Nov 25 - Anatomy of the Pelvis, Perineum and Reproductive Organs Flashcards
1
Q
What closes the pelvic cavity inferiorly? What is below this?
A
A musculofascial diaphragm, the pelvic diaphragm or pelvic floor. It supports the position of the viscera. Below the pelvic diaphragm is the perineum
2
Q
Describe the bony pelvis
A
It’s the lowermost portion of the trunk and lies below the abdomen. The cavities of both abdomen and pelvis are continuous and are referred to as the abdomino-pelvic cavity
3
Q
What is the false pelvis?
A
Aka the greater pelvis.
It protects the abdominal organs by the iliac bones
4
Q
What is the true pelvis?
A
Bony components that protect the organs of the pelvic cavity and provide framework for the perineum
5
Q
What separates the true pelvis from the false pelvis?
A
The pelvic brim, which is bounded posterior by the sacral promontory, laterally by the iliopectineal line, and anterioly by the pubic symphysis
6
Q
When does ossification of the three hip bones finish?
A
It is complete at the 20-25th year
7
Q
What the difference in the shape of the pelvic girdle between men and women?
A
In men, the pelvic girdle is steeper and the brim is heart shaped. In women the brim is more oval
8
Q
Name the two major pelvic ligaments?
A
The sacrotuberous ligament and the sacrospinous ligament
9
Q
Where does the sacrotuberous ligament attach?
A
It connects the posterolateral border of the sacrum with the ischial tuberosity
10
Q
Where does the sacrospinous ligament attach?
A
It connects the anterolateral border of the sacrum with the ischial spine
11
Q
Name the three major pelvic foramina
A
The greater sciatic foramen, the lesser sciatic foramen and the obturator foramen
12
Q
Describe the location of the greater sciatic foramen
A
It is located between the greater sciatic notch, the sacrospinous and sacrotuberous ligament
13
Q
Describe the location of the lesser sciatic foramen
A
It is located between the lesser sciated notch and both ligaments
14
Q
Describe the location of the obturator foramen? What closes the obturator foramen?
A
It is surrounded by the rami of the pubic and ischial bone and closed by the obturator membrane
15
Q
What is the most caudal part of the abdominopelvic cavity in women?
A
The rectouterine pouch aka the space of Douglas
16
Q
Why is the rectouterine pouch clinically important?
A
Can be the location of extrauterine pregnancies. Can be important in endometriosis, ovarian cancer, peritoneal metastasis
17
Q
What is adjacent to the rectouterine pouch?
A
The posterior fornix
18
Q
How can you access the rectouterine pouch?
A
Through the vagina and the rectum
19
Q
What is located anterior to the uterus?
A
The vesicouterine pouch
20
Q
What is the most caudal part of the abdominopelvic cavity in men?
A
The rectovesical pouch
21
Q
What makes up the pelvic diaphragm?
A
The coccygeus muscle and the levator ani muscle
22
Q
What makes up the levator ani muscle?
A
The iliococcygeus muscle, the pubococcygeus muscle and the puborectalis muscle
23
Q
How is fecal and urinary continence maintained?
A
The pelvic diaphragm, through tonic contraction
24
Q
Name the parts of the uterus
A
The fundus, the body, the cervix, the wall of the uterus
25
Describe the fundus of the uterus
Rounded superior part of the body above the oviducts, lies superior to the bladder
26
Describe the body of the uterus
The mobile part extending from cervix to fundus
27
Describe the cervix
It communicates with the vagina (external os) and the uterine lumen (internal os)
28
Name the three layers of the wall of the uterus
The endometrium (the inner lining), the myometrium (the thick muscle layer), the perimetrium (surrounding connective tissue
29
Describe the endometrium
It is a tissue highly dynamic under the influence of sex steroid hormones
30
Name the parts of the uterine (fallopian) tubes
The infundibulum, the ampulla, the isthmus, the uterine part
31
Describe the infundibulum of the uterine tubes
The frimbriated highly motile distal end that opens into the abdominal cavity; fimbriae move towards the ovulating surface of the ovary
32
Describe the ampulla of the uterine tubes
The widest and longest part (common location of extrauterine pregnancies)
33
Describe the isthmus of the uterine tubes
The thick-walled part that enters the uterus
34
Describe the uterine part of the uterine tubes
That traverses the uterine wall and opens into the uterine cavity
35
How are the ovaries connected to the uterus?
The ovarian ligament (the ovaries are also attached to the broad ligaments by the mesovarium)
36
What is the main blood supply of the ovary?
It derives from the abdominal aorta and reaches the ovary through the suspensory ligament of ovary (clinical term: infundibulopelvic ligament)
37
Describe the venous system of the ovaries
The right ovarian vein drains into the inferior vena cava and the left ovarian vein drains into the left renal vein
38
Name the ligaments of the uterus and ovary
The broad ligament, the mesovarium and mesosalpinx, the suspensory ligament of the ovary, the proper ligament of the ovary (ovarian ligament), and the round ligament of the uterus
39
Describe the broad ligament
Peritoneal fold reaching from the lateral pelvic wall to the uterus. It contains the uterine artery and the vein and autonomous nerves
40
Describe the mesovarium and the mesosalpinx
They are parts of the broad ligament reaching to ovary and uterine tube
41
Describe the suspensory ligament of the ovary
Carries ovarian blood and lymph vessels connecting the ovary to the retroperitoneal abdominal space
42
Describe the proper ligament of the ovary
Aka the ovarian ligament
| It is caudal connection to the uterus
43
Describe the round ligament of the uterus
It courses within the broad ligament. It connects the fundus of the uterus through the inguinal canal to the labia majora
44
Name the angle made up by the vagina and the body of the uterus
The angle of anteversion
45
Name the angle made up by the cervix and the body of the uterus
The angle of anteflexion
46
How are the fornices formed?
The vagina forms an anterior and posterior and two lateral fornices around the cervix
47
What are the functions of the fallopian tube?
Pick-up of ovulated oocytes (infundibulum)
Transport of the maturing oocyte (infundibulum and ampulla)
Nurishment of oocyte and blastocyst (ampulla)
Sperm reservoir (isthmus)
48
What are the functions of the ovary
Secretion of the steroid hormones estrogen (follicular granulosa cells) and progesteron (luteal cells of the corpus luteum)
Production of ova (ovarian follicles)
49
What are the functions of the vagina
Forms the inferior part of the birth canal
| Receives penis and ejaculate during sexual intercourse
50
Describe the functions of the uterus
Harbouring and nourishing the embryo/fetus (endometrium and myometrium)
51
What is the pelvic fascia?
It surrounds the pelvic organs below the peritoneum and contains blood and lymph vessels and ligaments which stabilize the position of the organs, e.g., the cardinal ligament (aka Mackenrodt ligament) for the uterus
52
Describe pain sensation of the uterus
Pain sensation from the fundus and body of the uterus travels along sympathetic nerve fibres to the lower thoracic and upper lumbar spinal cord (T10-L1)
53
Describe pain sensation of the cervix and the vagina
Pain sensation of the vagina and the cervix uteri travels along the parasympathetic pathway (S2-S4) to S2-S4 spinal sensory ganglia
54
How is the lower part of the vagina innervated?
The inferior part (lower 5th) of the vagina receives somatic innervation through the perineal branch of the pudendal nerve
55
Describe caudal epidural block during childbirth
Anaesthetic administered by catheter in the sacral canal (easy readministration). S2-S4 nerve roots are blocked resulting in anaesthesia of the complete birth canal including pain afferences from cervix and upper vagina and perineal pain afferences travelling with pudendal nerve. The lower limbs are usually not affected. The mother is aware of uterine contractions (pelvic pain line)
56
Describe the epidural block during childbirth
Anaesthetic administered L3-L4 and L4-L5 interspaces
57
Describe the pudendal nerve block during childbirth
Anaesthetic administered near ischial spine as peripheral nerve block. Anaesthesia effective for S2-S4 dermatomes and lower third of vagina. Not effective for cervix and upper part of the vagina. The mother is aware of uterine contractions. Readministration is problematic during prolonged birth phase
58
Describe the uterine artery
It come from the internal iliac artery and travels in the base of the broad ligament. The ovarian branch of the uterine artery anastomoses with the ovarian artery which brings the main blood supply to the ovary
59
What is the seminal vesicle?
It's an accessory gland that produces approximately 80% of seminal fluid. It lies posterior to the bladder and joins the ductus deferens for the ejaculatory duct
60
What is the ductus deferens?
Aka the vas deferens
Approximately 45 cm long muscular tube that connects the epididymis to the ejaculatory duct. It traverses the inguinal canal and enlarges to ampulla behind the bladder. It joins the seminal vesicle for the ejaculatory duct
61
What are testis?
They produce spermatozoa and testosterone
62
What ensheathes the testis and epididymis?
The tunica vaginalis testis
63
Describe the testicular arteries
They derive from the abdominal aorta and traverse the inguinal canal
64
Describe the testicular veins
The left testicular vein drains into the left renal vein and the right testicular vein into the inferior vena cava
65
Describe the lymphatic system of the testicles
Lymph vessels travel along testicular vessels to drain into the pre-aortic lymph nodes (lumbar nodes)
66
Why do testicles descend out of the abdominal through the inguinal canal?
For spermatozoa production, the testicles are required to be a degree or two lower than the body
67
How long does it take for spermatozoa to mature?
3 months
68
Describe the rectum
It's found at the distal end of the large intestine. It has a distensible rectal ampulla above the pelvic floor, which transitions into the anal canal
69
What is the function of the rectum?
Storage and controlled release of feces
70
Name the arteries of that supply the rectum?
The inferior mesenteric artery, the superior rectal artery, the middle rectal artery, the internal pudendal artery and the inferior rectal artery
71
Name the veins that supply the rectum?
The inferior mesenteric vein, the common iliac vein, the superior rectal vein, the middle rectal vein, the internal pudendal vein and the inferior rectal vein
72
Describe the internal anal sphincter
It is smooth muscle, under sympathetic control and normally permanently contracted to close the anal canal. Parasympathetics relax the smooth muscle
73
Describe the external anal sphincter
It is striated muscle, innervated by the pudendal nerve and allows voluntary closure of the anus. It is anchored to the perineal and anococcygeal body
74
Name the major parietal branches of the internal iliac artery
Iliolumbar artery, lateral sacral artery, superior gluteal artery, the obturator artery, the internal pudendal artery, the inferior gluteal artery
75
Name the major visceral branches of the internal iliac artery
The umbilical artery, the superior and inferior vesical artery, the middle recta artery, and the uterine artery
76
Where does the superior gluteal artery supply? What does the superior gluteal artery supply?
It runs betwen the lumbosacral trunk and 1st sacral nerve above the piriformis muscle. It supplies the gluteus medius and minimus muscle and tensor fasciae lata muscle
77
What does the internal pudendal artery supply?
The perineum (skin, muscles, erectile tissues), branches off inferior rectal artery
78
Where does the inferior gluteal artery run? What does it supply?
It separates 1 from 2 sacral nerve, leaves greater sciatic foramen inferior piriformis supplies pelvic diaphragm, gluteus maximus, hamstrings, quadratus femoris
79
Where does the umbilical artery travel?
The distal part obliterated as medial umbilical ligament, gives rise to superior vesical artery
80
What does the superior and inferior vesical artery supply?
The bladder and urete, seminal vesicle and prostate (in men)
81
What does the middle rectal artery supply?
The inferior rectum and seminal vesicles
82
What gives rise to the uterine artery?
May rise from umbilical or directly from internal iliac artery
83
What is found in the urogenital triangle of the diamond-shaped perineum?
The urogenital diaphragm, the urethra, the external gentialia
84
What is found in the anal triangle of the diamond-shaped perineum?
The anus and the anal canal, and the ischioanal fossae
85
Describe the perineum
It is the area inferior to the pelvic floor. The levator ani leave a gap (levator hiatus) for the passage of the urethra, vagina (in women) and the anal canal. The perineal membrane and associated muscular fibrous structures provides support in the area of the urogenital triangle
86
What makes up the roots of the external genitalia?
The bulb of the penis/clitoris, the crus of the penis/clitoris and the greater vestibular glands (in women)
87
Name the parts of the female perineum
The prepuce, the external urinary meatus, the labium majora (majus), the vestibule, the bartholin's duct, the vaginal orifice, the labium minus, the glans of the clitoris
88
What is within the scrotum?
It contains the testis, the epididymis and blood vessels
89
What innervates the scrotum?
The anterior branches from the ilioinguinal and genitofemoral nerves and the posterior branches from the pudendal nerve
90
Why can't the root of the penis be seen?
It is covered by the scrotal raphe
91
What supplies the penis with arterial blood?
All arteries are branches of the internal pudendal artery
92
What innervates the penis?
Sensory innervation is conveyed by the pudendal nerve (S2-S4): dorsal nerve of the penis
93
How is erection facilitated?
By fast influx of arterial blood into the corpora cavernosa
94
What covers the corpora cavernosa?
The tunica albuginea
95
What keeps the urethra open during erection?
The corpus spongiosum, a separate erectile body
96
What forms the corpora cavernosa?
The crura of the penile root converge anteriorly
97
What forms the corpus spongiosum?
The bulb of the penis continues anteriorly
98
How is erection accomplished?
It's a parasympathetic stimulation (S2-S4) of the pelvic sphlanchnic nerves (nervi errigentes). Arterial blood flows into the cavernous spaces in corpora cavernosa and at the same time, venous blood return is decreased by the pressure within the tunica albuginea
99
What does parasympatheic stimulation of the pelvic splanchnic nerves do?
It closes the arteriovenous anastomoses and relaxes smooth muscles in helicine arteries (branches of deep artery of the penis)
100
What do inhibitors of cGMP-selective phosphodiesterase-type 5 (PDE5) do?
They relax smooth muscles in helicane arteries
101
Describe emission
Sympathetic stimulation (L1/L2) stimulates peristalsis of the ductus deference and seminal vesicles. Semen and glandular secretions are delivered to the prostatic urethra through ejaculatory ducts
102
What happens during ejaculation?
Semen is expelled from the urethra, there is contraction of the bulbospongiosus muscle (S2-S4, pudendal nerve) and closure of the internal urethral sphincter (vesical sphincter)
103
Name the three parts of the male urethra
The internal urethral orifice, the prostatic urethra, the membranous part of the urethra, the spongy urethra and the external urethral orifice
104
What is the ischioanal fossae
The fat-filled space beneath the pelvic diaphragm, lateral to the anal canal
105
Name the fascia and the membrane of the perineal body? Which one is more superficial?
The superficial perineal fascia (aka Colles' fascia) is more superficial to the perineal membrane
106
Which pathological conditions are common in perianal region (ischioanal fossae)?
Anal fissure and fistulas, as well as peri-anal abscesses
107
What is the problem with anal fissures and fistulas?
They are extremely painful (inferior rectal nerves) and they can cause partial fecal incontinence (scar tissue can form, reducing sphincter function)
108
What is the problem is peri-anal abscesses?
They can spread to the other side (horseshoe-type) and they can spread into the pelvis
109
How are peri-anal abscesses treated?
They can be drained through the skin
110
What are peri-anal abscesses typically associated with?
Wounds, Crohn's disease
111
Describe the pudendal nerve
It exits the pelvis through the greater sciatic foramen, winds around the ischial spine and sacrospinous ligament, enters the pelvis again through the lesser sciatic foramen and reaches the perineum below the pelvic diaphragm
112
What does the pudendal nerve innervate?
Somatic nerve of the perineum (the voluntary sphincter muscles, the external urethral and the anal sphincter) and sensory supply for the perineal skin (including the posterior of the scrotum)
113
Describe the pudendal nerve block
Anaesthetic administered near the ischial spine that is effective for S2-S4 dermatomes and the lower part of the vagina. It is not effective for the cervix and the upper part of the vagina, so the mother is aware of uterine contractions and associated pain. Re-administration is problematic during prolonged birth phase
114
What is the pudendal nerve block useful for?
The reduce the perineal pain associated with the second stage of labour or with episiotomy or the repair thereof
