Dissociation of the abdominal reflexes

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Superficial, or cutaneous, reflexes are responses to stimulation of either the skin or mucous membrane elicited by a superficial stimulus, such as a light touch or scratch. The superficial reflexes obtained most often are the superficial abdominals and the cremasteric. The primary utility of superficial reflexes is related to the changes that occur with corticospinal tract lesions. In addition to causing hyperreflexia, spasticity and the emergence of pathologic reflexes, corticospinal tract lesions often also cause a decrease or absence of the superficial reflexes, and absence of superficial reflexes has particular significance when associated with increased DTRs or signs of corticospinal tract disease.

There are two types of abdominal reflexes, superficial and deep. The superficial abdominal reflexes consist of contraction of the abdominal muscles elicited by a light stroke or scratch of the anterior abdominal wall that pulls the umbilicus in the direction of the stimulus.(1-3) The deep abdominal muscle stretch reflexes are elicited by pressing down slightly on the anterior abdominal wall with the fingers, then tapping with a reflex hammer, which causes reflex muscle contraction. The abdominal muscle stretch reflexes are only minimally present in normal individuals.

Dissociation of reflexes is a difference in the activity level of the DTRs and the superficial reflexes. Brisk deep abdominal reflexes with absent superficial abdominal reflexes, termed dissociation of the abdominal reflexes, suggests a corticospinal tract lesion.(4) See Video A.1 from reference 2 for a demonstration. Dissociated abdominal reflexes can provide crude localization in disorders of the thoracic spinal cord, but are less reliable than a sensory level to pin prick.(3)

The video shows dissociation of the abdominal reflexes in a patient with a mild paraparesis following an episode of transverse myelitis involving the thoracic cord.


1. Campbell WW. DeJong's the neurologic examination, 7th ed. Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins, 2013.

2. Campbell WW. Clinical signs in neurology: a compendium. Philadelphia: Wolters Kluwer Health, 2016.

3. Dick JP. The deep tendon and the abdominal reflexes. J Neurol Neurosurg Psychiatry 2003;74:150–153.

4. Lehoczky T, Fodors T. Clinical significance of the dissociation of abdominal reflexes. Neurology 1953;3:453.