Mastoid fontanelle

The mastoid fontanelle is a soft spot located on the skull of infants, specifically in the area behind the ear known as the mastoid process.^[5] It is one of the several fontanelles that allow for the flexibility and growth of the skull during early development.

Location

The mastoid fontanelle is located on the posterior aspect of the head, just behind the ear. It is a small, triangular-shaped opening located at the level of the base of the skull.^[4] It is bordered by several bones, including the parietal bone, occipital bone, and temporal bone. The temporal bone also contains the auditory ossicles, which are small bones that are involved in hearing.^[6] The size of the mastoid fontanelle varies among individuals, but it is generally small, measuring only a few millimeters in size.

Structure

The mastoid fontanelle is a small opening in the bone of the skull, specifically the mastoid process, which is a projection of bone located behind the ear. The mastoid process is a part of the temporal bone, one of the bones that make up the skull.^[3]The temporal bone also contains the auditory ossicles, which are small bones that are involved in hearing.^[8] It is located just behind the ear, at the level of the base of the skull. The size of the mastoid fontanelle varies among individuals, but it is generally small, measuring only a few millimeters in size.

Function

The mastoid fontanelle has several important functions in the anatomy of the head and neck. One of its main functions is to provide a pathway for the transmission of sound waves from the external ear to the middle ear.^[7] Sound waves enter the external ear through the ear canal and pass through the auditory ossicles in the middle ear. From there, they are transmitted to the inner ear, where they are converted into neural signals that are interpreted by the brain as sound.^[2] In addition to its role in sound transmission, the mastoid fontanelle also serves as an important point of attachment for several muscles and ligaments in the head and neck.^[1] These muscles and ligaments help to stabilize the head and neck and allow for movement.

Clinical Significance

One of the main clinical uses of the mastoid fontanelle is in the diagnosis and treatment of ear infections. The mastoid fontanelle is often used as a point of access for the insertion of a tympanostomy tube, which is a small, hollow tube that is inserted into the ear to help drain fluid from the middle ear. This procedure is often performed on children with recurrent middle ear infections. In addition to its use in the treatment of ear infections, the mastoid fontanelle is also used in the diagnosis and treatment of other conditions that affect the ear and surrounding structures. For example, it may be used to access the auditory ossicles or to perform a biopsy of the mastoid bone.