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Hilton's law, espoused by John Hilton in a series of medical lectures given in 1860–1862, [1] is the observation that in the study of anatomy, the nerve supplying the muscles extending directly across and acting at a given joint not only supplies the muscle, but also innervates the joint and the skin overlying the muscle.
Muscles should be inserted over the knee joint, in the tibia or in the fibula. Muscles will be innervated by the tibial branch of the sciatic nerve. Muscle will participate in flexion of the knee joint and extension of the hip joint. Those muscles which fulfill all of the four criteria are called true hamstrings.
There is no interneuron in the pathway leading to contraction of the quadriceps muscle. Instead, the sensory neuron synapses directly on a motor neuron in the spinal cord. [ 3 ] However, there is an inhibitory interneuron used to relax the antagonistic hamstring muscle ( reciprocal innervation ).
It allows the motor neuron to transmit a signal to the muscle fiber, causing muscle contraction. [2] 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]
At the same time, signals travel up the spinal cord and cause contraction of the contralateral muscles of the hip and abdomen to shift the body’s center of gravity over the extended leg. To a large extent, the coordination of all these muscles and maintenance of equilibrium is mediated by the cerebellum and cerebral cortex. [5]
A muscle synergy is composed of agonist and synergistic muscles. An agonist muscle is a muscle that contracts individually, and it can cause a cascade of motion in neighboring muscles. Synergistic muscles aid the agonist muscles in motor control tasks, but they act against excess motion that the agonists may create.
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.
The posterior division then gives off the saphenous nerve as it converges with the femoral artery where it passes beneath the sartorius muscle. [3] The saphenous nerve lies in front of the femoral artery, behind the aponeurotic covering of the adductor canal, as far as the opening in the lower part of the adductor magnus muscle.