mass reflex

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Related to mass reflex: astereognosis

mass re·flex

in cases of gross injury to the spinal cord, as the stage of reflex activity follows the primary flaccidity of the shock, a condition arises in which a strong stimulus to any part of one of the paralyzed limbs will be followed by contraction of the hip, knee, and ankle of the same side and often, when the stimulus is applied to the middle line of the body, of both sides, as well as of the abdominal wall, and even evacuation of the bladder and sweating over an area corresponding to the level of the lesion.

mass reflex

an abnormal condition, seen in patients with transection of the spinal cord, characterized by a widespread nerve discharge. Stimulation below the level of the lesion results in flexor muscle spasms, incontinence of urine and feces, priapism, hypertension, and profuse sweating.
observations A mass reflex may be triggered by scratching or other painful stimulus to the skin, overdistension of the bladder or intestines, cold weather, prolonged sitting, or emotional stress. Muscle spasms may be so violent as to propel the patient off a bed or stretcher.
interventions Medications to reduce mass reflexes include diazepam, dantrolene, chlordiazepoxide, and meprobamate. Hubbard baths and exercises in warm water also help. Occasionally chordotomy, rhizotomy, peripheral nerve transection, or tenotomy may be necessary.
nursing considerations Nurses should avoid stimulating areas that trigger mass reflexes and should be prepared to accept them when they occur and to explain the cause to the patient. It is important to prevent decubitus ulcers and bladder infections in paraplegic and tetraplegic patients because they may also serve as triggers to initiate mass reflexes.

mass reflex

Autonomic dysfunction that may occur as a late consequence of transection of the spinal cord. It is marked by episodes of sweating, bradycardia, hypotension, urinary incontinence, and muscular spasms of the legs.
See also: reflex


1. a lump or collection of cohering particles.
2. that characteristic of matter which gives it inertia.

mass-action ratios
the ratio of substrate to product, where the predominance of one, usually the substrate, over the other thermodynamically favors a particular direction for a reaction.
inner cell mass
an internal cluster of cells at the embryonic pole of the blastocyst which develops into the body of the embryo.
lean body mass
that part of the body including all its components except neutral storage lipid; in essence, the fat-free mass of the body.
mass medication
(or immunization, or treatment, or prophylaxis, or testing, or screening) application of the procedure to all of the animals in the population, which may be as small as a herd or as large as a national herd. This sort of strategy has been used extensively and for many years in the control of diseases of animals, and has been the principal reason for the dramatic virtual eradication of the major plagues in many countries. The unintelligent extension of the strategy to the control of wastage caused by endemic disease has contributed most to the problem of residues of antibacterial drugs in the human food chain. See also mass medication.
mass number
the number used to express the mass of a nucleus, being the total number of nucleons, protons and neutrons in the nucleus of an atom or nuclide; symbol A.
mass reflex
reflex actions by all the body parts controlled by the part of the spinal cord which has been injured.
thalamic intermediate mass