thigh(redirected from second thigh)
Also found in: Dictionary, Thesaurus, Medical.
in man, the upper part of the lower extremity, between the hip joint and the knee joint. The upper boundary of the thigh is anteriorly the inguinal and posteriorly the gluteal fold. The lower boundary passes horizontally 4–5 cm above the edge of the patella. The femur serves as the skeleton of the thigh. Surface veins and nerves innervating the skin are located in the thigh’s subcutaneous layer of fat, as is the fascia (connective-tissue layer) covering the thigh’s musculature, which, with its extensions, forms a container (sheath) for each of the muscle groups and for the neurovascular bundle of the thigh.
Thigh muscles are divided into three groups. On the anterior surface are the quadriceps muscle, which effects straightening of the knee and partially participates in the flexing of the thigh at the hip joint, and the sartorius muscle, which bends the leg at the hip and knee joints and turns the thigh outward. On the inner side of the thigh are the pec-tineus, gracilis, and three adductor muscles; they all adduct the thigh and partially turn it inward. On the posterior side of the thigh lie the biceps, semitendinosus, and semimembranosus muscles, which bend the leg at the knee and straighten the thigh at the hip joint, and which turn the shin (the semitendinosus and semimembranosus inward, the biceps outward). The main artery of the thigh is the femoral artery. Its main branch is the deep femoral artery. Efflux of blood from the thigh is effected in the deep femoral vein. The principal groups of lymph nodes of the thigh are located in the inguinal region. Innervation of muscles and skin of the thigh is effected by the lumbar and sacral nerve plexuses.
IU. I. DENISOV-NIKOL’SKII