Perineum

27 March 2008

Layers of Scrotum & Testis

· Skin

· Dartos

· Ext. spermatic fascia

· Cremaster m.

· Int. spermatic fascia

· Parietal tunica vaginalis

· Visceral tunica vaginalis

· Tunica albuginea testis

Netter, 2003 pl. 370; Netter, 2006 pl. 387

Testis - coverings

· The testis is an abdominal organ

· It has remnants of peritoneum

- Tunica vaginalis

· Visceral & parietal layers

· A tough fibrous layer underlies the visceral tunica vaginalis

- Tunica albuginea testis

· Lobules of the testis are divided by septa

Netter, 2003 pl. 371; Netter, 2006, pl. 390

Testis - blood supply

· Arteries come from aorta, and veins drain to Inferior vena cava and Renal v.

· Testicular a. surrounded by venous plexus

- Pampiniform plexus

· Ductus deferens has a separate artery

· Lymphatics drain to abdominal lymphatic nodes

see Netter, 2003, pl. 370, 383; Netter, 2006 pl. 387, 403

see Moore & Dalley, 2006, Fig. 2-15

Structures of Testis in cross section

· Lobules

· Septa

· Rete testis

· Efferent ductules

· Epididymis

- head

- Body

- tail

· Ductus deferens

Netter, 2003 pl. 371; Netter, 2006 pl. 390

Structure of Penis

Three erectile bodies

· 2 corpora cavernosa

covered with ischiocavernosus mm.

· 1 corpus spongiosum

covered by bulbospongiosu m.

Penile urethra runs through corpus spongiosum.

The corpora cavernosa attach to the UG diaphragm and ischiopubic rami.

The corpus spongiosum is suspended from the UG diaphragm.

Netter, 2003 pl. 364, 365; Netter, 2006 pl. 381, 382

UG diaphragm a thin layer of muscle between the ischiopubic rami

Fascial layers on each side

Netter, 2003 pls. 364-367; Netter 2006 pl. 381-383

Prostate Gland supported by the UG diaphragm and is inferior to bladder

Urethra - 3 parts

· Prostatic

· Membranous

· Spongy (penile)

Rosse & Gaddum-Rosse, 1997, Fig. 28-13

Blood Supply & Innervation

· Internal pudendal a.

· Pudendal n.

· Posterior femoral cutaneous n.

· Anteriorly:

- anterior scrotal branch

- Genital branch Genitofemoral

Clemente 1997, pl. 301;

see Netter, 2003 pl. 391; Netter, 2006, pl. 411

Superficial Arteries & Veins

· Blood supply to the skin & subcutaneous tissue

· Superficial external pudendal a & v

· Deep external pudendal a

These are not the blood supply to erectile tissue

Rosse & Gaddum-Rosse, 1997, Fig. 28-25

In cross section, all three erectile bodies of penis surrounded by deep penile fascia.

Deep dorsal veins and dorsal arteries lie under the deep fascia

The corpora cavernosa are surrounded by a dense, non elastic tunica albuginea.

Central aa of penis in corpora cavernosa (give off helicine aa)

During erection, the corpora cavernosa swell. The non eleastic tunica stretches until it is taut. Continued increase in blood pressure makes the penis rigid.

Expansion also compresses deep dorsal veins against the deep fascia to restrict blood drainage.

Netter, 2003 pl. 364; Netter, 2006 pl. 382

Female Perineum

· Urogenital diaphragm

· Ischiocavernosus m.

· Bulbospongiosus m

· Clitoris

- crura

- glans

· Bulb of vestibuleUrethra

· Labia minora

· Vestibule of vagina

Clemente, 1997, Fig. 430

see Netter, 2003 pls. 360, 361; Netter, 2006 pl. 378, 379

Blood Supply & Innervation

· Internal pudendal a.

· Pudendal n.

· Posterior femoral cutaneous n.

· Anteriorly:

- anterior labial br.

- genital br. genitofemoral

Clemente, 1997, Fig. 277

see Netter, 2003 pls. 384, 393; Netter, 2006 pls. 404, 413