bio107lab6




 * MUSCLES OF SHOULDER AND UPPER ARM AND ROTATOR CUFF**


 * __Muscle__ __Action__**


 * PECTORALIS MAJOR- flexion, a__d__duction and medial rotation at shoulder**
 * DELTOID- A__b__duction at shoulder**
 * BICEPS BRACHII- flexion at elbow and shoulder, supination**
 * TRICEPS BRACHII - extension at elbow**
 * SERRATUS ANTERIOR- protracts shoulder, a__b__ducts and medially rotates scapula (upward)**
 * (++ protraction- to move anteriorly in the horizontal plane ++)**
 * TRAPEZIUS- may elevate, depress or rotate scapula; elevate clavicle; extend or hyperextend neck**
 * EXTERNAL OBLIQUES- compress abdomen; depress ribsflexes vertebral column**




 * UPPER ARM MUSCLES**


 * ROTATOR CUFF**



The __**//Rotator Cuff// is a group of muscles that work in the shoulder joint to keep the humerus from popping out**__. This makes the //Rotator Cuff// __critical__ for shoulder stability. There are four muscles in the //**__Rotator Cuff__**:// the //**Teres Minor**,// the //**Infraspinatus**,// the //**Supraspinatus**// and the //**Subscapularis**.// The //Rotator Cuff// is one of the primary areas of shoulder trauma; when someone has a shoulder injury, chances are very good that is related to injury in the //Rotator Cuff.// This trauma can be due to sudden injury or can be from overuse in undesirable movement patterns. The upright row exercise is a prime example of this undesirable movement pattern.
 * These muscles all work together to keep tension on the humerus, locking it into the shoulder joint**.