Answer:
Prostatic urethra , Membranous urethra and Spongy urethra
Explanation:
The three main parts of male urethra are -
a) Prostatic urethra - it is the widest of all three parts and starts from the neck of the urinary bladder and crosses the prostate gland.
b) Membranous urethra- It is narrowest of all three parts and is surrounded by external urethral sphincter
c) Spongy urethra - On dilation it forms navicular fossa and extends till the external urethral orifice. Also known as penile
