The phrase "a protrusion" is correct and usable in written English.
It can be used to describe something that sticks out or extends beyond a surface or boundary.
Example: "The rock formation had a noticeable protrusion that jutted out over the cliff."
Alternatives: "an extension" or "a bulge".
The island of Manhattan in mostly a protrusion of granite rising a few hundred feet from sea level.
An unusual feature is a protrusion on the rim that thrusts up to resemble the stem post of an ancient wooden ship.
In the spittle bug's case, the hind legs fold up against the body and are locked in place by a protrusion on the body.
My left toe is balanced on a protrusion about the size of a golf ball and my right toe is balanced on..
The procedure is for those who suffer primarily back pain, not the leg pain that occurs when a protrusion like a bulging disk presses onto the sciatic nerve.
Harris had been feeling a protrusion which would come and go throughout the summer, until team doctors told him Monday he would need surgery.
The ornamentation, a protrusion shaped like a boxing glove, often appears on just one of the fly's front legs.
We watched the fish, a protrusion inching slowly down the bird's elegant throat, and then we walked home through silent woods, catching each other's eye now and then, checking in, companionable and intimate, sharing the exhilarating quiet.
The Renaissance-style gold cup had a particular function: a protrusion inside it held a bezoar stone, then thought to be a poison absorber, which was found in the stomachs and intestines of llamas and alpacas.
The grown women who fall into their orbit are usually drunks or hookers or nut jobs (one of the good ones has a protrusion on her back in the shape of a sickle).
A protrusion is located on the edge of the surface, comprising conserved histidine and cysteines.
