Overview
This lecture covers the anatomy of the humerus bone, highlighting its major landmarks and features relevant for muscle attachment and articulation.
Main Features of the Humerus
- The humerus is the long bone of the upper arm, located below the shoulder.
- The head of the humerus is a rounded, ball-like structure at the proximal end.
- The anatomical neck is the narrow area just below the head of the humerus.
- The surgical neck is below the anatomical neck and is a common fracture site.
- The greater tubercle is a large bump on the lateral side of the humerus, near the head.
- The lesser tubercle is a smaller bump, located more medially and anteriorly.
- The deltoid tuberosity is a rough, raised area mid-shaft for deltoid muscle attachment.
Distal Humerus Features
- 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 humeral head always faces medially, helping identify left from right.
- The trochlea is a spool-shaped structure on the distal humerus that articulates with the ulna.
- The capitulum is a rounded knob on the distal humerus, articulating with the radius.
- The coronoid fossa is a small depression above the trochlea, receiving the coronoid process of the ulna when the elbow is flexed.
- The olecranon fossa is a large depression on the posterior distal humerus for the olecranon process of the ulna.
- The radial fossa is a small depression above the capitulum, receiving the head of the radius during elbow flexion.
Key Terms & Definitions
- Humerus — upper arm bone extending from shoulder to elbow.
- Head — rounded proximal end articulating with the shoulder.
- Anatomical neck — constricted area just below the humeral head.
- Surgical neck — narrow region below the anatomical neck; prone to fractures.
- Greater tubercle — large lateral bump for muscle attachment.
- Lesser tubercle — smaller, medial bump for muscle attachment.
- Deltoid tuberosity — mid-shaft rough area for deltoid muscle attachment.
- Medial epicondyle — inner distal prominence for forearm muscle attachment.
- Lateral epicondyle — outer distal prominence for muscle attachment.
- Trochlea — spool-shaped structure articulating with the ulna.
- Capitulum — rounded knob articulating with the radius.
- Coronoid fossa — anterior depression for the ulna's coronoid process.
- Olecranon fossa — posterior depression for the ulna's olecranon process.
- Radial fossa — anterior depression for the head of the radius.
Action Items / Next Steps
- Review labeled diagrams of the humerus to reinforce identification of key landmarks.
- Practice identifying humerus features on physical or virtual bone models.