I have seen in some severe rear-end accidents that people can develop TMJ problems. This painful condition was described recently in an article I paste below. Further information on TMJ injuries can be found at this link.
The temporomandibular joint (TMJ) is a gliding joint, formed by the condyle of the mandible and the temporal bone. The articulating surfaces of the mandible and temporal bone are separated by an articular disk (meniscus), which divides the joint cavity into 2 small spaces. The articular disk provides the gliding surface for the mandibular condyle, resulting in smooth joint movement.
Temporomandibular joint syndrome (TMJS) is the most common cause of facial pain after toothache. No unequivocal definition of the disease exists; discrepancies concerning the terminology, definitions, and practical treatment methods hinder uniform conception from becoming effective. TMJS can be classified broadly as (1) TMJS secondary to myofacial pain and dysfunction (MPD) and (2) TMJS secondary to true articular disease; the 2 types can be present at the same time, making diagnosis and treatment more challenging.
MPD type forms the majority of the cases of TMJS. Associated with pain without apparent destructive changes of TMJ on x-ray, it is characterized by its polyetiological nature and frequently is associated with bruxism and daytime jaw clenching in a stressed and anxious person. True intra- articular disease can be further specified as disk displacement disorder, chronic recurrent dislocations, degenerative joint disorders (DJDs), systemic arthritic conditions, ankylosis, infections, and malignancy.