The malleus cap: Anatomic description of cartilage of the lateral process of the malleus

Purpose: To anatomically describe a cartilaginous cap attached to the lateral process of the malleus.

Study design: Histologic and gross anatomic review.

Methods: Twenty temporal bones were histologically reviewed. The anatomical relationship between the tympanic membrane and malleus was then defined at the level of the lateral process of the malleus and the long process of the malleus. Separately, gross evaluation of these levels at the macroscopic level was undertaken through endoscopic imaging in five subjects.

Results: All temporal bones reviewed revealed the presence of a cartilaginous cap articulating between the tympanic membrane and the lateral process of the malleus. The cartilaginous cap was also readily identifiable in gross evaluation of the tympanic membrane from views lateral and medial to the tympanic membrane during endoscopic evaluation.

Conclusion: The cartilaginous cap of the lateral process of the malleus is an important and reliable anatomical structure of the middle ear that has not previously been described. Through knowledge of the structure surgeons may exploit its presence by creating a cleavage plane between the cartilaginous cap and the malleus during tympanoplasty, possibly allowing for safer and more efficient surgery.