Biceps tendon pathology encompasses degenerative, inflammatory, or traumatic lesions of the long head of biceps tendon (LHBT). LHBT originates from superior labrum (biceps origin) and supraglenoid tubercle, passes through the glenohumeral joint, and courses in the bicipital groove (intertubercular groove). The tendon is stabilized in the bicipital groove by the 'pulley system' formed by the transverse humeral ligament and subscapularis tendon — disruption of this system leads to tendon instability. The spectrum of tendon pathologies is wide: tendinosis (degenerative thickening and signal increase), tenosynovitis (sheath inflammation — peritendinous fluid accumulation), partial tear (partial fiber disruption), complete tear (clinically manifesting as Popeye deformity), subluxation and dislocation (medial displacement from bicipital groove — strong association with subscapularis tear). On MRI, tendon is evaluated in bicipital groove on axial and sagittal images; empty bicipital groove is pathognomonic for dislocation. US with dynamic assessment can detect intermittent subluxation and is complementary to MRI.
Age Range
30-70
Peak Age
45
Gender
Male predominant
Prevalence
Common
LHBT's susceptibility to pathology stems from its unique anatomic course — the tendon makes an intra-articular transition, is compressed in the bicipital groove, and exposed to constant mechanical friction during shoulder motion. In the bicipital groove, the tendon is held in place by the transverse humeral ligament; the subscapularis tendon plays a critical role in the medial pulley mechanism, preventing medial displacement of the LHBT. Subscapularis tear disrupts medial pulley integrity leading to biceps tendon subluxation/dislocation — this mechanism is the most common cause of LHBT instability. Tendinosis develops from chronic mechanical friction and degeneration: collagen type I fibers in the tendon matrix become disorganized, mucoid change (proteoglycan accumulation) and neovascularization develop — histopathologically angiofibroblastic degeneration predominates with minimal acute inflammation. Tenosynovitis is inflammation of the tendon sheath (synovial membrane) characterized by synovial fluid accumulation within the sheath — seen as peritendinous T2 hyperintense halo on MRI. After complete LHBT rupture, disruption occurs at the musculotendinous junction level, proximal tendon traction is lost, and the biceps muscle mass retracts distally by elastic recoil force creating 'Popeye' deformity. On MRI, empty groove sign in bicipital groove is pathognomonic for dislocation — tendon has displaced medially (over or under subscapularis) or into intra-articular space, with groove filled by fluid or fat tissue. Bright appearance of peritendinous fluid on T2 results from free water protons within the sheath having long T2 relaxation time — fat suppression distinguishes this fluid from surrounding fat tissue making it more conspicuous.
On axial T2 fat-sat MRI, non-visualization of LHBT in bicipital groove with groove filled with fluid or fat tissue. This finding is pathognomonic for biceps tendon dislocation or complete tear. In dislocation tendon displaces medially (over or under subscapularis), in complete tear tendon is not seen anywhere with distally retracted muscle. Strong association with subscapularis tear — medial pulley disruption is the main mechanism of dislocation.
On axial T2 fat-sat images, LHBT is not seen in bicipital groove — groove is filled with fluid or fat tissue. Tendon has displaced medially (over or under subscapularis) or into intra-articular space. Subscapularis tendon shows tear or partial tear (medial pulley disruption). Transverse humeral ligament may also be disrupted — ligament thickening or absence is evaluated on axial images. This finding is pathognomonic for biceps tendon dislocation and is critically important for surgical planning (tenodesis).
Report Sentence
LHBT is not seen in the bicipital groove with tendon displaced medially over subscapularis; consistent with biceps tendon dislocation.
On axial T2 fat-sat images, ring-shaped hyperintense fluid around LHBT within bicipital groove is seen. Fluid accumulation within tendon sheath indicates tenosynovitis. Isolated small amount of peritendinous fluid may be normal variant (especially on MRI obtained in internal rotation) but significant fluid increase, sheath diameter exceeding twice the tendon diameter, and clinical correlation diagnoses tenosynovitis. Tendon itself may be thickened or show signal increase (accompanying tendinosis). Tenosynovitis may be isolated or found with rotator cuff pathology, impingement syndrome, rheumatoid arthritis.
Report Sentence
Peritendinous fluid collection around LHBT in the bicipital groove is seen, consistent with biceps tenosynovitis.
On US, dynamic assessment of LHBT in bicipital groove is performed — during shoulder internal rotation tendon may subluxate or dislocate medially from groove. Static assessment shows absence or abnormal position of tendon in groove. In transverse sections, relationship between LHBT, lesser tuberosity, and greater tuberosity within bicipital groove is evaluated. During dynamic examination, tendon sliding medially from groove is observed in real-time as shoulder moves from neutral to internal rotation. US advantage is dynamic assessment capability — intermittent subluxation not detected on static MRI can be demonstrated on US. Additionally, US allows bilateral comparative assessment.
Report Sentence
LHBT shows medial subluxation during internal rotation on dynamic assessment in the bicipital groove on US.
On axial PD fat-sat images, LHBT is thicker than normal (>5 mm diameter) in bicipital groove with intermediate signal increase. Tendon continuity is maintained — this feature distinguishes tendinosis from partial tear. Tendon contour may be smooth or mildly irregular. In chronic tendinosis, tendon may have irregular contour and partial tear may be superimposed (focal hyperintense defect within tendon). Coronal oblique images assess signal change and thickening along the tendon length. Accompanying subacromial bursitis and rotator cuff tendinopathy should be investigated — LHBT pathology is frequently part of impingement syndrome spectrum.
Report Sentence
LHBT is thickened with intermediate signal increase in the bicipital groove, consistent with tendinosis.
On T2 fat-sat axial and sagittal images, LHBT is not seen in bicipital groove and intra-articular region — characterized by tendon absence and fluid in groove. Muscle mass has retracted distally (biceps muscle body displaced distally on sagittal images). Clinically 'Popeye' deformity (muscle bunching at distal arm) is seen. Complete tear usually occurs in bicipital groove or near origin. Degree of retraction reflects chronicity — minimal retraction in acute tear, significant retraction with muscle fatty infiltration in chronic tear. Tendon absence should be confirmed throughout the entire bicipital groove on axial images — segmental absence suggests partial tear.
Report Sentence
LHBT is not seen in the bicipital groove and intra-articular region consistent with complete tear; distal retraction of biceps muscle is present.
On longitudinal and transverse B-mode US, LHBT appears thicker than normal in bicipital groove with heterogeneous echotexture and loss of fibrillar pattern. Normal LHBT is a thin, hyperechoic oval structure with smooth fibrillar pattern (transverse section ~3-4 mm diameter). In tendinosis, increased diameter (>5 mm), hypoechoic areas (mucoid degeneration), and irregular fibrillar structure are seen. Power Doppler shows neovascularization (increased peritendinous and intratendinous vascularity) indicating active degenerative process. Comparative assessment with contralateral side reveals asymmetry.
Report Sentence
LHBT is thickened with heterogeneous echotexture in the bicipital groove on US, consistent with tendinosis.
On axial T1 and T2 fat-sat images, partial or complete tear of subscapularis tendon is seen — signal increase, thickening, or retraction at tendon insertion (lesser tuberosity). Subscapularis tear disrupts the medial pulley mechanism leading to LHBT instability — therefore subscapularis must always be evaluated when LHBT dislocation is detected. Uppermost partial tears are most common, involving separation of cranial fibers. Subscapularis tendon is traced to its lesser tuberosity attachment on axial images and tendon absence or retraction is assessed.
Report Sentence
Partial tear of the subscapularis tendon is noted, which should be evaluated for biceps tendon instability related to medial pulley insufficiency.
Criteria
Thickened tendon (>5 mm), intermediate signal increase, continuity maintained, no tear cleft
Distinct Features
Conservative treatment (NSAIDs, physiotherapy, peritendinous corticosteroid injection). Often seen with impingement syndrome. Risk of progression to partial tear in chronic tendinosis. Peritendinous fluid (tenosynovitis) may accompany but tendon continuity is maintained.
Criteria
Tendon displaced medially from bicipital groove (over/under subscapularis or intra-articular)
Distinct Features
Associated with subscapularis tear (in 95%+ of cases), medial pulley disruption mechanism. Surgical indication (tenodesis or tenotomy) present. Empty groove sign on axial MRI is pathognomonic. Transverse humeral ligament may also be disrupted.
Criteria
Tendon not seen on any slices, tendon absence in bicipital groove and intra-articular area, muscle retracted distally
Distinct Features
Clinically Popeye deformity. Usually low functional loss (20% supination strength loss). Conservative treatment acceptable in elderly, biceps tenodesis (tendon fixed to humerus) preferred in young and active patients. Cosmetic concern influences treatment decision.
Criteria
Peritendinous fluid around LHBT in bicipital groove, tendon sheath thickening, tendon normal or tendinosis may accompany
Distinct Features
Often associated with rotator cuff pathology or rheumatoid arthritis. Small amount of peritendinous fluid may be normal variant — >5 mm sheath thickness or sheath diameter exceeding twice tendon diameter is considered diagnostic. US-guided peritendinous corticosteroid injection is effective treatment option.
Distinguishing Feature
Labral tear is labrum pathology, biceps tendon pathology is different anatomy — but in SLAP lesion biceps origin is affected and both pathologies may coexist. On MR arthrography, gadolinium seeping under labrum shows labral tear, while peritendinous fluid in bicipital groove indicates tenosynovitis. In SLAP lesion, separation at the junction of superior labrum and biceps origin is seen.
Distinguishing Feature
Rotator cuff tear is subacromial tendon pathology characterized by T2 signal increase and tendon defect at supraspinatus/infraspinatus insertion; biceps tendon pathology is in bicipital groove location. Subscapularis tear connects both pathologies — it is both a rotator cuff pathology and a cause of LHBT instability.
Distinguishing Feature
Subacromial bursitis is characterized by bursal distension and fluid in subacromial-subdeltoid space; biceps tenosynovitis is characterized by peritendinous fluid around LHBT in bicipital groove — different anatomic localization and different bursa/sheath structures. Both pathologies may coexist in impingement syndrome.
Distinguishing Feature
Adhesive capsulitis shows thickening and enhancement of IGHL, CHL, and rotator interval with absent or minimal bursal distension. Biceps pathology shows localized findings in bicipital groove (peritendinous fluid, tendon thickening, empty groove). Axillary recess capacity is reduced in adhesive capsulitis.
Urgency
routineManagement
conservativeBiopsy
Not NeededFollow-up
specialist-referralBiceps tendon pathology treatment is planned by pathology type and may require multidisciplinary approach. Tendinosis and tenosynovitis are managed conservatively — NSAIDs, physiotherapy (biceps and rotator cuff strengthening), US-guided peritendinous corticosteroid injection (diagnostic and therapeutic). For biceps tendon dislocation and complete tear, two main surgical procedures exist: biceps tenodesis (tendon fixed to humerus — preferred in young, active, cosmetically concerned patients) and biceps tenotomy (tendon cut and released — preferred in elderly, low-demand, comorbid patients). Functional loss in complete tear is usually low (20% supination strength loss, 10% elbow flexion strength loss) and many patients gain adequate function with conservative treatment. In biceps dislocation with subscapularis tear, both pathologies should be addressed together — subscapularis repair + biceps tenodesis/tenotomy.
Biceps tendon pathologies are an important cause of shoulder pain. Tenosynovitis may be managed conservatively, while complete tears and unstable dislocations may require surgical intervention (tenodesis or tenotomy). If subscapularis tear and pulley lesion are associated, combined surgery should be planned.