Structure of Pelvic Wall Flashcards
1
Q
site in pelvic region that can be used for epidural injection
A
sacral hiatus
2
Q
Sacral Promontory (what is it)
A
anterior-superior margin of vertebra S1
3
Q
Sacral Canal (what is it, what does it contain within it)
A
caudal most part of vertebral canal
contains cauda equina
4
Q
Sacral hiatus (what is it)
A
inferior opening to the sacral canal
5
Q
Medial Mass of Sacrum (what is it)
A
fused vertebral bodies
6
Q
Lateral Mass of Sacrum (what is it)
A
fused transverse processes
7
Q
Median Crest of Sacrum (what is it)
A
fused spinous processes
8
Q
Anterior and Posterior Sacral Foramen ( what are they)
A
‘windows’ for exit of anterior and posterior rami of sacral spinal nerves
9
Q
Innominate bone (what is it made up of)
A
3 bones fused together
ilium
ischium
pubis
10
Q
acetabulum (what is it, what is it made from)
A
where ilium, ischium, and pubis join
cup-like depression for articulation with head of femur
11
Q
before ages 15-17 what holds the innominate bone together
A
only cartilage (prior to fusion)
12
Q
Ischial tuberosity (what is it, what attaches to it)
A
roughened, posterior inferior part of ischium
site of attachment for sacrotuberous ligament
13
Q
Ischial Spine (what is it, what attaches to it)
A
pointed process from posterior border of ischium
lies between greater and lesser sciatic notches
site of attachment of sacrospinous ligament and coccyges muscle
14
Q
What two parts of the ischium are key landmarks of the pelvis
A
ischial spine
ischial tuberosity
15
Q
Ischial Ramus (what is it)
A
inferior border of ischium, inferior to obturator foramen
16
Q
Greater Sciatic Notch (what is it, what makes up its borders)
A
deep indentation in posterior border of innominate bone superior to ischial spine
superior border- ilium
inferior border- ischium
17
Q
Lesser Sciatic Notch (what is it)
A
deep indentation in posterior border of ischium inferior to ischial spine
18
Q
Pubic Symphysis (what is it)
A
midline cartilaginous joint between right and left pubic bones
19
Q
Obturator Foramen (what is it)
A
hole between pubis and ischium
20
Q
Superior Ramus of Pubis (where is it)
A
superior to obturator foramen and extends into acetabulum
21
Q
Inferior Ramus of Pubis (where is it)
A
inferior to obturator foramen and extends into ischium
22
Q
Pubic Arch (what is it)
A
Angle between inferior rami and bodies of both pubes
23
Q
Pelvic Brim (what makes it up)
A
lateral mass of sacrum
arcuate line of ilium
pecten pubis and pubic crest
24
Q
Iliopectineal Line (what is it)
A
formed from pecten pubis and arcuate line
25
Pecten Pubis (what is it)
raised ridge along superior rams of pubis Lateral to pubic tubercle
26
Pubic Crest (what is it)
ridge Medial to the pubic tubercle on the body of the pubis
27
the superior margin of the pubic symphysis and the anterior superior iliac spine have what relation to each other
(in terms of orientation of the pelvis)
lie in same vertical plane
28
in a fracture of the pelvis one must assume damage to what two structures
urinary bladder
| urethra
29
what two joints are found in the vertebral column of the pelvis
lumbrosacral
| sacrococcygeal
30
Sacroiliac Joint (what is its purpose)
transmits weight of trunk to innominate bone (transferring weight to hear of femur in thigh)
31
Sacroiliac Joint (what is it made up of)
held together by strong-
interossous ligaments
anterior and posterior sacroilliac ligaments
32
Iliolumbar Ligament (what is it, where does it span)
strong accessory ligament from transverse process of L5 to iliac crest
33
Sacrotuberous Ligament (what and where is it)
broad attachment to sacrum and narrows inferiorly to attach to ischial tuberosity
posterior to the sacrospinous ligament
34
Sacrospinous Ligament (what and where is it)
triangular shape
attaches to lateral margin of sacrum and ischial spine
anterior to sacrotuberous ligament
35
What is the purpose of the sacrospinous and sacrotuberous ligaments
prevent sacrum and coccyx from rotating posteriorly due to weight of trunk (center of gravity is anterior to sacrum)
36
The presence of the sacrotuberous and sacrospinous ligaments give rise to what?
greater and lesser sciatic foramina
37
Greater Sciatic Foramen (what is it)
'window' through which neurovascular structures and a muscle (piriformis) pass from true pelvis into gluteal region
38
Lesser Sciatic Foramen (what is it)
'window' through which neurovascular structures and a muscle (obturator internus) pass from buttock to perineum
39
Obturator Membrane (where and what is it)
covers obturator foramen
| serves as site of muscle attachment
40
False Pelvis (what is it)
located above pelvic brim
| part of posterior wall of abdominal cavity
41
True Pelvis (contents)
```
lower part of GI tract
urogenital organs (urinary bladder, rectum, female reproductive organs, associated glands of both sexes)
```
42
True Pelvis (boundaries)
Pelvic Inlet- superior opening
| Pelvic Outlet- inferior opening
43
Pelvic Inlet (what is it, what are its borders)
superior opening of true pelvis
formed form pelvic brim (lateral mass of sacrum, iliopectineal line (arcuate line of ilium and pecten pubis), pubic crest)
44
Pelvic Outlet (what is it, what are its borders)
inferior opening of true pelvis
| bordered by tip of coccyx, sacrotuberous ligament, ischial tuberosity, inferior ramus of pubis, and pubic symphysis
45
measurements of what are used to determine the size of birth canal
pelvic inlet
46
Diagonal Conjugate Diameter (what is it a measurement of, where is it taken)
anteroposterior measurement of pelvic inlet
| between lower border of the pubic symphysis and the sacral promontory
47
what measurement is taken between pubic symphysis and sacral promontory
Diagonal Conjugate Diameter (anteroposterior diameter)
48
Transverse Diameter (what is it)
measurement of pelvic outlet
| distance between ischial tuberosities
49
The maximum measurement of pelvic inlet is what
transverse diameter
50
Maximum measurement of pelvic outlet is what
anteroposterior diameter
51
what happens to babies head during parturition
must rotate 90degrees between pelvic inlet and outlet
52
What structures of the pelvis are sexually dimorphic
pelvic inlet
pelvic outlet
angle of pubic arches
pelvic cavity
53
Pelvic Inlet (difference b/w male and female)
Male- kidney-shaped
| Female- Oval
54
Pelvic Outlet (difference b/w male and female)
Male- small
| Female- large
55
Angle of pubic arches (difference b/w male and female)
Male- narrow (60 degrees)
| Female- wide (90 degrees)
56
Pelvic Cavity (difference b/w male and female)
male- narrow
| Female- wide
57
the kidney shape of the male pelvic inlet is due to what
protrusion of sacral promontory into pelvic inlet
58
the large female pelvic outlet is due to what
greater distance b/w ischial tuberosities
59
The lateral wall of the true pelvis is formed by what structures
innominate bone (below pelvic brim)
obturator internus
sacrospinous ligament
sacrotuberous ligament
60
Obturator Internus (what is it)
muscle of lower extremity
61
Obturator Internus (origin and insertion)
Origin: obturator membrane and adjacent ischium and pubis
Insertion: tendon passes laterally out of true pelvis vis lesser sciatic foramen to enter buttocks and greater trochanter of femur
62
Obturator Fascia (what is it)
thick regional expression of endopelvic fascia covering obturator internus
63
Obturator Fascia (is continuous with what
endoabdominal fascia (above)
64
Anterior Wall of True Pelvis is formed by what?
pubic symphysis and bodies of pubic bones
65
Posterior wall of True Pelvis is Formed by what?
sacrum
coccyx
piriformis muscle
66
Piriformis Muscle (origin and insertion)
origin: sacrum
insertion: greater trochanter of femur (tendon passes laterally through greater sciatic foramen to enter gluteal region)
67
what muscle of the lower extremity's name means pear shaped
piriformis
68
what muscle of lower extremity passes through the greater sciatic foramen
piriformis
69
what muscle of lower extremity passes through the lesser sciatic foramen
obturator internus
70
Pelvic Diaphragm (what does it form, what is it, what does it do)
forms floor of true pelvis
thin muscle layer
supports pelvic viscera
71
the muscles of the pelvic diaphragm originate from where and attach to where
originate from innominate bone
| attach to or encircle structures in midline
72
the pelvic diaphragm is covered superiorly and inferiorly by what
endopelvic fascia
73
urogenital gap (what is it)
gap in anterior portion of pelvic diaphragm that allows for passage of urethra (both sexes) and vagina
74
Region above Pelvic Diaphragm (what is it, what does it contain)
main pelvic cavity of true pelvis
| contains: urinary bladder, rectum, uterus, etc
75
Region Below Pelvic Diaphragm (what is it, what does it contain)
called perineum
| contains genitalia and outlet of gut and urogenital system
76
perineum (what is it, what does it contain)
region below pelvic diaphragm
| contains genitalia and outlet of gut and urogenital system
77
muscles of the pelvic diaphragm are innervated by what and insert on what (in general)
innervated by ventral rami of lower sacral nerves (S4, S5)
| insert on midline structures (coccyx, sacrum)
78
what muscles make up the pelvic diaphragm
levator ani
| coccygeus
79
Levator Ani (origins and insertions)
```
origins:
anterior- body of pubis
middle- tendinous arch
posterior- ischial spine
insertions:
coccyx
anococcygeal body
perineal body
```
80
tendinous arch (what is it)
thickened line of obturator fascia covering obturator internus
81
Anococcygeal body (what is it)
fibrous raphe connecting anal canal and coccyx
82
Perineal body (what is it, where is it, what is it important for)
small mass of connective tissue (similar to central tendon of thoracic diaphragm) that muscles insert on
b/w anorectal junction and urogenital gap in pelvic diaphragm
important for maintaining support of pelvic viscera
83
what structure if torn during childbirth can result in collapse of organs (prolapse)
perineal body
84
Subdivisions of Levator Ani (name from medial to lateral)
Levator Prostate or Sphincter Vaginae
Puborectalis
Pubococcygeus
Iliococcygeus
85
```
Lavator Prostate (male) or Sphincter Vaginae (female)
(what is it)
```
most medial portion of levator ani
forms a sling around prostate or vagina (aids in support)
inserts into perineal body
86
Puborectalis (what is it)
medial middle portion of levator ani
| forms and important sling around anorectal junctions (acts as a sphincter)
87
what muscle (be specific) acts as a sphincter via a sling around anorectal junction
puborectalis (medial middle portion of levator ani)
88
what portion(s) of levator ani insert(s) on anococcygeal body and coccyx
pubococcygeus
| iliococcygeus
89
iliococcygeus (what is it, origin and insertion)
most lateral part of levator ani
| extends from tendinous arch and ischial spine to insert on coccyx and anococcygeal body
90
what forms the anterior 3/4 of pelvic diaphragm
levator ani
91
what forms posterior 1/4 of pelvic diaphragm
coccygeus
92
coccygeus (shape of muscle, continuos with what, located anterior to what)
triangular
"continuous" with levator ani
located anterior to sacrospinous ligament
93
levator ani (action)
supports pelvic viscera
| sphincter to anorectal junction (puborectalis portion)
94
coccygeus (origin, insertion, action, innervation)
O: ischial spine
I: sacrum and coccyx
A: Supports pelvic viscera
I: ventral rami of S4-S5
95
Midline Structures of Pelvic Diaphragm (name them from posterior to anterior)
```
Coccyx
anococcygeal body (or raphe)
anorectal junction
perineal body
urogenital gap (vagina anterior to perineal body and urethra anterior to vagina)
```
96
Endopelvic Fascia (what does it line/cover, what is it continuous with)
lines pelvic cavity
covers pelvic organs
continuous with endoabdominal fascia
97
Parietal Pelvic Fascia (what does it do)
invests muscles of pelvic walls (obturator internus)
covers superior and inferior surfaces of pelvic diaphragm
condensations of pelvic fascia hold organs in place
98
Visceral Pelvic Fascia (what is it)
fascia on surface of viscera
| continuous with parietal pelvic fascia
99
the lumbosacral plexus provides motor supply to what
most lower limb muscles
pelvic diaphragm
muscles of perineum
pelvic viscera
100
the lumbosacral plexus can be compressed by what and what does this do?
pelvic tumor (ex- rectal tumor)
head of fetus during childbirth
results in pain to lower limb (sciatica)
101
lumbosacral plexus provides sensory innervation to what
cutaneous sensory fibers to lower buttock and back of thigh
102
the lumbosacral plexus is made up of what nerves?
ventral rami of L4, L5 (lumbosacral trunk)
| ventral rami of S1, S2, S3, S4
103
sacral nerves emerge to join the lumbosacral plexus from where
sacral canal via anterior sacral foramina
104
the lumbosacral plexus is located anterior to what
piriformis muscle
105
what branches of the lumbosacral plexus exit the true pelvis through the greater sciatic foramen
Superior Gluteal Nerve
Inferior Gluteal Nerve
Sciatic Nerve
Posterior Cutaneous Nerve of Thigh
106
Superior Gluteal Nerve (course and supply to)
leaves pelvis though greater sciatic foramen above piriformis muscle
supply gluteal muscles
107
Inferior Gluteal Nerve (course and supply to)
leaves pelvis though greater sciatic foramen below piriformis muscle
supply gluteal muscles
108
what is the largest nerve in the body
sciatic nerve
109
sciatic nerve (what makes it up, course, supply to)
L4,5 and S1,2,3
| leaves pelvis through greater sciatic foramen below piriformis
110
Posterior Cutaneous Nerve of thigh (innervates what, name branches)
innervates back of thigh
| perineal branch to labium magus or posterior scrotum
111
what nerve of the lumbosacral plexus gives branches to the labium major or posterior scrotum
posterior cutaneous nerve of thigh
112
Pudendal Nerve (composed of what, course)
ventral rami of S2-4
exits pelvis through greater sciatic foramen and re-enters through lesser sciatic foramen to innervate somatic, skeletal muscles of perineum
113
Pudendal Nerve (supply to what)
motor to somatic skeltal muscles of perineum- external anal sphincter, bulbospongiosus and ischiocavernous muscles, sphincter urethrae, and deep and superficial transverse perineal muscles)
sensory- lower half of anal canal and skin of external genitalia
114
what branch(s) of the lumbosacral plexus passes through greater and lesser sciatic foramen
pudendal nerve
| nerve to obturator internus
115
what branches of the lumbosacral plexus do not leave the true pelvis
branches to pelvic diaphragm
| pelvic splanchnic nerves
116
pelvic splanchnic nerves (what are they, what do they innervate)
composed of parasympathetic preganglionic fibers
| innervate terminal ganglia which innervate all hindgut derivatives
