Spry Juncture, LLC
How to Evolve Gracefully
Extensor Indicis
Region
Origin & Insertion
['Origin: Posterior distal ulna and interosseous membrane', 'Insertion: Extensor expansion of 2nd digit']
Synergistic Muscles
['Extensor digitorum']
Joints
['Wrist', 'MCP, PIP, DIP of 2nd digit']
Primary Actions
['Extends index finger', 'Assists in wrist extension']
Nerve & Spinal Segment
Radial nerve (posterior interosseous branch)
Brachial plexus; C7–C8
Interesting
Allows isolated index extension. [Gray's Anatomy]
Reversal of Action
Lift hand toward extended finger (wrist stability cue)
Common Dysfunctions
Difficulty isolating index finger extension
How to Stretch
Flex index finger and wrist downward.
Trigger Points
How to Strengthen
Isolated index finger lifts.
Concentric Action
Extend index finger
Applications:
Useful in retraining isolated finger control post-neurologic injury
Eccentric Action
Lower finger from extended to flexed
Isotonic Action
Resisted extension with rubber band or putty
Related Conditions
['Tendonitis', 'Posterior interosseous nerve syndrome']
Isometric Action
Hold finger in extended position
Exercise Ideas
['Finger lifts', 'Rubber band extension', 'Putty pinch extension']