Triceps reflex

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The triceps reflex, a deep tendon reflex, is a reflex that elicits involuntary contraction of the triceps brachii muscle. It is sensed and transmitted by the radial nerve. [1] The reflex is tested as part of the neurological examination to assess the sensory and motor pathways within the C7 and C8 spinal nerves [2] .

Contents

Testing

The test can be performed by tapping the triceps tendon [3] [note 1] 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, [note 2] and indicates a normal reflex. [4] [5]

Reflex arc

The arc involves the stretch receptors in the triceps tendon, from where the information travels along the radial nerve, through the C7/C8 nerve root to the spinal cord, and the motor signal for contraction returns through the radial nerve. [note 3]

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. [6]

Other medical problems that may cause irregular reflexes include Hyperthyroidism.

Notes

  1. ↑ A tendon is a strip or sheet of connective tissue that 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
  2. ↑ A straightening at the elbow joint) of the forearm
  3. ↑ 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 potential through a sensory neuron, and comes in contact with a motor neuron at 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.

See also

Related Research Articles

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<span class="mw-page-title-main">Somatic nervous system</span> Part of the peripheral nervous system

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<span class="mw-page-title-main">Reflex arc</span> Neural pathway which controls a reflex

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<span class="mw-page-title-main">Clonus</span> Set of involuntary and rhythmic muscular contractions and relaxations

Clonus is a set of involuntary and rhythmic muscular contractions and relaxations. Clonus is a sign of certain neurological conditions, particularly associated with upper motor neuron lesions involving descending motor pathways, and in many cases is accompanied by spasticity. Unlike small spontaneous twitches known as fasciculations, clonus causes large motions that are usually initiated by a reflex. Studies have shown clonus beat frequency to range from three to eight Hz on average, and may last a few seconds to several minutes depending on the patient’s condition.

<span class="mw-page-title-main">Patellar reflex</span> Monosynaptic reflex

The patellar reflex, also called the knee reflex or knee-jerk, is a stretch reflex which tests the L2, L3, and L4 segments of the spinal cord. Many animals, most significantly humans, have been seen to have the patellar reflex, including dogs, cats, horses, and other mammalian species.

<span class="mw-page-title-main">Triceps</span> Muscle on the back of the upper arm

The triceps, or triceps brachii, is a large muscle on the back of the upper limb of many vertebrates. It consists of 3 parts: the medial, lateral, and long head. It is the muscle principally responsible for extension of the elbow joint.

Tendon reflex may refer to:

<span class="mw-page-title-main">Vestibulospinal tract</span>

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<span class="mw-page-title-main">Stretch reflex</span>

The stretch reflex, or more accurately "muscle stretch reflex", is a muscle contraction in response to stretching within the muscle. The reflex functions to maintain the muscle at a constant length. The term deep tendon reflex is often wrongfully used by many health workers and students to refer to this reflex. "Tendons have little to do with the response, other than being responsible for mechanically transmitting the sudden stretch from the reflex hammer to the muscle spindle. In addition, some muscles with stretch reflexes have no tendons ".

<span class="mw-page-title-main">Alpha motor neuron</span>

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Hyporeflexia is the reduction or absence of normal bodily reflexes (areflexia). It can be detected through the use of a reflex hammer and is the opposite of hyperreflexia.

Biceps reflex is a reflex test that examines the function of the C5 reflex arc and the C6 reflex arc. The test is performed by using a tendon hammer to quickly depress the biceps brachii tendon as it passes through the cubital fossa. Specifically, the test activates the stretch receptors inside the biceps brachii muscle which communicates mainly with the C5 spinal nerve and partially with the C6 spinal nerve to induce a reflex contraction of the biceps muscle and jerk of the forearm.

<span class="mw-page-title-main">Mesencephalic nucleus of trigeminal nerve</span>

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The Golgi tendon reflex (also called inverse stretch reflex, autogenic inhibition, tendon reflex) is an inhibitory effect on the muscle resulting from the muscle tension stimulating Golgi tendon organs (GTO) of the muscle, and hence it is self-induced. The reflex arc is a negative feedback mechanism preventing too much tension on the muscle and tendon. When the tension is extreme, the inhibition can be so great it overcomes the excitatory effects on the muscle's alpha motoneurons causing the muscle to suddenly relax. This reflex is also called the inverse myotatic reflex, because it is the inverse of the stretch reflex.

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<span class="mw-page-title-main">Cutaneous reflex in human locomotion</span>

Cutaneous, superficial, or skin reflexes, are activated by skin receptors and play a valuable role in locomotion, providing quick responses to unexpected environmental challenges. They have been shown to be important in responses to obstacles or stumbling, in preparing for visually challenging terrain, and for assistance in making adjustments when instability is introduced. In addition to the role in normal locomotion, cutaneous reflexes are being studied for their potential in enhancing rehabilitation therapy (physiotherapy) for people with gait abnormalities.

<span class="mw-page-title-main">Upper limb neurological examination</span>

An upper limb neurological examination is part of the neurological examination, and is used to assess the motor and sensory neurons which supply the upper limbs. This assessment helps to detect any impairment of the nervous system, being used both as a screening and an investigative tool. The examination findings when combined with a detailed history of a patient, can help a doctor reach a specific or differential diagnosis. This would enable the doctor to commence treatment if a specific diagnosis has been made, or order further investigations if there are differential diagnoses.

References

  1. ↑ General Practice Notebook - UK. "Triceps (anatomy)". General Practice Notebook - UK. Retrieved September 18, 2007.
  2. ↑ Walker, H. Kenneth (1990-01-01). Walker, H. Kenneth; Hall, W. Dallas; Hurst, J. Willis (eds.). Clinical Methods: The History, Physical, and Laboratory Examinations (3rd ed.). Boston: Butterworths. ISBN   040990077X. PMID   21250237.
  3. ↑ Jane M. Orient (2009). Sapira's Art and Science of Bedside Diagnosis. Lippincott Williams & Wilkins. pp. 570–. ISBN   978-1-60547-411-3 . Retrieved 4 July 2011.
  4. ↑ H. K. Walker; W. D. Hall; J. W. Hurst (1990). "Clinical Methods: The History, Physical and Laboratory Examinations - The triceps reflex". 3rd Edition. Butterworth Publishers. Retrieved September 18, 2007.
  5. ↑ General Practice Notebook - UK. "Triceps reflex". General Practice Notebook - UK. Retrieved September 18, 2007.
  6. ↑ General Practice Notebook - UK. "Absent reflexes". General Practice Notebook - UK. Retrieved September 18, 2007.
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