G.E.P. Atlas of Ultrasound  

 
The"Prepubien"                        (bulbo-cavernosus muscles):

Transvaginal sagittal section

 

 
  1. Prepubien.
  2. Symphysis pubis.
  3. Arcuate ligament.
  4. Anterior edge of the urethra.
  5. Urethral mucosa.