Action. Extends the thumb by pulling it dorsally. Innervation: C7-8. The radial nerve.

The extensor indicis muscle (m. extensor indicis) arises from the distal one third of the posterior surface of the ulna. Its tendon passes with the tendons of the common extendor of the fingers through the fourth canal under the retinaculum extensorum. There it joins the ulnar side of the tendon of the common extensor passing to the index finger and is continuous with the dorsal tedninous expansion of this finger.ICD 10 Coding makes you spend more time with patients and increase the quality of the care.