GENERAL INFORMATION
The semimembranosus is a muscle located in the posterior compartment of the thigh. It is one of the muscles that make up the hamstring muscle group. The semimembranosus plays an important role in lower limb movement, stability, and overall function.
ORIGIN
The semimembranosus originates from the ischial tuberosity, which is a bony prominence in the pelvis.
INSERTION POINT
The semimembranosus inserts onto the posterior surface of the medial condyle of the tibia, which is a bone in the lower leg.
MAJOR ARTERIES
The blood supply to the semimembranosus is provided by branches of the popliteal artery, including the perforating branches and genicular arteries. These arteries ensure the delivery of oxygen and nutrients to the muscle tissue.
NEURAL INNERVATION
The tibial division of the sciatic nerve innervates the semimembranosus. This nerve provides motor innervation for muscle contraction and sensory feedback.
TRIGGER POINT
Trigger points can develop in the semimembranosus muscle, leading to localised pain and discomfort. These trigger points may be caused by muscle overuse, poor posture, or muscle imbalances.
CONCENTRIC FUNCTION
The semimembranosus functions concentrically to flex the knee joint, bringing the lower leg closer to the buttocks. It also assists in the medial rotation of the leg when the knee is bent.
ECCENTRIC FUNCTION
The semimembranosus functions eccentrically to control knee extension and decelerate the lower leg during activities such as landing from a jump or running downhill.
ISOMETRIC FUNCTION
The semimembranosus can contract isometrically to stabilise the knee joint and maintain posture during standing or other weight-bearing activities.
RELATED MUSCLE-SCIENTIFIC NAMES
- Musculus semimembranosus: Key muscle of the hamstring group.
- Musculus ischiocruralis: Another term for the hamstring muscles.
ANTAGONIST
- Quadriceps femoris is the Primary muscle group responsible for knee extension, providing balanced movement with the semimembranosus.
COMMON INJURIES
- Strains or tears: These are common during activities that involve sudden acceleration or deceleration, such as sprinting or jumping.
- Tendinitis: Inflammation of the tendons.
- Tendinopathy: Degeneration of the tendons.
- Hamstring tendinosis: Chronic tendon injury.
EXERCISES FOR SEMIMEMBRANOSUS
- Hamstring curls: Perform lying or standing hamstring curls using resistance machines or resistance bands.
- Romanian deadlifts: Engage in this exercise to strengthen the hamstrings and improve hip hinge mechanics.
- Glute-ham raises: These exercises target both the hamstrings and the gluteal muscles for overall lower limb strength.
STRETCHES
- Standing hamstring stretch: Stand upright, lift one leg onto a stable surface, and lean forward from the hips while keeping the back straight.
- Supine hamstring stretch: Lie on your back, lift one leg toward the ceiling, and gently pull the leg toward your chest with a towel or strap.
- Seated hamstring stretch: Sit on the ground with one leg extended, bend the other leg with the foot against the inner thigh, and reach forward toward the extended leg while keeping the back straight.