- Discussion:
- along w/ EDC forms tunnel IV;
- Anatomy:
- origin: dorsal surface of distal half of ulna;
- insertion: index finger and EDC tendon at MCP level;
- action: extension of all phalanges of index finger;
- nerve: deep radial, C6, C7, C8;
- synergists: extensor digitorum;
- Exam: evaluated by having the patient make a fist, then extend index finger;
- Tendon Transfer:
- extensor indicis sometimes transferred surgically to replace torn EPL tendon;
- when performing tendon transfers the following are important:
- by sectioning EIP proximal to sagittal hood, one can perform tendon transfer, & also maintain independent extension of index finger;
- hazards:
- be aware that in some situations (RA) the EDC to the index finger may have ruptured, and in this case, extensor indicis transfer is contra-indicated;
- there are usually very few problems w/ extensor tendon lag if one does not tether or tighten the saggital fibers of the index finger
Independent index extension after extensor indicis proprius transfer.
Prevention of extensor lag after indicis proprius tendon transfer.
Extensor indicis proprius opponensplasty.
Independent index extension after indicis proprius transfer: excision of juncturae tendinum.