Supinator
From Ganfyd
| Supinator | |
|---|---|
 | |
| System: | Muscle |
| Function: | Supination of the forearm |
| Origin: | Supinator crest and supinator fossa of the ulna, lateral epicondyle of humerus, radial collateral ligament of the elbow, annular ligament |
| Branches: | |
| Insertion: | Anterior, lateral and posterior surfaces of neck and shaft of radius |
| Arterial supply: | |
| Venous drainage: | |
| Lymphatic drainage: | |
| Innervation: | Posterior interosseous nerve (C5, C6) |
| Vertebral levels: | |
| Search for Supinator in Gray's. | |
Supinator is a broad muscle that acts as the major supinator of the forearm.
Contents |
Shape
Supinator is broad and curves deeply around the proximal third of the radius. It consists of two heads, which form two sheets of fibres with different origins and insertions. The posterior interosseous nerve lies between the two heads.
Humeral (superficial) head
Originating from tendinous fibres from the lateral epicondyle of the humerus, radial collateral ligament and annular ligament, the superficial humeral head of supinator surrounds the upper part of the radius, inserting into the lateral edge of the radial tuberosity and oblique line of the radius, as far distal as the insertion of pronator teres.
Ulnar (deep) head
Originating from muscular attachments to the supinator crest and supinator fossa of the ulna, the deep ulnar head of supinator form a 'sling' around the neck of radius above the tuberosity, attaching to the posteromedial surface and inserting into the posterior and lateral surfaces of radius.
Actions
- Supination of the forearm
Joints Affected
Origin
Humeral head:
- Lateral epicondyle of humerus
- Radial collateral ligament of the elbow
- Annular ligament
Ulnar head:
Insertion
Humeral head:
Ulnar head:
- Lateral and medial neck and shaft of radius
Nerve Supply
Relations
- The posterior interosseous nerve runs between the two heads.
Clinical Relevance
- Forms the base of the cubital fossa
Variations
- The two heads are not always distinguishable at origin or insertion, often arising from or inserting into the same areas. The feature of two layers of fibres remains largely constant.
