Applied Anatomy of Bulbospongiosus Muscle: a Narrative Review

This review aims to provide a comprehensive analysis of the anatomy of the bulbospongiosus muscle (BSM) in males, highlighting its morphological features, anatomical variations, and clinical implications in ejaculatory process and urethral surgery. We analyzed papers published in the past 70 years in the databases of Pubmed, Embase and Scielo. We excluded case reports, editorials and opinions of specialists. Studies were excluded if they lacked clear anatomical descriptions of the BSM, if full-text access was unavailable, or if they were published in languages other than Portuguese, English, or Spanish. The BSM is part of the superficial muscular layer of the perineum The perineal arteries provide vascular supply to BSM and, toward the end of their path, give rise to several posterior scrotal branches that supply the skin and dartos muscle of the scrotum. The deep branch of pudendal nerve is primarily muscular and innervates the superficial transverse perineal, bulbospongiosus, ischiocavernosus, deep transverse perineal, and sphincter muscles of the membranous portion of the urethra. This revision concluded that the BSM is a paired skeletal striated muscle that originates from the perineal body enveloping the bulbar portion of the urethra. Stimulation of the dorsal nerve of the penis leads to BSM contraction that provides an indication of anatomic sacral nerve pathway integrity. BSM has some important clinical applications. The bulbar urethral stricture causes minimal alterations in the structure of the BSM during the surgical procedure and the BSM is highly sensitive to androgen and could be used in common androgenic activity evaluation.