Which ligament keeps the jaw from moving into the middle cranial fossa when the jaw is subjected to an impact?

Which ligament keeps the jaw from moving into the middle cranial fossa when the jaw is subjected to an impact?

• A. Temporomandibular ligament
• B. Stylomandibular ligament
• C. Sphenomandibular ligament
• D. Coronoid ligament

Answer: (A)

The key idea is that stability of the jaw against backward displacement during an impact is provided mainly by the lateral ligament of the temporomandibular joint. This temporomandibular ligament thickens the joint capsule on the side and runs from the zygomatic process of the temporal bone near the articular tubercle to the neck of the mandible. Its course and tension resist posterior translation of the condyle, helping prevent it from being driven into the middle cranial fossa when force is applied to the jaw. The other ligaments play different roles: the sphenomandibular and stylomandibular ligaments act as passive restraints that help limit how far the jaw can open and provide vertical support, but they’re not the primary preventers of posterior cranial dislocation. There isn’t a true coronoid ligament.

The key idea is that stability of the jaw against backward displacement during an impact is provided mainly by the lateral ligament of the temporomandibular joint. This temporomandibular ligament thickens the joint capsule on the side and runs from the zygomatic process of the temporal bone near the articular tubercle to the neck of the mandible. Its course and tension resist posterior translation of the condyle, helping prevent it from being driven into the middle cranial fossa when force is applied to the jaw.

The other ligaments play different roles: the sphenomandibular and stylomandibular ligaments act as passive restraints that help limit how far the jaw can open and provide vertical support, but they’re not the primary preventers of posterior cranial dislocation. There isn’t a true coronoid ligament.