What exactly is sesamoiditis?

Sesamoids. Are two bones found under the first metatarsal. -itis ususally connotates inflammation. However, pain in the sesamoids whether inflammation is present or not is commonly referred to as sesamoiditis.
Inflamation. Of one of the two small bones that are found under the first metatarsal.
There are two. Small bones the size of peanuts that sit under the first metatarsal head when they hurt the term is sesamoiditis..
Inflammation . Inflammation of the sesamoids. This refers to the bottom of the head of the 1st metatarsal bone under the big toe joint. In this area there are normally 2 small "pea like" bones with ligaments and tendons attach to in order to stabilize and allow gliding motion of joint. Sesamoiditis results when these bones and/or surrounding structures get inflammed from excessive pressure, stress or trauma.