Upper abdominal reflexes are supplied by nerve roots T9-T11. Lower abdominal reflexes are supplied by roots T11-T12.
These reflexes can be tested by lightly stroking the abdominal wall diagonally towards the umbilicus in each of the four quadrants of the abdomen.
Reflex contractions of the abdominal wall are absent in upper motor neurone lesions above the segmental level and also in patients who have had surgical operations interrupting the nerves. They can also be absent in normal people.
Often abdominal reflexes are lost early in multiple sclerosis, but late in motor neurone disease.
Last reviewed 01/2018