Joints Of Upper Extremity
The Shoulder or pectoral girdle connects the bones of the upper limb with axial skeleton. The girdle consists of clavicle and scapula. The clavicle meets the sternum at the sterno-clavicular joint and meets with the scapula at the acromioclavicular joints. The scapula has no direct connection with the axial skeleton, but is attached to the latter only by the muscles.
It is a saddle type of synovial joint. It is formed by sternal end of the clavicle and clavicular notch of manubrium sterni. The joint cavity is completely subdivided by a fibrocartilaginous articular disc which fuses with the capsule anteriorly and posteriorly.
It is a plane synovial joint. Bones forming the joint are the lateral end of the clavicle and clavicular facet on the medial
margin of the acromian process of scapula. The main bond of union is coracoclavicular ligament, which has two part, conoid (medial) and trapezoid (lateral). The weight of the upper limb is transmitted to the medial two-third of the clavicle and thence to the axial skeleton through the coraco-clavicular ligament.
Movement of the shoulder Girdle
Both acromio-clavicular and sternoclavicular joints allow gliding (translatory) and rotatory movements of scapula. The scapular gliding includes elevation, depression, protraction and retraction. The scapular rotation may be forward or backward as expressed by the movements of inferior angle of scapula.
Movements of scapula
Forward rotation of inferior angle fibers)(for overhead abduction)
Muscles causing movements
Pectoralis minor, serratus anterior
Rhomboideus minor, Trapezius
Trapezius (upper fibers), serratus anterior (lower
Levator scapulae, Rhomboideus major and minor