The Hamstrings

Hamstrings Muscles 

Injuries to the hamstring muscles are very common in sport. The hamstring muscles are antagonists (opposites) to the quadriceps muscles at the knee and are named for the cordlike attachments at the knee.

Hamstrings are primarily knee flexors and secondarily hip extensors. Inability to touch the floor with the fingers when the knees are straight is largely a result of a lack of flexibility of the hamstrings.

Rotation of the knee can occur when it is in a flexed position. Knee rotation is brought about by the hamstrings muscles. The biceps femoris provides the force for outward rotation, and the semitendinosus and semimembranosus cause the inward rotation.

 

Muscle Origin Insertion Action Palpation
Bicep Femoris Ischial tuberosity and the linea aspera Lateral condyle of the tibia and head of the fibula
  1. Extention of the hip
  2. Flexs the knee
  3. Externally rotates the knee
Lateral posterior side of the femur, near the knee
Semimembranosus Ischial tuberosity  Posterior surface medial condyle of the tibia
  1. Extention of the hip
  2. Flexs the knee
  3. Internally rotates the knee
Posterior medial aspect of the knee joint. Deep muscle ( only tendon can be palpated)
Semitendinosus¬† Ischial tuberosity  Upper anterior medial condyle of the tibia
  1. Extention of the hip
  2. Flexs the knee
  3. Internally rotates the knee
Superficial muscle the muscle belly and its tendon can be palpated

 

 

hamstring bruising