This is an contact gunshot entrance wound.
Since the barrel contacts the skin, the gases released by the fired round go into the subcutaneous tissue and cause the star-shaped laceration.
Note also the grey-black discoloration from the soot, as well as the faint abrasion ring.
Displayed here is an entrance at the left and an exit at the right.
This particular bullet struck at an angle to produce the ovoid entrance.
Exit wounds vary considerably in size and shape because the bullet can be deformed in its transit through the body.
There may be no exit wound at all if the bullet's energy is absorbed by the tissues.
Some bullets (such a "hollowpoint") are designed to deform so that all their energy will be converted to tissue damage and not exit.
Powder tattooing is seen in this intermediate range gunshot wound.
The actual entrance site is somewhat irregular, because the bullet can tumble in flight.
An abrasion ring, formed when the force of the gases entering below the skin blow the skin surface back against the muzzle of the gun, is seen here in this contact range gunshot wound to the right temple.
