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Flashcards in Rectum and Anus Deck (11):
1

RECTUM
- begins in front of ____ sacral vertebra, passes downward, ends in front of the _______________
- lower dilated portion: _____________
- peritoneum covers the _________ and ________ surfaces
- in the main pelvic cavity
- ____________________: the transverse folds of rectum; semi-
lunar transverse folds of the rectal wall that protrude into the rectum
Relations:
- Anterior
-- in males: sigmoid colon, coils of ileum, urinary bladder, vas deferens, seminal vesicles, prostate
-- in females: sigmoid colon, coils of ileum, _________
- Posterior - sacrum, coccyx, coccygeus, piriformis, levator ani
Blood supply:
- superior rectal artery from __________
- middle rectal artery from ___________
- inferior rectal artery from ____________

RECTUM
- begins in front of 3rd sacral vertebra, passes downward, ends in front of the tip of the coccyx
- lower dilated portion: rectal ampulla
- peritoneum covers the anterior and lateral surfaces
- in the main pelvic cavity
- valves of Houston: the transverse folds of rectum; semi-lunar transverse folds of the rectal wall that protrude into the rectum
Relations:
- Anterior
-- in males: sigmoid colon, coils of ileum, urinary bladder, vas deferens, seminal vesicles, prostate
-- in females: sigmoid colon, coils of ileum, vagina
- Posterior - sacrum, coccyx, coccygeus, piriformis, levator ani
Blood supply:
- superior rectal artery from IMA
- middle rectal artery from internal iliac artery
- inferior rectal artery from internal pudendal artery

2

RECTAL EXAMINATION (must-know)
In both sexes:
- posterior: (2)
- lateral: (2)
Female: (5)
Male: (7)

RECTAL EXAMINATION (must-know)
In both sexes:
- posterior: sacrum, coccyx
- lateral: ischiorectal fossa, ischial spines
Female:
- perineal body
- rectouterine pouch / cul-de-sac / pouch of Douglas
- vagina, cervix
- urogenital diaphragm
Male:
- perineal body
- urogenital diaphragm
- posterior surface of bladder
- seminal vesicle
- vas deferens
- prostate
- bulb of penis

3

ANAL CANAL
- begins where the rectal ampulla narrows at the level of the U-shaped sling formed by _____________ muscle
- located in the _____________
- begins at the level of the ___________ up to the anus
- normally collapsed except during defecation
- guarded by the internal sphincter (derived from circular muscles; involuntary) and external anal sphincter (three striated voluntary muscles)
__________/_________/_________ line - indicates the junction between superior and inferior parts

ANAL CANAL
- begins where the rectal ampulla narrows at the level of the U-shaped sling formed by puborectalis muscle
- located in the perineum
- begins at the level of the puborectalis up to the anus
- normally collapsed except during defecation
- guarded by the internal sphincter (derived from circular muscles; involuntary) and external anal sphincter (three striated voluntary muscles)
Dentate/pectinate/anorectal line - indicates the junction between superior and inferior parts

4

Upper part or lower part of the anal canal?
1) derived from hind gut endoderm
2) lined by simple columnar epithelium
3) with anal columns of Morgagni
4) supplied and drained by superior rectal
5) lymphatic drainage is to inferior mesenteric LN
6) sensitive to stretch
7) sensitive to pain, temperature, touch, pressure
8) lymphatic drainage is to superficial inguinal LN

1-6) upper part
7-8) lower part

5

HEMORRHOIDS
Internal hemorrhoids
- pain____ protrusions of the anal canal covered by ________
- contain dilated veins of the ____________ venous plexus
External hemorrhoids
- pain____ enlargements covered by ________ that contain dilated veins of the ____________ venous plexus

HEMORRHOIDS
Internal hemorrhoids
- painless protrusions of the anal canal covered by mucosa
- contain dilated veins of the internal rectal venous plexus
External hemorrhoids
- painful enlargements covered by skin that contain dilated veins of the external rectal venous plexus

6

On DRE, hemorrhoids may be palpated in what locations? (3)

L lateral
R anterior
R posterior

MNEMONIC: LL-RAP

7

Hirschsprung's Disease / Congenital ____________
- results from failure of peristalsis in the aganglionic segment

Megacolon

8

Meckel's Diverticulum
- most commonly: ______ diverticulum
- persistence of remnant of ___________ forming an outpouching located on the _____________ border of the ileum
- true diverticulum that is located approximately 2 _____ from the ileocecal region, occurs in about 2% of the population, about 2 ______ long and may contain ectopic __________ or ________ cells
- bleeding associated with ulceration of the ________ cells, obstruction and pain that is referred over the area of __________ or may mimic referred pain of ___________

Meckel's Diverticulum
- most commonly: ileal diverticulum
- persistence of remnant of vitelline duct forming an outpouching located on the antimesenteric border of the ileum
- true diverticulum that is located approximately 2 feet from the ileocecal region, occurs in about 2% of the population, about 2 inches long and may contain ectopic gastric or pancreatic cells
- bleeding associated with ulceration of the ectopic cells, obstruction and pain that is referred over the area of umbilicus or may mimic referred pain of appendicitis

9

Ascending and Transverse Colons (must-know)
- receive blood from ______ and parasympathetic fibers from the ________ nerve
Descending and Sigmoid Colons
- receive blood from ______ and parasympathetic fibers from the _________________ nerve from sacral nerves _______.

Ascending and Transverse Colons (must-know)
- receive blood from SMA and parasympathetic fibers from the vagus nerve
Descending and Sigmoid Colons
- receive blood from IMA and parasympathetic fibers from the pelvic splanchnic nerve from sacral nerves S2-S4

10

NERVE SUPPLY Rules
Foregut
- PS: _________
- S: Lower thoracic splanchnic nerves from ______
Midgut
- PS: _________
- S: Lower thoracic splanchnic nerves from ______
Hindgut
- PS: Pelvic splanchnic nerves from _______
- S: Lower thoracic and lumbar splanchnic nerves from ________

NERVE SUPPLY Rules
Foregut
- PS: Vagus nerve
- S: Lower thoracic splanchnic nerves from T5-T9
Midgut
- PS: Vagus nerve
- S: Lower thoracic splanchnic nerves from T5-T12
Hindgut
- PS: Pelvic splanchnic nerves from S2-S4
- S: Lower thoracic and lumbar splanchnic nerves from T11-L2

11

Pain in the foregut derivatives is generally perceived in the ___________ region.
Midgut - ___________ region
Hindgut - ___________ region

Pain in the foregut derivatives is generally perceived in the epigastric region.
Midgut - periumbilical region
Hindgut - hypogastric region