TBL 21 Flashcards

1
Q

What separates the abdominal cavity from the bony pelvis?

A

iliac crest

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2
Q

What is the bony pelvis subdivided into?

A

It is subdivided by the pelvic brim into the greater pelvis (which is occupied by the inferior abdominal viscera) and lesser pelvis

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3
Q

What is the pelvic brim?

A

It is the bony edge surrounding the pelvic inlet that opens into the lesser pelvic cavity

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4
Q

What distinguishes the pelvic cavity?

A

It is continuous with the greater pelvis and abdominal cavity but is angulated posteriorly from them.

It is bound by the hip bones, sacrum and coccyx.

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5
Q

What does the pelvic diaphragm form?

A

It forms the bowl-like floor of the cavity.

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6
Q

What does the piriformis muscle do?

A

It traverses the greater sciatic foramen to its distal attachment on the femur. It attaches proximally to the pelvic surface of vertebrae S2-S4.

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7
Q

What does the obturator internus muscle do?

A

It pads the lateral wall of the pelvic cavity

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8
Q

What is the tendinous arch formed by the obturator internus fascia used for?

A

It provides lateral attachment site for the levator ani, the broad muscular sheet forming most of the pelvic diaphragm

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9
Q

What is the pubococcygeus muscle?

A

It is the intermediate part of the levator ani. It attaches anteriorly to the body of the pubis and the tendinous arch.

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10
Q

What is the puborectalis muscle?

A

It is the medial part of the levator ani and it forms the puborectal sling.

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11
Q

What is the urogenital hiatus?

A

It is an anterior gap between the medial borders of the puborectalis for passage of the urethra and in females the vagina.

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12
Q

What is the iliococcygeus?

A

It forms the posterolateral part of the levator ani.

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13
Q

What happens to the levator ani muscles before they attach to the coccyx?

A

the merge posteriorly.

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14
Q

What is the levator ani controlled by?

A

voluntarily controlled by the spinal nerve S4

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15
Q

Why is the levator ani tonically contracted and when must it relax?

A

Its tonic contraction bends the anorectum anteriorly. The levator ani must relax to allow urination and defecation.

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16
Q

Which levator ani muscles are most commonly torn during childbirth and what are the consequences?

A

The pubococcygeus and puborectalis, the main and most medial parts of the levator ani are the most commonly torn muscles during childbirth. Weakening of the levator ani from tearing during childbirth may decrease support for the vagina, bladder, uterus or rectum. It can also alter the position of the neck of the bladder and the urethra.

This may cause urinary stress incontinence which is characterized by dribbling of urine when intra-abdominal pressure is raised during coughing or lifting.

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17
Q

What does the coccygeus msucle do?

A

It attaches to the deep surface of sacrospinous ligament and provides minor assistance to the levator ani in supporting the pelvic viscera.

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18
Q

What covers the obturator internus and levator ani muscles?

A

fibrous parietal pelvic fascia

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19
Q

What does adventitia of the pelvic organs do?

A

It constitutes the visceral pelvic fascia.

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20
Q

What happens to the space between the parietal and visceral pelvic fasciae?

A

Loose connective tissue fills the space but eventually they become continuous where organs penetrate the levator ani.

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21
Q

What suspends organs from the lateral walls of the pelvic cavity?

A

parietal fascia derived lateral ligaments of the bladder and rectum

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22
Q

What does the cardinal ligament do?

A

It suspends the uterine cervix and vagina from the lateral walls of the cavity.

It provides passage to vessels and periarterial nerve plexuses from the lateral walls of the pelvic cavity to the pelvic viscera

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23
Q

What are some branches of the internal iliac artery? What does the internal iliac artery generate?

A

superior and inferior gluteal arteries are branches

provides branches that supply the pelvic viscera

generates the umbilical arteries

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24
Q

What are vesicle arteries?

A

They arise from patent parts of the umbilical arteries

They supply the bladder

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25
Q

What forms medial umbilical ligaments?

A

obliterated parts of the umbilical arteries form the medial umbilical ligaments which are covered by medial umbilical folds

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26
Q

What forms the superior hypogastric plexus?

A

postsynaptic sympathetic fibers with accompanying visceral afferent fibers exit the prevertebral ganglia to form the intermesenteric plexus that descends along the abdominal aorta and at its terminal bifurcation forms the superior hypogastric plexus

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27
Q

What are the right and left hypogastric nerves?

A

Postsynaptic sympathetic fibers and visceral afferent fibers that continue from the superior hypogastric plexus which enter the pelvic cavity to join the right and left inferior hypogastric plexuses

28
Q

What is the importance of the inferior hypogastric plexuses?

A

branches from the pelvic splanchnic nerves join these plexuses

periarterial plexuses which are derived from the inferior hypogastric plexuses accompany branches of the internal iliac artery to the pelvic viscera

29
Q

What is the anatomical placement of the bladder?

A

It is seperated from the pubis by the retropubic space and the apex of the bladder is attached to the median umbilical ligament

30
Q

What is the importance of the fundus of the bladder?

A

It is opposite of the apex and forms the posterior surface of the baldder. The body seperates the apex and fundus

31
Q

What forms the neck of the bladder?

A

convergence of the inferolateral surfaces of the body of the bladder

32
Q

How can the filled bladder ascend to the level of the umbilicus?

A

As the bladder fills, it enters the greater pelvis as it ascends in the extraperitoneal fatty tissue of the anterior abdominal wall.

33
Q

How is cystotomy performed to prevent peritonitis?

A

It is approached superior to the pubic symphysis for the introduction of indwelling catheters or instruments without traversing the peritoneum and entering the peritoneal cavity.

Urinary calculi, foreign bodies and small tumors may also be removed from the bladder through a suprapubic extraperitoneal incision.

34
Q

In males, what does smooth muscle create around the neck of the bladder? What is its function

A

Involuntary internal urethral sphincter: It contracts during ejaculation to prevent retrograde ejaculation of semen into the bladder.
Some fibers assist in the opening the internal urethral orifice.

35
Q

In females, what works synergistically with the external urethral sphincter?

A

An internal urethral sphincter is not formed. Muscular slips of the pubococcygeus form the compressor urethrae muscle that works synergistically with the external urethral sphincter.

36
Q

What is anatomical significance of the bladder in females?

A

Fundus of bladder is associated with the vagina.

37
Q

What does reflection of the peritoneum surrounding the bladder area in females do?

A

Reflection of the parietal peritoneum off the superior surface of the bladder onto the uterus forms the vesicouterine.

Reflection of the peritoneum off the uterus onto the rectum forms the rectouterine pouch (of Douglas)

38
Q

What is the anatomical significance of the bladder in males?

A

The fundus of the bladder is anterior to the rectum.

39
Q

What does reflection of the parietal peritoneum form in males?

A

Reflection of parietal peritoneum that covers the superior surface of the bladder forms the rectovesical pouch.

40
Q

What forms the angles of the trigone of the bladder?

A

internal urethral orifice and ureteric orifices

41
Q

Why can rupture of the bladder cause urine extravasation either extraperitoneally or intraperitoneally?

A

Rupture of the superior part of the bladder frequently tears the peritoneum resulting in extravasation of urine into the peritoneal cavity. Posterior rupture of the bladder usually results in passage of urine extraperitoneally into the perineum.

42
Q

Why are bladder infections more common in females?

A

The female urethra is short, more distensible and is open to the exterior through the vestibule of the vagina.

43
Q

In males, what is the only structure that courses between the ureters and parietal peritoneum as the ureters pass from the retroperitoneal space in abdomen to the bladder in the pelvic cavity?

A

Ductus deferens which crosses the ureter with the ureteric fold of the peritoneum.

44
Q

What forms the urorectal septum?

A

Wedge of visceral mesoderm

It separates the hindgut-derived cloaca into the anterior urogenital sinus and posterior anorectal canal.

superior urogenital sinus –> bladder
inferior urogenital sinus –> urethra

45
Q

What forms the urachus and what does it do?

A

The bladder lumen is originally continuous with the lumen of the allantosis but obliteration of the allantosis lumen forms a fibrous cord remnant called the urachus.

The urachus connects the apex of the bladder with the umbilicus and the urachus eventually becomes the median umbilical ligament.

46
Q

What are ureteric buds?

A

Epithelial outgrowths from caudal ends of the mesonephric ducts just prior to their termination in the urogenital sinus

47
Q

What happens to the mesonephric ducts?

A

In both sexes, the caudal ends of the mesonephric ducts and proximal portions of the ureters are absorbed into the posterior wall of the bladder.

In males caudal portions of the mesonephric ducts become the ejaculatory ducts.

48
Q

In a histological section, what would indicate that the section was obtained from the superior wall of the bladder?

A

covering serosa

49
Q

What is the detrusor muscle?

A

Multiple layers of smooth muscle in the bladder wall.

Urination results from contraction of the detrusor muscle.

50
Q

In males, how is contraction of the detrusor muscle and internal urethral sphincter regulated during micturition?

A

Parasympathetic fibers are motor to the detrusor muscle and inhibitory to the internal urethral sphincter of the male bladder.

51
Q

How can a sympathetic response hamper urination in males?

A

The sympathetic innervation that stimulates ejaculation simultaneously causes contraction of the internal urethral sphincter to prevent reflux of semen into the bladder. A sympathetic response at moments other than ejaculation can cause the internal sphincter to contract, hampering the ability to urinate until parasymathetic inhibition of the sphincter occurs.

52
Q

What lines the bladder?

A

Like the renal pelvis and ureters, the bladder is lined by urothelium. This has tight junctions between the surface epithelial cells to make the urothelium impermeable to urine.

53
Q

Describe the urothelial cells.

A

Urothelial thickness varies with cyclic changes in urine volume.

Cells in the upper epithelial layers change shape and position by flattening and sliding over each other when the bladder fills. During micturition, the cells return to their resting shape and position.

54
Q

What happens to lymph from the bladder?

A

drains to the internal iliac nodes

efferent lymph –> common iliac lymph nodes –> lumbar lymph nodes –> thoracic duct

55
Q

What does the pelvic line follow?

A

The parietal peritoneum reflects from the abdominal wall onto superior surfaces of the pelvic cavity viscera. The pain line follows the contours of the peritoneal reflections.

56
Q

Describe the visceral pain referral of the superior wall of the bladder.

A

Superior wall of the bladder is above the pain line. Afferent fibers from the superior wall accompany sympathetic fibers in a serial retrograde pathway through inferior hypogastric plexuses, the hypogastric nerves, superior hypogastric plexus, and inferior mesenteric ganglion to the DRG at T12-L2.

Visceral pain sensations conveyed by these DRG are referred to the hypogastric region.

57
Q

What about pain referral from the rest of the bladder?

A

Aside from the superior wall, the bladder is below the pelvic pain line. Most of the bladder is supplied by afferent fibers that accompany branches of the pelvic splanchnic nerves. These sensory fibers convey visceral pain via the DRG at S2-S4 to the perineum.

58
Q

Where is the rectum and anal canal derived from?

A

distal hindgut and transform the posterior cloaca into the anorectal canal

59
Q

What does the rectal mucosa contain?

A

like the colon, it contains intestinal crypts mainly lined by goblet cells.

taeniae coli terminate in the sigmoid colon!

60
Q

What does the rectal muscularis externa consist of?

A

inner circular layer and outer longitudinal layer of smooth muscle

61
Q

What is the relation of the rectum to the coccyx and sacrum?

A

rectum follows the curve of the coccyx and sacrum.

puborectal sling forms an 80 angle anteroinferior to the tip of the coccyx. the sling creates the dilated ampulla of the rectum, which holds the accumulating fecal mass until defecation.

62
Q

How does the puborectal sling contribute to fecal incontinence?

A

The ability of the ampulla to relax to accomodate the initial and subsequent arrivals of fecal materials is another essential element of maintaining fecal continence.

63
Q

Which viscera can be palpated during rectal exams in males and females?

A

prostate and seminal glands (males) and cervix (females), sacrum, coccyx, ischial spines, tuberosities, enlarged internal iliac lymph nodes, thickening of ureters, swellings in ischioanal fossae, contents in rectovesical pouch. inflamed appendix

64
Q

Which artery supplies the rectum?

A

superior rectal artery (termination continuation of the IMA)

65
Q

Where does lymph from the rectum drain?

A

inferior mesenteric lymph nodes

66
Q

How is visceral pain referred in the rectum?

A

proximal portion of the rectum is covered by the parietal peritoneum (superior to the pelvic pain line). visceral pain from the proximal rectum is referred to the pubic (hypogastric region).

visceral pain from teh distal rectum (below the pelvic pain line) is referred bia DRG to S2-S4 to the posterior thighs and perineum.