There are many circumstances which a priori might lead one to regard the cremasteric reflex as an abdominal reflex at its lowest metameric level. In the first place, the contracting element, the cremasteric muscle, is justly regarded as the most caudal portion of the musculus obliquus internus abdominis, in other words, as being a portion of the muscular abdominal wall. Next, in many cases, one can from the anterior parts of its reflexogenous zone elicit a cremasteric and an abdominal reflex by the same stimulus (also the hypogastric reflex of Geigel, Dinkler, van Gehuchten and von Bechterew). Finally, these reflexes show great similarity as regards the reaction itself (a brisk, homolateral, or chiefly homolateral contraction) and the stimulus required (in most persons "stroking with a pin" is the best—often the only stimulus capable of eliciting the reflex)—both "zeitliche und örtliche Summation" being required, as Strümpell has pointed out.
MONRAD-KROHN H, KORNFELDT F. THE CREMASTERIC REFLEX IN ITS RELATION TO THE ABDOMINAL REFLEX. Arch NeurPsych. 1925;13(4):490–496. doi:10.1001/archneurpsyc.1925.02200100069004
Customize your JAMA Network experience by selecting one or more topics from the list below.