THE CLAVICLE::
It is a long bone without a marrow cavity it is situated just beneath the skin at the root of the neck it acts as a weight bearing strut or brace for the shoulder and allows the arm to swing clear of the trunk this bone usually breaks at the junction of the two curves
THE HUMERUS::
It is long bone of upper limb it consists of a shaft and expanded upper and lower extremities medially the upper end bears a rounded head and forms a ball and socket joint with the glenoid cavity of the scapu laterally the upper extremity of the humerus bears a prominence called the greater tuberosity and in front of this is the lesser tuberosity the upper half of the shaft is cylindrical but the lower half is flatened protruberances from the medial and lateral borders of the lower extremity of the bone are known respectively as the medial and lateral epicondyles a pulley shaped surface at the medial portion is known as trochlea it articulates with the trochlear notch of the ulna a rounded convex projection at the lateral portion is capitulum and it articulates with the head of the radius just above the articular surface deep depressions are present both on anterior surface is the coronoid fossa into which the coronoid process of the ulna fits when the elbow is flexed and on the posterior surface is the larger olecranon fossa for the olecranon process of the ulna when elbow is extended
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