Organization of the perineum

Applied anatomy


  • Colorectal carcinoma may spread thro lymphatics or blood secondaries are more likely to be found in the inferior left vascular segment of the liver… why?

  • The malignancy may spread to involve the closely related structures e.g cervix, vagina, prostate, urinary bladder e.t.c

  • Hemorrhoids (Rectal piles): internal hemorrhoids are varicosities of the tributaries of the tributaries of the superior rectal veins are covered by mucous membrane

  • External hemorrhoids are varicosities of the tributaries of the inferior rectal veins and are covered by skin

  • As there are multiple anastomoses between the venous plexuses of the rectal veins, these communicating veins may also be  dilated

  • Hemorrhoids prolapsing through the external anal sphincter may be compressed impeding the blood supply. They consequently tend to ulcerate and strangulate

  • The cause of most hemorrhoids is not known but they constitute an important sign of possible portal hypertension e.g. in liver cirrhosis

Rectal Examination

Digital rectal examination is useful in examining nearby structures such as:

  • Prostate
  • Cervix
  • Sacrum, coccyx, ischial spine, ischial tuberosity
  • Ureter
  • Internal iliac nodes
  • Contents of recto uterine, recto vesical and ischiorectal fossae


The rectum can be examined by a rectoscope in which case its normal curvatures must be born in mind

Rectocele: Herniation of the rectus

  • Can occur in parasitic worm infestations such as Trichuris trichuria in malnourished children. In the females it  occurs when there is a weakness of the fibromuscular layer of the posterior wall of the vagina.
  • The vagina tends to bulge through the vaginal orifice with the attached wall of the rectum
    It may also occur due to weaknening from whatever cause of the pelvic diaphragm



Anorectal malformations

  • Anal atresia

  • Imperforate anus

  • Rectovaginal/ rectovesical fistulae

Fissure / Fissure in ano

  • In chronically constipated persons, the anal valves may be torn by hard fecal material and the anal mucosa may also be torn. The tear is called anal fissure. It is usually inferior to the anal valves and is very painful because this region is supplied by somatic inferior rectal nerve

Peri- anal abscess

  • It may follow infection of the anal fissure and the infection may spread to the ischio rectal fossae or into the pelvis forming ischio rectal and pelvi rectal abscesses respectively.

Anal fistulae

  • This may develop as a result of the spreas of an infection. One end of the fistulae opens into the anal cana. The other end opens into an abscess in the ischio rectal fossa or into the peri anal skin

Prolapse of the uterus

  • This condition is rare. The uterus descends to an abnormally inferior level in the pelvis and in advanced cases the cervix protrudes through the vagina and pudendal cleft. Such prolapse usually results from severe stretching or tearing of the pelvic floor during child birth.

Bi manual palpation of the uterus

  • In this procedure , two fingers of the right hand are passed high in the vagina, whule the other hand is passed inferiorly and posteriorly on the hypogastric region of the anterior abdominal wall, just superior to the pubic symphysis. The size and characteristics of the uterus can be determined this way.

Hegars sign

  • Softening of the uterus isthmus. During early pregnancy the cervix feels as though it were separate from the body of the cervix during bimanual pelvic palpation.

Gardners duct/ cyst

  • The part of the mesonephric duct which forms the ductus deferens and the ejaculatory duct in the male may persist in the female as a duct of Gardner. It lies between the layers of the broad ligament along the lateral wall of the uterus or in the wall of the vagina.. Vestigial remnants of the mesonephric ducts may also give rise to Gartners ducts cysts.

Cervical dilatation

  • The cervical os is pin hole in size especially in nulliparous ladies. During labor, the cervix softens and dilates. It is capable of thinning upto 10cm. This softening and dilatation is an indicator of the progress of labor and is determined by digital vaginal examination but can also be done per rectum


  • This is surgical removal of the uterus and it is done due to severe uterine rupture, uterine cancer or uterine fibroids.

Tubal blockage- Leading cause of female infertility.

  • Commonly due to infection e.g gonorrhoea. The patency may be determined by injecting a radio opaque dye through the uterus then seeing if it enter the peritoneal cavity by radio graphic technique. This is called hysterosalpingograpgy

Tubal ligations

  • A common method if contraception. When both tubes are ligated through minilaparatomy or vaginally, the oocytes and sperms do not meet. The sperms die and are absorbed.

Spread of infections:

  • Because the female genital tract is in direct communication with the peritoneal cavity via the abdominal ostia of the uterine tubes, infection of the vagina, uterus and tubes may result in peritonitis. Conversely inflammation of the uterine tubes, salpingitis may result from infections that spread to the peritoneal cavity.

Fluid collection in the fallopian tubes

  • Pus- pyosalpinx
  • Blood- hemosalpinx
  • Serous fluid- hydrosalpinx.

Tubal pregnancy-

the most common type of ectopic pregnancy.  The usual result is tubal rupture, hemorrhage into the abdominopelvic cavity and death of the embryo during the first 8 weeks of pregnancy.


Ovulation pain (mittelschmerz)

  • At ovulation some women experience paraumbilical pain due to stretching of the ovarian wall. As afferent impulses from the ovary reach  the  CNS at T10 the pain is referred to the T10 dermatome (of pain of appendicitis).

Ovarian cysts:

  • Are common and of varying size. They may be so large as to necessitate removal of the ovary. If both ovaries are removed. Not only is the woman for ever infertile but the source of estrogen is removed. She will definitely require hormone replacement treatment.

Prostate, Urethra and bladder

  • Because of the close relationship of the prostate to the urethra. Enlargement of the prostate  commonly obstructs the urethra by compressing it. This causes urinary retention.

Urethral rupture and urine extravasation.

  • The spongy urethra is unprotected superiorly, the wall is thin and distensible.
  • It can be torn on falling astride over objects like iron bars (straddle injuries).
  • Because it extends into the superficial perineal pouch, urine may extravasate into this space and spread around the scrotum, penis and anterior abdominal wall.

Urethral constriction


  • The external urethral orifice and Membranous  urethra are normal constrictions.
  • The external urethral orifice is the narrowest part.

Urethral curves

  • Membranous part runs inferiorly and anteriorly as it passes through  the uro genital diaphragm/
    The prostatic part is concave anteriorly as it transverses the prostate. These curves must be born in mind during urethral cathetirisation.

  • Urethral strictures: This is the narrowing of the urethra, due to scar tissue. It may result from external trauma or infection.
    The urethra can be dilated by passing instruments called sounds. The procedure is called passage of sound.

The autonomic bladder:

In spinal cord injury/ diseases, the innervation of the external bladder sphincter is absent. It will contract reflexly on filling and expel the urne. The bladder is autonomous of voluntary control.


  • This is the creation of an opening in the urinary bladder. It may be done through the anterior abdominal wall to drain the bladder in urinary retention due to urethral stricture. A catheter may be introduced through the opening to drain urine.

Urinary bladder rupture.

  • Because of the high position of the distended bladder, it may be ruptured by injuries to the inferior part of the anterior abdominal wall, or by fractured bones of the pelvis. This may  result in escape of urine extra peritoneally or intra peritoneally. The majority of the tears are extra peritoneal.

  • Rupture of the superor part of the urinary bladder frequently tears the peritoneum resulting in extravasation of urine in the peritoneal cavity.

Bladder examinations:

  • A cystoscope can be introduced into the bladder through the urethra or by the suprapubic approach.
  • A dye can also be introduced  into the bladder through the urethra or by the supra pubic approach.
  • A dye can also be introduced into the bladder and the latter viewed radiographically. The picture is called a cystogram.