pendulous organ suspended from the front and sides of the pubic arch and containing the greater part of the urethra. In the flaccid condition it is cylindrical in shape, but when erect assumes the form of a triangular prism with rounded angles, one side of the prism forming the dorsum.
The Corpora Cavernosa Penis form the greater part of the substance of the penis.
For their anterior three-fourths they lie in intimate apposition with one another, but behind they diverge in the form of two tapering processes, known as the crura, which are firmly connected to the rami of the pubic arch.
Traced from behind forward, each crus begins by a blunt-pointed process in front of the tuberosity of the ischium.
Just before it meets its fellow it presents a slight enlargement, named by Kobelt the bulb of the corpus cavernosum penis.
Beyond this point the crus undergoes a constriction and merges into the corpus cavernosum proper, which retains a uniform diameter to its anterior end. Each corpus cavernosum penis ends abruptly in a rounded end
The urethra enters the bulb nearer to the upper than to the lower surface. On the latter there is a median sulcus, from which a thin fibrous septum projects into the substance of the bulb and divides it imperfectly into two lateral lobes or hemispheres.
Crosses through the prostate gland . There are several openings: (1) a small opening where sperm from the vas deferens and ejaculatory duct enters, (2) the prostatic ducts where fluid from the prostate enters, (3) an opening for the prostatic utricle , but nothing is added from it. These openings are collectively called the verumontanum
A small (1 or 2 cm) portion passing through the external urethral sphincter . This is the narrowest part of the urethra. It is located in the deep perineal pouch . The ducts from the bulbourethral glands enter here.
Hypospadias and epispadias are forms of abnormal development of the urethra in the male, where the meatus is not located at the distal end of the penis (it occurs lower than normal with hypospadias, and higher with epispadias). In a severe chordee , the urethra can develop between the penis and the scrotum .
Infection of the urethra is urethritis , said to be more common in females than males. Urethritis is a common cause of dysuria (pain when urinating).
Related to urethritis is so called urethral syndrome
Passage of kidney stones through the urethra can be painful and subsequently it can lead to urethral strictures .
The membranous part of the urethra is about 0.5 in. (1.3 cm) long and lies within the urogenital diaphragm, surrounded by the sphincter urethrae muscle; it is continuous above with the prostatic urethra and below with the penile urethra. It is the shortest and least dilatable part of the urethra).
Sphincter Urethrae Muscle
The sphincter urethrae muscle surrounds the urethra in the deep perineal pouch. It arises from the pubic arch on the two sides and passes medially to encircle the urethra portion of the urethra.
The bulbourethral glands are two small glands that lie beneath the sphincter urethrae muscle. Their ducts pierce the perineal membrane (inferior fascial layer of the urogenital diaphragm) and enter the penile The secretion is poured into the urethra as a result of erotic stimulation
The two testicles are egg-shaped male reproductive glands.
They are suspended in a pouch of loose skin called the scrotum below and behind the penis. In maturity, they are usually slightly smaller than a golf ball. It is normal for one testicle to be larger than the other
The testicles produce the hormone testosterone as well as sperm, the male reproductive cells.
Covered by tunica albuginea 1 Epididymis 2 Head of epididymis 3 Lobules of epididymis 4 Body of epididymis 5 Tail of epididymis 6 Duct of epididymis 7 Deferent duct (ductus deferens or vas deferens)
The vas deferens is a thick-walled tube about 18 in. (45 cm) long that conveys mature sperm from the epididymis to the ejaculatory duct and the urethra.
It arises from the lower end or tail of the epididymis and passes through the inguinal canal.
It emerges from the deep inguinal ring and passes around the lateral margin of the inferior epigastric artery
It then passes downward and backward on the lateral wall of the pelvis and crosses the ureter in the region of the ischial spine.
The vas deferens then runs medially and downward on the posterior surface of the bladder.
The terminal part of the vas deferens is dilated to form the ampulla of the vas deferens. The inferior end of the ampulla narrows down and joins the duct of the seminal vesicle to form the ejaculatory duct.
The function of the seminal vesicles is to produce a secretion that is added to the seminal fluid. The secretions nourish the spermatozoa. During ejaculation the seminal vesicles contract and expel their contents into the ejaculatory ducts, thus washing the spermatozoa out of the urethra.
Superiorly: The base of the prostate is continuous with the neck of the bladder, the smooth muscle passing without interruption from one organ to the other. The urethra enters the center of the base of the prostate.
Inferiorly: The apex of the prostate lies on the upper surface of the urogenital diaphragm. The urethra leaves the prostate just above the apex on the anterior surface (Fig. 7-16).
Anteriorly: The prostate is related to the symphysis pubis, separated from it by the extraperitoneal fat in the retropubic space (cave of Retzius). The prostate is connected to the posterior aspect of the pubic bones by the fascial puboprostatic ligaments
Posteriorly: The prostate is closely related to the anterior surface of the rectal ampulla and is separated from it by the rectovesical septum (fascia of Denonvilliers). This septum is formed in fetal life by the fusion of the walls of the lower end of the rectovesical pouch of peritoneum, which originally extended down to the perineal body.
The numerous glands of the prostate are embedded in a mixture of smooth muscle and connective tissue, and their ducts open into the prostatic urethra.
The prostate is incompletely divided into five lobes
The anterior lobe lies in front of the urethra and is devoid of glandular tissue.
The median, or middle, lobe is the wedge of gland situated between the urethra and the ejaculatory ducts. Its upper surface is related to the trigone of the bladder; it is rich in glands.
The posterior lobe is situated behind the urethra and below the ejaculatory ducts and also contains glandular tissue.
The right and left lateral lobes lie on either side of the urethra and are separated from one another by a shallow vertical groove on the posterior surface of the prostate. The lateral lobes contain many glands.
The prostate produces a thin, milky fluid containing citric acid and acid phosphatase that is added to the seminal fluid at the time of ejaculation. The smooth muscle, which surrounds the glands, squeezes the secretion into the prostatic urethra. The prostatic secretion is alkaline and helps neutralize the acidity in the vagina.
Branches of the inferior vesical and middle rectal arteries.
The veins form the prostatic venous plexus, which lies outside the capsule of the prostate (Fig. 7-16). The prostatic plexus receives the deep dorsal vein of the penis and numerous vesical veins and drains into the internal iliac veins.
Internal iliac nodes.
Inferior hypogastric plexuses. The sympathetic nerves stimulate the smooth muscle of the prostate during ejaculation