This allows urine to be expelled earlier in its course so that passage through the os penis does not occur. (marvistavet.com)
In the male dog, a bone called the «os penis» is located in the penis, surrounding the urethra. (marvistavet.com)
The flexibility of the non-bony part of the urethra plus the surgically enlarged urinary opening allows for smaller stones to pass rather than stick in the os penis. (marvistavet.com)