Now examine the penis. The end of the penis is covered by the:

• prepuce (foreskin in humans)

If needed, pull back the prepuce, or even pull the penis out of the prepuce with a hemostat. Now identify the:

• glans penis
• free end of the penis

Prior to puberty, the free end of the penis is attached to the prepuce and then gradually separates to the adult appearance as seen in the image. A prepubertal male may mount females or other males but can not extend his penis completely as would be seen in an adult male.

You should also be able to see the retractor penis muscle which is paired and serves to pull the penis back into the male when the errection or ejaculation is finished. The sigmoid flexure is a bend in the penis that allows it to fold when the the retractor penis muscle contracts or straightens out during erection.

In this image is the ischiocavernosus muscle. It may not be present if it was cut off during harvesting of the tract. The muscle contracts against the crus penis (paired, one on each side) to force blood into the penis and prevent its flow back out during erection. The muscle relaxes to allow the decreased blood flow and loss of erection.