Humerus
The humerus is the single bone of the upper arm, extending from the shoulder to the elbow. It articulates with the scapula at the shoulder and with the radius and ulna at the elbow.
Key Features
Articulations
- •Glenohumeral joint (head with glenoid) - ball and socket
- •Elbow joint (trochlea with ulna, capitulum with radius) - hinge
Muscle Attachments
Clinical Relevance
Surgical neck fractures can damage the axillary nerve (deltoid weakness). Midshaft fractures can damage the radial nerve (wrist drop). Supracondylar fractures in children can damage the brachial artery. Medial epicondyle fractures can affect the ulnar nerve.
Humerus FAQs
Common questions about this bone
The anatomical neck is the groove just below the head where the joint capsule attaches. The surgical neck is lower, between the tubercles and shaft, and is called 'surgical' because fractures commonly occur there and require surgical attention.
The radial nerve runs in the radial (spiral) groove on the posterior humerus. Midshaft humeral fractures can damage this nerve, causing wrist drop (inability to extend the wrist and fingers).
The long head of biceps tendon runs through the intertubercular groove. The groove's lips provide attachment for pectoralis major (lateral lip), latissimus dorsi and teres major (floor).
Tennis elbow (lateral epicondylitis) involves inflammation of the common extensor origin at the lateral epicondyle. Golfer's elbow (medial epicondylitis) affects the common flexor origin at the medial epicondyle.