Chapter 112 Penis and Prepuce

Question 1

What are the three parts of the penis?

Answer 1

Root, body and distal portion (aka glans)

Question 2

What is the name of the penile tissue that surrounds the urethra (for the entirety of its length?

Answer 2

Corpus spongiosum

(bulb of penis is a bilobed extension of corpus spongiosum)

Question 3

What anatomical areas make up body of penis?

Answer 3

Corpus spongiosum + corpus cavernosum

Question 4

What anatomical areas make up distal penis/glans penis

Answer 4

Bulbus glandis

Pars longa glandis

Question 5

What is another name for the os penis?

Answer 5

Baculum

Question 6

What are the four paired extrinsic muscles of the penis?

Answer 6

Ischiourethralis

Ischiocavernosus

Bulbospongiosus

Retractor penis

Question 7

Where do the retractor penis muscles arise from

Answer 7

Cd vertebrae 1 and 2, then blend with external anal sphincter

Question 8

Where do bulbospongiosus muscles arise from?

Answer 8

Tunica albuginea and external anal sphicter (and fuse with retractor penis at insertion)

Question 9

Label he diagram

Answer 9

Question 10

What is the primary vessel supplying the penis

Answer 10

Artery of the penis (from internal pudendal)

• Arteries of the bulb
• Deep arteries of the penis
• Dorsal artery of the penis

Question 11

Label the diagram

Answer 11

Question 12

What region does each of the main vessels of the penis supply?

Answer 12

Artery of the penis (branch of internal pudendal)

• Artery of bulb: Corpus spongiosum, penile urethra, pars longa glandis (surprisingly as very dor away an dorsal surface…)
• Deep artery of penis: Corpus cavernosum
• Dorsal artery of penis: corpus spongiosum, bulbus glandis, pars longa glandis

Question 13

What is the venous drainage of the penis?

Answer 13

Internal and external pudendal

Question 14

What is the main sensory nerve innervating the penis?

Answer 14

Dorsal nerve of penis

Question 15

In what % of cats is os penis readiographically visible?

Answer 15

40%

Question 16

How soon after castration do spines of penis in cats regress?

Answer 16

6 weeks

Question 17

What are the three layers of the prepuce?

Answer 17

External skin, inner layers are parietal and visceral epithelium (i..e outer layer of what i consider penis is actually viscera layer of prepuce)

Question 18

Which layer of prepuce has many lymph nodules and nodea

Answer 18

Parietal layer

Question 19

Where do the prepucial muscles originate from

Answer 19

Xiphoid (from cuaneous trunci)

Question 20

Label the diagram

Answer 20

Question 21

What are the two principal vessels supplying the parietal and viceral layers of the prepuce?

And the skin?

Answer 21

Dorsal artery of the penis and external pudendal

Skin = caudal superficial epigastric

Question 22

What are the two mechanisms –> erection

Answer 22

1. Expansion of arteris and contraction of veins –> expansion of cavernous bodies
2. Dorsal penile vein compressed against ischial arch by contraction of ischiocavernosus and bulbospongiosus

Question 23

Comment on relationship between penis and prepuce at birth

Answer 23

Pepucial and penile surfaces usually adherent + penile frenulum usually present

Separation of both with puberty

Question 24

What breed gets hypospadias?

Answer 24

Boston terrier

Question 25

What conditions are usually seen with hypospadia

Answer 25

Failure of fusion of prepuce Underdevelopment of penis

Question 26

What is treatment for hypospadia?

Answer 26

Not usually reconstructed as often no urethra distal to anomaly. Tx: excision of penile remnant + urethrostomy (poss via enlargement of existing opening) IF NECESSARY

Question 27

How are hypospadias classified?

Answer 27

Anal Perineal Scrotal Penile Glandular

Question 28

What are treatment options for os penis deformity (if necessary)

Answer 28

Fracture + realigment partial penile amputation

Question 29

How is os penis fracture managed

Answer 29

Conservative, u cath or plate (scrotal urethrostomy if callous --\> urethral obstruction)

Question 30

Describe technique for shortening prepuce (e.g. if performed partial penile amputation)

Answer 30

Technique for shortening of the prepuce in conjunction with partial penile amputation. A, A rectangular portion of ventral prepuce is excised. B, A sliding skin flap facilitates retraction of the cranial prepuce (arrows). C, The segments are apposed with two or three layers of suture.

Question 31

What clinical signs are seen with persistent penile frenulum?

Answer 31

Pain when penile extrusion attempted, licking, blanoprosthitis

Question 32

List 5 ddx for penile neoplasm

Answer 32

TVT, MCT, SCC, papilloma, HSA, OSA

Question 33

Describe technique for penile amp

Answer 33

Ablation of the external male genitalia. A, The skin is incised around the sides or base of the prepuce and scrotum. B, The penis is separated from the body wall, and its blood supply is temporarily occluded with a ligature or tourniquet proximal to the proposed transection site. The penile body is sharply severed. C, After hemostasis has been achieved, the tunica albuginea is apposed over the end of the transected penis. D-E, A urethrostomy is performed, and the remaining skin defect is closed.

Question 34

What type or urethrostomy hs been reported with subtotal peinle amputation? What is the benefit?

Answer 34

Prepucial urethrostomy. Doesnt --\> skin irritation

Question 35

What is paraphimosis

Answer 35

Paraphimosis = penis protrudes from the preputial sheath and cannot be replaced to its normal position

Question 36

hat are tx options for paraphimosis?

Answer 36

* Lube, hyperosmolar solution, local cooling If not successful * U cath to avoid urethral obstruction * Prepucial enlargement (excision of dorsal V in dogs, ventral in cats) * Phallopexy (remove a dorsal or ventral strip of visceral and parietal prepuce and suture together * +- Prepucial advancement

Question 37

What is phimosis

Answer 37

Phimosis is the inability to protrude the penis beyond the preputial orifice. May --\> blanoprosthitis if urine pooling in prepuce

Question 38

How is blanoprosthitis managed

Answer 38

* Flush with saline or dilute povodine-iodine or chlorhex * Curette lymphoid nodules * BReak down adhesions * Antimicrobial ointment Px guarded asss often recurrs

Question 39

What are the 2 most common tumours of external genitalia/prepuce?

Answer 39

MCT and SCC (ddx lympoma, TVT, perianal gland adenoma)

Question 40

What are the broad concepts necessary for prepucial reconstruction

Answer 40

Epihelial tissue i.e. skin (usually based on axial patttern flap from caudal superficial epigastric artery) Mucosal tissue (free buccal graft)

Question 41

What amount of penile tissue protrusion (due to prepucial hypoplasia) can be managed wiht prepucial advancement?

Answer 41

1.5 cm (usually unsuccessful if protrusion \>1.5cm ) Phallopexy or partial amp if still a problem