Consists of supraspinatus, infrasinatus, teres minor and subscapularis.
Supraspinatus
Infraspinatus
Teres Minor
Long head of the biceps tendon:
Arises from superior glenoid labrum, supraglenoid tubercle or both
Superiorly it is flat between supraspinatus and subscapularis tendons with roof formed by coracohumeral ligament
Courses within the rotator interval
Retained from cranial to caudal by coracohumeral ligament, superior glenohumeral ligament, transverse humeral ligament and pectoralis major tendon
In proximal groove tendon is usually is seen close to medial wall of bicepital groove
Rotator cuff interval:
Triangular region with base formed is by corocoid process base, superior margin by supraspinatus and inferior margin by subscapularis with apex located at transverse humeral ligament
Coracohumeral ligament and deep capsule blend to form the roof
Biceps tendon passes through rotator cuff interval
Rotator cuff interval also houses coracohumoral logament (CHL)
Coracohumeral ligament:
Courses above biceps tendon
Bifurcates and blends with adjacent cuff tendons and joint capsule
Anterior band of liament joins superior glenohumeral ligament to form reflection pulley and inserts into lesser tuberosity; stabilizes biceps tendon before it enters bicipital groove and protects it against anterior shearing stress
US:
Best position is hand in the back pocket
Appears as thick homogeneously echogenic band covering biceps tendon superiorly; less anisotrophic
2–3 mm thick
Deep margin is seen as thin hypoechoic layer bulging anteriorly from deep edge of supraspinatus tendon
Normal appearing ligament with no fluid around biceps tendon almost always indicates intact rotator cuff interval
Transverse humeral ligament:
Distal continuity with coracohumeral ligament
Composed of most superficial fibers of subscapularis tendon
Bridges lesser and greater tuberosities, thus bicipital sulcus becomes osteofibrous tunnel
Weak ligament and hence not a stabilizer for biceps tendon
US: Thin echogenic layer over bicipital sulcus
Biceptial groove:
Normally more than 3mm deep. Less than 3mm depth predisposes to bicepital tendon instability
Covered by transverse humeral ligament and this groove becomes tunnel
Pectoralis major tendon:
Flat tendon
Stabilizes biceps tendon distally
Seen anterior to myotendinous junction
Inserts into lateral lip of intertubercular groove
References:
1. Martinoli C et al. US of the Shoulder: Non–Rotator Cuff Disorders. Radiographics. 2003;23:381-401
2. Seibold C et al. Rotator Cuff: Evaluation with US and MR Imaging. Radiographics. 1999;19:685-705
