Physiology (motor skills)

The sciatic nerve is responsible for the movement of the thigh flexors. This includes: These muscles originate from the ischium (Os ischii) and are attached laterally to the lower leg (crus). Accordingly, they cause flexion and slight rotation in the knee joint.

In the hip joint, they are responsible for stabilizing the pelvis and, in synergy with other muscles, for the approach (adduction) and extension of the leg or hip. In addition, the sciatic nerve moves part of a muscle from another muscle group of the thigh, the so-called adductors. This muscle is the superficial part of the large adductor muscle. The common fibula nerve and the tibial nerve and its branches are together responsible for supplying the entire lower leg and foot muscles with nerve fibers.

The semitendinous muscle (Musculus semitendinosus)
The semimembranous muscle (Musculus semimembranosus)
The biceps muscle of the thigh (Musculus biceps femoris)

Physiology (Sensitivity)

The sciatic nerve originates from the spinal cord segments L4 to S3 and then, as the largest nerve in the human body, runs first through the so-called foramen piriforme and then between the flexors and adductors in the direction of the popliteal fossa. Then the sciatic nerve divides into its two lower leg branches, the tibialis nerve and the fibularis nerve. These two nerves then move further in the direction of the foot.

On the thigh, the nerve runs together with the vessels of the thigh, on the lower leg, the nerves run only partially with the vessels. Thus, a sensitive branch of the nerve runs on one of the lower leg bones. This nerve is the sensitive nerve that is responsible for putting the foot to sleep when sitting with your legs underfoot. If a so-called compartment syndrome occurs in the calf muscles, for example due to overstraining and subsequent swelling, the branch of the sciatic nerve that runs along it can also be damaged.