Anal canal & rectum Anatomy physiology

Rectum + Anal Canal Rectum Anal Canal pg 632 descends into pelvis no teniae coli longitudinal muscle layer complete rectal valves Anal Canal passes through levator ani muscle releases mucus to lubricate feces Internal anal sphincter involuntary, smooth m. External anal sphincter voluntary, skeletal m. Stratified squamosal epithelium at lower half pg 632

Perianal and Perirectal Anatomy Levator ani muscle Anorectal ring Deep external sphincter and Puborectalis muscle Anorectal ring – internal sphincter thickens and the puborectalis muslce can be palpated digitally For a distance of about 1 cm above the dentate line there is an epithelial linining may be columnar, transitional, or stratified squamous know as the transitional or the cloacogenic zone Rectal prolapse – transabdominal proctopexy Transansal via perineal rectosigmoidectomy or via a modified delorme procedure Conjoined longitudinal muscle Subcutaneous external sphincter

Defecation Reflex Stretching of rectum wall initiates reflex Spinal cord - parasympathetic signals sigmoid colon + rectum to contract + anal sphincter to relax (involuntary) If not ready-reflex ends- rectum relaxes Reflex initiated again until you go! Contraction of abdominal muscles, levator ani + diaphragm assists defecation (voluntary)

Pilonidial Disease (Nest of Hair) Aetiology: 1- Congenital Theory: 2- Acquired Theory: Sitting the buttocks take the wt…..hair broken off by friction …hair from nape of neck ,back or buttocks ….collect in the cleft of the nate . The reasons which support the Acquired T.:

The reasons which support the Acquired T.: 1- interdigital 2- age incidence. 3- no hair follicles 4- dead hair 5- most commonly affect men and hairy 6- recurrence is common

Pilonidal Disease

Pilonidal Sinus Clinical features Male >female :4 /1 Common adolescence &3rd decade White races Acute…. Painful swelling Chronic …. Discharging sinus ON exam: Chronic or recurring sinus …1st piece of coccyx Blood stained foul odour ,tuft of hair Acute exacerbation ..tender swelling Secondary opening

Differential diagnosis 1- Fistula in ano 2-post anal dermoid cyst 3-postanal dimple

Treatment Conservative treat.: - cleaning out track - frequent washing - long sitting Acute exacerbation (abscess): rest ,BSAB, bath ,drainage Operations:

Operations: Lay open tracks……suture the edge to skin Marsupial sing the sinus Excise all the Tracks and suturing with drain Excise all the Tracks and pack the wound then dressing (granulation tissue) Some injecting methylene blue Lateral incision to midline Rotational flap Bascom technique