigh. This nerve originates from the lumbar plexus and enters the medial thigh by passing through the obturator canal. The obturator nerve innervates most of the adductor muscles (including adductor magnus, longus and brevis, pectineus, and gracilis) and the skin on the medial side of the thigh (Anagnostopoulou et al., 2009).
The sciatic nerve innervates the posterior compartment of the thigh. It originates from the lumbosacral plexus and enters the posterior thigh from the gluteal region. The sciatic nerve divides into its two terminal branches (the tibial and common fibular nerve) and provides motor innervation to the hamstring muscles, including hamstring part of adductor magnus, biceps femoris, semimembranosus, and semitendinosus. Both the tibial and common fibular nerves descend further to innervate structures in the leg and foot. The posterior femoral cutaneous nerve, branch of the sacral plexus, provides cutaneous sensory innervation to the posterior thigh region.
Related parts of the anatomy
References
Anagnostopoulou, S., Kostopanagiotou, G., Paraskeuopoulos, T., Chantzi, C., Lolis, E. and Saranteas, T. (2009) 'Anatomic variations of the obturator nerve in the inguinal region: implications in conventional and ultrasound regional anesthesia techniques', Reg Anesth Pain Med, 34(1), pp. 33-9.
Ishiguro, S., Yokochi, A., Yoshioka, K., Asano, N., Deguchi, A., Iwasaki, Y., Sudo, A. and Maruyama, K. (2012) 'Anatomy and Clinical Implications of Ultrasound-Guided Selective Femoral Nerve Block', Anesthesia & Analgesia, 115(6), pp. 1467-1470.
