Abdominal reflex

An abdominal reflex is a superficial neurological reflex stimulated by stroking of the abdomen around the umbilicus. It can be helpful in determining the level of lesion in a neurology case. Being a superficial reflex, it is polysynaptic.^[1]

Procedure and components

Make the subject lie down comfortably on a bed in the supine position. Uncover the abdomen and see that his abdominal muscles are well relaxed. With a blunt object gently stroke on the abdominal skin from lateral to the medial aspect in all four quadrants. Observe the contraction of the abdominal muscles resulting in deviation of umbilicus towards the area stimulated. A normal positive response usually involves a contraction of the abdominal muscles, and the umbilicus moving towards the source of the stimulation. ^[2]

Roots involved

Thoracic 7th - 12th segments are involved ^[3]

Absent abdominal reflex

Abdominal reflex is noted as either present or absent. An absent response can be physiological. Physiological absent response can be due to obesity, tolerance, children, multiparous lax abdominal wall. Pathological absence can be due to

• Multiple sclerosis
• Motor neuron disease (late)
• Neurogenic bladder
• Brown-Séquard syndrome
• Chiari malformations

^[4]

Evolutionary significance

The local contraction of the abdominal muscles to an abdominal sensory stimulus was to protect the internal viscera from damage. ^[5]

References