What is AIN palsy?

What is AIN palsy?

Anterior Interosseous nerve (AIN) syndrome is a rare syndrome that comprises less than 1% of all upper extremity nerve palsies, arising due to compression or inflammation of the AIN of the forearm. The AIN is purely a motor branch of the median nerve that arises from its dorsomedial aspect, just inferior to the elbow.

What does the AIN nerve do?

Anterior Interosseous Nerve Syndrome. The AIN, a main branch of the median nerve, supplies motor function to the FPL, FDP of the index and middle fingers, and pronator quadratus muscles.

How is median nerve palsy treated?

Patients may be prescribed anti-inflammatory drugs, Physical or Occupational therapy, splints for the elbow and wrists, and corticosteroid injections as well. This is the most common treatment for CTS. Especially involving compression at the wrist, such as in CTS, it is possible to recover without treatment.

Where does AIN nerve come from?

Spinal nerves emerge from the spinal cord through spaces between the vertebrae. Each nerve emerges as two short branches (called spinal nerve roots): one at the front of the spinal cord and one at the back. Motor nerve root (anterior nerve root): The motor root emerges from the front of the spinal cord.

How do you test for an AIN nerve?

On a physical examination, the patient will show weakness of the FLP and FDP to the index finger with a positive Pinch Grip test (Froment’s sign); rather than making the “OK” sign, the patient will clap the sheet between the index finger and an extended thumb.

Does AIN go through carpal tunnel?

It passes distally, anteriorly along the interosseous membrane and innervates flexor pollicis longus, flexor digitorum profundus to index and middle finger as well as pronator quadratus, and supplies sensory feedback from the wrist bones, i.e. the carpal tunnel, not skin.

What causes anterior interosseous syndrome?

The exact pathophysiology can occur secondary to primary entrapment, direct trauma, or in more ambiguous or vague clinical presentations, the condition manifests following vial neuritis. Very similar syndromes can be caused by more proximal lesions, such as brachial plexus neuritis.

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