GENERAL INFORMATION
The biceps femoris 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 biceps femoris plays an important role in the movement and stability of the lower limb.
ORIGIN
The biceps femoris has two heads:
- Long head: Originates from the ischial tuberosity, which is a bony prominence in the pelvis.
- Short head: Originates from the lateral lip of the linea aspera and the lateral supracondylar ridge of the femur, which are bony ridges on the back of the femur bone.
INSERTION POINT
The biceps femoris inserts into two areas:
- Head of the fibula: The long head is inserted into the head of the fibula, which is the smaller bone of the lower leg.
- Lateral condyle of the tibia: The short head inserts onto the lateral condyle of the tibia, which is a bone in the lower leg.
MAJOR ARTERIES
The blood supply to the biceps femoris 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 biceps femoris is innervated by the tibial division of the sciatic nerve for the long head and the common fibular (peroneal) division of the sciatic nerve for the short head. These nerves provide motor innervation for muscle contraction and sensory feedback.
TRIGGER POINT
Trigger points can develop in the biceps femoris muscle, leading to localised pain and discomfort. These trigger points may be caused by muscle overuse, poor posture, or muscle imbalances.
CONCENTRIC FUNCTION
The biceps femoris functions concentrically to flex the knee joint, bringing the lower leg closer to the buttocks. It also assists in the external rotation of the leg when the knee is bent.
ECCENTRIC FUNCTION
The biceps femoris 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 biceps femoris can contract isometrically to stabilise the knee joint and maintain posture during standing or other weight-bearing activities.
RELATED MUSCLE-SCIENTIFIC NAMES
- Musculus biceps femoris: Primary muscle of the hamstring group.
- Musculus ischiocruralis: Another term for the hamstring muscles.
ANTAGONIST
- The quadriceps femoris is the Primary muscle group responsible for knee extension, providing balanced movement with the biceps femoris.
COMMON INJURIES
- Strains or tears: Common during sudden acceleration or deceleration, such as sprinting or kicking.
- 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.