The triceps reflex, a deep tendon reflex, is a reflex as it elicits involuntary contraction of the triceps brachii muscle. It is initiated by the Cervical (of the neck region) spinal nerve 7 nerve root (the small segment of the nerve that emerges from the spinal cord). The reflex is tested as part of the neurological examination to assess the sensory and motor pathways within the C6 and C7 spinal nerves.
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Testing
The test can be performed by tapping the triceps tendon with the sharp end of a reflex hammer while the forearm is hanging loose at a right angle to the arm. A sudden contraction of the triceps muscle causes extension, and indicates a normal reflex.
Reflex arc
The arc involves the stretch receptors in the triceps tendon, from where the information travels through the C7 nerve root to the spinal cord, and the motor signal for contraction returns through the radial nerve.
Test indicators
Absence of reflex
An absence of reflex can be an indicator of several medical conditions: Myopathy, neuropathy, spondylosis, sensory nerve disease, neuritis, potential lower motor neuron lesion, or poliomyelitis.
Other medical problems that may cause irregular reflexes include Hyperthyroidism.