Biceps jerk

Biceps Jerk is a neurological examination used to test the functionality of the biceps brachii muscle and the C5 and C6 spinal nerves. It is a type of deep tendon reflex (DTR) that is elicited by a sudden stretching of the biceps tendon.

Procedure

The biceps jerk is performed by having the patient's arm relaxed and flexed at the elbow with the palm facing upwards. The examiner then places their thumb over the biceps tendon and strikes their own thumb with a reflex hammer. The sudden stretch of the tendon should cause the biceps muscle to contract and the forearm to flex at the elbow.

Interpretation

The response to the biceps jerk can be graded on a scale from 0 to 4, with 0 indicating no response and 4 indicating a hyperactive response with clonus. A normal response is typically graded as 2. An absent or decreased response may indicate a lower motor neuron lesion, while an increased response may indicate an upper motor neuron lesion.

Clinical Significance

The biceps jerk can be used to help diagnose a variety of neurological conditions. For example, a decreased or absent biceps jerk may be seen in peripheral neuropathy, Guillain-Barré syndrome, and poliomyelitis. An increased biceps jerk may be seen in conditions such as stroke, multiple sclerosis, and spinal cord injury.

See Also

• Triceps jerk
• Brachioradialis reflex
• Patellar reflex
• Achilles reflex