Chapter 110 Vagina, Vestibule and Vulva

Question 1

What embyonic structure forms the uterus?

And the ductus deferens?

Answer 1

In female:

Paramesonephric ducts –> uretus. Mesonephric ducts regress.

In males:

Mesonephric ducts –> ductus deferens. Paramesonephric ducts regress

Question 2

What is the name of the embryonic stucture that progressed from caudally to separate rectum and urogenital sinus?

And what is the name of the laterlly located structures that along a midline genital raphe to separate anal opening from external genitalia?

Answer 2

Urorectal septum

Cloacal folds

Question 3

What is an alternative name for paramesonephric ducts?

Answer 3

Müllerian ducts

Question 4

How is the canine cervix positioned?

Answer 4

Obliquely: cranioventral caudodorsal

–> ventral fornix

Question 5

What type of epithelium lines vagina?

Answer 5

Stratified squamous, non-glandular

Question 6

What demarcates the vestibulovaginal junction?

Answer 6

A transverse palpable mucosal ridge

Transition from light pink, redundant vaginal mucosal folds –> smooth, red vestibular mucosa

Question 7

Where does urethral tubercle enter?

Answer 7

Ventral aspect of vestibule

1cm caudal to vestibulovaginal junction

Question 8

What is blood supply to vagina, urethra, vestibule?

And to vulva?

Answer 8

Vagina/urethra/vestibule: Vaginal artery (branch of internal pudendal, branch of internal iliac) –>

• caudal vesical artery
• urethral branch

Vulva: External pudendal a (perineal branches)

Question 9

What is drining LN of vagina/vestibule?

Answer 9

Internal iliac

Question 10

What is the autonomic innervation to vagina/vestibule?

And sensory?

Answer 10

Pelvic plexus

Pudendal n.

Question 11

List how the following fctors change during oestrus:

Progesterone

Vaginal cytology

Answer 11

Progesterone: >6-8 ng/mL

Vaginal cytology: cornificatioon of epithelial cells

(+ changes in vaginal mucosa appearance)

Question 12

What is typical bacterial population of canine vagina

Answer 12

Mixed resident population of aerobes, anaerobes, mycoplasma and ureaplasma spp.

(E. coli, staph, step, pasturella most common)

Question 13

Comment re presence of neutrophils in vaginal exudate

Answer 13

indicates inflammation.

large numbers shouldnt be present

Question 14

What size cystoscope is recommended in 3-5kg dogs?

And >10kg dogs?

Answer 14

2.7mm

4mm

Question 15

List 2 potential approaches to the vestibule/vagina

Answer 15

Episiotomy

Ventral approach (pelvic osteotomy)

Question 16

List 4 types of vestibulovaginal stenotic lesions

Answer 16

• Hypoplasia
• Imperforate hymen (due to retained epithelial tissue at transverse juntion of paramesonephric ducts with urogenital sinus)
• Vertical septum
• Double vagina

(due to retained epithelial tissue at point of fusion of paramesonephric ducts)

Question 17

List treatment options for vestibulovaginal stenotic lesions

Answer 17

• Endoscopic guided laser ablation (or scissors)
• Manual disruption
• Surgery;
  
  • Septum
    
    • Excison of septum
  • Annular
    
    • Partial thickness resection
    • T-shaped vaginoplasty (longitudinal cut, transversely closed)
  • Extensive lesions:
    
    • R+A
    • Vaginectomy

Question 18

What condition are rectovaginal fistulas typically associated with?

Answer 18

Atresia ani

Question 19

What are the two optioons for reconstruction of anal orifice in atresia ani?

Answer 19

• Relocation of anal dimple
• Fistula translocatioon (hypothesised that fistula may serve as a rate limiting internal sphincter i.e. better continence)

Question 20

How is anovulvular cleft managed?

Answer 20

Inverted V perineoplasty

Question 21

What two factors may influence occurrence of recessed vulva?

Answer 21

Breed and BW (medium or large breed)

Question 22

What are most common presenting sigsn in recessed vulva cases

Answer 22

• Perivulvar dermatitis (50%)
• Secondary to urine pooling (recurrent UTI, apparent incontinence (also approx 50% each)

Question 23

When and where does vaginal oedema occur

Tx?

Answer 23

Late prooestrus and oestrus

From ventral vaginal floor, just cranial to urethral tubercle

resolved after oestrus but high rate of recurrence so neutering recommended

Question 24

What N.b. re vaginal prolapse?

Answer 24

2/3 cases reported to have herniation of other organs i.e.take care nd be prepred to pexy colon/bladder/uterus if staying entire

Question 25

How is true vaginal prolapse distinguised from vaginal oedema?

Answer 25

Vaginal prolapse has doughnut shaped protrusion

Question 26

In dogs with intersex condition, when is a ‘clitoral’ bone os clitoris vs os penis?

what other procedure shoudl be performed if removing hypertrophic clitoris (if sore)

Answer 26

Os penis if urethra si located on cranial and dorsal aspect of the os.

Gonadectomy - confirmation of intersex anaomaly based on histo of gonads.

Question 27

What % of vv neoplasms are benign?

What is most common malignancy?

Answer 27

80%

most commonly leiomyoma (other fibroma, polyp, cyst)

leiomyosarcoma (TVT, TCC, rhabdomyosarc, osteosarc, chondrosarc, haemangiosarc neuroendocrine described)

Question 28

What is usua;l signalment of leiomyoma cases?

Answer 28

Older intact females i.e. appears to be hormonally driven

Question 29

How is wide resection of malignant vv tumours achieved?

Answer 29

Vulvovaginectomy + PU

Question 30

List two potential approaches for vulvovaginectomy

Answer 30

• Caudal approach (episiotomy or vuvlectomy - see pic)
• Coeliotomy
• (or combined)