Biceps Femoris

The Biceps Femoris, Semitendinosus, and Semimembranosus, which are posterior thigh muscles, comprise the Hamstring muscle group.

Anatomical Attachments:

• Origin: There are two heads of the biceps femoris. The long head attaches to the ischial tuberosity and the short head attaches to the linea aspera and the distal femur.
• Insertion: Attaches to the head of the fibula and the lateral condyle of the tibia.

Action: It flexes and rotates the leg, especially when the knee is flexed, and also extends the thigh.

Synergist:  

• Prime Movers: Gluteus maximus, Adductor magnus (posterior part).
• Accessory Movers: Semimembranosus, Semitendinosus, Biceps femoris (long head), Piriformis.

Antagonist: Iliopsoas, Pectineus, Tensor fasciae latae, Adductor brevis, Sartorius.

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Nerve Supply: Sciatic Nerve.

Vascular supply: Supply: Profunda femoris artery.

• Primary: The pain refers to the back of the knee into the calf and upward to the posterior thigh.
• Satellite or associated triggers: Long head of Biceps femoris, Quadriceps femoris group, Gastrocnemius, Iliopsoas, Adductor Magnus, Quadratus Lumborum, Thoracic Paraspinals and Rectus Abdominis.

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Trigger Point Signs and Symptoms: The pain may be experienced while sleeping. The posterior leg pain is worsened during walking, and persistent sitting may result in deep buttocks, anterior thigh, or pain being experienced in the popliteal fossa. There is also pain when rising from a seated position.

Trigger Point Activating and Perpetuating Factors: Sitting in a chair where ones feet do not touch the floor for long periods of time.

Differential Diagnosis: (Segmental, Subluxation, Somatic dysfunction) L5 radiculopathy, S1 or S2 Nerve Compression, Postlaminectomy pain syndrome, Bone cancer, Bone fracture, Pulled or torn Hamstring, Bruised ischial tuberosity, Deep vascular thrombosis (DVT), Lipedema, Multiple sclerosis, Rheumatoid Arthritis, Bursitis, Osteoarthritis, Tension Myalgia, Systemic lupus erythematosus, Fibromyalgia, Reflex sympathetic dystrophy (Complex regional pain syndrome), Coxa Plana, Cauda equina syndrome, Sprain/Strain, Systemic infections or inflammation, Eosinophilic fasciitis, Tetanus, Nutritional inadequacy, Metabolic imbalance, Toxicity, Side effects of medication.

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