Tympanic part of temporal bone

The tympanic part of temporal bone is a curved bony plate beneath the squamous part and ahead of the mastoid process. Inside, it merges with the petrous segment of the temporal bone. The tympanic part makes up the front wall, the base, and a segment of the back wall of the external acoustic meatus. The posterior wall then rises to form the anterior limit of the tympanomastoid fissure. Along its inner side, the tympanic plate features a narrow groove, the tympanic sulcus, which provides attachment for the tympanic membrane and its fibrocartilaginous tympanic ring. The front surface is concave and shapes the back wall of the mandibular fossa. Its rough outer edge outlines the boundary of the bony external ear canal and connects with the cartilaginous part. The inferior border of tympanic plate is sharp and branches out laterally to form, at its root, the sheath of the styloid process (vaginal process).