Humerus Landmarks and Features

Overview

This lecture covers the key anatomical features and landmarks of the humerus, the upper arm bone, highlighting structures important for muscle attachment and joint articulation.

Major Landmarks of the Humerus

• The humerus is the long bone of the upper arm.
• The head of the humerus is a rounded, ball-like structure that articulates with the shoulder.
• The anatomical neck is the slight constriction immediately below the head.
• The surgical neck is located just below the anatomical neck and is a common fracture site.
• The greater tubercle is a large bump lateral to the head, serving as a muscle attachment.
• The lesser tubercle is a smaller bump anterior and medial to the head.
• The deltoid tuberosity is a rough area along the shaft for deltoid muscle attachment.

Distal End Structures

• The medial epicondyle is a prominent projection on the inner (medial) side of the distal humerus.
• The lateral epicondyle is a smaller projection on the outer (lateral) side.
• The trochlea is a spool-shaped structure on the distal end, articulating with the ulna.
• The capitulum is a rounded structure next to the trochlea, articulating with the radius.

Fossae of the Humerus

• The coronoid fossa is a small depression above the trochlea on the anterior surface.
• The olecranon fossa is a larger depression on the posterior surface, above the trochlea.
• The radial fossa is a small depression above the capitulum on the anterior surface.

Key Terms & Definitions

• Humerus — long bone of the upper arm.
• Head of humerus — rounded, proximal end that fits into the shoulder socket.
• Anatomical neck — constriction directly below the humeral head.
• Surgical neck — area just below the anatomical neck; frequent fracture site.
• Greater tubercle — large, lateral bump for muscle attachment.
• Lesser tubercle — smaller, anterior bump for muscle attachment.
• Deltoid tuberosity — rough area on shaft for deltoid muscle attachment.
• Medial epicondyle — projection on the inner side of the distal humerus.
• Lateral epicondyle — projection on the outer side of the distal humerus.
• Trochlea — spool-shaped structure articulating with the ulna.
• Capitulum — rounded knob articulating with the radius.
• Coronoid fossa — anterior depression above the trochlea.
• Olecranon fossa — posterior depression above the trochlea.
• Radial fossa — anterior depression above the capitulum.

Action Items / Next Steps

• Review the labeled diagram of the humerus.
• Practice identifying these features on a model or illustration.