Uterus Masculinus or Utriculus Prostaticus of Male Animals

The uterus masculinus is a rudimentary structure and a remnant of the paramesonephric (Müllerian) duct in males.

It is located between the ampullae and the seminal vesicles, positioned on the caudal-dorsal surface of the urinary bladder, and cranial to the prostate gland. This structure is present in approximately 50–70% of bulls.

Species Variations of the Uterus Masculinus

Bull

The utriculus prostaticus of the bull is a vestigial structure and is the homologue of the uterus and vagina. It is inconstant and may not be present in all individuals.

Ram and Buck

The uterus masculinus of the ram and buck is similar to that of the ox in structure and origin.

Stallion

The utriculus prostaticus of the stallion is a fetal remnant of the Müllerian (paramesonephric) duct. It is centrally located on the caudal part of the dorsal surface of the urinary bladder.

This structure is flattened and tube-like, measuring approximately 7.5 to 10 cm in length. Its cranial part is narrow, lies within the genital fold, and gives rise to two slender cornua.

The caudal end of the tube passes beneath the isthmus of the prostate and may either:

• Open into the urethra at the summit of the colliculus seminalis,
• Join the duct of the seminal vesicle, or
• Terminate as a blind end.

Boar

The utriculus prostaticus in the boar is small and appears to be inconstant, meaning it may not be present in all individuals.

Dog

The utriculus prostaticus of the dog is present as a small, compressed sac located within the colliculus seminalis.

Rabbit

The utriculus prostaticus is inconstant in the rabbit, meaning its presence may vary between individuals.

Cock

The utriculus prostaticus is absent in the cock.