🦴 Ulna

The ulna, one of the two bones in the forearm, has several bony landmarks near the wrist joint. These include:

Styloid Process of the Ulna
- A prominent, pointed projection at the distal end of the ulna.
- Palpable on the medial (ulnar) side of the wrist.
- Serves as an attachment point for ligaments such as the ulnar collateral ligament of the wrist.
Head of the Ulna
- The rounded, distal end of the ulna.
- Articulates with the ulnar notch of the radius to form the distal radioulnar joint.
- Easily palpable on the dorsal aspect of the wrist.

Examples

Styloid Process

Diogenes, Jean-Leon Gerome, 1860

Muscle Attachments and Actions

Attachment Type	Muscle Name	Muscle Action
Muscle Origin	Abductor Pollicis Longus	Abducts the thumb
Muscle Origin	Extensor Indicis	Extends the index finger
Muscle Origin	Flexor Carpi Ulnaris	Flexes and adducts the wrist
Muscle Origin	Flexor Digitorum Profundus	Flexes the distal phalanges of the fingers (DIP joints)
Muscle Origin	Pronator Quadratus	Pronates the forearm
Muscle Origin	Supinator	Supinates the forearm
Muscle Insertion	Anconeus	Assists in elbow extension and stabilizes the elbow joint
Muscle Insertion	Brachialis	Primary flexor of the elbow
Muscle Insertion	Triceps	Extends the elbow

Muscles That Insert on the Ulna

Anterior Compartment of Forearm

Brachialis – Inserts on the ulnar tuberosity and coronoid process.
- Function: Strong elbow flexion.
Pronator Quadratus – Inserts on the anterior distal ulna.
- Function: Pronation of the forearm.

Posterior Compartment of Forearm

Triceps Brachii – Inserts on the olecranon process of the ulna.
- Function: Primary extensor of the elbow.
Anconeus – Inserts on the lateral surface of the olecranon and proximal ulna.
- Function: Assists elbow extension and stabilizes the elbow joint.
Flexor Digitorum Profundus – Inserts on the distal phalanges of digits 2–5, but originates on the ulna.
- Function: Flexes the distal interphalangeal joints of fingers.

Would you like diagrams or more details on specific muscles?