Seminal vesicle

The seminal vesicles are paired accessory sex glands of the male reproductive system. They produce seminal fluid that, together with sperm cells from the testicles, compromise the male ejaculate. Seminal fluid is rich in fructose which is essential for sperm cell survival.

Gross anatomy

The seminal vesicle is a tightly coiled structure measuring 4-5cm in length. If stretched out, the would be 10-15cm long. It is located supero-posteriorly to the prostate.

The excretory duct of the seminal vesicle unites with the ductus deferens to form the ejaculatory duct that connects with the prostatic urethra.

Relations

• 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

Arterial supply

• artery to the ductus deferens from superior or inferior vesical arteries ^3,4

Venous drainage

• vesical venous plexus into internal iliac veins

Lymphatic drainage

• drain to internal iliac lymph nodes ⁹

Innervation

• sympathetic fibers from the testicular and hypogastric plexuses ⁴

Congenital anomalies

• seminal vesicle agenesis ⁹

• seminal vesicle hypoplasia ¹¹

• seminal vesicle fusion ¹¹

• seminal vesicle dupliction ¹¹

• seminal vesicle cysts 

Radiographic features

Ultrasound

• fluid-filled structure located posteriorly and superiorly to the prostate gland ²

CT

• 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

MRI

• T1: low-to-intermediate signal

• T2: convoluted areas of high signal representing seminal fluid and low signal walls ⁵

Related pathology

• seminal vesicle cysts

• seminal vesicle amyloidosis

• seminal vesicle abscess

• cystic dilatation of the seminal vesicles