Prof. Dr. Shagufta Tahir Sahiwal Medical College SAHIWAL Pelvic Floor Anatomy Prof. Dr. Shagufta Tahir Sahiwal Medical College SAHIWAL

FEMALE PELVIC FLOOR The pelvis is the basin formed by muscles. The back wall is formed by the sacrum centrally & piriformis muscle laterally, the side walls are the right & left obturator internus muscles. The front wall is formed by symphysis pubis. The floor is formed by the levator ani muscles & the coccygeus muscles covering the sacrospinous ligaments.

1. Identify the bony walls and ligamentous landmarks of the pelvis. Iliopectineal Line Sacrotuberous Ligament Greater Sciatic Foramen Sacrospinous Ligament Lesser Sciatic Foramen Sacrospinous Ligament Sacrotuberous Ligament Pubic Symphysis Pubic Arch Ischial Tuberosity Sacrotuberous Ligament Pelvic Outlet Tip of Coccyx Ant. Sup. Iliac Spine Pubic symphysis Coccyx 1

Pelvic floor The priformis muscle courses from upper ½ of the sacrum straight outwards to the greater siaciatic foramen, to insert to the greater trochanter of the femur. The obturator internus muscle origintes from the bony edges of the obturator foramen and the entire inner surface of the obturator membrane to form a wide, fan shaped muscles. this muscle tappers into strong tendon, which then turns 120 degree to exit the pelvis through the lesser sciatic foramen to insert on to the greater trochanter with the piriformis tendons.

Pelvic floor The pelvic floor is also called pelvic diaphragm through which traverses urethra, the lower 1/3rd of vagina and the anal canal. These pass through levator hiatus or central opening between levator ani muscles of the pelvic diaphragm, passively resting on top of the posterior portion of the levator ani muscles named levator plates, are the upper 2/3rd of the vagina & rectum. Just below or inferior to the pelvic diaphragm is the perineum anteriorly and ischio-rectal fossa posteriorly.

Applied Anatomy Musculo-tendineous sheath that spans the pelvic outlet…. Paired levator ani Fasciae investing the muscles are continuous with visceral pelvic fascia above, perineal fascia below and obturator fascia laterally. The pelvic floor support urogenital organs & ano- rectum.

PELVIC DIAPHRAGM The floor is formed by upper surface of levator ani complex of muscles & coccygeus muscles. The coccygeus muscle is very thin, non-functional covering of strong sacro-spinous ligament. Levator ani- 3 parts, pubo-coccygeus, pubo-rectalis arise from back of the body of pubic bone anterior part of the obturator internus muscle. These muscles make levator hiatus through which urethera, lower 1/3rd of vagina and anal canal. Pubo-coccygeus surrounds lower 1/3rd of vagina & inserts in to the apex of the perineal body b/w vagina & ano-rectal junction. Pubo-rectalis is medial & inferior portion of the pubo- coccygeus muscle & meet with its counter part behind ano-rectal junction. The pubo-rectalis form right angle of the ano-rectal junction, which helps in maintenance of fecal continence.

4. Identify the pelvic diaphragm and its components Sphincter Vaginae (or Levator Prostatae) Pubic Symphysis Levator Prostatae or Sphincter Vaginae Urethra Pubic Symphysis Vagina Puborectalis Rectum Pubococcygeus Puborectalis Perineal Body Pubococcygeus Obturator Internus Coccyx Iliococcygeus Coccygeus Iliococcygeus Coccyx Coccygeus Sacrum Superior View Inferior View

Applied Anatomy of pelvic floor Supplied on superior surface by saceral nerve roots ( S2-S4), on inferior surface by the perineal branch of pudendal nerve. It has 3 parts according to its attachments ilio-coccygeus, pubo- coccygeus & ischio-coccygeus. Pubococcygeus divide in case of female into pubovaginalis & puborectalis, while in male pubouretheralis, this muscle also enclose 3 hiatus in its two arms which are urethra, vagina & rectum. Its medial part form a sling around rectum termed puborectalis,(1) it serve as part of sphincter mechanism & pelvic floor (2) its U-shaped sling pulls ano-rectal junction anteriorly towards pubis, resulting an angulation between rectum & anal canal called anorectal angle, probably this also help in maintaining continence. Anterior fibers of levator ani decend upon vagina in women termed as pubo-perineal muscle, they have been found damaged in women with urinary incontinence & pelvic organ prolapse after delivery.

Superficial perineal muscles Perineum is divided into 2 parts: urogenital triangle & anal triangle. The urogenital triangle has two layers of muscles, superficial & deep muscles, the boundry b/w two is tough perineal membrane. The superficial compartment contains tranversus perinei, bulbocavernosis & ishciocavernosis, innervated by pperineal branches of pudendal nerve. Deep compartment muscles are related to urinary incontinence, compressor urethra & urethrovaginal muscles. These muscles run over lower 1/3rd of urethra & are part of external urethral sphincter make urethrovesical junction down to perineal membrane. All of them innervated by perineal branches of pudendal nerve.

Superficial muscles showing deeper structures

Superficial muscles of pelvic floor

Applied Anatomy of pelvic floor Supplied on superior surface by saceral nerve roots ( S2-S4), on inferior surface by the perineal branch of pudendal nerve. It has 3 parts according to its attachments ilio-coccygeus, pubo- coccygeus & ischio-coccygeus. Pubococcygeus divide in case of female into pubovaginalis & puborectalis, while in male pubouretheralis, this muscle also enclose 3 hiatus in its two arms which are urethra, vagina & rectum. Its medial part form a sling around rectum termed puborectalis,(1) it serve as part of sphincter mechanism & pelvic floor (2) its U-shaped sling pulls ano-rectal junction anteriorly towards pubis, resulting an angulation between rectum & anal canal called anorectal angle, probably this also help in maintaining continence. Anterior fibers of levator ani decend upon vagina in women termed as pubo-perineal muscle, they have been found damaged in women with urinary incontinence & pelvic organ prolapse after delivery.

PERINEAL BODY Anchoring urogenital & anal triangle the perineal body is centrally located, found b/w vaginal introitus & the anus. Lower 1/3rd is fused with perineal body, while perineal body is anteriorly fused with vagina. The square based perineal body is 1 cm x 2 cm above or superior to the leval of ischial tuberosity. The apex of perineal body shapped like pyramid, is located at junction of lower 1/3rd with upper 2/3rd of the vagina with the middle one third.

2. Identify the normal position and anatomical relationships of the pelvic viscera Anteverted Anteflexed

Pelvic connective tissue support Level I : Cardinal ligaments & uterosacral ligaments. Level II ; suspend each side of vagina and rectum to the pelvic side wall. Level III: fusion of lower 1/3rd of vagina and anal canal with the pubococcygeus muscles & perineal body. Secures the vertical orientation of urethra, vagina & rectum in women while standing.

TERMINAL BRANCHES OF PUDENDAL NERVE

Anal sphincter Complex It consists of EAS & IAS separated by conjoint longitudinal coat . They form single unit but anatomically & physiologically are very distinct from each other. Surgical anal canal -4cm from verge to anorectal ring. Proximal canal lined by columnar epithelium arranged in columns called morgagni—branch of superior rectal artery supply each of them. 3 anal cushions keep continence of flatus & liquid stool- these are terminal radical of superior rectal artery & vein. The vessels are largest in the left-lateral, right-posterior & right- anterior quadrant of the anal canal. Dentate line- 2cm above verge anal valves create demarcation. Ano-derm covers 1-1.5 cm below dentate line- squamous epithelium supplied with somatic nerves.

Anatomy of EAS & IAS EAS : sub-divided into 3 parts, subcutaneous, superficial & deep. EAS is shorter anteriorly in females, deep EAS is intimate with pubo-rectalis, the sub- cutaneous part is circular may have attachment with perineal body anteriorly & ano-coccygeal ligament posteriorly. IAS: is thickened continuation of circular smooth muscles of bowel and ends with the well defined round edge 6-8 mm above the anal margins at the junction of superficial & subcutaneous part of the EAS. IAS: It is pale in appearance to naked eye.

Anal sphincter Complex It consists of EAS & IAS separated by conjoint longitudinal coat . They form single unit but anatomically & physiologically are very distinct from each other. Surgical anal canal -4cm from verge to anorectal ring. Proximal canal lined by columnar epithelium arranged in columns called morgagni—branch of superior rectal artery supply each of them. 3 anal cushions keep continence of flatus & liquid stool- these are terminal radical of superior rectal artery & vein. The vessels are largest in the left-lateral, right-posterior & right- anterior quadrant of the anal canal. Dentate line- 2cm above verge anal valves create demarcation. Ano-derm covers 1-1.5 cm below dentate line- squamous epithelium supplied with somatic nerves.

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