Hamstrings

Introduction

Illustration of the hamstring muscles

Diagram of the hamstring muscles. BF biceps femoris muscle, ST semitendinosus muscle, SM semimembranosus muscle, CT common tendon, CT(ft) free-tendon part of the common tendon. SN sciatic nerve, IT ischial tuberosity, FH fibular head, FT fat tissue in the space between the BF and ST/SMmuscles, (*) Popliteal vessels and nerve are interposed between the BF and ST/SM muscles

Series of short-axis ultrasound scans showing different views of the proximal part of the hamstrings (handle of the tuning fork). As the probe is moved in a proximal direction, the sections of the common tendon and the semimembranosus tendon can be seen approaching the sciatic nerve until a hyperechoic line is observed with a posterior acoustic shadow consistent with the ischial tuberosity. BFlh long head of the biceps femoris, ST semitendinosus muscle, AM adductor magnus muscle, SMT semimembranosus tendon, CT common tendon, CT (ft) free tendon part of the common tendon, (*) sciatic nerve

General

• Muscles: Biceps femoris, semitendinosus and semimembranosus
• Form the posterior compartment of the thigh
• Collectively act to extend at the hip and flex at the knee

Etymology

• "Ham": derived from the Old English ham or hom meaning the hollow or bend of the knee
  • From a Germanic base where it meant "crooked"
• Gained the meaning of the leg of an animal in the 15th century
• 'String' refers to tendons

Bicep Femoris

• Origin
  • Bicep Femoris (Short Head): Lateral lip of the linea aspera of the Femur
  • Bicep Femoris (Long Head): Ischial Tuberosity
• Insertion
  • Bicep Femoris (Short Head): Head of the Fibula and lateral condyle of the Tibia
  • Bicep Femoris (Long Head): Head of the Fibula and lateral condyle of the Tibia

Semitendinosus

• Origin: Lower, medial surface of the Ischial Tuberosity
• Insertion: Medial Tibia at the Pes Anserinus

Semimembranosus

• Origin: Ischial Tuberosity
• Insertion: Medial condyle of the Tibia

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Actions

Muscle Group

• Stabilize the knee
• Activate at the last quarter of the gait cycle to generate hip extension and resist knee extension
• Resist anterior translation of the tibia (together with the Anterior Cruciate Ligament)

Individual Muscle

• Bicep Femoris (Short Head)
  • Knee flexion and lateral rotation of the tibia
• Bicep Femoris (Long Head)
  • Knee flexion, lateral rotation of the tibia, and hip extension
• Semitendinosus
  • Knee flexion, lateral rotation of the tibia, and hip extension
• Semimembranosus
  • Knee flexion, lateral rotation of the tibia, and hip extension

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Artery

Biceps Femoris

• Deep femoral artery
• Inferior Gluteal Artery
• Popliteal Artery
• Perforating Arteries

Semitendiosus

• Deep Femoral Artery (first perforating branch)
• Medial Femoral Circumflex Artery
• Inferior Gluteal Artery
• Inferior Medical Geniculate Artery

Semimembranosus

• Femoral Artery (perforating branches)
• Popliteal Artery (perforating branches)

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Nerve

• Bicep Femoris: Short Head
  • Common Fibular Nerve (common peroneal)
• Bicps Femoris: Long Head
  • Tibial Nerve division of Sciatic Nerve
• Semitendiosus
  • Tibial Nerve division of Sciatic Nerve
• Semimembranosus
  • Tibial Nerve division of Sciatic Nerve

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Clinical Significance

Pathology

• Hamstring Strain
• Hamstring Tendonitis
• Ischial Tuberostiy Avulsion Fracture
  • Ischial apophyseal avulsion fractures account for between 1.4-4% of hamstring injuries

Procedural: Hip

• Hamstring Origin Percutaneous Needle Tenotomy
• Ischial Bursa Injection

Procedural: Knee

• Distal Biceps Femoris Injection
• Distal Semimembranosus Injection
• Pes Anserine Bursa Injection

Surgical

• Hamstring autografts are used in Anterior Cruciate Ligament reconstruction

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See Also

Hip

• Physical Exam Hip
• Hip Anatomy (Main)
• Hip Pain (Main)

Knee

• Physical Exam Knee
• Knee Anatomy (Main)
• Knee Pain (Main)

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