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General Surgery
Large Intestine and Anorectum Embryology, Surgical Anatomy and Physiology
Built from Skandalakis' Surgical Anatomy: The Embryologic and Anatomic Basis of Modern Surgery
What’s inside
8 sections · 186 slides
Overview
- Scope of this topic
Large intestine: selected topics
- Right colon flexure syndrome
- Triangular web at the hepatic flexure
- Rectosigmoid junction as a physiologic sphincter
- Delivery of stool from sigmoid colon to rectum
- Sigmoid adaptation during fecal storage
- Pressure response to slow sigmoid distension
- Pressure response to rapid sigmoid distension
- Hypertonic rectosigmoid junction syndrome
- Aganglionosis in a rectosigmoid sphincter biopsy
- Rectosigmoid sphincter achalasia: treatment
- Sigmoidomyotomy of the rectosigmoid junction
- Electrorectogram and the rectosigmoid pacemaker
- Evidence for a rectosigmoid pacemaker
- Rectosigmoid pacemaker and rectal motility
- Mass-squeeze contraction of the rectal detrusor
- Artificial pacemaker of the rectum
- Electrosigmoidogram compared with electrorectogram
- Electrorectogram: triphasic pacesetter potentials
- Electrosigmoidogram: monophasic pacesetter potentials
- Mass action of the sigmoid colon
- Tube and marsupialization colostomy
- Tube colostomy
- Marsupialization colostomy
Anorectum: embryology and a new anatomic concept
- Rationale for re-examining the anorectum
- The rectum and its neck as one unit
- Visceral component of the anal musculature
- Coronal section of the rectal muscle coats
- Diagrammatic coronal section of the rectal muscle coats
- Somatic component and the levator tunnel
- The levator tunnel
- Interdependence of visceral and somatic components
- Intersphincteric space and rectal mobilization
- Rectal mobilization for local removal of a rectal lesion
- Development of the hindgut to the perineal skin
- Embryologic development of the lower hindgut
- Sequence of lower hindgut development
- Stimulus to proctodeal dimpling and hindgut blood supply
- Rectal neck: definition and landmarks
- New anatomic features of the rectum
- Structural-functional adaptation of the rectal neck
- Rectal neck at rest and at defecation
- Congenital rectal anomalies: a new concept of genesis
- Congenital anomalies of the rectum
Anorectal sinus, band and epithelial debris
- Anorectal sinus and paraanal space
- Histology of the anorectal sinus, band and debris
- Anorectal sinus extending to the central space
- Anorectal band in the anal submucosa
- Epithelial debris in the anal submucosa
- Fate of the sinus and its anomalies
- Lesions attributed to sinus remnants
- Perirectal suppuration and fistula
- Epithelial debris beside a fistulous track
- Perianal spaces and the origin of anorectal abscess
- Anal sphincter mechanism and the perianal spaces
- The six perianal spaces
- Spread of central space infection
- Chronic anal fissure: pathology
- Epithelial debris in the floor of a chronic anal fissure
- Epithelial debris in a chronic anal fissure at higher power
- Anorectal sinus in the floor of a chronic anal fissure
- Mechanism of fissure formation and its site
- Mechanism of fissure formation
- The two weak areas of the rectal neck
- Treatment of chronic anal fissure
- Hemorrhoids: rectal neck pressure and the fibrous band
- Fibrous band in the lower rectal neck in hemorrhoids
- Mechanism of hemorrhoid formation
- Mechanism of hemorrhoid formation
- Urethral discharge, constipation and hemorrhoids
- Treatment of hemorrhoids by bandotomy and ligation
- Anorectal bandotomy for hemorrhoids
- Steps in hemorrhoid ligation
- Pruritus ani
- Epithelial debris in the dermis in pruritus ani
Anal sphincters, continence and defecation
- Classical account of the smooth anal musculature
- Three layers of the longitudinal anal muscle
- Central tendon and its septa
- The anorectal musculature
- External anal sphincter: classical against triple loop
- Triple loop system of the external sphincter
- Fascial compartments of the three sphincter loops
- The three loops of the external anal sphincter
- Levator ani and the reassignment of puborectalis
- Levator ani as rectal neck dilator
- Internal sphincter and involuntary continence
- Sphincters at rest and during defecation
- External sphincter and voluntary continence
- Voluntary inhibition reflex
- Voluntary inhibition reflex
- Sequence of the voluntary inhibition reflex
- Voluntary mechanical action
- Stress defecation
- Mechanism of stress defecation
- Single loop continence theory
- Fallacy of the anorectal ring
- Internal sphincter in the repair of anal incontinence
- Involuntary adaptation and injectable bulking agents
Mechanism of defecation
- Muscles of defecation
- Reflexes triggered by detrusor contraction
- Voluntary puborectalis contraction and straining
- Deflation reflex
- Interrupting and terminating defecation
- Vermicular contraction of the sphincter loops
- Deflation reflex as a diagnostic tool
Levator complex and related pathology
- Levator plate: lateral masses and crura
- Levator plate: lateral masses and crura
- Patterns of crural origin
- Patterns of crural origin
- Levator tunnel: dimensions and coats
- Vesical detrusor and neck within the levator tunnel
- Levator tunnel around the rectal neck
- Suspensory sling and puborectalis as the tunnel coats
- Individual sphincters arising from the puborectalis
- Individual and common sphincters of the puborectalis
- Levator tunnel around bladder and prostate
- Puborectalis giving rise to the external urethral sphincter
- Mass contraction of the pelvic floor muscles
- Hiatal ligament, pubovesical ligament and tunnel septum
- Dilator zone of the levator plate
- Dilator action of the anococcygeal raphe
- Double sphincteric control
- Levator complex and intrahiatal fixation
- Consequences of chronic straining
- Intrinsic and extrinsic components of evacuation
- Levator contraction at stool
- Normal electrorectogram
- Intrahiatal organ mobilization and sphincter-preserving excision
- Reversion to normal defecation after end colostomy
- Strainodynia
- Four types of strainodynia
- Sphincter strainodynia
- Levator strainodynia
- Detrusor strainodynia
- Oligofecorrhea: definition and common findings
- Oligofecorrhea: the three stages
Vascular supply, rectal contents and the pudendal nerve
- Hemorrhoidal venous plexus
- Submucosal rectal venous plexus after barium injection
- Adventitial and submucosal plexus with bladder opacification
- Collecting veins of the rectal adventitia
- Portosystemic communications in the rectum
- Hemorrhoidogenital veins from rectal neck to vesical plexus
- Implications for hemorrhoidogenesis and flow direction
- Anal cystography
- Female pelvic organs opacified through hemorrhoidogenital veins
- Rectourinary syndrome and pelvic infection
- Schistosomiasis and diagnostic imaging by the venous route
- Submucosal anal injection for pelvic malignancy
- Arterial pattern of the rectum
- Two arterial patterns and the smaller rectal arteries
- Superior rectal artery and transverse rectal arteries
- Angiogram of the superior rectal artery
- Mesorectum, the bloodless line and their surgical uses
- The bloodless line and wound healing
- Rectum: conduit or storage organ
- Barium enema showing stool in the rectum
- Stool above the upper rectal valve
- Why stools remain in the rectum
- Pudendal nerve: roots, cords and course
- Course of the pudendal nerve at the sacrospinous ligament
- Roots and cords of the pudendal nerve
- Pudendal nerve with an S1 contribution
- Inferior rectal and accessory rectal nerves
- Branches of the pudendal nerve in the pudendal canal
- Pudendal canal: anatomy and adaptation
- Structural-functional adaptation of the pudendal canal
- Dissection of the pudendal canal
- Pulley action and pudendal canal syndrome
- Pudendal canal decompression
- Pudendal canal decompression: perineal approach
- Pudendal canal decompression: posterior approach
- Take-home points
- References
- References (continued)
- References (continued)
- References (continued)
- Other investigators cited in the text
- Skandalakis' Surgical Anatomy: The Embryologic and Anatomic Basis of Modern Surgery
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