pars tensa

The pars tensa is the main, tightly stretched portion of the tympanic membrane, commonly known as the eardrum. This thin, semitransparent membrane separates the outer ear from the middle ear. It is about 8–10 mm in diameter and shaped like a flattened cone. The pars tensa is composed of three layers: an outer skin layer continuous with the ear canal, an inner mucous membrane layer continuous with the middle ear, and a middle layer of fibrous tissue that provides stiffness and tension. This structure is crucial for hearing and is sensitive to pain due to its rich supply of blood vessels and nerve fibers. The appearance and mobility of the tympanic membrane, including the pars tensa, are important indicators for diagnosing middle-ear conditions.1