Abos - Hand, Wrist, &forearm:neuropathies/neural Disorders/upper Extremity:anterior Interosseous Nerve Syndrome

Front 1

What is anterior interosseous nerve (AIN) syndrome?

Back 1

Anterior interosseous nerve compression
Mostly motor
Presents with pain

Front 2

In the forearm, what is the course of the AIN?

Back 2

Between the FDP and FPL

Front 3

What are the possible sites of compression?

Back 3

Pronator teres (PT)
FDP
Gantzer’s muscle (accessory head of FPL) rare

Front 4

Are the superficial flexors or deep flexors affected with AIN syndrome?

Back 4

Deep flexors

Front 5

What muscles are innervated by the AIN?

Back 5

FDP index and long
FPL
Pronator quadratus (PQ)

Front 6

How can the FDP and FPL be tested?

Back 6

Ask patient to make the "Ok" sign
with index finger and thumb
Flex thumb IP joint and flex DIP joint
of index finger

Front 7

How can the PQ be tested?

Back 7

Resisted pronation with the elbow flexed (eliminates contribution of pronator teres)

Front 8

lf the FPL is the only muscle affected, what diagnosis must be considered?

Back 8

FPL rupture (Mannerfelt-Noonan syndrome)

Front 9

lf bilateral involvement, what diagnosis must be considered?

Back 9

Parsonage-Turner syndrome

Front 10

What is the classic clinical presentation of this syndrome?

Back 10

Preceding shoulder pain followed by weakness

Front 11

What is the presumed etiology?

Back 11

Viral

Front 12

What study is helpful in the diagnosis of Parsonage-Turner syndrome?

Back 12

EMG