Karnataka PGET Orthopedics MCQ Answer 1

The Correct Answer is C

Carpal tunnel syndrome is related to pressure on the median nerve which is one of three important nerves that supply sensation to the hand.

As the nerve travels from the neck to the hand, it passes through a tunnel in the wrist: the carpal tunnel.

Like all nerves, the median nerve is a delicate structure. In the tunnel, the median nerve is accompanied by nine tendons, which are tough and fibrous.

The carpal tunnel has a normal resting pressure. In most of us the pressure is low. In some of us, the pressure is higher. Any activity that raises the pressure in the carpal tunnel affects the tendons and nerve. The tendons are durable and tolerate the pressure well. In contrast, the median nerve is delicate and is vulnerable to pressure changes. Even mild increases in pressure that are sustained over a prolonged period of time can result in symptoms of pain and numbness.

Nerves are like wires; they conduct electricity. If a nerve is compressed the speed of electrical conduction is slowed. In carpal tunnel syndrome, the speed of conduction of the median nerve is decreased. This delay in conduction can be measured.

Phalen’s Test
Tap anterior aspect of wrist (flexor retinaculum) with open hand supinated

Positive sign: parathesia or pain radiating into hands following median nerve distribution (palmar side of thumb, index, middle and lateral half of ring finger)

Indicates: carpal tunnel syndrome

Mechanism: action compresses further the carpal tunnel, which runs under flexor retinaculum

Adson’s Test
Patient seated with both arms externally rotated, flexed & abducted 90 degrees, opening & closing fists repeatedly for approximately 3 minutes

Positive sign: onset of symptoms (tingling and/or radicular pain in arms)

Indicates: thoracic outlet syndrome

Mechanism: action further compromises thoracic outlet and fisting creates need for more blood in arms, speeding up process

Category: Karnataka PGET 2007 MCQs