Extensor Indicis

The Extensor Indicis is a deep muscle of the posterior forearm.

Anatomical Attachments:

• Origin: Attaches to the dorsal surface of the ulnar and the interosseus membrane.
• Insertion: Attaches to the dorsum of the proximal phalanx of the index finger.

Action: Extends the index finger.

Synergist: Extensor digiti minimi, Extensor pollicis longus.

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Nerve Supply: Radial nerve (C6, C7, and C8).

Vascular supply: Posterior interosseus of the ulnar artery.

• Primary: The pain refers to the radial dorsal aspect of the wrist and hand, with no projection into the fingers.
• Satellite or associated triggers: Supinator, Brachioradialis, Extensor carpi radialis longus, Extensor carpi Ulnaris.

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Trigger Point Signs and Symptoms: Weakness of grip, stiffness and tenderness of the IP joints, cramping of fingers, soreness in the finger joints.

Trigger Point Activating and Perpetuating Factors: Repetitive forceful hand gripping, gardening, using hammers, writing for long periods, hand sewing or knitting

Differential Diagnosis: (Segmental, Subluxation, Somatic dysfunction) C5 C6 C7 or C8 radiculopathy, Carpal tunnel syndrome, Articular dysfunction, entrapment of posterior interosseus nerve, Arthritis, Bone cancer, Fracture of wrist or hand, Bursitis, Dislocation/Subluxation, Osteoarthritis, Rheumatoid Arthritis, Sprain/strain, Tendinitis, Dupuytren’s contracture, Osteoporosis, Ganglion cyst, Mixed Connective Tissue Disease, Systemic infections or inflammation, Nutritional inadequacy, Metabolic imbalance, Toxicity, Side effects of medication.

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