VIDEO
CONTENT
QUIZ
MATERIALS
Quick Facts
Key Features
Ossification
Variations
Surface Anatomy
Clinical Correlates
Quick Facts about the Ulna
- Location: Forearm
- Bone Type: Long bone
- Key Features: Head, body, olecranon, trochlear notch, radial notch, ulnar styloid process
- Articulates With: Humerus, radius
- Arterial Supply: Anterior and posterior interosseous arteries, radial artery, ulnar artery
Key Features & Anatomical Relations of the Ulna
- General Structure: The ulna is the longer of the two forearm bones.
- Classification: It is a long bone.
- Parts: Proximal part, body, distal part.
- Surfaces: Anterior, posterior, and medial surfaces, along with anterior, posterior, and interosseous borders.
- Landmarks: Head, olecranon, trochlear notch, radial notch, tuberosity of ulna, ulnar styloid process.
Location and Articulation
- Position: Proximal to the articular disc of the distal radioulnar joint, distal to the humerus, medial to the radius.
- Joints: Forms the elbow joint with the humerus, and the proximal and distal radioulnar joints with the radius.
- Carpal Relation: Does not articulate with carpal bones, separated by the articular disc of the distal radioulnar joint.
Ossification of the Ulna
- Ossification Centers: There are four main ossification centers in the ulna:
- Body: Appears around the eighth week in utero.
- Proximal Part: Has two centers, appearing between the ninth and eleventh years.
- Distal Part: Appears around the fifth to sixth years.
- Fusion: The proximal part fuses with the body by the ages of 14-18; the distal part by 17-18 years.
Variations in Ulna Anatomy
- Developmental Anomalies: Hypoplasia, or partial/complete aplasia, may occur due to interrupted growth of the ulnar epiphyses.
Surface Anatomy of the Ulna
- Palpable Points:
- Olecranon: Forms the elbow’s apex when the forearm is flexed and is subcutaneous.
- Posterior Border: Can be palpated along its entire length.
- Head: Located by palpating the medial aspect of the wrist joint.
- Ulnar Styloid Process: Notable as a large prominence on the medial, dorsal side of the wrist.
Clinical Correlates
- Ulnar fractures, such as Monteggia fractures
- Radioulnar synostosis