Quick Facts
Location: Tympanic cavity of the middle ear.
Bone Type: Irregular bone.
Key Features: Body, long limb, short limb, and lenticular process.
Articulates With: Malleus and stapes.
Arterial Supply: Anterior tympanic and stylomastoid arteries.
Key Features & Anatomical Relations
The incus is one of the three auditory ossicles, the other two being the malleus and stapes. It is a small, anvil-like bone that’s found in the tympanic cavity of the middle ear in the temporal bone. It is classified as an irregular bone and includes the following bony features:
- parts: body, long limb, and short limb;
- landmarks: lenticular process and articular facet for malleus.
More information regarding these bony features can be found in the Parts and Landmarks tabs for this bone.
The incus is located:
- anterolateral to the stapes;
- posteromedial to the malleus.
It articulates with the:
- stapes at the incudostapedial joint;
- malleus at the incudomallear joint.
Ossification
Ossification of the incus occurs at one ossification center, which is found in its long process and appears in utero during the fourth month. The incus is fully developed by the time of birth (Standring, 2016).
List of Clinical Correlates
- Dislocation
- Incus ankylosis
- Cholesteatoma
References
Standring, S. (2016) Gray's Anatomy: The Anatomical Basis of Clinical Practice. Gray's Anatomy Series 41st edn.: Elsevier Limited.
Learn more about this topic from other Elsevier products
Incus
After the incus and malleus separate from Meckel's cartilage and the stapes separates from Reichert's cartilage, the surrounding crest cells retract to create an air-filled space and undergo a mesenchymal-to-epithelial transition to form the dorsal portion of the middle ear cavity lining (Thompson & Tucker, 2013).
