Extensor indicis at a glance
- What it is
- A deep forearm muscle giving the index finger independent extension.
- Location
- Origin: posterior surface of the distal ulna and interosseous membrane. Insertion: extensor expansion of the index finger.
- Function
- Extends the index finger, allowing pointing.
- Body system
- Muscular · paired (left and right)
- FMA ID
- FMA38525 (Foundational Model of Anatomy)
Key facts
- Innervation: posterior interosseous nerve (C7–C8)
- Its tendon runs in the fourth dorsal compartment and lies on the ulnar side of the extensor digitorum tendon to the index finger.
Clinical relevance
Its tendon is often transferred to restore thumb extension after rupture of extensor pollicis longus.
Structures next to the extensor indicis
The nearest named structures in the 3D model, measured from the centre of each part:
- Palmar metacarpal artery · cardiovascular
- Oblique head of adductor pollicis · muscular
- Transverse head of adductor pollicis · muscular
- Flexor pollicis brevis · muscular
- Dorsal interossei of hand · muscular
- Third metacarpal bone · skeletal
- Second metacarpal bone · skeletal
- Dorsal venous network of hand · cardiovascular
- Superficial head of flexor pollicis brevis · muscular
- Deep palmar arch · cardiovascular
References
- Foundational Model of Anatomy: Extensor indicis (FMA38525). EMBL-EBI Ontology Lookup Service.
- OpenStax. Anatomy and Physiology 2e, §11.2 Naming Skeletal Muscles. Rice University, 2022.
- Mitsuhashi N. et al. (2009). BodyParts3D: 3D structure database for anatomical concepts. Nucleic Acids Research 37, D782–D785. Data © The Database Center for Life Science, CC BY 4.0.
Related anatomy
Explore the whole body in the interactive 3D human anatomy model, or browse the A–Z list of human structures.