Shoulder joint


A ball and socket joint.

A complex structure consisting of bony, muscular, and ligamentous structures.

Consists of a number of joints including the acroclavicular, glenohumeral, sternoclavicular, and scapulothoracic joint.

Head of the humerus is the ball and it fits into a shallow hollow in the scapula, the socket, known as the glenoid.

The ball and socket are covered by articular cartilage.

The joint is lined with a capsule that contains joint fluid.

The capsule attaches to the glenoid by the labrum, a rubbery structure, and provides stability to the shoulder during movement.

The rotator cuff tendons connect the scapula and the humerus and the muscles provide motion to the shoulder joint.

The rotator cuff agent aids in the movement of the joint and it also plays a significant role in stabilizing the glenohumeral joint.

Its movement is related to the four rotator cuff muscles, supraspinatus, infraspinatus, teres minor, and subscapularis.

The supraspinatus muscle initiates abduction.

The infraspinatus muscle initiates external rotation.

The teres minor muscle initiates external rotation and some adduction

The subscapularis initiates adduction and internal rotation.

One of the most flexible joints in the body.

The joint is highly dependent on static and dynamic stabilizers.

Static stabilizers include the bony architecture the capsuloligamentous complex and glenoid labrum.

The rotator cuff muscles provide primary dynamic stabilization to the joint.

Most common joint to dislocate.

Rotator cuff and labral tears are common injuries to the shoulder following trauma.

Arthritis and trauma can injure the smooth surfaces of the joint and lead to limited range of motion and pain.

The bursa is the area above the rotator cuff tendons but below the top bone of the shoulder, the acromion.

The bursa allows for smooth movement between the tendon and the bone.

The bursa may be inflamed with associated pain and limited range of motion.

Surgery with arthroscopy subacromial decompression is the standard treatment for impingement syndrome.

Arthroscopy surgery via a small incision evaluates the intra-articular structures and inspection of the bursa.

Via arthroscopy shoulder surgery the bursa can be removed with its inflammation and provides improved visualization.

If the coracoacromial ligament is frayed or torn, the impingement lesion, the ligament can be released from the edge of the acromion with the arthroscope and the spur in front of the acromion can be removed.

With the arthroscope the rotator cuff or labral tears can also be evaluated.

Rotator cuff injuries are common and often present with posterior and/or lateral shoulder pain, and examination includes inspection from both the anterior and posterior viewpoints.

Clinical exam includes palpation of the entire length of the clavicle from the sterno-clavicular joint to the acromio-clavicular joint, as well as for tenderness of the anterior biceps tendon.

Special exam tests for the shoulder include the apprehension test for shoulder subluxation or reduced dislocation, the Hawkins’ and/or Neer’s impingement test for rotator cuff bursitis or tendonitis, the Yergason’s and Speed’s test for long head of the biceps tendonitis, and the drop arm test for a severe rotator cuff tear.

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