The prevertebral space lies posterior to the retropharyngeal space and is separated from it by the prevertebral fascia. Infection of the prevertebral space often originates from osteomyelitis of the cervical vertebrae. This infection is frequently caused by staphylococci and may lead to spinal cord damage unless treated by an approach that combines immobilization, antistaphylococcal antibiotics, and external drainage. The parapharyngeal space is demarcated by the parotid gland and internal pterygoid muscle laterally and by the superior constrictor muscle medially. The internal jugular vein, carotid artery, and cranial nerves IX, X, and XII pass through the space.
Infection can reach the parapharyngeal space from the pharynx or from parotid or dental foci.
Patients have severe trismus, externally visible inflammation behind the angle of the jaw, and inflammation in the lateral wall of the pharynx with medial displacement of the tonsil. Pharyngitis and dental infections may also lead to postanginal sepsis. Facial swelling is an early diagnostic clue to this syndrome. CT is important for detecting abscesses, and ultrasonography is helpful for identifying jugular vein thrombosis. Anaerobic gram-negative bacilli, such as Fusobacterium species, are typically responsible for the condition.