- Triceps reflex
The triceps reflex, a deep tendon reflex, is a reflex as it
involuntarycontraction of the triceps brachii muscle. It is initiated by the Cervical (of the neck region) spinal nerve7 nerve root (the small segment of the nerve that emerges from the spinal cord).Cite web|url=http://www.gpnotebook.co.uk/simplepage.cfm?ID=751829070|title=Triceps (anatomy)|accessyear=2007|accessmonthday=September 18|publisher=General Practice Notebook - UK|author=General Practice Notebook - UK|language=English] The reflex is tested as part of the neurological examinationto assess the sensory and motor pathways within the C7 and C8 spinal nerves.
The test is performed by tapping the
tendonA tendon is a strip or sheet of connective tissuethat transmits the force generated by the contraction of muscle to the bone by attaching with it. Thus, in simple words, a tendon attaches a muscle to a bone] with the sharp end of a reflex hammerwhile the forearmis hanging loose at a right angle to the arm. A sudden contraction of the triceps muscle causes extensionA straightening at the elbow joint) of the forearm] , and indicates a normal reflex.Cite web|url=http://www.ncbi.nlm.nih.gov/books/bv.fcgi?indexed=google&rid=cm.figgrp.1539|title=Clinical Methods: The History, Physical and Laboratory Examinations - The triceps reflex|accessyear=2007|accessmonthday=September 18|publisher=Butterworth Publishers|year=1990|author=H. K. Walker, W. D. Hall, J. W. Hurst|work=3rd Edition|language=English] Cite web|url=http://www.gpnotebook.co.uk/simplepage.cfm?ID=-825229274|title=Triceps reflex|accessyear=2007|accessmonthday=September 18|publisher=General Practice Notebook - UK|author=General Practice Notebook - UK|language=English]
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 back through the
radial nerve.A reflex arc is the path in the nervous system through which the sensory information (stimulation—sudden stretching of the triceps tendon in this case) travels to the spinal cord in form of an action potentialthrough a sensory neuron, and comes in contact with a motor neuronat a synapse, which also carries an action potential back to the muscle of origin and results in its (triceps's) contraction. Note that the contact between the sensory and motor neurons does not require immediate involvement of the brain making it involuntary, though the sensation of stretch (as the hammer hits the skin and tendon beneath) and contraction of the muscle are both sent to the brain making the subject aware of the entire testing procedure.]
* Normal: There are no problems detected.
* Absence of a reflex (areflexia): If no reflex is elicited then it is essential to try again with "reinforcement", with the patient clenching his or her teeth just as the reflex hammer strikes.
* Hyper-reflexia (a response far larger than considered normal): Indicates a potential
upper motor neuronelesion.
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 neurone lesion, or poliomyelitis.Cite web|url=http://www.gpnotebook.co.uk/simplepage.cfm?ID=-1529872361&linkID=33992&cook=no|title=Absent reflexes|accessyear=2007|accessmonthday=September 18|publisher=General Practice Notebook - UK|author=General Practice Notebook - UK|language=English]
Other medical problems that may cause irregular reflexes include
Golgi tendon organ
* [http://academic.uofs.edu/faculty/kosmahle1/courses/pt351/lab351/reflx-c7.htm Illustration of reflex testing]
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