a. Head (Caput humeri) is a large, rounded, prominence that extends medially from the bone's proximal end. It articulates with the glenoid fossa of the scapula to form the glenohumeral joint or shoulder joint.
b. Greater Tubercle (Tuberculum majus) is a large, roughened area located lateral to the head. The supraspinatus, infraspinatus and teres minor muscles attach to this elevation.
c. Lesser Tubercle (Tuberculum minus) is a roughened area located medial to the greater tubercle. It serves as the insertion site for the subscapularis muscle.
d. Intertubercular Groove or Sulcus (Sulcus inter-tubercularis) is a narrow, longitudinal depression between the greater and lesser tubercles. This indentation, which is also called the bicipital groove, is a passageway for the tendon of the long head of the biceps brachii. The pectoralis major, teres major and latissimus dorsi muscles also attach here.
e. Anatomical Neck (Collum anatomicum) is a grooved constriction between the head and tubercles that serves as an attachment point for the articular (joint) capsule.
f. Surgical Neck (Collum chirurgicum humeri) is an region inferior to the tubercles where the bone narrows and fractures often occur.
g. Shaft or Body (corpus humeri) is the elongagted, cylinder shaped middle portion of the bone. Its relatively smooth surface is the insertion point for muscles that move the upper arm and the origin point for muscles that move the lower arm.
h. Deltoid Tuberosity (Tuberositas deltoidea) is a raised, roughened area located on the lateral side of the shaft at its midpoint. It is an attachment point for the deltoid muscle.
i. Lateral Epicondyle (Epicondylus lateralis) is a rounded projection at the distolateral end of the humerus. The posterior surface of the lateral epicondyle serves as an attachment point for some of the muscles that extend the wrist and fingers of the hand.
j. Supracondylar Ridge (Crista supracondylaris lateralis) is the roughened margin located above the lateral epicondyle. The brachioradialis muscle attaches along this edge of the bone.
k. Medial Epicondyle (Epicondylus medialis) is a rounded projection at the distomedial end of the humerus. Some of the muscles that flex the forearm, wrist, and fingers attach to anterior surface of this marking.
l. Capitulum (Capitulum humeri) is a small, knob-like prominence on the distolateral end of the humerus. It articulates with the head of the radius bone at the elbow joint.
m. Trochlea (Trochlea humeri) is a pulley-shaped formation located medial to the capitulum. This region articulates with the trochlear notch of the ulna bone at the elbow joint.
n. Coronoid Fossa (Fossa coronoidea) is a depression located superior to the anterior aspect of the trochlea. This region provides space for the coronoid process of the ulna when the forearm is flexed.
o. Radial Notch (Fossa radialis) is a small depression located superior to the capitulum. This region provides space for the head of the radius when the forearm is flexed.