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The hamstrings are innervated by the sciatic nerve, specifically by a main branch of it: the tibial nerve. (The short head of the biceps femoris is innervated by the common fibular nerve). The sciatic nerve runs along the longitudinal axis of the compartment, giving the cited terminal branches close to the superior angle of the popliteal fossa.
However, there is an inhibitory interneuron used to relax the antagonistic hamstring muscle (reciprocal innervation). This test of a basic automatic reflex may be influenced by the patient consciously inhibiting or exaggerating the response; the doctor may use the Jendrassik maneuver in order to ensure a more valid reflex test.
Cutaneous innervation of the lower limbs is the nerve supply to areas of the skin of the lower limbs (including the feet) which are supplied by specific cutaneous nerves. Modern texts are in agreement about which areas of the skin are served by which nerves , but there are minor variations in some of the details.
The three 'true' hamstrings cross both the hip and the knee joint and are therefore involved in knee flexion and hip extension. The short head of the biceps femoris crosses only one joint (knee) and is therefore not involved in hip extension. With its divergent origin and innervation, it is sometimes excluded from the 'hamstring ...
Muscles require innervation to function—and even just to maintain muscle tone, avoiding atrophy. In the neuromuscular system, nerves from the central nervous system and the peripheral nervous system are linked and work together with muscles. [3]
The semimembranosus muscle (/ ˌ s ɛ m i ˌ m ɛ m b r ə ˈ n oʊ s ə s /) is the most medial of the three hamstring muscles in the thigh. It is so named because it has a flat tendon of origin. It lies posteromedially in the thigh, deep to the semitendinosus muscle. It extends the hip joint and flexes the knee joint.
The muscle is supplied by the inferior gluteal nerve which arises from the dorsal branches of the ventral rami of the fifth (L5), the first and second sacral nerves. [2]The lumbosacral trunk, which is made up of L5 and a small branch of L4, effectively connects the lumbar and sacral plexuses. [3]
Abduction of the flexed thigh is important in the action of walking because it shifts the body weight to the opposite side of the foot being lifted, which prevents falling. The action of the lateral rotators can be understood by crossing the legs to rest an ankle on the knee of the other leg.