Clinical Evaluation of the Hamstring Muscles

The clinical examination of hamstring function, as described, involves several key steps to assess the strength and integrity of the hamstring muscles. Here’s a summary of the process:

1. Positioning the Patient: The patient is placed prone (lying face down) with their hips and lower extremities hanging freely off the edge of the examination table. This positioning allows for an unobstructed evaluation of the hamstring muscles.
2. Examining Knee Flexion: The examiner assesses whether the patient can flex (bend) the knees against gravity and resistance. This action primarily tests the strength and functionality of the hamstring muscles.
3. Palpation for Muscle Activity:
   • Medially: The medial side is palpated to assess the activity of the semitendinosus and semimembranosus muscles.
   • Laterally: Palpation on the lateral side of the thigh assesses the activity of the biceps femoris.
4. Understanding the Hamstring Muscles:
   • Biceps Femoris: This muscle has two parts – the long head, arising from the ischium and inserted into the head of the fibula, and the short head, originating from the femur and joining the long head in its insertion.
   • Semitendinosus: Along with the biceps femoris, it originates from a common point but diverges as it descends medially.
   • Semimembranosus: Originates from the ischial tuberosity, descending medially to insert on the proximal tibia.
5. Nerve Supply: All hamstring muscles are innervated by the tibial division of the sciatic nerve, except for the short head of the biceps femoris, which is supplied by the common peroneal nerve.
6. Clinical Relevance: It’s important to assess hamstring muscle function in cases of injury to the hamstring muscle or tendon, or if there’s potential damage to the sciatic nerve, affecting either its tibial or common peroneal divisions.

This examination is crucial for diagnosing hamstring injuries or nerve issues affecting the leg. In cases of hamstring strain or sciatic nerve injury, these tests can provide valuable information about the extent and specific location of the injury. For detailed demonstrations and further information, it’s advisable to consult clinical resources or medical professionals specialized in this area.