Answer
The head of the humerus is the round extremity that articulates with the glenoid cavity of the scapula to form the glenohumeral joint. Just distal to the head of the humerus is an oblique groove; this is the anatomic neck of the humerus.. The greater tubercle is a lateral projection which is distal to the anatomic neck and inferior to the acromion of the scapula.; the lesser tubercle is situated similarly but projects anteriorly. Just distal to the tubercles, where the head of the humerus tapers into the shaft is a constriction; this is the surgical neck, so called because it is a frequent site of fractures of the humerus.
The projections at the proximal end of the humerus are the head, the greater tubercle and the lesser tubercle. At the distal end, the points at which the humerus articulates with the radius are the capitulum( articulates with the ulnar head); the radial fossa ( articulates with radius in flexed forearm.)
The trochlea of the humerus articulates with the trochlear notch of the ulna ; the coronoid fossa of the humerus receives the coronoid process of the ulna; the olecranon fossa of the humerus articulates with the olecranon of the ulna when the forearm is extended. Two distal humeral projections, the lateral and medial epicondyles provide points of attachment for some tendons and muscles of the forearm.
Work Step by Step
The anatomic neck of the humerus:
This is an oblique groove just distal to the anatomical head of the humerus.
The surgical neck of the humerus.
The surgical neck of the humerus is just distal to the greater and lesser tubercles, at a location where the head of the humerus tapers into the shaft--the tubercles are points of attachment for rotator cuff muscles..
At the distal end of the humerus important anatomic points that relate to the radius are capitulum and the radial fossa. Humeral sites that are in relation to the ulna are the trochlea, coronoid fossa and the olecranon fossa.
