case 7 anatomy

Question 1

bladder

Answer 1

The bladder is a hollow, muscular organ that acts as a temporary store for urine. It is a distensible organ and therefore its size, shape and position changes according to its fullness. In the adult the empty bladder is located entirely within the pelvis. As the bladder fills it ascends into the greater pelvis where it lies within the extraperitoneal fascia of the abdominal wall.
in the infant and young child the bladder projects into the abdomen even when empty.

The bladder is surrounded by endopelvic fascia. This fascia consists of loose, areolar, fatty connective tissue that is packed between adjacent structures.

The empty bladder takes the shape of a boat. It presents an apex, base (fundus), body, superior surface, neck, and two inferolateral surfaces.

Question 2

When a patient has urinary retention access to the bladder can be achieved through which region of the abdominal wall?

Answer 2

hypogastric

Question 3

apex of the bladder

Answer 3

Lies anteriorly, behind the upper margin of symphasis pubis. It is attached to the umbilicus by the median umbilical ligament

Question 4

Base/fundus of the bladder

Answer 4

Faces posteriorly, it is triangular in shape and slightly convex.

Question 5

body of the bladder

Answer 5

The major portion of the bladder which is located between the apex and the base.

Question 6

superior surface of the bladder

Answer 6

This is covered with peritoneum, it bulges into the abdominal cavity when distended.

Question 7

neck of the bladder

Answer 7

This structure is held in position by the puboprostatic (male) or the pubovesical (female) ligaments

Question 8

inferolateral surface of the bladder

Answer 8

Lies adjacent to the pubic bone and the retropubic fat pad

Question 9

relations of the bladder

Answer 9

The anterior and lateral relations are the same in both the male and female.
Anterior-ant abdominal wall, retropubic pad, symphasis pubis
Lateral- obturator internus, levator ani
superior-body of uterus, coils of ileum, uterovesical pouch, peritoneal cavity, sigmoid colon
inferior-urogenital diaphragm(the deep transverse perineal and the sphincter urethrae.) prostate
posterior-vagina, vas deferens, retrovesical pouch , seminal vesicles, rectum

Question 10

wall of the bladder-internal surface

Answer 10

The bladder wall consists of the same four layers as that of the ureter: epithelium, lamina propria, muscularis and adventia.
Internal surface:
The epithelium and underlying lamina propria are loosely connected to the muscular layer of the bladder. This allows the mucosa to be thrown into folds when the bladder is empty and to flatten out as the bladder fills. However, one area on the base of the bladder always appears smooth because the mucosa is firmly attached to the underlying muscle.

Question 11

What is the name given to this smooth region of the bladder

Answer 11

trigone-As its name suggests this region is triangular in shape. Each of the three angles of the triangle presents a small ostium: two superiorly and one inferiorly.

Question 12

prevent reflux of urine from the bladder to the ureter

Answer 12

the ureters pass obliquely through the detrusor muscle on their way to the ureteric orifices of the trigone. In addition, fibres of the detrusor muscle encircle the ureteric orifices and these tighten when the uterus contracts.

Question 13

blood supply of the bladder

Answer 13

The bladder receives arterial blood from the superior vesical arteries and the inferior vesical (males) or vaginal arteries (females).

Question 14

innervation of the bladder

Answer 14

The bladder is innervated by the autonomic nervous system and receives fibres mainly via the inferior hypogastric plexus.

Parasympathetic innervation is thought to be the major controller of bladder filling and emptying. Parasympathetic fibres provide motor innervation to the detrusor muscle and inhibitory fibres to the internal sphincter.

Sympathetic fibres may be inhibitory to the detrusor muscle and provide motor innervation to the internal sphincter. However, it is thought that sympathetic innervation is mainly responsible for vasomotor function in the bladder
Sensory information from the bladder may be concerned with reflexes or pain. Reflex afferents follow the course of the parasympathetic fibres.

In order to understand the route of transmission of pain sensation from the bladder you need to understand the concept of the pelvic pain line. Pelvic organs that are in contact with the peritoneum are said to be above the pelvic pain line whilst structures that do not contact the peritoneum are said to be below the pelvic pain line.

Visceral afferent information from structures above the pelvic pain line follows the course of the sympathetic fibres. Visceral afferent information from structures below the pelvic pain line follows the course of the parasympathetic fibres. Pain from above the pelvic pain line is more consciously perceived. Note that when discussing the colon, the pelvic pain line is midway along the length of the sigmoid colon.

Question 15

urethra

Answer 15

The urethra is a muscular tube that conveys urine from the bladder to the external urethral orifice. The male urethra is approximately 20cm long. It extends from the internal urethral orifice to the external urethral orifice which is located on the tip of the glans penis. As well as conveying urine the male urethra also provides a passageway for semen. The male urethra is divided into 4 parts; intramural, prostatic, intermembranous and spongy. The axis of the female urethra lies parallel to that of the vagina and passes with it through the pelvic diaphragm, external urethral sphincter and perineal membrane

Question 16

lymph supply of the urethrer

Answer 16

Most lymph from the female urethra drains into the sacral and internal iliac lymph nodes but some vessels drain into the inguinal lymph nodes. In the male, most lymph from the urethra drains into the internal iliac nodes but some drains into the external iliac nodes. In addition, lymph from the spongy urethra drains into the inguinal nodes.

Question 17

prostate gland

Answer 17

The prostate gland is the largest accessory gland of the male reproductive system. It is a branched tubuloalveolar gland which is embedded in a fibromuscular stroma. It the healthy adult male it is the size of a walnut and it surrounds the prostatic urethra. It has an apex, base, anterior posterior and inferolateral surfaces.

Question 18

peritoneum

Answer 18

The peritoneum passes from the anterior abdominal wall over the pelvic organs and passes over the anterolateral aspect of the rectum.
In the male pelvis, you must be able to identify the:
•	Symphasis pubis
•	Superior surface of the bladder
•	Superior surface of seminal vesicles
•	Rectovesical pouch
•	Rectum
•	Paravesical fossae
•	Pararectal fossae
In the female pelvis, you must be able to identify the:
•	Symphasis pubis
•	Superior surface of the bladder
•	Vesicouterine pouch
•	Fundus and body of the uterus
•	Rectouterine pouch (of Douglas)
•	Rectum
•	Paravesical fossae
•	Pararectal fossae
•	Broad ligament
•	Uterine tubes & ovaries

Question 19

ureters

Answer 19

The ureters are retroperitoneal. They cross the bifurcation of the common iliac artery, where the external iliac artery begins. It is at this point that they cross the pelvic brim and become “pelvic ureters”.
The ureters have 3 constrictions, which are therefore potential sites for renal calculi formation:
- At its origin = Pelviureteric junction.
- Pelvic brim = Where it crosses the external iliac artery.
- Just before it terminates in the bladder = Vesicoureteric junction

Question 20

bladder

Answer 20

The urinary bladder, a hollow viscus with strong muscular walls, is characterized by its dispensability. The empty bladder lies entirely within the pelvic cavity. As the bladder fills, it enters the greater pelvis as it ascends in the extraperitoneal fatty tissue of the anterior abdominal wall. In some individuals, a full bladder may ascend to the level of the umbilicus.
The bladder is surrounded by endopelvic fascia. This fascia consists of loose, areolar, fatty connective tissue that is packed between adjacent structures.
The bladder is separated from the pubic bones by the potential retropubic space (of Retzius) and lies mostly inferior to the peritoneum, resting on the pubic bones and pubic symphasis anteriorly and the prostate (males) or anterior wall of the vagina posteriorly.It is relatively free within the extraperitoneal subcutaneous fatty tissue, except for its neck, which is held firmly by the lateral ligaments of bladder and the tendinous arch of the pelvic fascia - especially its anterior component, the puboprostatic ligament in males and the pubovesical ligament in females.
In females, since the posterior aspect of the bladder rests directly upon the anterior wall of the vagina, the lateral attachment of the vagina to the tendinous arch of the pelvic fascia, the paracolpium, is an indirect but important factor in supporting the urinary bladder.

Question 21

relations of the bladder

Answer 21

• Anterior: Pubic symphasis.
• Posterior: In males – Rectovesical pouch, seminal vesicles, ductus deferentes. In females – Uterovesical pouch, vagina, and cervix.
• Superior: Intestine, and body of uterus in females.
• Inferolateral: Retropubic space, pubic bones, and fascia covering the levator ani & the superior obturator internus muscles.

Question 22

walls of the bladder

Answer 22

The walls of the bladder are composed mainly by the detrusor muscle.
Toward the neck of the male bladder, the muscle fibers form the involuntary internal urethral sphincter. This sphincter contracts during ejaculation to prevent retrograde ejaculation (ejaculatory reflux) of semen into the bladder. Some fibers run radially and assist in opening the internal urethral orifice. In males, the muscle fibers in the neck of the bladder are continuous with the fibromuscular tissue of the prostate, whereas in females these fibers are continuous with muscle fibers in the wall of the urethra.
The bladder is lined with transitional epithelium, like the ureters, allowing the bladder to stretch. The lining mucosa is arranged in folds which also allow the bladder to stretch to accommodate urine.
There is an area of mucosa that is smooth, called the bladder trigone. The ureteric orifices and the internal urethral orifice mark the angles of the trigone.
The ureters travel inferomedially through the wall of the bladder in an oblique plane. This oblique plane forms a one-way “flap valve”. The internal pressure of the filling bladder causes the internal passage to collapse.

Question 23

arterial supply of the bladder

Answer 23

The main arteries supplying the bladder are branches of the internal iliac arteries.
The superior vesical arteries supply anterosuperior parts of the bladder.
In males, the inferior vesical arteries supply the fundus and neck of the bladder.
In females, the vaginal arteries replace the inferior vesical arteries and send small branches to posteroinferior parts of the bladder.

Question 24

venous drainage of the bladder

Answer 24

The veins draining blood from the bladder correspond to the arteries and are tributaries of the internal iliac veins.
In males, the vesical venous plexus is continuous with the prostatic venous plexus, and the combined plexus complex envelops the fundus of the bladder and prostate, the seminal glands, the ductus deferentes, and the inferior ends of the ureters. It also receives blood from the deep dorsal
vein of the penis, which drains into the prostatic venous plexus. The vesical venous plexus is the part of the plexus complex that is most directly associated with the bladder itself. It mainly drains through the inferior vesical veins into the internal iliac veins.
In females, the vesical venous plexus envelops the pelvic part of the urethra and the neck of the bladder, receives blood from the dorsal vein of the clitoris, and communicates with the vaginal or uterovaginal venous plexus.

Question 25

innervation of the bladder

Answer 25

Sympathetic innervation – Vesical (pelvic) plexuses, primarily via hypogastric plexuses and nerves. (Lower thoracic, upper lumbar spinal cord segments).
Parasympathetic innervation – Pelvic splanchnic nerves and the inferior hypogastric plexus. (Sacral spinal cord segments).
The parasympathetic fibres provide motor innervation to the detrusor muscle and inhibitory to the internal urethral sphincter of the male bladder, allowing urine to flow into the urethra. Sympathetic innervation has the opposite effect.
Sensory fibers from most of the bladder are visceral; reflex afferents follow the course of the parasympathetic fibers, as do those transmitting pain sensations (such as results from overdistension) from the inferior part of the bladder.
The superior surface of the bladder is covered with peritoneum and is therefore superior to the pelvic pain line; thus pain fibers from the superior bladder follow the sympathetic fibers retrogradely to the inferior thoracic and upper lumbar spinal ganglia (T11–L2 or L3).

Question 26

lymph drainage of the bladder

Answer 26

Lymph from the bladder drains into the external and internal iliac lymph nodes. The internal iliac lymph nodes are usually the primary site of lymphadenopathy related to bladder pathology.
Lymph from the bladder neck may drain into the sacral or common iliac nodes.

Question 27

differences between the male and female urethra

Answer 27

The female urethra is distensible because it contains considerable elastic tissue, as well as smooth muscle. It can be easily dilated without injury; consequently, the passage of catheters or cystoscopes is easier in females than in males. Infections of the urethra, and especially the bladder, are more common in women because the female urethra is short, more distensible, and is open to the exterior through the vestibule of the vagina

Question 28

female urethra

Answer 28

The female urethra (approximately 4 cm long and 6 mm in diameter) passes anteroinferiorly from the internal urethral orifice of the urinary bladder, posterior and then inferior to the pubic symphysis, to the external urethral orifice. The musculature surrounding the internal urethral orifice of the female bladder is not organized into an internal sphincter. In females, the external urethral orifice is located in the vestibule, the cleft between the labia minora of the external genitalia, directly anterior to the vaginal orifice. The urethra lies anterior to the vagina (forming an elevation in the anterior vaginal wall). The urethra passes with the vagina through the pelvic diaphragm, external urethral sphincter, and perineal membrane. Urethral glands are present, particularly in the superior part of the urethra. One group of glands on each side, the paraurethral glands, are homologs to the prostate. These glands have a common paraurethral duct, which opens (one on each side) near the external urethral orifice.
Blood Supply – Urethral artery (branch of internal pudendal) and vaginal artery. The veins follow the arteries and have similar names.
Innervation – Nerves to the urethra: Vesical plexus & pudendal nerve. Nerves from the urethra: Mostly pelvic splanchnic nerves, but the termination of the urethra has signals transmitted via the pudendal nerve. All afferent nerves = S2-S4.

Question 29

male urethra

Answer 29

The male urethra originates at the bladder neck and terminates at the urethral meatus on the glans penis. It is roughly 15-25 cm long in the adult and forms an “S” curve when viewed from a median sagittal plane in an upright, flaccid position.
The male urethra is often divided into 4 segments on the basis of its investing structures:
• Preprostatic urethra (the bladder neck).
• Prostatic urethra.
• Membranous (or intermediate) urethra.
• Spongy (or penile) urethra.

Question 30

prostatic urethra

Answer 30

It originates in the region of the bladder neck, courses roughly 2.5 cm inferiorly, and terminates at the membranous urethra. It lies in a retropubic location and is bordered superiorly by the bladder and supported inferiorly by the external urethral sphincter muscle and the urogenital diaphragm. It is invested in the prostate.

Question 31

membranous urethra

Answer 31

: The shortest and least distensible portion of the urethra. This region spans from the apex of the prostate to the bulb of the penis. It is invested in the external urethral sphincter muscle and the perineal membrane. The external sphincter is related anteriorly to the dorsal venous complex and is connected to the puboprostatic ligaments and the suspensory ligament of the penis. The external urethral sphincter muscle and the perineal membrane fix the urethra firmly to the ischial rami and inferior pubic rami, rendering this portion of the urethra susceptible to disruption with pelvic fracture.

Question 32

spongy urethra

Answer 32

The spongy urethra is the region that spans the corpus spongiosum of the penis. It is divided into the pendulous urethra and the bulbous (or bulbar) urethra. The pendulous urethra is invested in the corpus spongiosum of the penis in the pendulous portion of the penis. The urethra is located concentrically within the corpus spongiosum. The bulbous urethra is invested in the bulb of the penis, the portion of corpus spongiosum that lies between the split corpora cavernosa in the superficial perineal space.

Question 33

male blood supply and innervation to urethra

Answer 33

Male proximal (pre-prostatic & prostatic) urethra:
Blood Supply – Prostatic branches of the inferior vesical & middle rectal arteries. The veins from the proximal 2 parts of the urethra drain into the prostatic venous plexus.
Innervation – Sympathetic, parasympathetic, and visceral afferent nerve fibres run together in nerves of the prostatic plexus (arising from the inferior hypogastric plexus).
Male distal (membranous & spongy) urethra:
Blood Supply – Arterial branches arise from the dorsal artery of the penis. Veins accompany the arteries and have similar names.
Innervation - Membranous urethra has the same innervation as the proximal urethra. The spongy urethra has sympathetic innervation from lumbar splanchnic nerves and parasympathetic innervation from pelvic splanchnic nerves (sacral spinal cord level). It transmits visceral afferent fibres alongside the parasympathetic fibres to sacral spinal sensory ganglia. Somatic innervation is provided via the dorsal nerve of the penis (branch of pudendal nerve).

Question 34

lymph drainage of the urethra

Answer 34

The lymphatic vessels of the membranous and prostatic urethrae in males and the whole of the urethra in the female, pass to the internal iliac nodes, although a few may enter the external nodes. Vessels coming from the spongy urethra drain with the glans penis into the deep inguinal nodes. Some of the vessels may enter the superficial inguinal nodes and may pass through the inguinal canal to reach the external iliac nodes.
From these nodes they drain into the lateral aortic nodes. From the nodes, efferents issue to the lumbar lymph trunk. The lumbar lymph trunks help to form the abdominal confluence of lymph ducts or the cisterna chyli. Cisterna chyli drains into thoracic duct.

Question 35

prostate gland

Answer 35

The prostate is about 3 cm long, 4 cm wide, and 2 cm in depth from anterior to posterior (about the size of a walnut). It is the largest accessory gland of the male reproductive system. The prostate is firm and surrounds the prostatic urethra. The glandular part makes up approximately 2/3 of the prostate. The other 1/3 is fibromuscular.
The fibrous capsule of the prostate is dense and neurovascular, incorporating the prostatic plexuses of veins and nerves. All this is surrounded by the visceral layer of the pelvic fascia, forming a fibrous prostatic sheath that is thin anteriorly, continuous anterolaterally with the puboprostatic ligaments, and dense posteriorly where it blends with the rectovesical septum.
The prostate has:
• A base closely related to the neck of the bladder.
• An apex that is in contact with fascia on the superior aspect of the urethral sphincter and deep perineal muscles.
• A muscular anterior surface, featuring mostly transversely oriented muscle fibers forming a vertical, trough-like hemisphincter (rhabdosphincter), which is part of the urethral sphincter. The anterior surface is separated from the pubic symphysis by retroperitoneal fat in the retropubic space.
• A posterior surface that is related to the ampulla of the rectum.
• 2 x inferolateral surfaces that are related to the levator ani.
The prostate has an isthmus and 2 lobes (right & left), although they are not very distinct, anatomically. The more medial parts of lobules in these lobes tend to undergo hormone-induced hypertrophy in advanced age, forming an actual middle lobule that lies between the urethra and the ejaculatory ducts, near to the neck of the bladder. Enlargement of the prostate can cause problems with urination, such as difficulty initiating the process and incomplete emptying, etc. It can be detected via a digital rectal examination.Prostatic ducts (about 20-30 in number) open mainly into the prostatic sinuses that lie on either side of the seminal colliculus on the posterior wall of the prostatic urethra. Prostatic fluid provides ~20% of the volume of semen.

Question 36

blood supply lymph and innervation of the prostate

Answer 36

: Prostatic arteries are mainly branches of the internal iliac artery, especially the inferior vesical arteries but also the internal pudendal and middle rectal arteries. The veins join to form a plexus around the sides and base of the prostate. This prostatic venous plexus, between the fibrous capsule of the prostate and the prostatic sheath, drains into the internal iliac veins.
Lymphatic Drainage: Lymph primarily drains into the obturator and internal iliac lymph nodes. There is also some drainage into external iliac, presacral, and paraaortic lymph nodes.
Innervation: Autonomic innervation arises from pelvic plexuses from S2-S4, except for the sympathetic fibres which arise from L1-L2. The autonomic fibres run to the prostate via the cavernous nerves. Parasympathetic innervation causes prostatic secretion, whereas sympathetic innervation causes contraction of the smooth muscle of the capsule and the stroma. The pudendal nerve provides somatic innervation to the striated sphincter and the levator ani.