Question

IN COMPLETE SENTENCES AND NOT IN A TABLE.

Highlight moments of the; Sternoclavicular joints, Acromioclavicular joints scapular and glenohumeral joint during movements of the shoulder and shoulder girdle. List out the key muscles involved, highlighting their origins and insertions as well as their contributions to the outlined movements.

Answer 1

Sternoclavicular joint- The sternoclavicular joint(synovial joint) is a gliding joint formed by the large sternal extremity of the clavicle,articulating with clavicular facet on the sternum.The sternoclavicular joint is the only articulation between the upper extremity and the axial skeleton.

Its is strenthened by three ligaments- sternoclavicular ligament,interclavicular ligament, costoclavicular ligament

Movements- Elevation, depression, transverse axis (forward and backward), longitudinal axis(rotation)

Acromioclavicular joint- it is formed by the outer end of the clavicle articulating with the acromian process of the scapula.The joint is stabilized by two sets of ligaments; the coracoacromial ligament and the coracoclavicular ligament.

Movement - Anterior and Posterior movement, rotation and tilting of the acromian during various movements of the arm.

Shoulder girdle movements- The slight gliding movements possible between the clavicle and the scapula,and the play of the scapula on the chest wall are of interest only in so far as they enhance the freedom of mpovement of the humerous at the shoulder joint.

Shoulder movements- sternoclavicular joint, acromialclavicular movement, genohumeral joint, scapulothoracic joint.

The shoulder girdle is very mobile,enabling movements like protraction,retraction,elevation,depression and rotation of the scapula.All these movements are facilitated by several muscles,namely the rhomboid major and minor,the trepezius, subclavius, pectoralis minor and levator scapulae muscles.

Glenohumeral joint - The glenohumeral joint is also called shoulder joint is a synovial joint of the ball and socket variety. The head of the humerous forming one third of a sphere articulates within the glenoid cavity or the scapula. the cavity is deepened by the attachement of a fibro cartilaginous rim,the glenoid labrum. The bones are united together by ligaments which form a very loose capsule.blood circulate in this joint by theanterior circumflexand posterior circumflex humeral vessels,suprascapular and sub scapular vessels.

Movement of the shoulder- flexion(pectorials major,deltoid muscles)

Extension which is done by deltoid,letissimus, dorsi muscles.

Adduction which is done by pectorial major,latissimus dorsi,short head od biceps brachii,long head of triceps brachii muscles.

Abduction which done by serratus anterior, trapezius muscles.

Medial rotation which is done by pectorialis majors,deltoid, letissimus dorsi, teres major muscles.