Anatomy of Muscle Connections in Male Urethra and Anorectal Canal.

What is it about?

The study aimed to elucidate the male urethral muscular structure and its relationship with the anorectal canal muscles. Eight male cadavers were used, and a multifaceted approach was employed, including macroscopic anatomical examination, histological analysis, and 3D reconstruction. The membranous portion of the urethra had three muscle layers: longitudinal and circular muscles (smooth muscle) and the external urethral sphincter (skeletal muscle). The external urethral sphincter had a horseshoe shape, with its posterior ends continuing to the external anal sphincter, forming a 3D ring-like sphincter. The study revealed skeletal and smooth muscle connections between the male urethra and anorectal canal, enabling urethral compression and closure.

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Why is it important?

The research is important as it aims to elucidate the male urethral muscular structure and its relationship with the anorectal canal muscles. This study provides an anatomical foundation for understanding the function of the urethra and can contribute to the prevention, diagnosis, and treatment of urinary incontinence. Key Takeaways: 1. The membranous portion of the urethra has three muscle layers: the longitudinal and circular muscles (smooth muscle) and the external urethral sphincter (skeletal muscle). 2. The circular urethral muscle is continuously positioned posterior to the longitudinal muscle of the rectum. 3. The external urethral sphincter, horseshoe-shaped in cross-section, surrounds the urethra and envelops only the anterior and lateral sides, with the posterior muscle ends extending posteroinferiorly and continuously with the external anal sphincter to form large, ring-shaped structures. 4. The urethra has two sphincters for closure: the internal and external urethral sphincters.