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Ligaments of the Glenohumeral Joint.There are several important ligaments inthe shoulder. Ligaments are soft tissuestructures that connect bones to bones.

 A joint capsule is a watertight sac thatsurrounds a joint. In the shoulder, the joint capsule is formed by a group of ligaments that connect the humerus tothe glenoid. These ligaments are the

main source of stability for the shoulder.They help hold the shoulder in placeand keep it from dislocating. These arethe glenohumeral ligaments (GHL)

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 Another ligament links the coracoid tothe acromion - coracoacromial ligament

(CAL). This ligament can thicken andcause Impingement SyndromeLigaments attach the clavicle to theacromion in the AC joint.Two ligaments connect the clavicle to

the scapula by attaching to thecoracoid  process, a bony ridge on the scapula -coracoclavicular ligaments (CCL)Ligaments of the Shoulder Complex: y  CCL - coracoclavicular ligaments 

y  CAL - coracoacromial ligaments y  SGHL - Superior GlenoHumeral 

Ligament  

y  M GHL - M uperior GlenoHumeral Ligament  

y  I GHL - I nferior GlenoHumeral Ligament  

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 Ligaments of the Rotator Cuff The tendons of the rotator cuff are the next layer in the shoulder joint. Tendons are much likeligaments, except that tendons attach muscles to bone. Muscles move the bones by pulling onthe tendons. One important tendon that travels through the shoulder joint is the bicepstendon .The biceps tendon actually begins at the top of the shoulder socket (the glenoid) andthen passes across the front of the shoulder to connect to the biceps muscle. (The biceps is themuscle that weightlifters are always showing off).The rotator cuff tendons are a group of four tendons that connect the deepest layer of musclesto the humerus. They are the tendons of the rotator cuff muscles (left)Tendons of the shoulder: From front to back: y  Subscapularis 

y  Biceps Tendon 

y  Supraspinatus 

y  I nfraspinatus 

y  Teres M inor  

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 Muscles of the Shoulder There are 30 muscles providing movement and support for the shoulder complex. 15 musclesmove and stabilize the scapula; 9 muscles provide for glenohumeral joint motion; and 6 supportthe scapula on the thoraxThere are three important groups of muscles around the shoulder:1. Surface muscles (Extrinsic):y  The large deltoid muscle forms the outer layer of muscle. This is the largest, strongest

muscle of the shoulder. The deltoid muscle takes over lifting the arm once the arm is awayfrom the side.

y  Pectoralis Major provides movement and support in the front of the shoulder 2. Deep muscles (Intrinsic):y  The rotator cuff tendons attach to the deep rotator cuff muscles. These 4 muscles are

involved in raising the arm from the side and rotating the shoulder in the many directions.The rotator cuff mechanism also helps keep the shoulder joint stable by holding the humeralhead in the glenoid socket. These muscles are: subscapularis, supraspinatus, infraspinatusand teres minor.

3. Back Muscles (Posterior):y  These muscles are at the back of the shoulder that stabilise and move the scapula on the

trunk of the body. This group includes the trapezius, rhomboids, levator scapulae, and theserratus anterior muscles; and are concerned with stabilisation and rotation of the scapula.

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 Bursas of the Shoulder Sandwiched between the rotator cuff muscles and the outer layer of large bulky muscles is a structure known as a bursa. Bursae areeverywhere in the body. They are found wherever two body partsmove against one another and there is no joint to reduce the friction. Abursa is simply a sac between two moving surfaces that contains asmall amount of lubricating fluid.

Think of a bursa like this: If you press your hands together and slidethem against one another, you produce some friction. In fact, whenyour hands are cold you may rub them together briskly to create heatfrom the friction. Now imagine that you hold in your hands a smallplastic sack that contains a few drops of salad oil. This sack would letyour hands glide freely against each other without a great deal of friction.