Biceps long head
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biceps brachii long head anatomy origin insertion function tendon
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Here is a complete overview of the Long Head of the Biceps Brachii:
Fig. 7.64 - Coracobrachialis, Biceps Brachii, and Brachialis Muscles (Gray's Anatomy for Students)
Anatomy
| Feature | Long Head |
|---|---|
| Origin | Supraglenoid tubercle of the scapula |
| Course | Tendon passes intra-articularly through the glenohumeral joint, superior to the humeral head, exits at the intertubercular sulcus (bicipital groove) |
| Groove retainment | Held in the intertubercular sulcus by the transverse humeral ligament (spanning the greater and lesser tubercles) |
| Insertion | Radial tuberosity; also gives off the bicipital aponeurosis to the antebrachial fascia |
| Innervation | Musculocutaneous nerve (C5, C6) |
The long head tendon is unique in that it is the only muscle tendon in the body that travels through a synovial joint cavity before forming a muscle belly - Gray's Anatomy for Students, p. 852.
Functions
- Elbow flexion - powerful flexor, acting at the elbow joint
- Forearm supination - the most powerful supinator when the elbow is flexed at 90°; supination force is lost if the elbow is extended
- Shoulder flexion - accessory flexor at the glenohumeral joint (both heads cross the shoulder)
- Humeral head depression/stabilization - the long head prevents superior migration of the humeral head during deltoid contraction, providing dynamic shoulder stability - THIEME Atlas of Anatomy, p. (block 2909)
Clinical Relevance
1. Bicipital Tendinitis (Bicipital Tendinopathy)
- Caused by friction on the long head tendon as it passes through the bicipital groove
- Often co-exists with impingement syndrome, rotator cuff tears (especially subscapularis), and bicipital groove stenosis
- Clinically: anterior shoulder pain, tenderness over the bicipital groove with the arm externally rotated ~10°
- Positive tests: Speed's test, Yergason's test (pain on resisted supination at 90° elbow flexion)
- Management: strengthening + corticosteroid injection into biceps sheath → surgical release/tenodesis for refractory cases - Miller's Review of Orthopaedics, 9th Ed.
2. Tendon Subluxation/Dislocation
- Most commonly associated with a partial or complete subscapularis tear or tear of the transverse humeral ligament / coracohumeral ligament (CHL)
- Results in medial displacement of the tendon out of the groove
- In 200 patients with rotator cuff tears, biceps tendon instability was present in 45% - Campbell's Operative Orthopaedics, 15th Ed.
- Clinically: palpable click on shoulder abduction + external rotation
3. Acute Rupture
- Usually occurs proximally (at the bicipital groove) with vigorous exercise or eccentric loading
- Acute pain followed by the classic "Popeye deformity" - a visible ball of muscle belly that drops distally due to retraction of the long head
- In young, active patients: surgical repair is recommended promptly
- In older patients: rupture may be relatively painless; non-operative management often acceptable since significant functional loss is uncommon (strength deficit mainly in supination, not flexion) - Harrison's Principles of Internal Medicine, 22nd Ed.
4. Surgical Options
- Tenotomy (release without repair): risk of cosmetic "Popeye" deformity and subjective cramping; weakness is minimal
- Tenodesis (re-anchoring the tendon): preserves cosmesis and reduces cramping; subpectoral technique preferred to avoid residual "groove pain" from retained tendon in the intertubercular groove - Miller's Review of Orthopaedics, 9th Ed.
Quick Summary
The long head of the biceps is anatomically notable for its intra-articular course through the glenohumeral joint - a route that makes it prone to mechanical wear, tendinopathy, and rupture, particularly in the setting of shoulder impingement or rotator cuff pathology.
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