Classification
- Type: Synovial ball-and-socket
- Degrees of freedom: 3 (flexion/extension, abduction/adduction, internal/external rotation)
- Region: Shoulder complex (along with the acromioclavicular, sternoclavicular, and scapulothoracic articulations)
Articular Surfaces
- Humeral head (convex): Large, rounded, approximately one-third of a sphere. Covered with hyaline cartilage, thickest centrally. Faces medially, superiorly, and posteriorly in the anatomical position.
- Glenoid fossa (concave): Shallow, pear-shaped cavity on the lateral scapula. Only about one-third to one-fourth the size of the humeral head — a significant mismatch that explains the joint's inherent instability.
- Glenoid labrum: A fibrocartilaginous ring attached to the rim of the glenoid fossa. The labrum deepens the socket by approximately 50%, increasing the contact area and improving stability. The superior labrum is the attachment point for the long head of the biceps tendon (the biceps-labral complex). Labral tears (SLAP lesions, Bankart lesions) directly compromise joint stability.
- Cartilage: Hyaline cartilage on both articular surfaces. The joint cavity is the largest in the body relative to the articulating surfaces.
Movements and ROM
| Movement | Normal ROM | Plane | Muscles Producing |
|---|---|---|---|
| Flexion | 180° | Sagittal | anatomy/muscles/anterior-deltoid, anatomy/muscles/coracobrachialis, anatomy/muscles/biceps-brachii (long head), anatomy/muscles/pectoralis-major (clavicular head) |
| Extension | 50–60° | Sagittal | anatomy/muscles/posterior-deltoid, anatomy/muscles/latissimus-dorsi, anatomy/muscles/teres-major, anatomy/muscles/triceps-brachii (long head) |
| Abduction | 180° | Frontal | anatomy/muscles/middle-deltoid, anatomy/muscles/supraspinatus (initiates first 15–30°) |
| Adduction | 0° (to midline) | Frontal | anatomy/muscles/pectoralis-major, anatomy/muscles/latissimus-dorsi, anatomy/muscles/teres-major |
| Internal rotation (IR) | 60–100° | Transverse | anatomy/muscles/subscapularis, anatomy/muscles/pectoralis-major, anatomy/muscles/latissimus-dorsi, anatomy/muscles/teres-major, anatomy/muscles/anterior-deltoid |
| External rotation (ER) | 80–90° | Transverse | anatomy/muscles/infraspinatus, anatomy/muscles/teres-minor, anatomy/muscles/posterior-deltoid |
| Horizontal adduction | 130° | Transverse | anatomy/muscles/pectoralis-major, anatomy/muscles/anterior-deltoid |
| Horizontal abduction | 45° | Transverse | anatomy/muscles/posterior-deltoid, anatomy/muscles/infraspinatus, anatomy/muscles/teres-minor |
Scapulohumeral rhythm: Full shoulder abduction and flexion to 180° requires coordinated GH and scapulothoracic motion in a 2:1 ratio — for every 3° of total shoulder elevation, 2° occur at the GH joint and 1° at the scapulothoracic articulation. Disruption of this rhythm (dyskinesis) is a common finding in shoulder pathology and is often observable during AROM assessment.
Capsular Pattern
ER > Abduction > IR This means that when the GH capsule is restricted (as in adhesive capsulitis), external rotation is the most limited, followed by abduction, then internal rotation. This is one of the most important capsular patterns to memorize — it distinguishes capsular pathology (adhesive capsulitis, OA) from non-capsular patterns (rotator cuff tendinopathy, bursitis). If ROM restriction does not follow this pattern, the capsule is not the primary problem.Resting Position
- 55° abduction, 30° horizontal adduction, neutral rotation
- This is the position where the joint capsule is most relaxed and joint volume is greatest
- Use this position for joint mobilization and joint play assessment
Close-Packed Position
- Full abduction with external rotation
- Maximum bony congruence, capsule and ligaments at maximum tension
- Use for ligamentous integrity testing — do NOT mobilize in this position
End-Feels
| Movement | Normal End-Feel | Type |
|---|---|---|
| Flexion | Tissue stretch | Capsular (firm) — posterior capsule and posterior shoulder muscles limit further motion |
| Extension | Tissue stretch | Capsular (firm) — anterior capsule, pectoralis major, anterior deltoid |
| Abduction | Tissue stretch | Capsular (firm) — inferior capsule and adductors; may become bony at full elevation |
| Internal rotation | Tissue stretch | Capsular (firm) — posterior capsule, infraspinatus, teres minor |
| External rotation | Capsular (firm) | The classic GH capsular end-feel — anterior capsule and subscapularis |
| Horizontal adduction | Tissue approximation / tissue stretch | Depends on muscle mass; firm with capsular component |
Abnormal end-feels: An empty end-feel (patient stops motion due to severe pain before any mechanical resistance is felt) suggests acute pathology — possible fracture, dislocation, or acute bursitis. A springy end-feel at end-range abduction may indicate a labral body or loose body blocking motion. A hard (bony) end-feel in a direction that should be capsular suggests OA or osteophyte formation.
Ligaments
Superior Glenohumeral Ligament (SGHL)
- Attachments: Superior glenoid labrum and base of the coracoid process → superior aspect of the lesser tuberosity of the humerus
- Function: Resists inferior translation (prevents downward slipping) of the humeral head when the arm is at the side in adduction. Works with the coracohumeral ligament to form the "rotator interval" sling.
- Injury mechanism: Rarely injured in isolation. Damage occurs as part of multi-directional instability or superior labral tears.
- Assessment test: No specific isolated test; assessed as part of inferior instability testing (sulcus sign)
- Condition link: Multi-directional instability, conditions/shoulder-labral-injury
Middle Glenohumeral Ligament (MGHL)
- Attachments: Superior glenoid labrum (anterior) → lesser tuberosity of the humerus (anterior aspect)
- Function: Resists anterior translation and external rotation when the arm is abducted to approximately 45°. Limits ER in mid-range positions.
- Injury mechanism: Forced ER with moderate abduction. The MGHL is the most variable GH ligament — absent in up to 30% of the population, which predisposes those individuals to anterior instability.
- Assessment test: Anterior drawer test at 45° abduction
- Condition link: Anterior instability, recurrent subluxation
Inferior Glenohumeral Ligament (IGHL)
- Attachments: Inferior glenoid labrum → inferior anatomical neck of the humerus. Forms a hammock-like complex with anterior band, posterior band, and axillary pouch.
- Function: The most important stabilizer against anterior dislocation. The anterior band resists anterior translation when the arm is abducted to 90° and externally rotated (the apprehension position). The posterior band resists posterior translation. The axillary pouch supports the humeral head inferiorly during abduction.
- Injury mechanism: Forced abduction with external rotation — the classic anterior dislocation mechanism (e.g., falling on an outstretched hand with the arm overhead, or forced ER during a tackle). Damage to the IGHL almost always accompanies anterior dislocation. Bankart lesion (labral avulsion at the IGHL attachment) is the most common structural consequence.
- Grade classification: Grade I — microscopic tears, stable, local tenderness; Grade II — partial tear, mild laxity on apprehension testing; Grade III — complete tear, significant laxity, positive apprehension/relocation
- Assessment test: Apprehension test (arm at 90° abduction and ER — patient reports feeling that the shoulder will "pop out"), relocation test (posterior force reduces apprehension), anterior drawer test
- Condition link: conditions/shoulder-dislocation, conditions/shoulder-labral-injury, recurrent anterior instability
Coracohumeral Ligament (CHL)
- Attachments: Base of the coracoid process → greater and lesser tuberosities of the humerus, bridging the rotator interval
- Function: Resists inferior translation and ER when the arm is adducted. Reinforces the rotator interval (the gap between supraspinatus and subscapularis tendons). The CHL tightens in adhesive capsulitis — its contracture is a major contributor to the loss of ER seen early in the condition.
- Injury mechanism: Rarely injured by trauma. More commonly becomes pathologically shortened and fibrotic in adhesive capsulitis.
- Assessment test: Assessed indirectly through ER limitation with the arm at the side; CHL contracture is a component of the adhesive capsulitis capsular pattern
- Condition link: conditions/adhesive-capsulitis
Coracoacromial Ligament (CAL)
- Attachments: Coracoid process → anterior surface of the acromion
- Function: Forms the coracoacromial arch (a rigid "roof" over the rotator cuff and subacromial bursa). This ligament does not connect bone to bone across the GH joint — it connects two parts of the scapula and acts as a structural barrier. The arch prevents superior migration of the humeral head and protects the rotator cuff from direct trauma from above.
- Injury mechanism: Not typically "injured" but becomes clinically important in subacromial impingement — the rotator cuff tendons (especially supraspinatus) and subacromial bursa are compressed against the coracoacromial arch during overhead movements. Repeated impingement leads to tendinopathy, bursitis, and eventual rotator cuff tears.
- Assessment test: Neer impingement test (passive flexion with scapular stabilization), Hawkins-Kennedy test (90° flexion + IR — compresses supraspinatus against CAL)
- Condition link: conditions/subacromial-impingement, conditions/rotator-cuff-injuries
Transverse Humeral Ligament (THL)
- Attachments: Greater tuberosity → lesser tuberosity of the humerus, bridging the bicipital (intertubercular) groove
- Function: Holds the long head of the biceps tendon within the bicipital groove during shoulder motion. Prevents the biceps tendon from subluxing medially during ER.
- Injury mechanism: Forced ER, repetitive overhead motions, or trauma that ruptures or stretches the THL allows the biceps tendon to sublux or dislocate from the groove. Chronic degeneration from subacromial impingement can also weaken this ligament.
- Assessment test: Speed's test (resisted shoulder flexion with elbow extended and forearm supinated — pain in the bicipital groove), Yergason's test (resisted supination and ER with elbow at 90° — tests the biceps tendon's stability in the groove)
- Condition link: Biceps tendinopathy, biceps tendon subluxation, conditions/rotator-cuff-injuries
Mobilization Techniques
Hands-on instruction is required. The descriptions below provide clinical reference detail for understanding and supervised practice. They are not a substitute for instructor-led technique training. Correct hand placement, force dosage, and tissue response interpretation require hands-on coaching and feedback.
Convex-Concave Rule at the GH Joint
The humeral head is convex articulating on the concave glenoid fossa. When the convex surface moves on a fixed concave surface, the glide occurs in the opposite direction to the restricted movement. This rule determines the mobilization direction for every GH technique:| Restricted Movement | Glide Direction | Reasoning |
|---|---|---|
| Abduction | Inferior glide | Abduction moves the humerus superiorly → convex on concave → glide opposite → inferior |
| Internal rotation | Posterior glide | IR moves the humeral head anteriorly → glide opposite → posterior |
| Horizontal adduction | Posterior glide | Horizontal adduction moves the humeral head anteriorly → glide opposite → posterior |
| External rotation | Anterior glide | ER moves the humeral head posteriorly → glide opposite → anterior |
General Contraindications (All GH Mobilizations)
- Absolute: Joint instability or hypermobility (Beighton score ≥4), acute fracture, active joint infection, malignancy near the joint, acute inflammatory arthritis (RA flare with pannus), joint ankylosis
- Relative (modify grade): Osteoporosis (use Grade I–II only), total shoulder replacement (follow surgeon protocol), EDS or connective tissue disorder (mobilization generally contraindicated — the joint is already hypermobile), acute post-dislocation (wait for healing and surgeon clearance)
- Grade-specific: If Grade I–II oscillations produce pain, do not progress to Grade III–IV
Inferior Glenohumeral Glide
Purpose: Restores abduction. The inferior glide stretches the superior capsule and coracohumeral ligament, which are the primary restraints to abduction. This is often the first mobilization performed in adhesive capsulitis because abduction loss is functionally disabling. Patient position:- Supine on the treatment table
- Arm positioned in the resting position: approximately 55° abduction, 30° horizontal adduction, neutral rotation
- A small towel roll under the proximal humerus can help maintain the resting position
- The patient should be relaxed — muscle guarding defeats the mobilization
- Stabilizing hand: Placed on the superior aspect of the shoulder girdle (over the acromion and lateral clavicle) to prevent the scapula from moving inferiorly. Apply firm but comfortable downward stabilization pressure. The scapula must remain fixed — if it moves with the humerus, you are translating the entire shoulder girdle, not mobilizing the GH joint.
- Mobilizing hand: Web space or thenar eminence contacts the proximal humerus as close to the joint line as possible, just distal to the acromion on the lateral arm. Grip the proximal humerus firmly but not painfully.
- Apply a slow, sustained or oscillatory force directed inferiorly (toward the patient's feet) along the long axis of the humerus
- Grade I–II (pain modulation): Small to large amplitude oscillations within the available pain-free range. Stay well short of tissue resistance. Use for acute adhesive capsulitis or when the joint is painful and irritable. These grades stimulate mechanoreceptors (gate control) to reduce pain. Can be used daily.
- Grade III–IV (mobility): Large to small amplitude oscillations at the end of available range, into the resistance of the capsule. You should feel the capsule's tissue resistance and oscillate into it. Use when the goal is to stretch the capsule and restore range. Use 3–5 times per week.
- Rhythm: slow, rhythmic oscillations — approximately 1–2 per second
- Duration: 30–60 seconds per set, 3–5 sets. Reassess PROM between sets.
- What to feel for: tissue creep (a gradual yielding of the end-feel barrier over successive sets), a shift from hard capsular resistance to a softer, more yielding end-feel
- Capsular end-feel on PROM into abduction
- ROM restriction following the GH capsular pattern (ER > abd > IR)
- Joint play assessment reveals decreased inferior glide
- Perform AFTER soft tissue release of muscles crossing the joint (especially deltoid, supraspinatus, upper trapezius) — reducing muscular guarding first allows the capsule to be accessed more effectively
- Common error: Mobilizing with the arm at 0° abduction instead of the resting position — less effective and more uncomfortable.
- Common error: Failing to stabilize the scapula — the entire shoulder complex translates and no arthrokinematic motion occurs.
- Reassessment: Re-test PROM abduction after mobilization. An increase of 5-15° indicates an effective technique.
- Integration: Perform after myofascial release of subscapularis and pectoralis minor.
Posterior Glenohumeral Glide
Purpose: Restores internal rotation and horizontal adduction. The posterior glide stretches the anterior capsule, anterior band of the IGHL, and the coracohumeral ligament. Restoring posterior glide is critical for functional overhead reaching and behind-the-back movements. Patient position:- Supine on the treatment table
- Arm positioned at approximately 90° of shoulder flexion (arm pointing toward the ceiling), elbow flexed to 90°
- Alternatively, use the resting position (55° abduction) for more acute or irritable joints
- A folded towel under the posterior scapula can improve stabilization
- Stabilizing hand: Placed under the scapula (posterior aspect) or cupping the posterior shoulder to stabilize the scapula against the table. The table surface itself often provides adequate posterior stabilization.
- Mobilizing hand: Both hands grip the proximal humerus anteriorly. The thenar eminences and palms contact the anterior proximal humerus just distal to the joint line. The elbows are positioned so that force is directed straight posteriorly (toward the table).
- Apply a slow, sustained or oscillatory force directed posteriorly (toward the table) perpendicular to the long axis of the humerus
- Grade I–II: Small oscillations within pain-free range — for pain modulation in acute anterior shoulder tightness
- Grade III–IV: Oscillations into the posterior end-range resistance — stretching the anterior capsule. The anterior capsule should be felt as a firm barrier. Apply rhythmic pressure into and slightly past this barrier.
- Same rhythm, duration, and set parameters as the inferior glide
- What to feel for: a progressive softening of the anterior capsular barrier, increased posterior excursion of the humeral head with successive sets
- Decreased IR on PROM with a capsular (firm) end-feel
- Loss of horizontal adduction (e.g., difficulty reaching across the body)
- Part of the capsular pattern treatment in adhesive capsulitis (treating the IR component)
- Joint play assessment reveals decreased posterior glide
- Common error: Directing force at an angle rather than straight posteriorly — produces a combined glide that is less effective.
- Common error: Positioning the arm in full flexion rather than 90° — the anterior capsule is slack and there is nothing to stretch.
- Posterior capsule tightness: If IR/horizontal adduction is restricted but ER is full (non-capsular pattern), consider posterior capsule tightness instead of global restriction — common in overhead athletes.
- Reassessment: Re-test IR and horizontal adduction PROM. Improvement confirms the anterior capsule was the limiting structure.
Anterior Glenohumeral Glide
Purpose: Restores external rotation. The anterior glide stretches the posterior capsule. This technique is essential for restoring ER, which is the first and most restricted movement in the GH capsular pattern. Patient position — prone:- Prone on the treatment table
- Arm hanging off the edge of the table or resting on a low stool
- Shoulder at approximately 55° abduction (resting position), elbow flexed
- A towel roll under the anterior shoulder (coracoid region) helps stabilize the scapula
- Supine with the arm at 90° abduction, elbow flexed to 90°, forearm resting on the table or supported
- The clinician reaches under the posterior proximal humerus and applies an anterior-directed force
- This position is often easier for patients who cannot tolerate prone positioning
- Stabilizing hand: Placed on the posterior scapula (spine of scapula or acromion) to prevent scapular protraction. The table supports the anterior scapula.
- Mobilizing hand: Thenar eminence or heel of the hand contacts the posterior proximal humerus, just distal to the posterior joint line. The force is directed anteriorly (toward the floor in prone).
- Apply a slow, sustained or oscillatory force directed anteriorly
- Grade I–II: Small oscillations for pain modulation — appropriate when ER is severely restricted and painful (common in early adhesive capsulitis)
- Grade III–IV: Oscillations into the anterior end-range resistance, stretching the posterior capsule. The posterior capsule should be felt as a firm barrier. Oscillate into and slightly past this barrier rhythmically.
- Same rhythm, duration, and set parameters as the inferior glide
- Decreased ER on PROM with a capsular (firm) end-feel
- First intervention in the GH capsular pattern — because ER is the most restricted movement, restoring it often has the greatest functional impact (e.g., reaching up for a seatbelt, combing hair)
- Joint play assessment reveals decreased anterior glide
- Common error: Mobilizing in the close-packed position (full abduction + ER) — locks the joint and prevents arthrokinematic motion.
- Common error (prone): Force applied to mid-shaft humerus creates rotation rather than translation — contact proximal humerus near the joint line.
- Reassessment: Re-test ER PROM. Improvement of 5-10° per session is reasonable in chronic capsular restriction.
- Integration: Perform after release of subscapularis and pectoralis minor.
Muscles Crossing This Joint
Rotator Cuff
The four rotator cuff muscles are the primary dynamic stabilizers of the GH joint. They compress the humeral head into the glenoid during all shoulder movements, providing the stability that the shallow socket cannot.- anatomy/muscles/supraspinatus — initiates abduction (first 15–30°), compresses humeral head into glenoid; most commonly injured rotator cuff muscle (subacromial impingement)
- anatomy/muscles/infraspinatus — external rotation, posterior stabilization; second most commonly torn rotator cuff muscle
- anatomy/muscles/teres-minor — external rotation (assists infraspinatus), posterior stabilization
- anatomy/muscles/subscapularis — internal rotation, anterior stabilization; the largest and strongest rotator cuff muscle; its contracture is a major contributor to adhesive capsulitis
Prime Movers
- anatomy/muscles/deltoid — anterior fibers: flexion, IR; middle fibers: abduction; posterior fibers: extension, ER
- anatomy/muscles/pectoralis-major — flexion (clavicular head), adduction, IR, horizontal adduction
- anatomy/muscles/latissimus-dorsi — extension, adduction, IR
- anatomy/muscles/teres-major — extension, adduction, IR (often called "lat's little helper")
Accessory Movers
- anatomy/muscles/biceps-brachii — long head: shoulder flexion, superior humeral head depression (dynamic stabilizer); long head tendon traverses the joint in the bicipital groove
- anatomy/muscles/triceps-brachii — long head: shoulder extension, adduction
- anatomy/muscles/coracobrachialis — flexion, adduction
Conditions Affecting This Joint
- conditions/adhesive-capsulitis — progressive capsular fibrosis following the GH capsular pattern (ER > abd > IR); the defining GH capsular pathology
- conditions/rotator-cuff-injuries — tendinopathy, partial tears, full-thickness tears of one or more cuff muscles; supraspinatus most commonly affected
- conditions/subacromial-impingement — compression of supraspinatus tendon and subacromial bursa under the coracoacromial arch during overhead movements
- conditions/shoulder-dislocation — anterior dislocation (>95% of cases) damages IGHL and labrum (Bankart lesion); associated with Hill-Sachs lesion (posterior humeral head compression fracture)
- conditions/shoulder-labral-injury — SLAP lesions (superior labrum anterior to posterior), Bankart lesions (inferior labrum), labral fraying
- conditions/osteoarthritis — less common than hip or knee OA but follows the same capsular pattern; loss of joint space and osteophyte formation
Clinical Notes
- Soft tissue health determines GH function. Without the labrum, rotator cuff, and ligamentous complex, the humeral head would fall off the shallow glenoid. This is why soft tissue pathology dominates shoulder complaints.
- Disrupted scapulohumeral rhythm is visible during AROM — the patient "shrugs" to elevate (upper trap substitution) or the scapula wings. Always observe rhythm during shoulder assessment as it indicates compensatory dysfunction beyond the GH joint.
- Why GH problems are so common. Three factors converge: (1) shallow glenoid with minimal bony support, (2) rotator cuff tendons in the narrow subacromial space vulnerable to impingement, and (3) the huge range of activities placing different demands on different structures.
- Assessment sequence for GH restriction. Determine whether the restriction follows the capsular pattern (ER > abd > IR = capsular pathology) or not (isolated painful arc at 60-120° = impingement; isolated ER loss = posterior capsule tightness in overhead athletes). This distinction drives treatment decisions.
- The inferior capsule is key. In adhesive capsulitis, the inferior capsular pouch (axillary recess) is the first and most severely affected structure, which is why inferior GH mobilization is typically the first technique applied.
Key Takeaways
- Capsular pattern ER > abduction > IR distinguishes capsular pathology from non-capsular; this single finding drives all subsequent treatment decisions.
- Convex-concave rule: convex humeral head on concave glenoid means glide is opposite to the restricted movement (restricted abduction = inferior glide; restricted ER = anterior glide; restricted IR = posterior glide).
- The IGHL is the most important stabilizer against anterior dislocation — forced abduction with ER is the classic injury mechanism producing Bankart lesions.
- Always mobilize near the resting position (55° abduction, 30° horizontal adduction, neutral rotation) — never in the close-packed position.
- Joint mobilization follows soft tissue release: address rotator cuff hypertonia and scapular muscle restrictions before performing capsular techniques.