Humerus

Function

The arm's long lever. Its ball-shaped head swivels in the glenoid for the body's most mobile joint, while its spool-shaped lower end hinges the forearm and its spiral groove spirals the radial nerve safely around the shaft.

Landmarks

• Head
• Anatomical and surgical necks
• Greater and lesser tubercles
• Intertubercular (bicipital) groove
• Deltoid tuberosity
• Spiral (radial) groove
• Medial and lateral epicondyles
• Trochlea
• Capitulum
• Olecranon and coronoid fossae

Articulations (joints)

• Scapula (shoulder joint)
• Radius and ulna (elbow joint)

Clinical relevance

Midshaft fractures risk radial nerve palsy with wrist drop; anterior shoulder dislocations tear the greater tubercle and stretch the axillary nerve. Supracondylar fractures in children threaten the brachial artery.