GENERAL INFORMATION
The posterior compartment, also known as the hamstring muscle group, is located at the back of the thigh. It consists of three main muscles: the biceps femoris, semitendinosus, and semimembranosus. The posterior compartment is responsible for various functions, including knee flexion, hip extension, and stabilisation of the lower limb during walking, running, and jumping.
ORIGIN
The posterior compartment hamstring muscles have the following origins:
- Biceps femoris (long head): Ischial tuberosity of the pelvis.
- Biceps femoris (short head): Lateral lip of the linea aspera and the lateral supracondylar ridge of the femur.
- Semitendinosus: Ischial tuberosity.
- Semimembranosus: Ischial tuberosity.
INSERTION POINT
The posterior compartment hamstring muscles are inserted into different areas:
- Biceps femoris: Head of the fibula and lateral condyle of the tibia.
- Semitendinosus: Medial surface of the upper tibia, just below the condyle.
- Semimembranosus: Posterior medial surface of the tibia below the condyle.
MAJOR ARTERIES
The posterior compartment of the hamstring receives its blood supply from the branches of the popliteal artery, including the medial and lateral genicular arteries. These arteries ensure adequate oxygen and nutrient supply to the muscles.
NEURAL INNERVATION
The tibial division of the sciatic nerve primarily innervates the hamstring muscles. The biceps femoris (long head) also receives innervation from the common fibular (peroneal) division of the sciatic nerve. These nerves provide motor innervation for muscle contraction and proprioceptive feedback.
TRIGGER POINT
Trigger points can develop in the posterior compartment hamstring muscles, leading to localised pain and discomfort. These trigger points may be caused by factors such as muscle overuse, poor posture, or muscle imbalances.
CONCENTRIC FUNCTION
The posterior compartment hamstring muscles function concentrically to flex the knee joint, bringing the lower leg closer to the buttocks during movements such as walking, running, and climbing stairs. They also assist in hip extension, helping to move the thigh backwards.
ECCENTRIC FUNCTION
The hamstring muscles function eccentrically to control knee extension and decelerate the lower leg during activities such as landing from a jump or running downhill.
ISOMETRIC FUNCTION
The posterior compartment hamstring muscles can contract isometrically to stabilise the knee joint and maintain posture during standing or other weight-bearing activities.
RELATED MUSCLE-SCIENTIFIC NAMES
- Biceps femoris (Musculus biceps femoris)
- Semitendinosus (Musculus semitendinosus)
- Semimembranosus (Musculus semimembranosus)
ANTAGONIST
The primary antagonist of the posterior compartment hamstring muscles is the quadriceps femoris, which is responsible for knee extension. The coordinated action of both muscle groups allows for smooth and controlled movements of the lower limb.
COMMON INJURIES
- Strains or tears: Occur during activities involving 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
- 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.