Presentation on theme: "Colorectal Conference 7/21/05 Peter M. Kaye, M.D."— Presentation transcript:
1 Colorectal Conference 7/21/05 Peter M. Kaye, M.D. Pelvic Floor AnatomyColorectal Conference7/21/05Peter M. Kaye, M.D.
2 The Pelvic Floor Musculotendinous hammock or sling Termination of the pelvic outletMuscles of the pelvisAnal sphincter complexLevator ani musclesSupport the abdominal and pelvic organsConnect the pelvis to the vertebral columnMaintain continence
4 Internal Anal Sphincter Extension of the circular muscle layer of the rectumConstant maximal contraction50-85% of resting anal toneAutonomic innervationParasympathetic…..S2-4Sympathetic……..thoracolumbar ganglia (L5)Suggested that both parasympathetic and sympathetic innervation cause inhibition of contraction
5 Conjoined Longitudinal Muscle Extension of the longitudinal muscle layer of the rectum, along with levator ani muscle fibersStructural support, anchoring the anorectum to the pelvis
6 External Anal Sphincter Multiple layers of striated muscleVoluntary contractions to prevent fecal leak25-30% of resting anal toneSomatic innervation from the inferior rectal branch of the pudendal nerve (S2-3) and the perineal branch of S4
7 Levator Ani Muscles Pubococcygeus Iliococcygeus Puborectalis Ischiococcygeus
8 Puborectalis U-shaped, medial most located levator ani muscle Pulls the anorectal junction anteriorly, forming the anorectal anglePelvic floor muscle vs. sphincter muscle?
9 Functional AnatomyPuborectalis and the anorectal angle allow for gross fecal continenceRelieves pressure from the sphincter processThe sphinter complex is responsible for gas and liquid continenceDefecationRelaxation of the puborectalisContraction of the other levator muscles
10 Functional Anatomy Rectal prolapse Laxity in sphincter complex and levator muscles