NERVE LIBRARY · Upper limb

Posterior interosseous nerve

Posterior interosseous nerve · PIN

Finger extension weakness with preserved skin sensation. Wrist extension may remain, often with radial deviation.

Roots / nucleus
Predominantly C7–C8
Function
Motor
3D protocols
1 related protocols

01Course and sensory territory

Continuation of the deep radial branch, without a cutaneous sensory territory.

02Motor supply

EIP, EDC, ECU and thumb extensors.

03Localization clues

Finger extension weakness with preserved skin sensation. Wrist extension may remain, often with radial deviation.

04Combine the studies

Compare PIN muscles with brachioradialis, ECRL and triceps, and include non-radial C7–C8 muscles.

Explore the related 3D protocols

Radial motor to extensor indicis propriusG1 / G2 / Stimulation ↗

These retain the existing source-supported landmarks and references. The 3D model is educational; clinical work requires palpation and measured distances.

Related muscles

Extensor indicis proprius · C7–C8, predominantly C8Extensor digitorum communis · C7–C8

Connect to a clinical question

Brachial Plexopathy
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References and further reading

Educational synthesis; independent neuromuscular specialist review is pending. Publication dates and compilation dates are distinct. This is an original teaching synthesis; consult the source for complete methods and criteria.