Functional anatomy of the female pelvic floor and lower urinary tract Stefano Floris, MD, PhD Department of Obstetrics and Gynaecology Ospedale San Giovanni di Dio, Gorizia, Italy
ANATOMY URINARY CONTINENCE FUNCTION PELVIC ORGAN SUPPORT
Pelvic floor composition peritoneum viscera endopelvic fascia levator ani muscles perineal membrane external genital muscles
Key structures -Endopelvic Fascia -Pelvic Diaphragm -Urogenital Diaphragm -Obturator foramen -Sacrospinous ligament -Urethra Key considerations -Overall structure and function of pelvic floor -The vaginal-uterine axis -Circumferential support of vagina and uterus -Anterior vaginal and urethral support
Pelvic Bones 3-D Pubic symphysis Sacrum
Pelvic Bones 3-D Oerlich 1983
Pelvic Bones Pubocoxygeal muscle Ileocoxygeal muscle
Bone Ligaments
Pelvic floor supports pubic symphysis urethra pubourethral lig. vagina & uterus cardinal lig. uterosacral lig. rectum sacrum
Viscero-fascial layer - Combination of pelvic viscera and endopelvic fascia - Attaches and suspends the pelvic organs to the pelvis wall (Ricci and Thom 1954; Ulhenhuts and Nolley 1957; De Lancey 1992) - Continous sheet-like mesentery - Parametrium and paracolpium - Ligaments and fascia : supportive structures with prominent blood vessels, nerves and fibrous tissue
Viscero-fascial layer support lateral Level I Level II fusion Levator ani 12
NORMAL VAGINAL AXIS AND THREE LEVELS OF SUPPORT OF UTERUS AND VAGINA
Normal vaginal axis (axes!!)
Possible defects in POP urethra Lateral defect anterior vaginal wall Transverse defect vaginal vault Central defect posterior vaginal wall anus
Pelvic Organ Prolapse
2D Pelvic Floor Muscles - superior view
The pelvic floor muscles
The puborectalis muscle (inferior fibres of pubococcygeus)
The puborectalis muscle
Muscular components of pubococcygeus muscle Large diameter slow twitch type I fibers predominant- provide static visceral support Fast twitch type II fibers-assists in active closure of pelvic visceral organs 40% of women have lost function or coordination of this muscle
3-D Pelvic Floor Muscles - superior view
Pelvic Floor Muscles - 3D lateral and posterior view
Anatomic variations of the pelvic floor nerves adjacent to the sacrospinous ligament
Levator ani nerve Takeyama et al. Int Urogynecol J 2008
Levator ani nerve and the inserted mesh The levator ani nerve forms a common trunk with pelvic splanchnic nerve and crosses the inside of sacrospinous ligament, whereas the pudendal nerve runs to the outside of the sacrospinous ligament Takeyama et al. Int Urogynecol J 2008
Pelvic Floor Muscles Obturator muscle
Innervation of the levator ani muscles Grigorescu et al. Int Urogynecol J 2008
Sacrospinous ligament and coccygeal muscle Coccygeal muscle Oerlich 1983
Perineal membrane and external genital muscles 2-D Superficial muscular layer 3-D Superficial muscular layer ischiocavernosus Trasverse superficial perineal muscle bulbospongiosus
Obturator nerve and artery (internal view)
Obturator nerve
Striated urogenital sphincter muscle DeLancey 2003
Urethral and para-urethral muscles Oerlich 1983
Topography of urethral and para-urethral structures APPROXIMATE LOCATION (%) REGION OF URETHRA PARA-URETHRAL STRUCTURES 0-20 INTRAMURAL URETHRAL LUMEN TRAVERSES THE BLADDER WALL 20-60 MID-URETHRA SPHINCTER URETHRAE MUSCLE PUBOVESICAL MUSCLE 60-80 PERINEAL MEMBRANE VAGINO-LEVATOR ATTACHMENT COMPRESSOR URETHRAE MUSCLE URETHROVAGINAL SPHINCTER MUSCLE 80-100 DISTAL URETHRA BULBOCAVERNOSUS MUSCLE DeLancey JOL Obstet Gynecol1986
PREMENOPAUSE From Hollihn KU, 1997 POSTMENOPAUSE
Ultrasound in urogynaecology Urethral lumen Circular striated muscle Urethral mucosa
Lower Urinary Tract Innervation Pelvic Nerve (Parasympathetic) Hypogastric Nerve (Sympathetic) ACh NE +M 3 - β 3 +α 1 +N Pudendal Nerve (Somatic) ACh
Bladder filling and urine storage require: Accomodation of increasing volumes of urine at a low intravesical pressure and with appropriate sensation A bladder outlet that is closed at rest and remains so during increases in intraabdominal pressure Absence of involuntary bladder contractions (detrusor overactivity or hyperreflexia)
Bladder emptying requires A coordinated contraction by the bladder smooth musculature of adequate magnitude and duration Concomitant lowering of resistance at the level of the smooth sphincter and of the striated sphincter Absence of anatomic obstruction
Role of Norepinephrine and Serotonin Depression-Pain Perception Dysregulation of NE and 5-HT is strongly associated with depression 1 NE and 5-HT also modulate pain sensitivity through their presence in the descending pain pathway 2,3 NE and 5-HT play a central role in lower urinary tract function 4 NeuroUrology 1. Fields H. Neuropsychiatry Neuropsychol Behav Neurol. 1991;4(1):83-92. 2. Verma S, Gallagher RM. Int Rev Psychiatry. 2000;12(2):103-114. 3. Blier P, Abbott FV. J Psychiatry Neurosci. 2001;26(1):37-43. 4. Thor KB, Katofiasc MA. J Pharmacol Exp Ther. 1995;274(2):1014-1024.
Serotonin and norepinephrine are involved in the functioning of the lower urinary tract Stress Urinary Incontinence (SUI) Sacral spinal cord Smooth bladder muscle Serotonin and norepinephrine work centrally and play key roles in lower urinary tract function including contraction of the striated urethral sphincter 1 Pudendal Nerve Striated urethral sphincter muscle Urge Urinary Incontinence 2 Anticholinergic agents work peripherally on the bladder to treat urge urinary incontinence/oab 2 1. degroat WC. Basic neurophysiology and neuropharmacology. In: Abrams P, et al, eds. Incontinence. Health Publishing Ltd.; 1999:105-154. 2. Kreder D, et al. Eur Urol. 2002;41:588-595.
Space of Retzius (drawn from cadaver dissection) DeLancey JOL 1989
Space of Retzius (photo of cadaver dissection) Ashton-Miller et al. Scand J Urol Nephrol Suppl. 2005
Relationship of the supportive tissues of the urethra DeLancey JOL. Neurourol Urodyn 1989
Urethropelvic ligament P U Pubourethral urethropelvic
PUBOURETHRAL LIGAMENT Pubis P bladder U Pubourethral
THE HAMMOCK HYPOTHESIS DeLancey JOL. Am J Obstet Gynecol 1994
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