Bone
Ulna
Forearm bone on the little-finger side
High-yield
Triceps pulls on the olecranon to straighten the elbow. At the wrist, an articular disc separates the ulnar head from the carpal bones, so the ulna has no direct carpal articulation.
Overview
The ulna is broad near the elbow, where its trochlear notch forms the main hinge with the humerus. It narrows toward the wrist and works with the radius and interosseous membrane to support the forearm.
Reference facts
- Bone type
- A long bone on the medial side of the forearm
- Key landmarks
- Proximal olecranon, coronoid process, trochlear notch, radial notch and ulnar tuberosity; distal head and styloid
- Articulations
- Humeral trochlea at the elbow; radius at the proximal and distal radioulnar joints
Clinical correlation
A Monteggia injury combines an ulnar fracture with displacement of the radial head. Clinicians check elbow alignment when evaluating an ulnar injury because the associated dislocation can otherwise be missed.
Frequently asked questions
What type of bone is the ulna?
A long bone on the medial side of the forearm.
What does the ulna articulate with?
Humeral trochlea at the elbow; radius at the proximal and distal radioulnar joints.
What are the key landmarks of the ulna?
Proximal olecranon, coronoid process, trochlear notch, radial notch and ulnar tuberosity; distal head and styloid.