Lower limb and pelvic cavity Flashcards
(131 cards)
1
Q
What makes up the bony pelvis?
A
The bony pelvis consists of the two hip bones (also known as innominate or pelvic bones), the sacrum and the coccyx.
2
Q
What are the articulations with the bony pelvis?
A
Sacroiliac joints (x2) – between the ilium of the hip bones, and the sacrum
Sacrococcygeal symphysis – between the sacrum and the coccyx.
Pubic symphysis – between the pubis bodies of the two hip bones.
3
Q
What are the roles of the pelvis?
A
Transfer of weight from the upper axial skeleton to the lower appendicular components of the skeleton, especially during movement.
Provides attachment for a number of muscles and ligaments used in locomotion.
Contains and protects the abdominopelvic and pelvic viscera.
4
Q
What are the greater and lesser pelvis?
A
Greater pelvis (false pelvis) – located superiorly, it provides support of the lower abdominal viscera (such as a ileum and sigmoid colon). It has little obstetric relevance. Lesser pelvis (true pelvis) – located inferiorly. Within the lesser pelvis reside the pelvic cavity and pelvic viscera.
5
Q
What is the pelvic inlet and the pelvic rim?
A
The junction between the greater and lesser pelvis is known as the pelvic inlet. The outer bony edges of the pelvic inlet are called the pelvic brim.
The pelvic inlet marks the boundary between the greater pelvis and lesser pelvis. Its size is defined by its edge, the pelvic brim.
6
Q
What are the borders of the pelvic inlet?
A
Posterior – sacral promontory (the superior portion of the sacrum) and sacral wings (ala).
Lateral – arcuate line on the inner surface of the ilium, and the pectineal line on the superior pubic ramus.
Anterior – pubic symphysis.
7
Q
What determines the dynamics of the birth canal?
A
The pelvic inlet determines the size and shape of the birth canal, with the prominent ridges key areas of muscle and ligament attachment.
8
Q
What is the linea terminalis?
A
The combined pectineal line, arcuate line and sacral promontory.
9
Q
What is the Iliopectineal line?
A
The combined arcuate and pectineal lines. This represents the lateral border of the pelvic inlet.
10
Q
What are the borders of the pelvic outlet?
A
Posterior: The tip of the coccyx
Lateral: The ischial tuberosities and the inferior margin of the sacrotuberous ligament
Anterior: The pubic arch (the inferior border of the ischiopubic rami).
11
Q
What is the sub pubic angle?
A
The angle beneath the pubic arch is known as the sub-pubic angle and is of a greater size in women.
12
Q
What are the characteristic features of a female pelvis?
A
A wider and broader structure yet it is lighter in weight
An oval-shaped inlet compared with the heart-shaped android pelvis.
Less prominent ischial spines, allowing for a greater bispinous diameter
A greater angled sub-pubic arch, more than 80-90 degrees.
A sacrum which is shorter, more curved and with a less pronounced sacral promontory.
13
Q
How can the female pelvic extend during child birth?
A
In addition to the bony adaptations, the sacrotuberous and sacrospinous ligaments can stretch under the influence of progesterone and increase the size of the outlet further.
14
Q
What are the roles of the bladder?
A
Temporary storage of urine – the bladder is a hollow organ with distensible walls. It has a folded internal lining (known as rugae), which allows it to accommodate up to 300-400ml of urine in healthy adults.
Assists in the expulsion of urine – the musculature of the bladder contracts during micturition, with concomitant relaxation of the sphincters.
15
Q
What is the appearance of the bladder?
A
The appearance of the bladder varies depending on the amount of urine stored. When full, it exhibits an oval shape, and when empty it is flattened by the overlying bowel.
16
Q
What are the external features of the bladder?
A
Apex – located superiorly, pointing towards the pubic symphysis. It is connected to the umbilicus by the median umbilical ligament (a remnant of the urachus).
Body – main part of the bladder, located between the apex and the fundus
Fundus (or base) – located posteriorly. It is triangular-shaped, with the tip of the triangle pointing backwards.
Neck – formed by the convergence of the fundus and the two inferolateral surfaces. It is continuous with the urethra.
17
Q
How does urine enter and exit the bladder?
A
Urine enters the bladder through the left and right ureters, and exits via the urethra.
18
Q
What is the trigone of the bladder?
A
A triangular area located within the fundus of the bladder.
In contrast to the rest of the internal bladder, the trigone has smooth walls (this is explained by the different embryological origin: the trigone is developed by the integration of two mesonephric ducts at the base of the bladder).
19
Q
What is the rugae of the bladder?
A
When the bladder is empty, the mucosa has numerous folds called rugae. The rugae and transitional epithelium allow the bladder to expand as it fills.
20
Q
What is the submucosa of the bladder?
A
The second layer in the walls is the submucosa, which supports the mucous membrane. It is composed of connective tissue with elastic fibers.
21
Q
What is the detrusor muscle?
A
In order to contract during micturition, the bladder wall contains specialised smooth muscle – known as detrusor muscle. Its fibres are orientated in multiple directions, thus retaining structural integrity when stretched. It receives innervation from both the sympathetic and parasympathetic nervous systems.
22
Q
What happens when the detrusor muscle becomes hypertrophic?
A
The fibers of the detrusor muscle often become hypertrophic (presenting as prominent trabeculae) in order to compensate for increased workload of the bladder emptying. This is very common in conditions that obstruct the urine outflow such as benign prostatic hyperplasia.
23
Q
What are the two sphincters in the urethra?
A
Internal urethral sphincter:
Male – consists of circular smooth fibres, which are under autonomic control. It is thought to prevent seminal regurgitation during ejaculation.
Females – thought to be a functional sphincter (i.e. no sphincteric muscle present). It is formed by the anatomy of the bladder neck and proximal urethra.
External urethral sphincter – has the same structure in both sexes. It is skeletal muscle, and under voluntary control. However, in males the external sphincteric mechanism is more complex, as it correlates with fibers of the rectourethralis muscle and the levator ani muscle.
24
Q
What is the arterial supply of the bladder?
A
Arterial supply is via the superior vesical branch of the internal iliac artery. In males, this is supplemented by the inferior vesical artery, and in females by the vaginal arteries. In both sexes, the obturator and inferior gluteal arteries may also contribute small branches.
25
What is the venous drainage of the bladder?
Venous drainage is achieved by the vesical venous plexus, which empties into the internal iliac veins. The vesical plexus in males is in continuity at the retropubic space with the prostate venous plexus (plexus of Santorini), which also receives blood from the dorsal vein of the penis.
26
What is the nervous supply of the bladder?
Sympathetic – hypogastric nerve (T12 – L2). It causes relaxation of the detrusor muscle, promoting urine retention.
Parasympathetic – pelvic nerve (S2-S4). Increased signals from this nerve causes contraction of the detrusor muscle, stimulating micturition.
Somatic – pudendal nerve (S2-4). It innervates the external urethral sphincter, providing voluntary control over micturition.
Sensory (afferent) nerves - found in the bladder wall and signal the need to urinate when the bladder becomes full to the brain.
27
What is the bladder stretch reflex?
The bladder stretch reflex is a primitive spinal reflex, in which micturition is stimulated in response to stretch of the bladder wall. It is analogous to a muscle spinal reflex, such as the patella reflex.
28
What happens when toddlers are potty trained?
During toilet training in infants, this spinal reflex is overridden by the higher centres of the brain, to give voluntary control over micturition.
29
What is the reflex arc of micturition?
Bladder fills with urine, and the bladder walls stretch. Sensory nerves detect stretch and transmit this information to the spinal cord.
Interneurons within the spinal cord relay the signal to the parasympathetic efferents (the pelvic nerve).
The pelvic nerve acts to contract the detrusor muscle, and stimulate micturition.
30
How can the bladder stretch reflex be damaged?
Spinal injuries (where the descending inhibition cannot reach the bladder), and in neurodegenerative diseases (where the brain is unable to generate inhibition).
31
What is the Interureteric bar?
A useful landmark during examination of the inside of the bladder using a telescope (cystoscopy), the two ureters can be seen discharging urine at either end of the bar.
32
What is benign prostatic hypertrophy?
The prostate gland completely encircles the urethra. With progressing age enlargement of the prostatic tissue (hypertrophy) is common and may lead to complete blockage of the urethra and the inability to pass any urine. This requires emergency catheterisation.
33
Where can prostatic cancer metastase to?
Venous drainage from the prostate passes into a plexus of veins which lie anterior to the sacrum and communicate with veins which run up to the azygos vein in the chest. These veins communicate with veins in the vertebral bodies.
The veins do not have valves so can flow in either direction. During inspiration the negative pressure in the chest sucks blood up the veins but during expiration gravity pulls it back down again. Tumour cells travel up the veins and then pass down into the vertebral bodies where they may attach and cause a metastasis.
34
What are the effects of a loss of brain control in micturition?
Loss of brain control: bladder fills, spinal cord knows that the bladder is full but this does not reach the brain. Spinal cord asks brain permission to empty, brain does not reply so spinal cord controls a complete normal emptying of the bladder. The patient suddenly and unexpectedly passes urine with no control, there is low pressure in the bladder so no risk of renal failure.
35
What are the effects of a loss of sensation in micturition?
Loss of sensation: spinal cord and brain cannot know that the bladder is full so do not tell it to empty. Bladder fills up and the patient continually dribbles urine with high pressure in the bladder and kidney which rapidly progresses to kidney damage. Patient has no awareness of the full bladder.
36
What are the effects of a loss of the spinal motor control in micturition?
Loss of the spinal cord motor control: patient knows that the bladder is full but cannot empty it. High pressure in the bladder and renal failure.
37
What is a rectal prostate examination?
Prostatic disease is very common and palpation (feeling) the prostate is useful. As the prostate lies immediately anterior to the rectum examination through the anal canal is possible.
38
What are the major features of the uterus?
The pear-shaped uterus is a hollow muscular organ about 8cm long.
It communicates laterally with the uterine tubes and inferiorly with the vagina. For description, the uterus is divided into the fundus (above the uterine tubes), the body and the cervix.
39
What is the angle of the uterus?
The body of the uterus is typically bent forwards: ante-flexed and lies on the superior surface of the bladder. The junction between the body and the cervix may be tilted forwards (ante-verted) or backwards (retro-verted).
40
What is the internal and external os?
The cervix has a narrow lumen, the cervical canal which communicates with the uterine cavity via the internal os and with the vagina via the external os.
41
What are layers of the uterus?
Peritoneum – a double layered membrane, continuous with the abdominal peritoneum.
Myometrium – thick smooth muscle layer. Cells of this layer undergo hypertrophy and hyperplasia during pregnancy in preparation to expel the fetus at birth.
Endometrium – inner mucous membrane lining the uterus. It can be further subdivided into 2 parts:
- Deep stratum basalis: Changes little throughout the menstrual cycle and is not shed at menstruation.
- Superficial stratum functionalis: Proliferates in response to oestrogens, and becomes secretory in response to progesterone. It is shed during menstruation and regenerates from cells in the stratum basalis layer.
42
What are the vaginal fornices?
The lower part of the cervix lies inside the vagina creating spaces, the vaginal fornices around the edge of the cervix.
43
How is cervix held in place?
The position of the cervix is stabilised by tone of the levator ani muscle and by condensations of pelvic fascia, the cardinal ligaments. The cardinal ligaments run from the lateral wall of the cervix to the lateral pelvic sidewall at the base of the broad ligament.
44
What are the ligaments in the female reproductive system?
Broad Ligament: double layer of peritoneum attaching the sides of the uterus to the pelvis. It acts as a mesentery for the uterus and contributes to maintaining it in position.
Round Ligament: A remnant of the gubernaculum extending from the uterine horns to the labia majora via the inguinal canal. It functions to maintain the anteverted position of the uterus.
Ovarian Ligament: Joins the ovaries to the uterus.
Cardinal Ligament: Located at the base of the broad ligament, the cardinal ligament extends from the cervix to the lateral pelvic walls. It contains the uterine artery and vein in addition to providing support to the uterus.
Uterosacral Ligament: Extends from the cervix to the sacrum. It provides support to the uterus.
45
What is the arterial supply and venous drainage of the uterus?
The blood supply to the uterus is via the uterine artery. Venous drainage is via a plexus in the broad ligament that drains into the uterine veins.
46
What is the lymphatic drainage of the uterus?
Lymphatic drainage of the uterus is via the iliac, sacral, aortic and inguinal lymph nodes.
47
What is the nervous supply of the uterus?
Sympathetic nerve fibres of the uterus arise from the uterovaginal plexus. This largely comprises the anterior and intermediate parts of the inferior hypogastric plexus.
Parasympathetic fibres of the uterus are derived from the pelvic splanchnic nerves (S2-S4).
The cervix is largely innervated by the inferior nerve fibres of the uterovaginal plexus.
The afferent fibres mostly ascend through the inferior hypogastric plexus to enter the spinal cord via T10-T12 and L1 nerve fibres.
48
What are the uterine tubes?
The paired uterine tubes (or fallopian tubes, oviducts, salpinx) are about 10cm long and are found running in the upper border of the broad ligament. Near the uterus the tubes have a narrow isthmus.
49
What is the role of the uterine tubes?
The main function of the uterine tubes is to assist in the transfer and transport of the ovum from the ovary, to the uterus.
50
What is the structure of the uterine tubes?
Laterally the tubes have a dilated ampulla, leading into a funnel-shaped infundibulum. The free edge of the funnel is broken up into finger-like projections, the fimbriae, which are draped over the ovary. In this region the uterine tubes open into the peritoneal cavity at the ostium.
51
What is the lymphatic drainage of the uterine tubes?
Lymphatic drainage is via the iliac, sacral and aortic lymph nodes.
52
What is the innervation of the uterine tubes?
The uterine tubes receive both sympathetic and parasympathetic innervation via nerve fibres from the ovarian and uterine (pelvic) plexuses. Sensory afferent fibres run from T11- L1.
53
What are the ovaries?
The ovaries are almond-shaped organs about 4cm long and 2cm wide. They are attached to the posterior of the broad ligament by a short mesentery, the mesovarium.
54
Where are the ovaries located?
The position of the ovary is not fixed, but it frequently lies in the ovarian fossa, formed by the angle between the internal and external iliac arteries. The ureter and the obturator nerve and vessels are close relations of the ovarian fossa.
55
What is the arterial supply of the ovaries?
The blood supply of the ovaries is derived directly from the abdominal aorta close to the origins of the renal arteries.
56
What is the venous drainage of the ovaries?
Venous drainage is achieved by paired ovarian veins. The left ovarian vein drains into the left renal vein, and the right ovarian vein drains directly into the inferior vena cava.
57
How are the ovaries innervated?
The ovaries receive sympathetic and parasympathetic innervation from the ovarian and uterine (pelvic) plexuses, respectively. The nerves reach the ovaries via the suspensory ligament of the ovary, to enter the ovary at the hilum.
58
What are the functions of the ovaries?
To produce oocytes (female gametes) in preparation for fertilisation.
To produce the sex steroid hormones oestrogen and progesterone, in response to pituitary gonadotrophins (LH and FSH).
59
What are the ligaments of the ovaries?
Suspensory ligament of ovary – fold of peritoneum extending from the mesovarium to the pelvic wall. Contains neurovascular structures.
Ligament of ovary – extends from the ovary to the fundus of the uterus. It then continues from the uterus to the connective tissue of the labium majus, as the round ligament of uterus.
60
What is the vagina?
The vagina is the female organ of copulation and the excretory duct of the uterus. It is about 10cm long. It has a blind-ended vault in the region of the cervix and terminated below at the introitus by opening into the vestibule between the labia minora.
61
Where is the vagina?
The vagina passses through the pelvic floor, the upper two thirds of the vagina lie in the pelvic cavity and the lower one third in the perineum. The vagina is closely related to the bladder anteriorly and the urethra is embedded in the anterior wall of its lower third.
62
What are the roles of the vagina?
Sexual intercourse – receives the penis and ejaculate, assisting in its transport to the uterus.
Childbirth – expands to provide a channel for delivery of a newborn from the uterus.
Menstruation – serves as a canal for menstrual fluid and tissue to leave the body.
63
What is the structure of the vagina?
The vagina is a fibromuscular tube with anterior and posterior walls – these are normally collapsed and thus in contact with one another.
64
What is the shape of the vagina?
The shape of the vagina is not a round tunnel. In the transverse plane it is more like an “H” lying on the side. At the upper ending, the vagina surrounds the cervix, creating two domes (fornices or vaults): an anterior and a (deeper) posterior one.
65
What is the posterior fornix?
The posterior fornix is important as it acts like a natural reservoir for semen after intravaginal ejaculation. The semen retained in the fornix liquefies in the next 20-30 mins, allowing for easier permeation through the cervical canal.
66
What is the arterial supply of the vagina?
The arterial supply to the vagina is via the uterine and vaginal arteries – both branches of the internal iliac artery.
67
What is the venous drainage of the vagina?
Venous return is by the vaginal venous plexus, which drains into the internal iliac veins via the uterine vein.
68
What is the innervation of the vagina?
Innervation is predominantly from the autonomic nervous system. Parasympathetic and sympathetic nerves arise from the uterovaginal nerve plexus (in turn a subsidiary of the inferior hypogastric plexus).
Only the inferior 1/5 of the vagina receives somatic innervation. This is via a branch of the pudendal nerve, the deep perineal nerve.
69
What is the role of the vulva?
Acts as sensory tissue during sexual intercourse
Assists in micturition by directing the flow of urine
Protects the internal female reproductive tract from infection.
70
What is the mons pubis?
The mons pubis is a rounded, hair bearing elevation of the skin located in front of the pubic symphysis.
71
What is the labia majora?
Extending posteriorly from the mons pubis are the labia majora, prominent hair-bearing folds of skins which cover the vestibule.
They extend from the mons pubis posteriorly to the posterior commissure (a depression overlying the perineal body).
Embryologically derived from labioscrotal swellings
72
What is the labia minora?
The vestibule is bounded laterally by soft folds of hairless skin, the labia minora.
They fuse anteriorly to form the hood of the clitoris and extend posteriorly either side of the vaginal opening.
They merge posteriorly, creating a fold of skin known as the fourchette.
Embryologically derived from urethral folds
73
What is the vestibule?
The area enclosed by the labia minora. It contains the openings of the vagina (external vaginal orifice, vaginal introitus) and urethra.
74
What are Bartholin’s glands?
Secrete lubricating mucus from small ducts during sexual arousal. They are located either side of the vaginal orifice.
75
What is the clitoris?
Located under the clitoral hood. It is formed of erectile corpora cavernosa tissue, which becomes engorged with blood during sexual stimulation.
76
What is the arterial supply to the vulva?
The arterial supply to the vulva is from the paired internal and external pudendal arteries (branches of the internal iliac).
77
What is the venous drainage of the vulva?
Venous drainage is achieved via the pudendal veins, with smaller labial veins contributing as tributaries.
78
How is the vulva innervated?
To describe the sensory distribution, the vulva can be divided into anterior and posterior sections:
Anterior – ilioinguinal nerve, genital branch of the genitofemoral nerve
Posterior – pudendal nerve, posterior cutaneous nerve of the thigh.
79
How is the clitoris and vestibule innervated?
The clitoris and the vestibule also receive parasympathetic innervation from the cavernous nerves – derived from the uterovaginal plexus.
80
What is the urethra like in females?
In females, the urethra is relatively short (approximately 4cm). It begins at the neck of the bladder, and passes inferiorly through the perineal membrane and muscular pelvic floor. The urethra opens directly onto the perineum, in an area between the labia minora, known as the vestibule.
81
What is the arterial supply and venous drainage of the female urethra?
The arterial supply to the female urethra is via the internal pudendal arteries, vaginal arteries and inferior vesical branches of the vaginal arteries. Venous drainage is given by veins of the same names.
82
What are the anatomical borders of the perineum?
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Anterior – pubic symphysis.
Posterior – tip of the coccyx.
Laterally – inferior pubic rami and inferior ischial rami, and the sacrotuberous ligament.
Roof – pelvic floor.
Base – skin and fascia.
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83
How can the perineum be subdivided?
The perineum can be subdivided by a theoretical line drawn transversely between the ischial tuberosities. This split forms the anterior urogenital triangle and the posterior anal triangle. These triangles are associated with different components of the perineum.
84
What are the surface borders of the perineum?
Anterior – mons pubis in females, base of the penis in males.
Laterally – medial surfaces of the thighs.
Posterior – superior end of the intergluteal cleft.
85
What is the anal triangle?
The anal triangle is the posterior half of the perineum. It is bounded by the coccyx, sacrotuberous ligaments, and a theoretical line between the ischial tuberosities.
86
What is the content of the anal triangle?
Anal aperture – the opening of the anus.
External anal sphincter muscle – voluntary muscle responsible for opening and closing the anus.
Ischioanal fossae (x2) – spaces located laterally to the anus.
87
What are the ischioanal fossae?
These fossae contain fat and connective tissue, which allow for expansion of the anal canal during defecation. They extend from the skin of the anal region (inferiorly) to the pelvic diaphragm (superiorly).
88
What is the urogenital triangle?
The urogenital triangle is the anterior half of the perineum. It is bounded by the pubic symphysis, ischiopubic rami, and a theorectical line between the two ischial tuberosities. The triangle is associated with the structures of the urogenital system – the external genitalia and urethra.
89
What are the layers of the urogenital triangle?
Deep perineal pouch – a potential space between the deep fascia of the pelvic floor and the perineal membrane.
Perineal membrane – a layer of tough fascia, which is perforated by the urethra (and the vagina in the female).
Superficial perineal pouch – a potential space between the perineal membrane and the superficial perineal fascia.
Perineal fascia – a continuity of the abdominal fascia that has two components: deep and superficial fascia
Skin – The urethral and vaginal orifices open out onto the skin.
90
What is the perineal body?
The perineal body is an irregular fibromuscular mass. It is located at the junction of the urogenital and anal triangles – the central point of the perineum. This structure contains skeletal muscle, smooth muscle and collagenous and elastic fibres.
91
Which muscles attached to the perineal body?
Levator ani (part of the pelvic floor).
Bulbospongiosus muscle.
Superficial and deep transverse perineal muscles.
External anal sphincter muscle.
External urethral sphincter muscle fibres.
92
What is the role of the perineal body?
In women, it acts as a tear resistant body between the vagina and the external anal sphincter, supporting the posterior part of the vaginal wall against prolapse. In the male, it lies between the bulb of penis and the anus.
93
What is the neurovascular supply to the perineum?
The major neurovascular supply to the perineum is from the pudendal nerve (S2 to S4) and the internal pudendal artery.
94
What is bartholinitis?
Normally, the Bartholin’s glands are not detected on physical examination. However, if the duct becomes blocked, then these glands can swell to form fluid-filled cysts.
These cysts can become infected and inflamed, a condition known as bartholinitis. The most common cause of infection is from bacteria such as Staphylococcus spp. and Escherichia coli.
95
What is the pelvic floor?
The pelvic floor is a funnel-shaped structure. It attaches to the walls of the lesser pelvis, separating the pelvic cavity from the perineum inferiorly (region which includes the genitalia and anus).
96
What are the roles of the pelvic floor muscles?
Support of abdominopelvic viscera (bladder, intestines, uterus etc.) through their tonic contraction.
Resistance to increases in intra-pelvic/abdominal pressure during activities such as coughing or lifting heavy objects.
Urinary and faecal continence. The muscle fibres have a sphincter action on the rectum and urethra. They relax to allow urination and defecation.
97
What is the Levator ani?
Innervated by the anterior ramus of S4 and branches of the pudendal nerve (roots S2, S3 and S4).
The levator ani is a broad sheet of muscle. It is composed of three separate paired muscles; pubococcygeus, puborectalis and iliococcygeus.
98
What is the Puborectalis?
The puborectalis muscle is a U-shaped sling, extending from the bodies of the pubic bones, past the urogenital hiatus, around the anal canal. Its tonic contraction bends the canal anteriorly, creating the anorectal angle (90 degrees) at the anorectal junction (where the rectum meets the anus).
Some fibers of the puborectalis muscle (pre-rectal fibers) form another U-shaped sling that flank the urethra in the male and the urethra and vagina in the female
99
What is the function of the puborectalis?
The main function of this thick muscle is to maintain faecal continence – during defecation this muscle relaxes.
Some fibers are very important in preserving urinary continence, especially during abrupt increase of the intra-abdominal pressure i.e. during sneezing.
100
What is the pubococcygeus?
The muscle fibres of the pubococcygeus are the main constituent of the levator ani. They arise from the body of the pubic bone and the anterior aspect of the tendinous arch. The fibres travel around the margin of the urogenital hiatus and run posteromedially, attaching at the coccyx and anococcygeal ligament.
101
What is the iliococcygeus?
The iliococcygeus has thin muscle fibres, which start anteriorly at the ischial spines and posterior aspect of the tendinous arch. They attach posteriorly to the coccyx and the anococcygeal ligament.
This part of the levator ani is the actual “levator” of the three: its action elevates the pelvic floor and the anorectal canal.
102
What is the coccygeus?
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The coccygeus (or ischiococcygeus) is the smaller, and most posterior pelvic floor component – as the levator ani muscles are situated anteriorly.
It originates from the ischial spines and travels to the lateral aspect of the sacrum and coccyx, along the sacrospinous ligament.
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103
What are the male organs of reproduction?
The male organs of reproduction include the paired testes, epididymis, ducti deferentia, seminal vesicles, ejaculatory ducts, bulbo-urethral glands as well as the prostate gland and penis.
104
What are the seminal vesicles?
Each seminal vesicle is a lobulated sac, about 4 cm long, lying lateral to the ampulla of the vas.
105
What is the function of the seminal vesicles?
They do not store spermatozoa, but secrete a thick alkaline fluid which forms the bulk (70%) of the seminal fluid. Each side of the duct of the seminal vesicle terminated in an ejaculatory duct which pierces the back of the prostate gland, running through its substance to enter the prostatic urethra.
106
What is the structure of the seminal vesicles?
Internally the gland has a honeycombed, lobulated structure with a mucosa lined by pseudostratified columnar epithelium. These columnar cells are highly influenced by testosterone, growing taller with higher levels, and are responsible for the production of seminal secretions.
107
What are the different fluids produced by the seminal vesicles?
Alkaline fluid – neutralises the acidity of the male urethra and vagina in order to facilitate the survival of spermatozoa.
Fructose – provides an energy source for spermatozoa.
Prostaglandins – have a role in suppressing the female immune response to foreign semen.
Clotting factors – designed to keep semen in the female reproductive tract post-ejaculation.
108
Other than the fluids from the seminal vesicles, what makes up the semen?
The remaining volume of semen is made up of testicular spermatozoa, prostatic secretions and mucus from the bulbourethral gland.
109
What is the arterial supply to the seminal vesicles?
The arteries to the seminal gland are derived from the inferior vesicle, internal pudendal and middle rectal arteries, all of which stem from the internal iliac artery.
110
What is the prostate gland?
The prostate gland is a roughly spherical fibromuscular gland about the size of a walnut. It lies against the neck of the bladder and is pierced by the urethra and ejaculatory ducts.
111
What is the role of the prostate gland?
It secretes proteolytic enzymes into the semen, which act to break down clotting factors in the ejaculate. This allows the semen to remain in a fluid state, moving throughout the female reproductive tract for potential fertilisation.
112
What are benign and malignant tumours of the prostate?
Both benign and malignant tumours of the prostate are common in older men. Benign tumours frequently occur in that part of the prostate above and between the ejaculatory ducts (the median lobe). Though benign, these tumours interfere with urination.
113
Where is the prostate gland?
The prostate is positioned inferiorly to the neck of the bladder and superiorly to the external urethral sphincter, with the levator ani muscle lying inferolaterally to the gland.
114
What are the zones of the prostate?
Central zone – surrounds the ejaculatory ducts, comprising approximately 25% of normal prostate volume.
Transitional zone – located centrally and surrounds the urethra, comprising approximately 5-10% of normal prostate volume.
Peripheral zone – makes up the main body of the gland (approximately 65%) and is located posteriorly.
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Where in the prostate is benign prostatic hyperplasia most likely to occur?
The glands of the transitional zone are those that typically undergo benign hyperplasia (BPH)
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Where in the prostate is prostatic carcinoma most likely to occur?
The ducts of the glands from the peripheral zone are vertically emptying in the prostatic urethra; that may explain the tendency of these glands to permit urine reflux.
That also explains the high incidence of acute and chronic inflammation found in these compartments, a fact that may be linked to the high incidence of prostate carcinoma at the peripheral zone.
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What is the fibromuscular stroma?
The fibromuscular stroma (or fourth zone for some) is situated anteriorly in the gland. It merges with the tissue of the urogenital diaphragm. This part of the gland is actually the result of interaction of the prostate gland budding around the urethra during prostate embryogenesis and the common horseshoe-like muscle precursor of the smooth and striated muscle that will eventually form the internal and external urethra sphincter.
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What is the arterial supply of the prostate?
The arterial supply to the prostate comes from the prostatic arteries, which are mainly derived from the internal iliac arteries. Some branches may also arise from the internal pudendal and middle rectal arteries.
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What is the venous drainage of the prostate?
Venous drainage of the prostate is via the prostatic venous plexus, draining into the internal iliac veins.
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What is the innervation of the prostate?
The prostate receives sympathetic, parasympathetic and sensory innervation from the inferior hypogastric plexus. The smooth muscle of the prostate gland is innervated by sympathetic fibres, which activate during ejaculation.
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What is the male urethra like?
This fibromuscular tube conducts urine and semen and is about 15-20cm long.
It passes from the internal urethral meatus of the bladder to the external urethral meatus of the glans penis.
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What are the different parts of the male urethra?
It has a prostatic part (3cm) where it descends through the prostate gland a, a membranous part (1cm) where it traverses the urogenital diaphragm and a spongy or penile part (15cm) travelling through the bulb, corpus spongiosum and glans of the penis.
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What does the male urethra do?
In addition to urine, the male urethra transports semen – a fluid containing spermatozoa and sex gland secretions.
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What is the arterial supply of the male urethra?
Prostatic urethra – supplied by the inferior vesical artery (branch of the internal iliac artery which also supplies the lower part of the bladder).
Membranous urethra – supplied by the bulbourethral artery (branch of the internal pudendal artery)
Penile urethra – supplied directly by branches of the internal pudendal artery.
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What is the innervation for the male urethra?
The nerve supply to the male urethra is derived from the prostatic plexus, which contains a mixture of sympathetic, parasympathetic and visceral afferent fibres.
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What is the pathway of the sperm?
The sperm migrate from of the seminiferous tubules (site of production) to the epididymis. Within the epididymis, the sperm mature while they are stored in this structure.
The ejaculation process begins as the penis fills with blood and becomes erect. With sufficient stimulation, mature sperm travel from the epididymis through the vas deferens, a muscular tube, which propels sperm forward through smooth muscle contractions. The sperm arrive first at the ampulla, where secretions from the seminal vesicle are added.
From the ampulla, seminal fluid is propelled forward through the ejaculatory ducts toward the urethra, passing first by the prostate gland, where a milky fluid is added to form semen. Finally, the semen is ejaculated through the far end of the urethra.
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What is a Hystero-salpingogram?
The contrast medium is injected through the cervix and flows through the uterus, fallopian tubes and into the peritoneal cavity, these appear white on the X-ray.
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What is urinary retention?
Inability to pass urine because of benign hypertrophy of the prostate gland is common, the emergency treatment is placement of a catheter through the prostate.
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What might cause urinary incontinence?
Neurological control of micturition, muscle weakness and vaginal ‘hernias’ may all result in the inability to store urine in the bladder.
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What is a vaginal hernia?
The vagina passes through a large hole in the pelvic floor, particularly after child birth. The uterus, bladder, urethra or rectum may herniate through this hole. These are known as uterine prolapse, cystocele, urethrocele and rectocele respectively.
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What is pelvic inflammatory disease?
The fallopian tube opens directly into the peritoneal cavity and provides a route from the exterior of the body into the cavity. Sexually acquired infection can easily spread into the abdominal cavity through the tube. This infects the pelvic part of the cavity - pelvic inflammatory disease.
