Human cremaster muscle and cremasteric reflex: A comprehensive review. Issue 6 (June 2020)

• Record Type: Journal Article
• Authors: Sengul, Gulgun; Ertekin, Cumhur
• Is Part Of: Clinical neurophysiology. Volume 131:Issue 6(2020:Jun.)
• Page Start: 1354
• Page End: 1364
• Publication Date: 2020-06
• Subjects: Cremaster muscle -- Cremasteric reflex -- Electrophysiology -- EMG -- Genitofemoral nerve; Neurophysiology -- Periodicals; Electroencephalography -- Periodicals; Electromyography -- Periodicals; Neurology -- Periodicals; 612.8
• DOI: 10.1016/j.clinph.2020.03.011
• Languages: English
• ISSNs: 1388-2457

Abstract

Highlights: Genitofemoral nerve motor conduction time and cremasteric reflex are useful for assessment of inguinal hernia complications. Transcranial magnetic stimulation elicits a descending motor response in the cremaster muscle (CM), although its voluntary control is not essential. Sacrolumbar intersegmental reflex circuit and CM activity are useful for evaluating ejaculatory dysfunction. Abstract: Objective: Human research on the cremaster muscle (CM), cremasteric reflex (CMR) and genitofemoral nerve (GFN) and reports on their clinical applications using electrophysiological and histological techniques are rare. We aimed to present a detailed review of the human CM and CMR based on our earlier publications and relevant literature. Methods: Electromyography (EMG) of the CM was recorded using disposable needle electrodes. CMR was obtained with tactile and/or electrical stimulation of the inner thigh. Transcranial magnetic stimulation (TMS) and magnetic stimulation of the upper lumbar roots were applied; GFN was stimulated using a surface electrode at the anterior superior iliac spine. Results: CM striated fibers comprised multiple motor end plates. CM needle EMG results were similar to those of the limb muscles in chronic neurogenic disorders. TMS produced clear-cut evoked motor responses from CM. GFN motor conduction time to CM was absent or delayed in patients with inguinal hernia. EMG of CM was abnormal in 40% of patients with premature ejaculation. Conclusion: CM is different from other skeletal muscles both morphologically and physiologically. Intersegmental sacrolumbar reflexes are useful for evaluating ejaculatory dysfunction. Significance: CM is an important muscle for testis thermoregulation and sexual reflexes. Neurophysiological techniques are available for physiological and clinical studies.