Anatomy of Pelvis Flashcards
1
Q
What does the bony pelvis (pelvic girdle) include?
A
The right and left pelvic bones, a fusion of the ilium, ischium and pubis, the sacrum and coccyx.
2
Q
What is the pelvic inlet?
A
The circular opening where the abdominal cavity is continuous with the pelvic cavity. The sacral promontory protrudes into this opening as its posterior midline boundary.
3
Q
What is the pelvic outlet?
A
Diamond shaped and bounded by the pubic symphysis, pubic arches, inferior pubic rami, ischial rami, sacrotuberous ligament and coccyx.
4
Q
What is the sciatic notch?
A
Between the posterior inferior iliac spine and the ischial spine. The sacrospinous ligament changes this notch into an opening, the greater sciatic foramen?
5
Q
What forament does the sacrospinous ligament create?
A
The greater sciatic foramen. It changes the sciatic notch into the greater sciatic foramen.
6
Q
What are the differences between the pelvic inlet in females and males?
A
Females-wide, oval or circula
Male- narrow, heart shaped
7
Q
What are the differences between the sacrum in males and females?
A
Female-short straight
Male-long and prominent
8
Q
What are the differences between the coccyx in males and female?
A
female-straighter
Male-curves ventrally
9
Q
What are the differences between the sciatic notch in males and females?
A
Females-wide
males-narrow
10
Q
What are the differences between the subpubic angle in females and males?
A
Female-broad, rounded (80-85 degrees)
Male-deep, acute (50-60 degrees)
11
Q
What do the muscles of the pelvis do?
A
They support our viscera
12
Q
What are the pelvic wall muscles?
A
The piriformis and the obturator internus.
13
Q
What does the pelvic floor consist of?
A
The pelvic diaphragm and urogenital diaphragm.
14
Q
What is the pelvic diaphragm?
A
The levator ani and the coccygeus muscles, thin sheets of muscle that the urethra, vagina and rectum pass through.
15
Q
What is the levator ani made up of?
A
The iliococcygeus and the pubococcygeus.
16
Q
What does the levator ani do?
A
It contracts when abdominal pressure is raised to support the pelvic organs.
17
Q
What does the pubococcygeus do?
A
It helps maintain urinary and fecal continence.
18
Q
What does the puborectalis do?
A
It relaxes and contracts the anorectal angle to control defication, and aids in voluntary control of micturition.
19
Q
Where is the coccygeus and what does it do?
A
The coccygeus is deep to the sacrospinous ligament, it pulls the coccyx forward after defecation.
20
Q
What does the female reproductive tract consist of?
A
The vagina, uterus, uterine (fallopian) tubes and paired ovaries.
21
Q
What are the female external genitalia?
A
The clitoris and labia (minora and majora)
22
Q
What are the four regions of the uterus? Where are they located?
A
- Th fundus is the upper area in which the uterine tubes connect to the uterus.
- The body starts below the level of the uterine tubes and continues downward until the uterine walls and cavity begin to narrow.
- The isthmus is lower than the body, it is a narrow neck region
- The cervix extends from the isthmus until the opening of the vagina.
23
Q
What is the normal position of the uterus?
A
Anteverted or anteflexed, oriented anteriorly toward the bladder.
24
Q
What is the angle between the uterine body and isthmus?
A
Flexion
25
What is the angle betwwen the cervical canal and vagina?
Version
26
What is a retroverted or retroflexed uterus?
When the uterus is oriented posteriorly toward the rectum, it is a normal anatomical variation.
27
What is the broad ligament?
Peritoneum that drapes over the female reproductive tract.
28
What is the broad ligament divided into and what do they cover?
1. mesometrium is the mesentery of the uterus and is adjacent to the uterus
2. mesovarium is the mesentery of the ovary
3. Mesosalpinx is the mesentery of the uterine tube (also called a salpinx).
Vessels, nerves and lymphatics travel via these mesenteries.
29
Name other peritoneal ligament besides the broad ligament. Where are they located
1. Suspensory ligament of the ovary- through which the ovarian vessels travel from the abdominal aorta to the ovary
2. The ovarian ligament- Attaches the inferomedial pole of the ovary to the uterus
3. The round ligament of the uterus- continuous with the ovarian ligament and travels from the uterus laterally to enter the deep inguinal ring.
30
What are the 2 peritoneal pouches or recesses between organs? Where are they?
1. The vesicouterin pouch is between the bladder and the uterus
2. The rectouterine pouch (of douglas) is between the uterus and rectum.
31
What are the fascial ligaments that help support the pelvic organs? Where are they located?
Pubovesical ligaments-from bones to bladder
Transverse cervical- ligaments (cardinal ligaments) from uterus to the lateral pelvic wall.
Uterosacral ligament-from uterus to sacrum.
32
What ligaments can be damaged by multiparity, birth trauma, obesity, chronic cough, and heavy lifting causing stress inceontinece or bladder prolapse (pubovesical ligaments) or varying degrees of uterine prolapse.
The pubovesicle ligament, transverse cervical ligaments, and the uterosacral ligaments.
33
How can the pubovesicle ligament, transverse cervical ligaments, and the uterosacral ligaments be damaged.
multiparity, birth trauma, obesity, chronic cough, and heavy lifting causing stress inceontinece or bladder prolapse (pubovesical ligaments) or varying degrees of uterine prolapse.
34
What does the male reproductive tract consist of?
The prostate, seminal vesicles, vas (ductus deferens) and the testes.
35
Which male structures are subperitoneal and closely associated with the urethra?
The prostate and seminal vesicle.
36
What does the vas deferens connect?
They are attached to the tested. The vas derens ascends from the scrotum in the spermatic cord, passes through the inguinal canal, and then courses retroperitoneally to join the duct of the seminal vesicles and the ejaculatory ducts.
37
Where are the ejactulatory ducts?
They are embedded in the prostate.
38
Describe the course of semen during ejactulation?
Semen passes from the seminiferous tubules in the testis, to the epididymis, a coiled tube continuous with the vas deferens, from the vas deferens to the ejactulatory ducts, enters the urethra and exits via the tip of the penis.
39
What is the tunica vaginalis?
A pouch of peritoneum that attaches to the anterior and lateral aspect of the testes. It has a visceral and parietal layer.
40
What does the descent of the testis from?
The inguinal canal and the spermatic cord, which is covered by layers derived from the abdominal wall.
41
What covers the inguinal canal and spermatic cord?
Layers derived from the abdominal wall:
External spermatic fascia-external oblique aponeurosis
Cremasteric fascia/muscle-internal oblique muscle
Internal Spermatic fascia- transversalis fascia.
42
What is a hernia in the inguinal canal called?
An indirect hernia. It passes through the inguinal canal (into the deep inguinal canal, out of the superficial ring into the scrotum) lateral to the epigastric vessels.
43
Describe a direct inguinal hernia.
It bulges directly through the abdominal wall, medial to the inferior epigastric vessels, lateral to the rectus abdominus muscle, and superior the inguinal ligament.
44
What is the area where direct inguinal hernias occur?
The inguinal (Hesselbach's triangle)
45
What supplies the reproductive system?
Internal iliac artery which is a branch of the common iliac artery.
46
What are the internal ilac branches common to males and females?
```
Iliolumbar
Lateral Sacral
Superior gluteal
Inferior gluteal
Internal pudendal-inferior rectal branch
Umbilical-(superior) vesicle arteries to the bladder
Obturator
Middle rectal
```
47
What arteries are specific to females?
The uterine and vaginal arteries
48
What arteries are specific to males?
Vas deferens branch (deferential artery) off the umbilical artery
49
If blood supply is from the internal iliac artery, how does lymph flow?
From the internal iliac nodes, then the common iliac nodes, and finally the lateral aortic (lumbar nodes)
50
Where do the superficial and deep inguinal nodes receive lymph from?
The perineum and lower limb.
51
Where do the superficial and deep inguinal nodes drain into?
Into external iliac nodes, then common iliac nodes and then finally lateral aortic nodes.
52
If the blood supply is from the aorta how does lymph flow?
Directly to the lateral aortic nodes (ovaries and testes). It then drains to the cisterna chyli and the thoracic duct.
53
What are the skin and skeletal muscles of the pelvis innervated by?
The anterior (ventral) rami of the lumbosacral (L4-S4) and coccygeal spinal nerves, which from plexuses of the same names.
54
What are the smooth muscle and glands of the pelvic viscera innervated by?
Pelvic splanchnic neves (S2-S4, parasympathetic)
| Thoracic, lumbar and sacral splanchnic (T10-12 and L1-L2, sympathetic).
55
How do visceral afferents from the intraperitoneal pelvic viscera travel?
via the hypogastric nerves to the aortic plexus and lumbar splanchnic nerves (sympathetics).
56
How do visceral afferents from the subperitoneal pelvic viscera travel?
Via the pelvic splanchnic nerves to S2-S4 (Parasympathetics)
57
How do afferent fibers from the lower vagina and perineum travel?
Via the pudendal nerves S2-S4
58
How is micturition regulated (urination/voiding)
By an autonomic spinal cord reflex: the micturition reflex.
59
What does the bladder consist of?
A main portion (body) that collect urine and a funnel shaped extension (neck) that connects to the urethra.
60
What lines the bladder lumen?
A transitional epithelium
61
What makes up the bulk of the bladder wall?
Three poorly defined layers of smooth muscle that make up the detrusor muscle.
62
What is the detrusor muscle?
The bulk of the bladder wall.
63
What does the internal urethral sphincter consist of?
Smooth muscle cells extending from the detrusor muscle
64
What does the external urethral sphincter composed of?
Voluntary striated muscle fibers.
65
What does the micturition involve (in terms of impulses)
Impulses traveling from the bladder to the sacral spinal cord and from the sacral spinal cord back to the bladder.
66
What is the micturition reflex controled by?
It can be inhibited or facilitated by neurons located in the cerebral cortex of the brainstem.
67
What are the two phases of micturition?
A filling phase and an emptying or voiding phase. Both of which require coordinated interaction between the bladder and the nervous system.
68
What nervous system predominates during the filling phase?
The sympathetic nervous system.
69
Where do the preganglionic neurons originate of the sympathetic nervous system that controls the filling phase? Where do they go?
Spinal cord levels L1-L2
They are carried to the inferior hypogastric plexus via the lumbar and sacral splanchnic nerves.
They synapse of the hypogastric plexus giving rise to the hypogastric nerves.
70
What do hypogastric nerves do?
They cause relaxation of the detrusor muscle and contraction of the internal urethral sphincter to allow bladder filling.
71
What is the micturition reflex regulated by?
The sensory stretch fibers in the bladder wall and parasympathetic fibers located in the pelvic splanchnic nerves.
72
Where is the micturition reflex located and what is it regulated by?
Within the sacral spinal cord and is regulated by higher centers of the brain.
73
When do first senses for voluntary bladder emptying occur?
At a volume of 150ml.
| Fullness is at 400-500ml.
74
How is sensory information from the bladder conveyed?
Via visceral afferent fibers associated with the pelvic splanchnic nerves that synapse on parasympathetic neurons in the sacral spinal cord because contraction of the detrusor muscle.
It is also conveyed to the brain.
75
How is the micturition reflex inhibited?
Efferent impulses from the brain inhibit pre-ganglionic parasympathetic neurons in the sacral spinal cord and continue to stimulate contraction of the external sphincted via the pudendal nerve.
76
When voiding is appropriate what happens to the nerves?
Visceral afferents running with the pelvic sphanchnic nerves stimulate the preganglionic parasympathetic neurons in the sacral spinal cord causing contraction of the detrusor muscle.
77
What do visceral afferent running with the pelvic splanchnic nerves also stimulate?
Ascending pathways to the brain that results in a conscious desire to urinate.
78
What do descending impulses do?
They decrease the sympathetic output via the hypogastric plexus to the internal urethral sphincter allowing relaxation.
Descedning signals further stimulate the parasympathetic system resulting in contraction of the detrusor muscle.
79
What do descending signals inhibit?
pudendal nerve activity allowing for voluntary relaxation of the external urethral sphincter.
80
What is the perineum?
A diamond shaped area below the pelvic floor and between the thighs.
81
How is the perineum divided?
Into two triangles by drawing a line between the ischial tuberosities.
82
What are the two triangles of the perineum?
1. The anterior urogenital triangle- associated with openings of the urinary systems and the reproductive systems and function to anchor the external genitalia
2. The posterior angle triangle contains the anus and the external anal sphincter.
83
What is the urogenital triangle divided into?
A deep perineal pouch and a superficial perineal pouch separated by a fascial membrane known as the perineal membrane.
84
What is the deep perineal pouch?
A potential space between the pelvic diaphragm and the perineal membrane. It contains part of the urethra, the external urethral sphincter, and the deep transverse perineal muscle.
85
In males what does the deep perineal pouch contain?
the bulbourethral glands.
86
In females what does the perineal pouch contain?
part of the vagina, the compressor urethrae, and the sphincter urethrovaginalis.
87
What is the perineal membrane?
A tough fascia that provides attachment for the external genitalia and helps support the pelvic organs.
88
What is the superficial perineal pouch?
A potential space between the perineal membrane and the perineal fascia. It contains the external genitalia.
89
What is the perineal body?
A connective tissue structure (central tendon) into which pelvic floor and perineal muscles attach. It is the midline of the perineum.
90
What are the two sets of erectile tissue composing the male external genitalia?
The corpora cavernosa and the corpus spongiosum compose the penis.
91
What are the two sets of erectile tissue composing the female external genitalia?
The vestibular bulbs (bulb of the vestibule) lie deep to the labia majora and are separated by the vaginal opening
The crura of the clitoris join to form the body and glands of the clitoris.
92
What are the proximal ends of the erectile tissues covered by?
Thin skeletal muscles that contract to move blood volume during orgasm.
93
What is the bulbospongiousm?
It covers the proximal end of the corpus spongiosum, or the bulb of the penis in males.
It covers the vestibular bulbs in the female.
94
What is the ischiocavernosum?
It covers the proximal end of the corpora cavernosa (crus of the penis) in male. It covers the crus of the clitoris in the female. It lies along the pubic ramus on each side.
95
What is the superficial transverse perineal muscles?
They run transversely across the posterior border of the urogenital triangle from the ischial tuberosity to insert into the perineal body, along with the bulbospongiosum and external anal sphincter.
96
What controls erection and orgasm?
The autonomic nervous system (parasympathetics-pelvic splanchnic nerves S2-S4). They function in erection by vasodilating (relaxing) the arteries in the penis and clitoris so they fill with blood and crimp the veins so there is no drainage of the blood.
97
What controls orgasm/ejaculation?
The sympathetics (lumbar splanchnics L1-L2) function in orgasm/ejaculation by initiating contraction of the smooth muscle by the epidymal ducts, vas deferens, seminal vesicles and prostate to move sperm toward the prostatic urethra.
98
What does the pudendal nerve do (anterior rami or spinal nerves S2,3,4)?
It provides sensory and motor innervation to the levator and perineum. It exits the greater sciatic foramen, passes over the sacrospinous ligament and enters the lesser sciatic foramen under the sacrotuberous ligament to enter the pudendal (Alock's) canal.
99
Where does the pudendal nerve travel?
It exits the greater sciatic foramen, passes over the sacrospinous ligament and enters the lesser sciatic foramen under the sacrotuberous ligament to enter the pudendal (Alock's) canal.
100
Where do afferent fibers from the intraperitoneal viscera (uterine) go back with?
The sympathetics (lumbar splanchnic nerves L1-L2)
101
Where do afferent fibers from the subperitoneal viscera (cervix and bladder) go back with?
parasympathetics (pelvic splanchnic S2-S4)
102
Where do afferent fibers of the lower vagina and perineum travel with?
The pudendal nerve (S2-S4)
