Semitendinosus and Semimembranosus: Pain Pattern and Treatment
The semitendinosus and semimembranosus are the two inner hamstrings, running side by side from the sit bone down the inner back of the thigh to the inside of the knee. They bend the knee and pull the hip back. Their documented pattern is pain at the sit bone and along the crease under the buttock, running down the inner back of the thigh to the back of the knee, worst on a hard chair. This is a sub-page of the hamstrings group page.
Attachments and action
Origin: Both from the ischial tuberosity, the sit bone.
Insertion: Semitendinosus to the upper inner tibia in the pes anserinus; semimembranosus to the back of the medial condyle of the tibia.
Action: Flexion of the knee and extension of the hip; with the knee bent they rotate the lower leg inward.
Where the pain is felt: The sit bone and the crease under the buttock. Down the inner back of the thigh. The back of the knee and a short way into the upper inner calf. Worst sitting on a hard chair.
Common causes: A chair that is too high, so the front edge presses the back of the thigh; sitting for hours on a hard seat; a pulled hamstring that healed short; a fall onto the sit bone; sprinting and kicking; a leg-length difference.
Patients say: "It hurts to sit on my sit bone." "It runs down the inside of the back of my thigh." An ache at the back of the knee after sitting. Pain that wakes them when they turn.
When to get evaluated: Back-of-thigh pain with numbness, tingling, or weakness in the foot needs the sciatic nerve and the spine assessed. Calf swelling, warmth, or redness needs a blood clot ruled out first. A sudden tear with bruising needs a hamstring tear assessed.
How this muscle is examined and treated
Examination tests knee flexion with the lower leg turned in against resistance, measures hamstring length, and presses the inner hamstrings from the sit bone to the knee for the points that reproduce the sitting pain. Needling here addresses the two muscles along the inner back of the thigh. Assessment and treatment happen in the same visit.
Related conditions
Hip & Glute PainKnee PainSciatica
This page is educational. It describes muscle referral patterns commonly associated with pain; it does not diagnose your condition. Individual patterns vary. For evaluation of your specific pain, see a licensed clinician. Seek immediate medical care for emergencies. Eugene Baek, L.Ac. · New Jersey License 25MZ00080600