The proximal epiphysis - proximal extremity or end of the humerus features the head, which forms a ball and socket-type joint with the glenoid cavity of the scapula.

Overall, the proximal epiphysis features the following anatomical landmarks:

Head - the hemispherical-shaped most proximal structure that has a smooth articular surface, which is covered with hyaline cartilage; it faces in the medial, superior, and posterior direction; the head articulates with the glenoid cavity of the scapula;
Anatomical neck - a narrowing that encircles the head; it separates the head from the greater and lesser tubercles and is a site to which attaches the capsule of the shoulder joint;
Lesser tubercle - a small and blunt eminence found anterolateral to the head; the lateral aspect of this tubercle forms the medial margin of the intertubercular sulcus; the lesser tubercle has a smooth, palpable muscular impression that serves as an insertion site for the subscapularis muscle; the lesser tubercle also is an attachment site for the transverse humeral ligament;
Greater tubercle - a large and blunt eminence that is found posterior to the lesser tubercle; the greater tubercle projects more laterally and is the most lateral part of the proximal epiphysis; the lateral aspect of the greater tubercle is covered by the deltoid muscle, which gives the shoulder its rounded shape; the greater tubercle also has several rugosities that mark attachment sites for three of four rotator cuff muscles (supraspinatus muscle, infraspinatus muscle, and teres minor muscle); the lateral aspect of the greater tubercle also has several vascular foramina; and finally, this landmark also serves as an attachment site for the transverse humeral ligament;

Intertubercular sulcus (bicipital groove) - a deep groove that extends longitudinally down the proximal epiphysis; it starts between both tubercles separating them; the bicipital groove lodges the tendon of the long head of the biceps brachii and the ascending branch of the anterior circumflex humeral artery; additionally, the transverse humeral ligament stretches over the groove at its proximal aspect, forming a canal; this sulcus is limited by the lateral and medial lips:
- Crest of the lesser tubercle - a relatively sharp ridge that extends from the lesser tubercle and forms the medial lip of the intertubercular sulcus; it serves as an attachment site for the teres major muscle and latissimus dorsi muscle;
- Crest of the greater tubercle - also a relatively sharp ridge that extends from the greater tubercle and forms the lateral lip of the intertubercular sulcus; it gives attachment to the tendon of the pectoralis major muscle;
Surgical neck - a short and narrow segment right below the tubercles; it links the head with the shaft and is also the structure that marks the end of the proximal extremity; the surgical neck is a common fracture site; in close proximity to the surgical neck goes the axillary nerve and the anterior circumflex humeral artery and posterior circumflex humeral artery (branches of the axillary artery), meaning that they can get damaged during injuries.

Note: 3D model displays the left humerus.

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Humerus (proximal epiphysis)