Chapter 2 - Male External Genitalia

Question 1

Root of penis

Answer 1

• situated in superficial perineal pouch
• has 3 masses of erectile tissue i.e., 2 crura, 1 bulb
• Crus attached to pubic arch
• crus covered by ischiocavernosus
• bulb attached to perineal membrane b/w crura
• bulb covered by bulbospongiosus
• bulb pierced by urethra which shows intrabulbar fossa

Question 2

Body of penis

Answer 2

• continuous with root
• 3 masses of erectile tissue i.e., 2 corpora cavernosa, 1 corpus spongiosum
• C. cavernosa are forward continuations of crura
• C.C terminate near glans penis
• Covered by tunica albuginea
• C. spongiosum is forward continuation of bulb
• C.S forms glans penis (conical enlargement)
• C.S traversed by urethra

Question 3

Glans penis

Answer 3

• Base of glans has projecting margin - corona glandis
• Within glans, urethra shows dilatation called navicular fossa
• Skin at neck is folded to form prepuce/foreskin
• Prepuce can be retracted to expose glans
• Median fold of skin on undersurface - frenulum
• Potential space b/w glans and prepuce - preputial sac
• Neck has sebaceous glands which secrete smegma that collects in preputial sac

Question 4

Superficial fascia of penis

Answer 4

• loosely arranged areolar tissue devoid of fat
• continuous with membranous layer of superficial fascia of abdomen above
• contans superficial dorsal vein of penis

Question 5

Deep fascia of penis

Answer 5

• Buck’s fascia
• Surrounds all 3 layers of erectile tissue
• Does not extend to glans
• Deep to it, there are deep dorsal veins, dorsal A, dorsal N
• continuous with Dartos and fascia of urinogenital triangle

Question 6

Supports of body of penis

Answer 6

1. Fundiform ligament: extends down from linea alba and splits to enclose penis
2. Suspensory ligament: deep to fundiform ligament. Extends from pubic symphysis and blends with fascia on each side of penis.

Question 7

Arteries of penis

Answer 7

A) 3 branches of internal pudendal A

1. Deep A of penis: runs in C. cavernosum and breaks up into helicine A
2. Dorsal A of penis: supplies glans, distal C. spongiosum, prepuce, frenulum
3. A of bulb of penis: supplies bulb and proximal C. spongiosum

B) Femoral A gives superficial external pudendal A - supplies skin and fascia of penis

Question 8

Veins of penis

Answer 8

1. Superficial dorsal V - drains prepuce, skin - empties into external pudendal V
2. Deep dorsal V
   - deep to Buck’s fascia
   - drains glans, C. cavernosa
   - passes deep to suspensory ligament
   - divides into right, left branches
   - connects with internal pudendal V
   - enters prostatic plexus

Question 9

Nerve supply of penis

Answer 9

SENSORY

1. Dorsal N of penis
2. Ilioinguinal N
3. Root by perineal branch of pudendal N

AUTONOMIC

1. Pelvic, prostatic plexus
2. Sympathetic - S2-S4
3. Pudendal N

Question 10

Lymphatic drainage of penis

Answer 10

Glans - deep inguinal nodes/ glands of Cloquet

Rest - superficial inguinal nodes

Question 11

External features of scrotum

Answer 11

• cutaneous bag containing testes, epididymis and lower parts of spermatic cord
  1. Externally divided into right and left by raphae which continues on undersurface and along perineum
  2. Left half hangs lower than right due to > length of left spermatic cord
  3. When cold, it is short and corrugated
  4. When warm, it is elongated and flaccid
  5. Contraction and relaxation is due to dartos muscle

Question 12

Layers of scrotum

Answer 12

1. Skin
2. Dartos muscle replaces superficial fascia
3. External spermatic fascia from ext. oblique M
4. Cremasteric fascia from int. oblique muscle
5. Internal spermatic fascia from fascia transversalis

Question 13

Blood supply of scrotum

Answer 13

1. Superficial external pudendal
2. Deep external pudendal
3. Scrotal branches of internal pudendal
4. Cremasteric branch of inferior epigastric

Question 14

Nerve supply of scrotum

Answer 14

Ant 1/3 - L1 segment through ilioinguinal, genital branch of genitofemoral N

Post 2/3 - S3 segment through posterior scrotal branches of pudendal, perineal branch of posterior cutaneous N of thigh

Dartos M - genital branch of genitofemoral N

Question 15

External features of testis

Answer 15

• homologous to ovary
• lies obliquely
• 2 poles, 2 borders, 2 surfaces

Question 16

Poles of testis

Answer 16

• Upper and lower poles are convex and smooth
• Upper provides attachment for spermatic cord
• Appendix of testis is attached to upper pole. It is remnant of paramesonephric duct.

Question 17

Borders of penis

Answer 17

Anterior

• convex, smooth
• completely covered by tunica vaginalis

Posterior

• straight
• partially covered by tunica vaginalis
• has epididymis along lateral surface
• medial surface is separated from epididymis by extension of tunica vaginalis called sinus of epididymis

Question 18

Coverings of testis

Answer 18

1. Layers of scrotum
2. Tunica vaginalis
   - lower persistent processus vaginalis
   - has parietal and visceral layer
   - covers entire testis except posterior border
3. Tunica albuginea
   - dense, fibrous
   - posterior border thickens to form mediastinum testis
   - mediastinum testis is an incomplete vertical septum
   - septa extend from it and divide testis into 200-300 lobules
4. Tunica vasculosa
   - innermost, vascular coat

Question 19

Arterial supply of testis

Answer 19

1. Testicular artery
   - branch of abdominal aorta
   - reaches DIR
   - enters spermatic cord
   - supplies tunica albuginea
   - ramify in tunica vasculosa

Question 20

Venous drainage of Testis

Answer 20

1. Pampiniform plexus
   - anterior part around testicular artery
   - middle part around ductus defferens
   - posterior part isolated
   - condenses into 4 V at SIR and into 2 V at DIR
   - drains into IVC on right and left renal vein on left

Question 21

Lymphatic drainage of testis

Answer 21

Preaortic and paraaortic nodes at level of L2

Question 22

Nerve supply of testis

Answer 22

T10 segment

renal and aortic plexus

Question 23

Vessels of epididymis

Answer 23

1. Testicular artery
2. Sympathetic N through testicular plexus
3. T11-L1 segments