The viscerocranium, also known as the splanchnocranium, is a component of the skull that houses and protects the viscera, or internal organs, of the head and neck. It consists of several bones, including the mandible, hyoid bone, and auditory ossicles.
Structure
The viscerocranium is made up of several bones, including:
- Mandible: The mandible, or lower jawbone, is a U-shaped bone that articulates with the temporal bone of the skull at the temporomandibular joint (TMJ). It supports the lower teeth and allows for the movement necessary for speaking, swallowing, and chewing.
- Hyoid bone: The hyoid bone is a small, U-shaped bone located in the neck between the mandible and the larynx. It serves as a point of attachment for the muscles of the tongue, pharynx, and larynx and is important in the movement of these structures during swallowing and speaking.
- Auditory ossicles: The auditory ossicles are three small bones located in the middle ear that transmit sound waves from the eardrum to the inner ear. These bones include the malleus (hammer), incus (anvil), and stapes (stirrup).
Location
The viscerocranium is located within the head and neck region and is composed of several bones that have different locations within this area. The mandible is located in the lower portion of the face, below the maxilla and the nasal bones. The hyoid bone is located in the neck, above the larynx and below the mandible. The auditory ossicles are located within the middle ear, which is a small cavity within the temporal bone of the skull.
Function
The viscerocranium serves several important functions, including:
- Support for the head and neck: The mandible and hyoid bone provide structural support for the head and neck, helping to maintain the position and stability of these structures.
- Facilitation of speech and swallowing: The mandible, hyoid bone, and auditory ossicles all play a role in the movement and function of the structures necessary for speech and swallowing. The mandible allows for the movement necessary for chewing and swallowing, while the hyoid bone and auditory ossicles are involved in the movement of the larynx and pharynx during these processes.
- Protection of the viscera: The viscerocranium helps to protect the internal organs of the head and neck, including the brain, eyes, ears, and other structures.
Clinical Significance
There are several clinical conditions that can affect the viscerocranium and its associated structures, including:
- Temporomandibular joint disorders (TMD): TMD is a group of disorders that affect the temporomandibular joint (TMJ) and the muscles that control the jaw. Symptoms of TMD may include pain, difficulty opening and closing the jaw, and clicking or popping sounds when moving the jaw.
- Fractures: Fractures of the mandible or hyoid bone can occur due to trauma, such as a fall or car accident. These fractures may require treatment with immobilization or surgery.
- Ear infections: Infections of the middle ear, known as otitis media, can result in inflammation and swelling of the auditory ossicles. These infections may cause hearing loss and may require treatment with antibiotics.
