Vaginal artery (VA), uterine artery (UA)

Muscular tube formed by smooth muscle and elastic connective fibers

Serves as excretory duct for uterus, female organ for copulation, and part of birth canal

Extends up and back from vestibule of external genitalia to surround cervix of uterus

Has anterior and posterior walls, normally in apposition, with longer posterior wall

Superiorly, cervix projects downward and backward into vagina and divides vagina into shallow anterior, deep posterior, and lateral fornices

Upper 1/2 of vagina lies above pelvic floor, lower 1/2 lies within perineum

Lined with stratified squamous epithelium

Inner mucosal surface of wall form rugae when collapsed

Thin mucosal fold called hymen surrounds entrance to vaginal orifice

Outer surface (adventitial coat) is thin fibrous layer continuous with surrounding endopelvic fascia

Vasculature

• ○
  

  Arterial supply

  
  
  
  
  • –
    

    VA: Can branch directly from internal iliac artery (anterior trunk) or sometimes from inferior vesical artery or UA

    
    
  • –
    

    Vaginal branches of UA

    
    
  • –
    

    Branches of VA and UA anastomose to form 2 median longitudinal vessels: Azygos arteries, 1 in front and 1 behind vagina

  
  
  
  
• ○
  

  Venous drainage

  
  
  
  
  • –
    

    Form venous plexus around vagina

    
    
  • –
    

    Eventually drains to internal iliac veins

  
  

Variations with age

• ○
  

  Menarche: 7-10 cm long

  
  
• ○
  

  Postmenopausal: Shrinks in length and diameter; fornices virtually disappear

Anterior

• ○
  

  Superior: Bladder base

  
  
• ○
  

  Inferior: Urethra

Posterior

• ○
  

  Upper 1/3: Rectouterine pouch of Douglas

  
  
• ○
  

  Middle 1/3: Ampulla of rectum

  
  
• ○
  

  Lower 1/3: Perineal body

Lateral

• ○
  

  Upper 1/3: Ureters

  
  
• ○
  

  Middle 1/3: Levator ani and pelvic fascia

  
  
• ○
  

  Lower 1/3: Bulb of vestibule, urogenital diaphragm, and bulbospongiosus muscles

Ligamentous supports

• ○
  

  Upper 1/3: Levator ani muscles, transverse cervical (cardinal), pubocervical, and sacrocervical ligaments

  
  
• ○
  

  Middle 1/3: Urogenital diaphragm

  
  
• ○
  

  Lower 1/3: Perineal body

Transabdominal US with distended bladder is standard imaging technique

• ○
  

  Caudal angulation on both longitudinal and transverse scans

  
  
• ○
  

  Commonly found at/near sagittal midline of pelvis

  
  
• ○
  

  Length and wall thickness vary in response to bladder and rectal filling

  
  
• ○
  

  Combined thickness of anterior and posterior vaginal walls should not exceed 1 cm for transabdominal scan with distended bladder

  
  
• ○
  

  Characteristic appearance of 3 parallel lines

  
  
  
  
  • –
    

    Highly echogenic mucosa centrally, may be difficult to visualize if stretched by distended bladder

    
    
  • –
    

    Moderately hypoechoic muscular walls

  
  

Transperineal US with nondistended bladder for assessment of uterine prolapse or for difficult cases

• ○
  

  Vagina, especially vaginal canal, is less well defined

Transvaginal US may require withdrawal of transducer so as not to compress pathology

Uterus and upper vagina are formed from paired müllerian (paramesonephric) ducts

Paired ducts meet in midline and fuse, forming uterovaginal canal

Lower vagina is formed from urogenital sinus

Ligamentous support of pelvic organs may be damaged or become lax, leading to uterine prolapse or prolapse of vaginal walls

Cystocele: Sagging of bladder with bulging of anterior vaginal wall

Rectocele: Sagging of ampulla of rectum with bulging of posterior vaginal wall

Best to be investigated by transperineal US supplemented with 3D

Failure of müllerian duct development ± fusion

Vagina most commonly affected in uterus didelphys (class III anomaly); vaginal septum seen in ~ 75% of cases

Hematocolpos from imperforate hymen or vaginal septum may be evaluated by transperineal US

Common site: Rectouterine pouch of Douglas

Transvaginal approach allows US-guided drainage of pelvic abscess without surgery

Transvaginal US is used for egg retrieval in assisted reproduction

Persistent sexual arousal during sleep in postmenopausal women

VA blood flow as 1 diagnostic aid

VA normally shows high-resistance flow

During sexual arousal, increased blood flow to VA with low-resistance spectral waveform