Biceps jerk -Method of elicitation

It is a deep tendon reflex of the upper limb
Innervation  of - Biceps Jerk
C5 -5th cervical segment
Method of elicitation

• The elbow remains semiflexed at right angle with a semipronated position of the forearm. 
• The upper limb may rest on patient s abdomen or upon the examiners  left hand.
• Place your left thumb or index finger on the biceps tendon in the cubital fossa and tap suddenly over your finger. 
• Normal response -there is contraction of the biceps muscle with flexion of the elbow.

What is Paradoxical Biceps Jerk?
It is characterised by the following components

• Absent biceps
• Exaggerated triceps
• Indicate the lesion of spinal cord at  at C5 level

Indicate the lesion of spinal cord at  at С5 level in INVERSION OF BICEPS JERK (lesion at С 5 segment), there is no contraction of biceps during elicitation of biceps jerk but one can see the contraction of triceps (as C6 takes upperhand). Inversion of a jerk localises the level of lesion in the spinal cord. Usually inversion ol supinator and biceps jerks are seen together.

Nerve  involved is  Musculocutaneous nerve