Starting with movements

 Flexion 180/Extension  Abduction  Adduction  IR 70-80/ ER 80-90(at 0 and 90 degrees)

 Great ROM  Little stability  Inconsistent support from the ligaments  Increased reliance on muscular support  Many structures in a small area

 Shoulder Complex:  Sternum(manubrium)  Clavicle  Scapula  Humerus

 The Deltoid muscle is used in all side lifting movements and any movement of the humerus on the Scapula. It is divided into three portions, anterior, middle and posterior, with the fibres having different roles due to their orientation.  Actions: Anterior portion – Shoulder flexion and internal rotation. Posterior portion – Shoulder extension and external rotation. All fibres – Shoulder abduction.  Typical Use: Lifting.

 The Supraspinatus muscle is one of the four muscles which make up the rotator cuff. Its main function is to stabilize the upper arm by holding the head of the humerus in position. It is important in throwing motions to control any forward motion of the head of humerus.  Actions: Abduction. Stabilization of the humerus and shoulder joint.  Typical use: Holding shopping bags away from the body

 The Infraspinatus muscle assists the lifting of the arm while turning the arm outward (external rotation). It is the main external rotator of the shoulder joint.  It is one of the four rotator cuff muscles crossing the shoulder joint and is commonly injured.  Actions: Shoulder abduction. External rotation. Stabilizes the shoulder joint  Typical use: Brushing hair

 The Teres Major is only functional when the Rhomboids fix the scapula. This muscle mainly helps the Latissimus Dorsi.  Action:  Medially rotates and adducts arm. Stabilizes the shoulder joint.  Typical use: Tucking your shirt into the back of your jeans.

 The Teres Minor is one of the four rotator cuff muscles surrounding the shoulder. Its main action, along with the Infraspinatus is to externally rotate the shoulder joint. It assists the lifting of the arm during outward turning (external rotation) of the arm.  There are two Teres muscles, the other being Teres Major. The other muscles whose tendons form the rotator cuff are: The infraspinatus muscle, which (like the teres minor) helps in the outward turning (external rotation) of the arm. The supraspinatus muscle which is responsible for elevating the arm and moving it away from the body; and The subscapularis muscle, which moves the arm by turning it inward (internal rotation).  Actions: External rotation. Shoulder abduction and stabilizes shoulder joint.

 The Latissimus Dorsi muscle is one of the largest in the body.  It is a powerful extensor muscle of the arm and is used extensively in chinning and climbing and its basic function is to pull the shoulders downward and towards the back.  It extends from the spine, hip and ribs to the upper arm.  They are commonly known at ‘the lats’.  Actions: Extends, adducts and medially rotates arm. Helps with deep inspiration and forced expiration

 Pectoralis major is the largest and most superficial of the two chest muscles. Pec Major and the anterior fibres of Deltoid work closely together. Pec-fly and push-up exercises are good for the Pectoralis major.  Actions: Clavicular head : flexes and adducts arm. Sternal head : adducts and medially rotates arm. Accessory for inspiration.  Typical use: Applying a roll-on deodorant.

 Supraspinatus  abduction/external rotation  Infraspinatus  external rotation/horizontal abduction  Teres Minor  external rotation/horizontal abduction  Subscapularis  internal rotation

 Bursa- fluid filled sack between a tendon and a bone, consistency of a raw egg. Basically the bursa is a cushion that reduces friction.  Ligaments-a sheet or band of tough fibrous tissue that connects bones or cartilage at a joint or supports an organ, muscle, or other body part  Page 436 figure 18-3