A 15-year-old boy detained in the maximum-security Oakhill Youth Center in Laurel assaulted and severely injured a teacher at the facility yesterday, Oakhill officials said.

The teacher, Elsie Traylor, was listed in satisfactory condition late yesterday at Greater Laurel Hospital, where she was undergoing emergency treatment. A hospital spokesman said Traylor was suffering from bruises and cuts on her face and neck. The spokesman said the cuts on Traylor's neck indicated she had been bitten.

The assault occurred during the noon lunch period at Oakhill, a youth corrections center administered by the District of Columbia. The 130 teen-age boys assigned to Oakhill had just left a classroom building for their residences, administrator Preston Gazaway said.

Traylor was eating lunch in her office in the classroom building after teaching an art class when she heard knocking from inside a locked bathroom, Gazaway said.

Traylor reportedly unlocked the door, and was assaulted by a youth who had been inside the bathroom, Gazaway said.

Gazaway said the doors of the classroom building are regularly locked after morning instruction, and that the youth had apparently been inadvertantly locked inside the bathroom by a guard.

The youth was being questioned by U.S. Park Police yesterday afternoon. Gazaway said Oakhill officials plan to file assault charges against the youth.