Biceps Femoris – Origin, Insertion, Nerve Supply, Function

Last updated: February 8, 2026Reviewed date: February 8, 2026Reading time: 4 min read
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Biceps Femoris is the most lateral component of the so-called hamstring muscles. Classically, this muscle's insertion into the head of the fibula has been described but further details of its anatomy have not been universally appreciated. Additional insertions into the crural fascia and tibia have...

For severe symptoms, danger signs, pregnancy, child illness, or sudden worsening, seek urgent medical care.

বাংলা রোগী নোট এখনো যোগ করা হয়নি। পোস্ট এডিটরে “RX Bangla Patient Mode” বক্স থেকে সহজ বাংলা সারাংশ যোগ করুন।

এই তথ্য শিক্ষা ও সচেতনতার জন্য। এটি ডাক্তারি পরীক্ষা, রোগ নির্ণয় বা প্রেসক্রিপশনের বিকল্প নয়।

Article Summary

Biceps Femoris is the most lateral component of the so-called hamstring muscles. Classically, this muscle's insertion into the head of the fibula has been described but further details of its anatomy have not been universally appreciated. Additional insertions into the crural fascia and tibia have been described. We dissected 56 cadavers paying especially close attention to the insertion of the biceps femoris muscle. The tendon...

Key Takeaways

  • This article explains Origin in simple medical language.
  • This article explains Insertion in simple medical language.
  • This article explains Arterial Supply in simple medical language.
  • This article explains Nerve Supply in simple medical language.
Educational health guideWritten for patient understanding and clinical awareness.
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Seek urgent medical care if you notice

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  • Severe symptoms, breathing difficulty, fainting, confusion, or rapidly worsening illness.
  • New weakness, severe pain, high fever, or symptoms after a serious injury.
  • Any symptom that feels urgent, unusual, or unsafe for the patient.
1

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2

See a doctor

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Definition

Biceps Femoris is the most lateral component of the so-called hamstring muscles. Classically, this muscle’s insertion into the head of the fibula has been described but further details of its anatomy have not been universally appreciated. Additional insertions into the crural fascia and tibia have been described. We dissected 56 cadavers paying especially close attention to the insertion of the biceps femoris muscle. The tendon of this muscle was found to have both medial and lateral slips each with an anterior and posterior component. The biceps femoris (also biceps femoris muscle, latin musculus biceps femoris) is a two-headed muscle of the lower limb located in the posterior region of the thigh. The biceps femoris has two portions – the long head and the short head.

The biceps femoris is one of the hamstring muscles at the back of the thigh. It originates in two places: the ischium (lower, rear portion of the pelvis, or hipbone) and the back of the femur (thighbone). The fibres of these two origins join and are attached at the head of the fibula and tibia, the bones of the lower leg. This muscle extends the thigh, rotates it outward, and flexes the leg at the knee.

Biceps Femoris - Origin, Insertion, Nerve Supply, Function

Origin

It has two heads of origin:

  • The long head  – arises from the lower and inner impression on the posterior part of the tuberosity of the ischium. This is a common tendon origin with the semitendinosus muscle, and from the lower part of the sacrotuberous ligament.
  • The short head –  arises from the lateral lip of the linea aspera, between the adductor Magnus and vastus lateralis extending up almost as high as the insertion of the gluteus maximus, from the lateral prolongation of the linea aspera to within 5 cm. of the lateral condyle; and from the lateral intermuscular septum.[rx]

Insertion

  • Inferiorly, the aponeurosis condenses to form a tendon which predominantly inserts onto the lateral side of the head of the fibula. There is a second small insertional attachment by a small tendon slip into the lateral condyle of the tibia.[rx]
  • At its insertion, the tendon divides into two portions, which embrace the fibular collateral ligament of the knee joint. Together, this joining of tendons is commonly referred to as the conjoined tendon of the knee.[rx][rx]

Arterial Supply

The muscle’s vascular supply is derived from the anastomoses of several arteries: the perforating branches of the profundal femoris artery, the inferior gluteal artery, and the popliteal artery.[rx]

  • Inferior gluteal artery
  • Perforating arteries
  • Popliteal artery

Nerve Supply

It is a composite muscle as the short head of the biceps femoris develops in the flexor compartment of the thigh and is thus innervated by a common fibular branch of the sciatic nerve (L5, S1), while the long head is innervated by the tibial branch of the sciatic nerve (L5, S1).[rx]

  • Long head – a tibial division of the sciatic nerve (L5-S2)
  • Short head – a common peroneal division of the sciatic nerve

or

  • Long head –  tibial nerve
  • Short head – common peroneal nerve

Function

  • Flexes knee joint
  • Laterally rotates knee joint (when the knee is flexed)
  • Extends hip joint (long head only)
  • External rotation of the thigh (long head only)
  • Long head –  flexes the knee, extends hip, laterally rotates lower leg when knee slightly flexed, assists in lateral rotation of the thigh when hip extended
  • Short head – flexes the knee, laterally rotates lower leg when knee slightly flexed

Functional contributions

  • Through a reversed origin insertion action, the long head gives posterior stability to the pelvis
  • Both heads provide rotary stability by preventing forward dislocation of the tibia on the femur during flexion
  • Its contributions to the arcuate ligament complex at the posterolateral corner of the knee also provide varus and rotatory stability to the knee.

References

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What to tell the doctor

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Tests to discuss

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Avoid these mistakes

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Safe first steps

  • Rest, drink safe water, and observe symptoms carefully.
  • Keep a written note of symptoms, duration, temperature, medicines already taken, and allergy history.
  • Seek medical care quickly if symptoms are severe, worsening, or unusual for the patient.

OTC medicine safety

  • For mild pain or fever, ask a registered pharmacist or doctor before using common over-the-counter pain/fever medicines.
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Avoid these mistakes

  • Do not start antibiotics without a proper medical decision.
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Get urgent help if

  • Severe symptoms, confusion, fainting, breathing difficulty, chest pain, severe dehydration, or sudden weakness need urgent medical care.
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Doctor to discuss: Doctor / qualified healthcare provider
Tests to discuss with doctor
  • Basic vital signs: temperature, pulse, blood pressure, oxygen level if needed
  • Relevant blood, urine, imaging, or specialist tests only after clinical assessment
Questions to ask
  • What is the most likely cause of my symptoms?
  • Which warning signs mean I should go to emergency care?
  • Which tests are really needed now?
  • Which medicines are safe for my age, pregnancy status, allergy, kidney/liver/stomach condition, and current medicines?

Emergency warning signs such as chest pain, severe breathing difficulty, sudden weakness, confusion, severe dehydration, major injury, or loss of bladder/bowel control need urgent medical care. Do not wait for online information.

Safe pathway to proper treatment

Care roadmap for: Biceps Femoris – Origin, Insertion, Nerve Supply, Function

Use this simple roadmap to understand the next safe steps. It is educational and does not replace examination by a doctor.

Go to emergency care if you notice:
  • Severe or rapidly worsening symptoms
  • Breathing difficulty, chest pain, fainting, confusion, severe weakness, major injury, or severe dehydration
Doctor / service to discuss: Qualified healthcare provider; specialist depends on symptoms and examination.
  1. Step 1

    Check danger signs first

    If danger signs are present, seek emergency care and do not wait for online information.

  2. Step 2

    Record the symptom story

    Write when symptoms started, severity, medicines already taken, allergies, pregnancy status, and test results.

  3. Step 3

    Visit a qualified clinician

    A doctor, nurse, or qualified healthcare provider can examine you and decide which tests or treatment are needed.

  4. Step 4

    Do only useful tests

    Do tests after clinical assessment. Avoid unnecessary tests, random antibiotics, or repeated medicines without diagnosis.

  5. Step 5

    Follow up and return early if worse

    If symptoms worsen, new warning signs appear, or treatment is not helping, return for review quickly.

Rural patient practical tips
  • Take a written symptom diary and all previous prescriptions/test reports.
  • Do not hide medicines already taken, even herbal or over-the-counter medicines.
  • Ask which warning signs mean urgent referral to hospital.

This roadmap is for education. A real diagnosis and treatment plan requires history, examination, and clinical judgment.

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Frequently Asked Questions

Is this article a replacement for a doctor?

No. It is educational content only. Patients should consult a qualified clinician for diagnosis and treatment.

When should I seek urgent care?

Seek urgent care for severe symptoms, rapidly worsening condition, breathing difficulty, severe pain, neurological changes, or any emergency warning sign.

References

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