Male Pelvis and perineum

Question 1

Ureter function and features

Answer 1

A. Ureter
1. Function: muscular tube which transports urine from kidney to urinary bladder.

2. General Features
   a. Primary retroperitoneal.
   b. Course inferomedially along posterior abdominal body wall, descends over pelvic brim to enter pelvis, then along lateral pelvic wall to enter posterior bladder wall.

Question 2

Ureter clinical correlation: ureteric calculus

Answer 2

can cause complete obstruction of ureter, especially in 3 sites:

a. At renal pelvis/ureteric junction.
b. At passage over pelvic brim.
c. At entry into urinary bladder.

Question 3

arterial supply to urerter

Answer 3

a. Upper 1/3 – renal a/v
b. Middle 1/3 – gonadal, aorta, common iliac aa/vv.
c. Lower 1/3 – internal iliac a/v

Question 4

lymphatic drainage of the ureter

Answer 4

a. Upper 1/3 → lumbar lymph nodes.
b. Middle 1/3 → common iliac lymph nodes.
c. Lower 1/3 → common, external, internal iliac lymph nodes

Question 5

Bladder: relationships

Answer 5

a. Anterior - pubic bones and symphysis
b. Posterior – rectum, seminal vesicle, ductus deferens, rectovesical pouch.
c. Lateral - muscles of pelvic wall and pelvic diaphragm
d. Inferior – prostate

Question 6

Bladder: features

Answer 6

a. Apex – posterior to pubic symphysis; median umbilical ligament
b. Neck – inferior portion; surrounds internal urethral orifice
c. Superior surface
d. Inferolateral surfaces (2)
e. Posterior (base) surface – point at which ureters enter bladder

Question 7

Bladder: structure

Answer 7

a. Distendable muscular sac lined by transitional epithelium.
b. Detrusor muscle layer – 3 layers of smooth muscle; not well-organized.
c. Fibrous CT adventitia containing blood vessels and nerves.
d. Trigone
1. Triangular area between the ureteral orifices and internal urethral orifice.
2. Superior border marked by interureteric crest; inferior border marked by uvula (slight elevation proximal to internal urethral orifice).
3. Trigonal muscle is an extension of ureteric muscle; prevents reflux of urine into ureter (sympathetic innervation).

Question 8

Bladder: peritoneum and supporting ligaments

Answer 8

a. Peritonealized only on superior surface.
b. Lateral ligament of bladder (thickening of endopelvic fascia)
c. Puboprostatic – attaches neck to pubic bone

Question 9

Bladder: vascular supply

Answer 9

a. Arteries:
1. Superior vesicle a.
2. Inferior vesicle a.
b. Veins:
1. Vesicle venous plexus → internal iliac v.
2. Also, venous connections to sacral veins → internal vertebral venous plexus.

Question 10

Bladder: lymphatic drainage

Answer 10

a. Superior and lateral surfaces → external iliac nodes.
b. Base and neck → internal iliac nodes.
c. Neck also drains posteriorly → sacral lymph nodes

Question 11

Cystocele

Answer 11

(more common in females)

a. A cystocele (fallen bladder) can result from a weakening of the pelvic diaphragm and/or fascias which support the bladder. Most common cause of a cystocele is childbirth; can also result from obesity, chronic constipation, or heavy lifting.
b. Can cause urinary incontinence as well as incomplete emptying of the bladder.

Question 12

Suprapubic cystostomy

Answer 12

a. The full bladder extends superior to pubic symphysis, but remains deep to peritoneum. This provides access to bladder for inserting catheters.
b. Because the bladder is subperitoneal, this allows for access without compromising the peritoneal cavity.

Question 13

Male Urethra: portions

Answer 13

a. Intramural urethra (pelvic)
1. Extends through neck of bladder
2. Encircled by internal portion of sphincter urethrae muscle. This portion of the muscle is sympathetically innervated and has two functions: maintains urinary continence and prevents retrograde movement of semen during ejaculation.

b. Prostatic urethra (pelvic)
1. Urethral crest – posteromedian ridge of mucosa
2. Seminal colliculus – rounded eminence on urethral crest; has central opening for ejaculatory duct.
3. Prostatic sinuses – lateral grooves on either side of urethral crest; contains openings for prostatic ducts.
4. Prostatic utricle – remnant of paramesonephric duct.

c. Membranous urethra (perineum)
1. Passes through the deep space of the UG triangle.
2. Surrounded by the external portion of the sphincter urethrae mm. This portion of the muscle is skeletal and controls urinary continence.

3. Spongy (penile) urethra (perineum)
   a. Courses through corpus spongiosum of penis
   b. 2 swellings; in bulb (urethral ampulla) and in glans (navicular fossa)
   c. Receives bulbourethral secretions.
   d. External urethral orifice at distal end.

Question 14

Male urethra: lymphatic drainage

Answer 14

a. Pelvic and membranous portions drain to internal iliac nodes.
b. Distal spongy portion drains to deep inguinal lymph nodes.

Question 15

Male urethra: associated glands

Answer 15

a. Bulbourethral Glands (Cowper’s Glands)
1. Paired tubuloalveolar glands; located in deep perineal space.
2. Secrete mucus into membranous urethra; lubrication and neutralizes acidic urine.
b. Urethral – mucous-secreting

Question 16

Urethral catheterization

Answer 16

Knowledge of the anatomy of male urethra is vital when inserting catheters. There are two curves along the course of the male urethra; one within the membranous urethra and one within the spongy urethra. The membranous portion of the urethra is most frequently damaged.

Question 17

Urethral rupture

Answer 17

a. Membranous urethra can rupture with pelvic girdle fractures; blood/urine can extravasate into deep perineal space and extraperitoneal spaces of pelvis.
b. Spongy urethra can be ruptured within the bulb as a result of a forceful blow or incorrectly inserted catheter; blood and urine can extravasate into superficial perineal space, scrotum, penis, and anterior abdominal wall.

Question 18

Rectum

Answer 18

1. Terminal 6-8” of large bowel; originates at SV3 as a continuation of the sigmoid colon (rectosigmoind junction); terminates at anal canal (anorectal junction).
2. External features
   a. Sacral flexure – anterior concavity following curvature of sacrum.
   b. Teniae coli spread out as continuous layer of longitudinal muscle.
   c. Anorectal flexure – sharp angulation maintained by puborectalis muscle.
3. Anatomical relationships:
   a. Anterior – bladder, ductus deferens, seminal glands, prostate
   b. Posterior – sacrum, coccyx

Question 19

Rectum: vascular supply

Answer 19

a. Arteries
1. Superior rectal a.
a. Branch of inferior mesenteric a.
b. Supples: mucosa/muscular portions of rectum
2. Middle rectal a.
a. Branch of internal iliac a.
b. Supplies: muscular layers of rectum
b. Veins
1. Superior rectal v. – drains to hepatic portal system
2. Middle rectal v.- tributary of internal iliac v.

Question 20

Rectum: lymphatic drainage

Answer 20

a. Rectosigmoid junction drains to inferior mesenteric nodes.
b. Lateral portion drains to pararectal nodes → internal iliac nodes.
c. Inferior half drains to sacral and internal iliac lymph nodes.

Question 21

Anal canal and Ischioanal fossa

Answer 21

1. Extends from pelvic diaphragm (anorectal junction) to anus (external orifice).
2. Ischioanal fossa
   a. Fat-filled space allowing for expansion of rectum/anal canal during defecation.
   b. Boundaries
3. Posterior – sacrotuberous ligament, gluteus maximus
4. Anterior – posterior border of UG diaphragm
5. Lateral – obturator internus
6. Medial – external anal sphincter and anal canal
7. Medial superior – levator ani
   c. The ischioanal fossae communicate posteriorly via the deep postanal space.
   d. Anterior recess – extends anteriorly; superior to UG diaphragm

Question 22

Clinical correlation: Ischio-anal abscesses

Answer 22

These can be caused by inflammation of the anal sinuses (cryptitis), a tear in the anal mucosa (from trauma or constipation). These can spread to the opposite ischioanal fossa via the deep postanal space.

Question 23

Internal features of the anal canal

Answer 23

a. Anal columns – folds of mucosa containing superior rectal vv.
b. Anal valves – folds of epithelium superficial to anal sinuses.
c. Pectinate line is formed along the anal valves and represents the site where the cloacal membrane was located developmentally. This line represents a change in:
1. Embryonic derivation
a. Superior to pectinate line – hindgut (endoderm)
b. Inferior to pectinate line – proctodeum (ectoderm)
2. Nerve supply
a. Superior – autonomic innervation
b. Inferior – somatic innervation
3. Epithelial lining
a. Superior – typical GI mucous lining
b. Inferior – stratified squamous
4. Venous drainage
a. Superior – drains to superior and middle rectal vv.
b. Inferior – drains to inferior rectal vv
5. Lymphatic drainage
a. Superior to pectinate line – internal iliac lymph nodes
b. Inferior to pectinate line – superficial inguinal lymph nodes

Question 24

Sphincters of Anal Canal

Answer 24

a. Internal anal sphincter
1. Smooth mm
2. Sympathetic fibers (L1, L2) cause constriction of sphincter.
3. Parasympathetic fibers (S2-S4) cause relaxation of sphincter.

b. External anal sphincter
1. Skeletal mm
2. Innervated by inferior rectal n.

Question 25

5. Blood Supply of Anal Canal

Answer 25

a. Arterial Supply
1. Superior rectal a. – superior to pectinate line
2. Middle rectal a. – forms anastomoses between superior and inferior rectal a.
3. Inferior rectal a. – inferior to pectinate line

b. Venous drainage
1. Internal rectal venous plexus (submucosal)
a. Superior rectal v. – drains superior to pectinate line
b. Inferior rectal v. – drains inferior to pectinate line
2. Muscular rectal venous plexus
a. Middle rectal v.
3. External rectal venous plexus
a. Encircles anal sphincter; subcutaneous
b. Drains primarily to inferior rectal v.

Question 26

CLINICAL CORRELATION: Hemorrhoids

Answer 26

1. Internal hemorrhoids (piles)
   a. Dilated veins of internal rectal venous plexus.
   b. Usually painless; can be painful if they swell and protrude through anus.
   c. May produce bright red bleeding.
   d. May be an indication of hypertension (portocaval venous anastomoses).
   e. Other causes (pregnancy, constipation).
2. External hemorrhoids
   a. Dilated veins of external rectal venous plexus (inferior rectal veins).
   b. Risk factors: pregnancy, constipation, increased intra-abdominal pressure.
   c. Usually painful.

Question 27

Scrotum

Answer 27

1. Skin, muscle, and fascia containing the testes and associated ducts.
2. A midline scrotal septum divides into right and left halves.

Question 28

Scrotal muscles

Answer 28

3. Muscles; warming/cooling mechanisms
   a. Dartos muscle is responsible for wrinkling of scrotal skin.
   b. Cremaster muscle is skeletal muscle extending into scrotum from spermatic cord; responsible for elevating/lowering testes.
   c. CLINICAL CORRELATION – Cremaster reflex. Stimulated by lightly stroking the skin on the medial aspect of the superior thigh (afferent stimulation of the ilioinguinal nerve); this will then trigger a contraction of the cremaster muscle and a unilateral elevation of the testis. This reflex is hyperactive in babies/toddlers.

Question 29

Scrotum vascular supply and lymphatic drainage

Answer 29

a. Anterior scrotal aa. (from external pudendal aa.) and vv
b. Posterior scrotal aa. (from perineal aa.) and vv

5. Lymphatic drainage - superficial inguinal lymph nodes
6. CLINICAL CORRELATION – lymphogenous metastatic spread of scrotal cancers will be to superficial inguinal lymph nodes.

Question 30

Scrotum innervation

Answer 30

a. Anterior scrotal nn. (L1; from ilioinguinal nn)
b. Posterior scrotal nn. (S3; from pudendal nn.)
c. Perineal branch of posterior cutaneous nerve of thigh

Question 31

Testes: function and coverings

Answer 31

1. Function: produce spermatozoa and male hormones.
2. Coverings
   a. Tunica albuginea – thick fibrous layer
   b. Tunica vaginalis – parietal/visceral layers
   c. Internal spermatic fascia
   d. Cremaster muscle
   e. External spermatic fascia
   f. Dartos fascia and muscle
   g. Skin

Question 32

Testes: Vascular supply

Answer 32

a. Testicular a.
b. Pampiniform plexus of veins – will form the testicular v.
1. Left – drains to renal v.
2. Right – drains to IVC.
3. Thermoregulatory mechanism; cools arterial blood

Question 33

Testicular varicocele

Answer 33

4. CLINICAL CORRELATION – Testicular varicocele – varicosity of the pampiniform plexus. Physicians describe palpation of a testicular varicocele as “a bag of worms”. Can result from defective vein valves or from obstruction of the left renal vein.

Question 34

innervation of the testicular plexus

Answer 34

sympathetic fibers from T10-T11

Question 35

Testicular lymphatic drainage

Answer 35

lumbar lymph nodes

CLINICAL CORRELATION – lymphogenous metastasis of testicular cancer is common. Very important to note that testicular lymph drains directly to lumbar lymph nodes.

Question 36

Hydrocele of Spermatic Cord/Testis

Answer 36

Sometimes serous fluid builds up within the tunica vaginalis; common in newborns. In adults, it can occur as the result of inflammation.

Question 37

Hematocele

Answer 37

bleeding within tunica vaginalis. Usually from direct trauma and tearing of testicular artery or vein. Can be differentiated from hydrocele by transillumination.

Question 38

Appendix of testis

Answer 38

Appendix of testis (remnant of the paramesonephric duct) and appendix of the epididymis (remnant of the mesonephric duct) are only clinically relevant if they become infected or inflamed.

Question 39

Epididymis

Answer 39

1. Function: long, coiled duct which stores spermatozoa.
2. Lies on posterior portion of testes within scrotum
3. Portions (head, body, tail)
4. Covered with tunica vaginalis; sinus of the epididymis is a recess of tunica vaginalis between body of epididymis and posterolateral testis.

Question 40

Spermatocele

Answer 40

retention cyst in the epididymis; typically near head; often contain both milky fluid and sperm.

Question 41

Epididymal Cyst

Answer 41

cyst anywhere within the epididymis which typically contain a clear fluid.

Question 42

Spermatic cord: contents and coverings

Answer 42

1. Contents:
   a. Ductus deferens
   b. Testicular a. – branch of abdominal aorta; supplies testes and epididymis
   c. Artery of ductus deferens – branch of superior vesicle a
   d. Pampiniform plexus of veins
   e. Autonomic testicular nerve plexus
   f. Lymphatic vessels – drain testes and epididymis to lumbar nodes

Question 43

Torsion of spermatic cord

Answer 43

is a twisting of the structures within the spermatic cord. This can cause testicular necrosis due to obstruction of the testicular artery. Can also result in edema due to obstruction of pampiniform plexus.

Question 44

Ductus Deferens: function and course

Answer 44

1. Function: Muscular tube which transports sperm from epididymis to prostatic urethra.
2. Course:
   a. Passes through inguinal canal and deep inguinal ring to enter pelvis.
   b. Crosses superior to ureter at posterolateral corner of bladder.
   c. Travels superior, then medial to the seminal gland.
   d. Joins the duct of the seminal gland to form the ejaculatory duct.

Question 45

Ductus Deferense: structure and Vascular supplly

Answer 45

3. Structure
   a. 3 layers of smooth muscle
   b. Ampulla - dilation of duct near its termination
4. Vascular Supply
   a. Arterial – artery of the ductus deferens; anastomoses distally with testicular a.
   b. Venous
5. Inguinal portion drains to testicular vein.
6. Pelvic portion drains to prostatic venous plexus.

Question 46

deferentectomy

Answer 46

A deferentectomy (vasectomy) is a surgical procedure in which a portion of ductus deferens is excised; semen no longer contains sperm.

Question 47

Seminal Glands: Function

Answer 47

1. Function: Produces about 70% of seminal fluid.
   a. Thick liquid, fructose rich (source of energy for sperm motility)
   b. Contains substances which stimulate contraction of uterus and enhance sperm motility.

Question 48

Seminal glands: anatomical relationships

Answer 48

a. Anterior – urinary bladder, ureters
b. Posterior – rectum
c. Medial – ampulla of ductus deferens

Question 49

Seminal glands: structure

Answer 49

a. Paired, simple coiled tubular glands with scattered layer of smooth mm.
b. In each gland, a single duct joins with the ductus deferens to form ejaculatory duct.

Question 50

Seminal glands: vascular supply

Answer 50

a. Arterial – branches from inferior vesicle

b. Venous - vesicle/prostatic plexuses

Question 51

Rectal palpation

Answer 51

rectal palpation can allow the physician to palpate and examine the seminal glands (example: swelling due to abscesses).

Question 52

Ejaculatory duct

Answer 52

1. Formed from merging of seminal gland duct and ductus deferens.
2. Courses through the prostate.
3. Opens on seminal colliculus within prostatic uretha.

Question 53

Prostate: function and relationships

Answer 53

1. Function: Produces and secretes seminal fluid (20% of volume of semen); slightly alkaline secretion (rich in citric acid, acid phosphatase, amylase); enhances sperm motility.
2. Anatomical relationships:
   a. Anterior – pubis
   b. Posterior – rectum
   c. Superior – bladder
   d. Inferior – UG diaphragm

Question 54

Prostate: structure and features

Answer 54

3. Structure – compound tubuloalveolar gland; ducts empty to prostatic urethra.
4. Features:
   a. Base: superior portion
   b. Apex: inferior portion
   c. Anterior, posterior, inferolateral surfaces

Question 55

Prostatic lobes

Answer 55

a. Anatomical lobes
1. Isthmus of the prostate – anterior to the urethra; fibromuscular region.
2. Middle lobe (or region) and peripheral region
b. Clinical “zones”
1. Transitional zone (area around urethra) – most common site for BPH
2. Central zone (area around ejaculatory duct)
3. Peripheral zone – most common site for carcinomas
4. The transitional zone + the central zone = the middle lobe

Question 56

Prostate: vascular supply

Answer 56

6. Vascular Supply
   a. Arterial – branches from inferior vesicle
   b. Venous
7. Prostatic venous plexus; drains to internal iliac veins.
8. Prostatic venous plexus communicates with internal vertebral venous plexus; cancer cells can spread to brain and vertebrae via the internal vertebral venous plexus.

Question 57

7. CLINICAL CORRELATION: Benign Prostatic Hyperplasia (BPH)

Answer 57

a. Common; most men will develop BPH with age.
b. Enlarged prostate can impede urination by compressing urethra; can also push upward on the uvula making it difficult to open the urethra and causing urine retention; can also push upward on the trigone making it difficult to close the urethra, producing the sensation of constantly having to urinate.

Question 58

Penis: function and supporting ligaments

Answer 58

a. Function
1. Reproductive: male copulatory organ; delivers sperm to female reproductive tract.
2. Urinary: contains penile urethra
b. Supporting ligaments
1. Fundiform ligament – linea alba to dartos fascia of scrotum.
2. Suspensory ligament of the penis – pubic symphysis to deep fascia of penis.

Question 59

Penis: fascias

Answer 59

1. Superficial – Dartos
2. Deep – Buck’s
3. Tunica Albuginea

Question 60

Penis: features

Answer 60

1. Root
   a. Located in superficial perineal space
   b. Crura (corpus cavernosum) – covered by ischiocavernosus muscle
   c. Bulb (corpus cavernosum) – covered by bulbospongiosus muscle
2. Body (shaft)
3. Glans
   a. Distal expansion of corpus spongiosum
   b. Prepuce – double layer of skin and fascia over glans penis

Question 61

Erectile bodies

Answer 61

1. Corpus spongiosum
   a. Midventral erectile body; contains spongy urethra
   b. Forms bulb of penis and glans penis
2. Corpora cavernosa
   a. Paired, dorsal erectile bodies
   b. Form crura of the penis which attach to the ischiopubic rami
3. Erectile bodies are covered with a dense CT called tunica albuginea.

Question 62

Penis: vascular supply and lymphatic drainage

Answer 62

f. Vascular supply
1. Arteries
a. Dorsal aa. of the penis
b. Deep aa. of the penis (courses through corpus cavernosum)
c. Arteries to the bulb of the penis
2. Veins
a. Superficial dorsal v. of penis (drains to external pudendal v.)
b. Deep dorsal v. of the penis (drains to prostatic venous plexus)

g. Lymphatic drainage – superficial inguinal lymph nodes

Question 63

Penis: innervation

Answer 63

1. Pudendal nerve (sensory, sympathetic)

2. Cavernous nerves (parasympathetic) (see autonomics lecture)

Question 64

Bulbourethral Glands (Cowper’s Glands)

Answer 64

1. Paired tubuloalveolar glands; located in deep perineal space.
2. Secrete mucus into membranous urethra; lubrication and neutralizes acidic urine.

Question 65

Urogenital triangle muscles

Answer 65

1. All are innervated by the pudendal nerve (perineal branch).
2. Superficial perineal space
   a. Superficial transverse perineal – supports perineal body.
   b. Bulbospongiosus – surrounds bulb of penis; empties urethra during urination/ejaculation; maintains erection by compressing bulb of penis.
   c. Ishiocavernosus – surrounds crura; maintains erection by compressing crura.
3. Deep perineal space (these muscles make up the UG diaphragm)
   a. Deep transverse perineal
   b. Sphincter urethrae (composed of skeletal and smooth muscle)