Seminal vesicle

Last revised by Yahya Baba on 28 Aug 2021

The seminal vesicles are paired accessory sex glands of the male reproductive system. The seminal vesicle produces over two-thirds of the ejaculate and is very high in fructose. 

The seminal vesicle is actually a 10-15 cm long tubular structure but is coiled tightly so it only measures 4-5 cm in length. It is located superiorly and posteriorly to the prostate.

The excretory duct of the seminal vesicle unites with the ductus deferens to form the ejaculatory duct

  • anteriorly: base of bladder
  • inferiorly and anteriorly: prostate
  • posteriorly: rectovesical fascia
  • medially: ampulla of ductus deferens
  • laterally: prostatic venous plexus
  • superiorly: tips of the seminal vesicles covered by the peritoneum of the rectovesical pouch
  • drain to internal iliac lymph nodes 9
  • sympathetic fibers from the testicular and hypogastric plexuses 4
  • fluid-filled structure located posteriorly and superiorly to the prostate gland 2
  • has a typical "bow-tie" appearance and soft-tissue density; located between the prostate and the bladder 2,5
  • normally separated from the bladder by a fat plane
  • normally are less than 1.5 cm in diameter, beyond that they can be considered dilated 5
  • according to one publication the mean length was estimated to be around 3 cm with the mean width at around 1.5 cm 6

  • they may be larger in those with autosomal dominant polycystic kidney disease 7

  • T1: low-to-intermediate signal
  • T2: convoluted areas of high signal representing seminal fluid and low signal walls 5

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Cases and figures

  • Figure 1: prostate gland and seminal vesicles (Gray's illustration)
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  • Figure 2: anatomy of the penis (Gray's illustration)
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  • Case 1: left seminal vesicle agenesis
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