Subscapularis Tears

• What the pulley is. The biceps reflection pulley is a sling at the entrance of the bicipital groove formed by the superior glenohumeral ligament (SGHL) and coracohumeral ligament (CHL), reinforced medially by the superior border of the subscapularis and laterally by fibres of the supraspinatus; it holds the long head of biceps in the groove.
• Why an upper-subscap tear destabilises the biceps. The upper subscapularis is the medial wall of this sling, so a tear of the upper fibres opens the medial pulley and the biceps subluxes or dislocates medially — seen on axial MRI as the biceps lying medial to the groove, often draped over or into the torn subscapularis. This is the classic "hidden lesion", easily missed if only the main cuff is inspected.
• The comma-sign link. The comma sign the topic relies on is precisely the SGHL/CHL (pulley) tissue avulsed with the superolateral subscapularis corner — following the comma leads you both to the retracted subscapularis stump and to the disrupted pulley.
• The practical consequence. Because the tear and the biceps instability share the pulley, an unstable biceps must not be left in situ — hence the routine tenotomy or tenodesis at subscapularis repair (the biceps-side decision-making is developed in the biceps topic).

• Indication. A symptomatic irreparable anterior cuff (advanced fatty infiltration, retraction, attritional tissue) in a patient with functional demand, preserved passive motion and no significant glenohumeral arthritis — arthritis or a massive combined tear points instead to reverse arthroplasty.
• The subcoracoid (Resch) technique. The superior half-to-two-thirds of the pectoralis major is detached and routed deep to (behind) the conjoint tendon to the lesser tuberosity; passing behind the conjoint tendon redirects the muscle's line of pull to better approximate the subscapularis vector, with the conjoint tendon acting as a pulley.
• The supracoracoid alternative. Transfer superficial to (in front of) the conjoint tendon is technically simpler but more non-anatomic (a straighter, transverse pull) and risks tethering the musculocutaneous nerve — ease versus a less physiological vector.
• Its ceiling, and the alternatives. Because pectoralis major pulls in a different plane from the subscapularis, the transfer reliably relieves pain and restores anterior stability but only partially restores internal-rotation strength; a lower-trapezius or latissimus dorsi transfer is a more line-of-pull-matched option some now prefer, with no head-to-head trials to separate them.

Global epidemiology. Subscapularis involvement is found in roughly 10-25% of surgically treated rotator cuff tears, but arthroscopic series report a far higher rate of upper-fibre lesions (up to 27-30% of all shoulder arthroscopies in some cohorts) once surgeons actively look for them. The classic isolated traumatic tear (forced hyperextension/external rotation) affects predominantly middle-aged men; degenerative anterosuperior tears affect both sexes in the 6th-7th decades.

Related pages: Rotator Cuff Tears is the parent topic and carries the posterosuperior cuff on which the Goutallier grading carded here was actually derived; Massive Rotator Cuff Tears for the anterosuperior escape pattern that a subscapularis tear produces when the supraspinatus has also failed, which is the situation none of the transfer series above studied; Biceps Tendon Pathology and Proximal Biceps Ruptures for the long head, whose medial subluxation out of the groove is the single most reliable imaging clue to a subscapularis tear and whose pulley is the 'hidden lesion' this page describes; Subcoracoid Impingement for the narrowed coracohumeral interval that both causes and accompanies upper-border tears, and for the coracoplasty decision; Lesser Tuberosity Fractures for the bony equivalent of the same avulsion, which is repaired as a fracture rather than as a tendon and is the diagnosis to exclude in the adolescent; Pectoralis Major Anatomy and Pectoralis Major Rupture for the donor in the Resch transfer, including the sternal-versus-clavicular head distinction that determines the vector; Musculocutaneous Nerve Anatomy for the structure at risk when the transfer is routed behind the conjoint tendon, and Axillary Nerve Anatomy for the nerve Gerber warns must be protected during open repair; Anterior Shoulder Instability for the differential in a patient whose dominant complaint is giving way rather than weakness; Reverse Total Shoulder Arthroplasty for the endpoint when the anterosuperior cuff is unreconstructable; and Shoulder Arthroplasty Complications for subscapularis failure after anatomic replacement, which is now the commonest setting in which this tendon is found deficient.