NERVE LIBRARY · Upper limb

Anterior interosseous nerve

Anterior interosseous nerve · AIN

Weak thumb IP and index DIP flexion produces a flattened tip-to-tip pinch or incomplete OK sign.

Roots / nucleus
Predominantly C8–T1
Function
Motor
3D protocols
1 related protocols

01Course and sensory territory

A deep median branch without a cutaneous sensory territory.

02Motor supply

Flexor pollicis longus, index-finger FDP and pronator quadratus.

03Localization clues

Weak thumb IP and index DIP flexion produces a flattened tip-to-tip pinch or incomplete OK sign.

04Combine the studies

Compare AIN and non-AIN median muscles with other C8–T1 muscles. History and imaging help assess neuritis or proximal fascicular lesions.

Explore the related 3D protocols

Median motorG1 / 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

Flexor pollicis longus · C8–T1Index flexor digitorum profundus · C8–T1Pronator quadratus · C8–T1

Connect to a clinical question

Localize median slowing at the wristBrachial 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.