Neurovascular Nerves
Nerves
Although considerable individual variation exists, predominant patterns of nerve supply about the knee have been described. Two distinct groups of nerve have been identified. The first a posterior group includes the posterior articular branch of the tibial nerve and obturator nerves. The second group is the anterior group and includes the articular branches of the femoral, common peroneal and saphenous nerves.
The obturator nerve arises from the lumbar spine (L2,3,4). The obturator nerve supplies the adductor thigh muscles on the inner side of the thigh.
The femoral nerve arises from the lumbar spine (L2,3,4). It enters the leg passing under the inguinal ligament and supplies the quadriceps muscles as well as the knee joint. The saphenous nerve is a terminal branch of the femoral nerve which runs down the inner aspect of the leg into the foot.
The sciatic nerve is derived from the sacral plexus (L4,5, S1,2,3) and is made up of the tibial (medial) and common peroneal (lateral) nerves contained within a common connective tissue sheath. The sciatic nerve enters the leg posteriorily and runs down the back of the thigh. It splits into the tibial and common peroneal nerve above the knee. The tibial nerve supplies the superficial and deep hamstring muscles as well as the muscles of the posterior compartment of the leg including the gastrocnemius and soleus muscles. The common peroneal nerve supplies the anterior and lateral compartments of the leg including the peroneal muscles.
The tibial nerve is the larger of the two divisions of the sciatic nerve. It runs vertically through the popliteal fossa directly underneath the fascia and is the most superficial of the neurovascular structures behind the knee. The common peroneal nerve separates from the tibial portion of the sciatic nerve at the apex of the popliteal fossa and then follows the tendon of the biceps femoris along the upper lateral margin of the popliteal fossa to the back of the head of the fibula. The nerve then winds round the neck of the fibula and passes deep to the peroneus longus muscles and divides into the superficial and deep peroneal nerves.
All these nerves give off branches to the knee joint during their passage down the leg.
Not only do these nerves supply the knee joint but they also supply the skin of the knee (cutaneous innovation). The nerve supply to the skin of the knee comes primarily from the femoral nerve, obturator nerve, tibial nerve and common peroneal nerves.
