Bony Pelvis and Pelvic Wall Flashcards

1
Q

The _____ and _____ lines delineate the pelvic brim

A

Pectineal; arcuate

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2
Q

Which ligaments of the pelvic girdle are strong and extensive, supporting the sacrum as it acts as a wedge separating the hip bones?

A

Sacroiliac ligaments

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3
Q

What 2 ligaments prevent rotation of the sacrum/coccyx and together with the hip bone create the greater and lesser sciatic foramen?

A

Sacrotuberous ligament

Sacrospinous ligament

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4
Q

AP compression produces fractures of what part of the hip bones?

A

Pelvic rami

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5
Q

Lateral forces on the pelvis squeeze the ____ and ____ together, breaking both

A

Acetabulum; ilia

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6
Q

What are the weak areas of the pelvis subject to injury?

A

Pubic rami
Acetabulum
SI joints
Ala

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7
Q

What are the borders of the lesser or “true” pelvis?

A

Superior: pelvic brim (pelvic inlet)

Inferior: muscular pelvic diaphragm

Lateral and anterior: lower 1/2 of hip bones

Posterior: sacrum + coccyx

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8
Q

What region is considered the greater or “false” pelvis?

A

Superior to pelvic brim; occupied by abdominal viscera

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9
Q

What bone associated with the pelvis provides predominant support for abdominal weight?

A

Pubic bone

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10
Q

______ pelvis = normal male type

______ pelvis = normal female type

A

Android

Gynecoid

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11
Q

Compare the greater sciatic notch in males vs. females

A

Males: narrow (~70 degrees); inverted V

Females: almost 90 degrees

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12
Q

Compres the obturator foramen in males vs. females

A

Males: round

Females: oval

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13
Q

Compare the pubic arch and subpubic angle in males vs. females

A

Males: narrow (~70 degrees)

Females: wide (greater than 80 degrees)

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14
Q

Compare the pelvic outlet in males vs. females

A

Males: comparatively small

Females: comparatively large

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15
Q

Origin/insertion/innervation of obturator internus

A

Origin: ilium/ischium surface; obturator membrane

Insertion: greater trochanter

Innervation: obturator n.

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16
Q

Origin/insertion/innervation of piriformis m.

A

Origin: S2-4 surface, superior margin of greater sciatic notch; sacrotuberous ligament

Insertion: greater trochanter

Innervation: S1-S2

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17
Q

Origin/insertion/innervation of coccygeus m.

A

Origin: ischial spine

Insertion: inferior end of sacrum and coccyx

Innervation: S4-5

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18
Q

Actions of coccygeus m.

A

Support pelvic viscera; flex coccyx

19
Q

In addition to being part of the pelvic wall, the ________ and ________ mm rotate the thigh laterally (both attach to the greater trochanter of femur)

A

Piriformis; obturator internus

20
Q

The pelvic diaphragm is made up of 4 mm. named for their ____

A

Origin

21
Q

What are the 4 muscles that make up the pelvic diaphragm (and their origins)?

A

(Ischio) coccygeus m. — ischial spine

Iliococcygeus m. — tendinous arch

Pubococcygeus m. — pubis

Puborectalis m. — pubis

22
Q

Of the 4 muscles that make up the pelvic diaphragm, the iliococcygeus, pubococcygeus, and puborectalis mm. elevate the anal canal and together are called the ____ _____

A

Levator ani

23
Q

The tendinous arch of the levator ani is a thickening of the ______ fascia between the ischial spine and body of pubis

A

Obturator

24
Q

What muscle helps maintain fecal continence, relaxing during both urination and defecation, and is distinct from the external and internal anal sphincters?

A

Puborectalis m.

25
Q

The ________ is the passageway for the rectum, urethra, and in females the vagina. it is formed by the anterior gap between the levator ani muscles

A

Urogenital (levator) hiatus

26
Q

What muscles associated with the urogenital hiatus are the most susceptible to tearing during birth being most medial and large parts of the levator ani?

A

Pubococcygeus m.

Puborectalis m.

27
Q

The _____ _____ sits inferior to the pelvic floor, is diamond-shaped, and is filled primarily with fat

A

Ischiorectal fossae

28
Q

The ischiorectal fossae can be divided into 2 triangles: the _____ triangle and _____ triangle

A

Anal

Urogenital

29
Q

The _____ membrane spans between rami in the ischiorectal fossae

A

Perineal

30
Q

The ischiorectal fossae allows movement of the ____ _____ and expansion of the _____ canal. It contains ________ to the anal canal and some to the perineum

A

Pelvic diaphragm; anal; neurovasculature

31
Q

The anal canal begins at the level when the rectum ‘perforates’ the ______ ____.

The ____ _____ are the associated longitudinal ridges

The ____ _____ are the associated folds at the base of the above structures

The ____ _____ are small recesses adjacent to the above structures, and function to exude mucus facilitating defecation

A

Levator ani

Anal columns

Anal valves

Anal sinuses

32
Q

The internal anal sphincter is made up of inner circular _____ muscle, which is involuntary. It is kept in _____ contraction except when feces fill the rectum

It is responsible for ______% of resting anal tone

A

Smooth; tonic

55-85%

33
Q

The external anal sphincter is made up of ______ muscle, which is voluntary. It is responsible for _____% of resting anal tone

A

Skeletal; 15-30

34
Q

What are the 3 parts of the external anal sphincter?

A

Subcutaneous
Superficial
Deep (puborectalis)

35
Q

______ are essentially enlarged and collapsed varicosities of normal venous anatomy that may be a major clinical consequence of portal hypertension

A

Hemorrhoids

36
Q

_________ ________ = prolapse of rectal mucosa; due to weakened muscularis mucosa (bleeding often bright red due to abundant arteriovenous anastomoses within internal rectal venous plexus)

A

Internal hemorrhoids

37
Q

Describe external hemorrhoids

A

External venous plexus covered with epidermis

38
Q

What anatomical landmark is used to classify type of hemorrhoids as external vs. internal?

A

Pectinate line

39
Q

How is the pectinate line used to classify whether hemorrhoid is external or internal? Which type is painful vs. not painful?

A

Internal hemorrhoids are above the pectinate line and are NOT painful

External hemorrhoids are below the pectinate line and are painful

40
Q

How does rectal innervation differ above vs. below the pectinate line?

A

Above: inferior hypogastric plexus (visceral)

Below: inferior rectal nn (somatic)

41
Q

How does venous drainage differ in the rectum above vs. below the pectinate line?

A

Above: primarily to superior rectal vein (portal)

Below: primarily to inferior rectal veins (systemic)

42
Q

How does destination of lymph drainage differ above vs. below the pectinate line?

A

Above: internal iliac LNs, inferior mesenteric

Below: superficial inguinal LNs

43
Q

How does embryological epithelial origin differ in the rectum above vs. below the pectinate line?

A

Above: endoderm

Below: ectoderm