Male genital organs pdf - Pelvis

Basic Anatomy

without interruption from one organ to the other. The

the neck of the bladder, the smooth muscle passing

The base of the prostate is continuous with

Superiorly:

Relations

margins of the prostatic utricle (see Fig. 7.16).

the prostate to open into the prostatic urethra at the lateral

tory ducts pierce the upper part of the posterior surface of

against the urogenital diaphragm below. The two ejacula

which lies

apex,

lies against the bladder neck above, and an

which

Fig. 7.16). The somewhat conical prostate has a

The prostate is surrounded by a fibrous capsule (see

above and the urogenital diaphragm below (see Fig. 7.16).

1.25 in. (3 cm) long and lies between the neck of the bladder

rounds the prostatic urethra (see Figs. 7.4 and 7.16). It is about

The prostate is a fibromuscular glandular organ that sur

Location and Description

the prostatic urethra.

tatic utricle; their function is to drain the seminal fluid into

static part of the urethra, close to the margins of the pros

the posterior surface of the prostate and open into the pro

the seminal vesicle (Fig. 7.16). The ejaculatory ducts pierce

are formed by the union of the vas deferens and the duct of

The two ejaculatory ducts are each <1 in. (2.5 cm) long and

thus washing the spermatozoa out of the urethra.

contract and expel their contents into the ejaculatory ducts,

the spermatozoa. During ejaculation, the seminal vesicles

that is added to the seminal fluid. The secretions nourish

The function of the seminal vesicles is to produce a secretion

Function

The internal iliac nodes.

Lymph Drainage

The veins drain into the internal iliac veins.

Veins

The inferior vesicle and middle rectal arteries.

Arteries

embedded in connective tissue.

Each seminal vesicle consists of a much-coiled tube

ejaculatory duct.

the same side to form the

each seminal vesicle narrows and joins the vas deferens of

vesicles are related to the rectum (see Fig. 7.4). Inferiorly,

terminal part of the vas deferens. Posteriorly, the seminal

(see Fig. 7.13). On the medial side of each vesicle lies the

(5 cm) long lying on the posterior surface of the bladder

The seminal vesicles are two lobulated organs about 2 in.

Seminal Vesicles

ejaculatory duct.

the duct of the seminal vesicle to form the

The inferior end of the ampulla narrows down and joins

ampulla of the vas deferens.

deferens is dilated to form the

of the bladder (see Fig. 7.11). The terminal part of the vas

275

Blood Supply

Ejaculatory Ducts

-
-

Prostate

base,

■

bladder wall

sphincter vesicae

prostate

sphincter urethrae

spinal cord

FIGURE 7.15

then runs medially and downward on the posterior surface

the ureter in the region of the ischial spine. The vas deferens

and backward on the lateral wall of the pelvis and crosses

epigastric artery (see Fig. 7.11). It then passes downward

nal ring and passes around the lateral margin of the inferior

through the inguinal canal. It emerges from the deep ingui

from the lower end or tail of the epididymis and passes

epididymis to the ejaculatory duct and the urethra. It arises

(45 cm) long that conveys mature sperm from the

The vas deferens is a thick-walled tube about 18 in.

Vas Deferens

are described on page 131.

epididymides

testes

The

during the second or third year of life.

Voluntary control of micturition is normally developed

which compresses the bladder neck.

closes the urethra; this is assisted by the sphincter vesicae,

accomplished by contracting the sphincter urethrae, which

segments of the cord. Voluntary control of micturition is

with the corticospinal tracts to the 2nd, 3rd, and 4th sacral

rition are favorable. The inhibitory fibers pass downward

of the cerebral cortex until the time and place for mictu

omitted for clarity.

to the bladder are shown; the sympathetic fibers have been

ous system and the parasympathetic efferent fibers passing

sensory fibers from the bladder entering the central nerv

The afferent

of the spinal cord in the upper thoracic region. Destruction

Nervous control of the bladder after section

of the sacral segments of the spinal cord. B.

Male Genital Organs

and

276

CHAPTER 7

The Pelvis: Part II—The Pelvic Cavity

mucous membrane

bladder

vesicle veins

capsule

of prostate

prostatic venous plexus

openings of prostatic glands

urogenital diaphragm

urethral crest

prostatic utricle

prostatic sinus

levator ani

visceral pelvic fascia

bladder

median lobe

urethra

anterior lobe

ejaculatory duct

posterior lobe

anal

canal

prostatic sinus

prostatic urethra

glands of prostate

urethral crest

capsule of prostate

prostatic venous plexus

fascial sheath of prostate

FIGURE 7.16

Prostate in coronal section

lies in front of the urethra and

anterior lobe

Fig. 7.16). The

The prostate is incompletely divided into five lobes (see

ducts open into the prostatic urethra.

mixture of smooth muscle and connective tissue, and their

The numerous glands of the prostate are embedded in a

Structure of the Prostate

pubis (see Fig. 7.16).

ers of the levator ani as they run posteriorly from the

The prostate is embraced by the anterior fib

Laterally:

extended down to the perineal body.

the rectovesical pouch of peritoneum, which originally

in fetal life by the fusion of the walls of the lower end of

This septum is formed

tum (fascia of Denonvilliers).

rectovesical sep

ampulla and is separated from it by the

closely related to the anterior surface of the rectal

The prostate (see Figs. 7.4 and 7.16) is

Posteriorly:

(see Fig. 7.4).

puboprostatic ligaments

nected to the posterior aspect of the pubic bones by the

The prostate is con

(cave of Retzius).

retropubic space

extraperitoneal fat

pubis, separated from it by the

The prostate is related to the symphysis

Anteriorly:

(see Fig. 7.16).

the prostate just above the apex on the anterior surface

surface of the urogenital diaphragm. The urethra leaves

The apex of the prostate lies on the upper

Inferiorly:

Fig. 7.4).

urethra enters the center of the base of the prostate (see

openings of the ejaculatory ducts on the margin of the prostatic utricle.

and horizontal section

sagittal section

(A),

(B),

(C). In the coronal section, note the

■

in the

fascial

■

Basic Anatomy

ous vesical veins and drains into the internal iliac veins.

plexus receives the deep dorsal vein of the penis and numer

side the capsule of the prostate (see Fig. 7.16). The prostatic

which lies out

prostatic venous plexus,

The veins form the

Veins

Branches of the inferior vesical and middle rectal arteries.

Arteries

tralize the acidity in the vagina.

urethra. The prostatic secretion is alkaline and helps neu

rounds the glands, squeezes the secretion into the prostatic

at the time of ejaculation. The smooth muscle, which sur

acid and acid phosphatase that is added to the seminal fluid

The prostate produces a thin, milky fluid containing citric

Function of the Prostate

of the prostate. The lateral lobes contain many glands.

another by a shallow vertical groove on the posterior surface

lie on either side of the urethra and are separated from one

left lateral lobes

right

contains glandular tissue. The

behind the urethra and below the ejaculatory ducts and also

is situated

posterior lobe

the bladder; it is rich in glands. The

ejaculatory ducts. Its upper surface is related to the trigone of

is the wedge of gland situated between the urethra and the

middle, lobe

median,

is devoid of glandular tissue. The

ulate the smooth muscle of the prostate during ejaculation.

Inferior hypogastric plexuses. The sympathetic nerves stim

Nerve Supply

Internal iliac nodes.

Lymph Drainage

277

and

Blood Supply

Prostate Examination

prostate. Cancer cells enter the skull via this route by floating up

vertebral veins exist. During coughing and sneezing or abdomi

Many connections between the prostatic venous plexus and the

are valveless, and are drained by several large trunks directly

adds to the patient’s

(Fig. 7.17). The stagnant urine frequently becomes infected,

stagnant urine behind the urethral orifice within the bladder

enlarged median lobe) results in the formation of a pouch of

plication. The enlargement of the uvula vesicae (owing to the

culty in passing urine and the stream is weak. Back-pressure

the gland produces elongation and lateral compression and

micturate. The enlargement of the median and lateral lobes of

into the prostatic urethra causes an intense reflex desire to

cae, located at the neck of the bladder. The leakage of urine

hormonal control of the gland. The median lobe of the gland

than 50 years. The cause is possibly an imbalance in the

Benign enlargement of the prostate is common in men older

tate, this protein appears in the blood in increased amounts. The

It has been shown that trace amounts of proteins produced

producing this enzyme cannot discharge their secretion into the

The prostate can be examined clinically by palpation by perform-

ing a rectal examination (see page 311). The examiner’s gloved

finger can feel the posterior surface of the prostate through the

anterior rectal wall.

Prostate Activity and Disease

It is now generally believed that the normal glandular activity of

the prostate is controlled by the androgens and estrogens cir-

culating in the bloodstream. The secretions of the prostate are

poured into the urethra during ejaculation and are added to the

seminal fluid. Acid phosphatase is an important enzyme pres-

ent in the secretion in large amounts. When the glandular cells

ducts, as in carcinoma of the prostate, the serum acid phospha-

tase level of the blood rises.

specifically by prostatic epithelial cells are found in peripheral

blood. In certain prostatic diseases, notably cancer of the pros-

specific protein level can be measured by a simple laboratory

test called the PSA test.

Benign Enlargement of the Prostate

enlarges upward and encroaches within the sphincter vesi-

distortion of the urethra so that the patient experiences diffi-

effects on the ureters and both kidneys are a common com-

and the inflamed bladder (cystitis)

symptoms.

In all operations on the prostate, the surgeon regards the

prostatic venous plexus with respect. The veins have thin walls,

into the internal iliac veins. Damage to these veins can result in

a severe hemorrhage.

Prostate Cancer and the Prostatic Venous Plexus

nal straining, it is possible for prostatic venous blood to flow in a

reverse direction and enter the vertebral veins. This explains the

frequent occurrence of skeletal metastases in the lower verte-

bral column and pelvic bones of patients with carcinoma of the

the valveless prostatic and vertebral veins.

C L I N I C A L N O T E S

enlarged median lobe of prostate

bladder wall

ejaculatory duct

posterior lobe

urethra

sphincter
vesicae

pouch of
stagnant urine

FIGURE 7.17

Sagittal section of a prostate that had under

der pouch filled with stagnant urine behind the prostate.

gone benign enlargement of the median lobe. Note the blad-

278

CHAPTER 7

lateral to the lateral fornix of the vagina, to enter the bladder.

artery (Figs. 7.18 and 7.19). The ureter then runs forward,

of the broad ligament, where it is crossed by the uterine

spine. It then turns forward and medially beneath the base

behind the ovary until it reaches the region of the ischial

ward and backward in front of the internal iliac artery and

cation of the common iliac artery (Fig. 7.18). It runs down

The ureter crosses over the pelvic inlet in front of the bifur

sections.

the pelvic cavity in the female are described in the following

as described previously. The contents of the anterior part of

occupy the posterior part of the pelvic cavity (see Fig. 7.5),

The rectum, sigmoid colon, and terminal coils of ileum

Pelvic Viscera in the Female

directly in contact with the abdominal wall.

the anterior abdominal wall so that the bladder becomes

up into the abdomen and peels off the peritoneum from

to remember that as the bladder fills, the superior wall rises

not cover the lateral surfaces of the bladder. It is important

bladder passes laterally to the lateral pelvic walls and does

The peritoneum covering the superior surface of the

the erect position, is the rectovesical pouch (see Fig. 7.4).

abdominopelvic peritoneal cavity, when the patient is in

abdominal wall. It is thus seen that the lowest part of the

continuous with the parietal peritoneum on the posterior

surfaces of the upper third of the rectum. It then becomes

the middle third of the rectum and the front and lateral

The peritoneum then passes up on the front of

pouch.

rectovesical

aspect of the rectum, forming the shallow

nal vesicles. Here, it sweeps backward to reach the anterior

a short distance until it reaches the upper ends of the semi

then runs down on the posterior surface of the bladder for

nal wall onto the upper surface of the urinary bladder. It

The peritoneum passes down from the anterior abdomi

pelvis in a sagittal plane (see Fig. 7.4).

The peritoneum is best understood by tracing it around the

covers and supports the pelvic viscera (see Fig.7.16).

The visceral pelvic fascia is a layer of connective tissue that

Visceral Pelvic Fascia

openings of the two ejaculatory ducts (see Fig. 7.16).

in females. On the edge of the mouth of the utricle are the

which is an analog of the uterus and vagina

static utricle,

pro

the summit of the urethral crest is a depression, the

the prostatic glands open into these grooves. On

sinus;

prostatic

On each side of this ridge is a groove called the

(see Fig. 7.16).

urethral crest

longitudinal ridge called the

On the posterior wall is a

portion of the entire urethra.

prostatic urethra is the widest and most dilatable

The

with the membranous part of the urethra (see Fig. 7.16).

tate from the base to the apex, where it becomes continuous

begins at the neck of the bladder. It passes through the pros

The prostatic urethra is about 1.25 in. (3 cm) long and

The Pelvis: Part II—The Pelvic Cavity

Prostatic Urethra

Peritoneum

Ureters

-
-

psoas

ilium

internal iliac artery

uterine artery

ureter

obturator internus

levator ani

posterior fornix

anterior fornix

vagina

bladder

inferior epigastric artery

round ligament of uterus

uterine tube

round ligament of ovary

ovary

external iliac vessels

urethra

FIGURE 7.18

y, the uterine tube, and the vagina.

Right half of the pelvis showing the ovar