Specialists

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Partial Thickness Rotator Cuff Tears: Treatment

It is important to understand that not all full thickness rotator cuff tears are alike, and that some complete tears are compatible with excellent function and minimal discomfort. Armed with biomechanical models, basic engineering principles, and kinematic studies of patients with known rotator cuff tears, Burkhart defined the “functional rotator cuff tear.”

His reasoning was […]

Dynamic Stability Factors

Glenohumeral stability is mainly achieved through dynamic factors. Active contraction of the rotator cuff contributes to joint stabilization by coordinated muscular activity and by secondary tightening of the ligamentous constraints. This effect works in combination with the concavity-compression mechanism, in which muscle contraction causes compression of nearly congruent articular surfaces into one another.

The rotator […]

Biomechanics of Shoulder Stability-Static Stability Factor

The glenohumeral joint is inherently unstable, with the large humeral head articulating with the small and shallow glenoid. Static stability is provided by the orientation of the articular surfaces, the articular conformity of humerus and the glenoid, the glenoid labrum, the negative intra-articular pressure, the adhesion-cohesion of synovial joint fluid, and the glenohumeral joint capsule […]

Rotator Cuff Muscles

The RTC is composed of the supraspinatus, the infraspinatus, the subscapularis, and the teres minor muscles. The tendinous portion of the supraspinatus interdigitates with the subscapularis and the infraspinatus to form a common, continuous insertion on the humeral head, enveloping approximately 75% of the GH articulation and with a mean area of insertion on the […]

Long Head of the Biceps

The long head of the biceps tendon has a variable origin, with 30% to 40% originating at the supraglenoid tubercle, 45% to 60% directly from the labrum, and 25% to 30% from both. It travels obliquely within the shoulder joint, then turns sharply to exit inferiorly beneath the transverse humeral ligament along the bicipital groove. […]

Humerus

The proximal humerus is composed of the humeral head, the lesser and greater tuberosities, the bicipital groove, and the proximal humeral shaft, and it is highly variable. The anatomical neck lies at the junction of the articular surface of the head and the greater tuberosity and humeral shaft. The surgical neck lies below the greater […]

Biomechanics

The most common mechanism of injury to the axillary nerve is closed trauma involving a traction injury to the shoulder,such as stretching of the nerve over the humeral head during an anterior shoulder dislocation. The incidence of axillary nerve injury has been reported to be between 19% and 55% following an anterior shoulder dislocation and […]

Impingement Syndrome

Impingement can be defined as a trapping of the soft tissues in the subacromial space, between the acromion and the humeral head. The entrapment of the soft tissues when moving the shoulder may lead to a painful reaction. Athletes, including tennis players, swimmers, throwers, and weightlifters, who make repetitive movements of the arms above the […]

Shoulder Instability

It is important to make a distinction between laxity and instability. Shoulder laxity is a translation of the humeral head on the glenoid (socket) in the absence of clinical symptoms or pathologic changes. This means that normal shoulders may be lax without being unstable. When the laxity results in clinical symptoms and is associated with […]

Slap Tear

SYMPTOMS

There is sharp impingement-type shoulder pain and weakness when trying to perform specific overhead activities, such as throwing a ball or serving in tennis.

AETIOLOGY

The SLAP ligament (Superior Labrum Anterior to Posterior) is the superior part of the glenoid labrum. Besides stabilising and centring the humeral head to the glenoid, it […]