Lesions of the parapharyngeal space. Role of MR imaging.

Because the parapharyngeal space is one of the deep spaces of the upper neck, it is a difficult region to examine clinically. On each side of the head, this space is located lateral to the pharynx and medial to the ramus of the mandible, the pterygoid muscles, and the parotid gland. It is only with bimanual palpation that any small fullness within this space may be clinically appreciated. When a parapharyngeal mass is sufficiently large, it displaces the lateral pharyngeal wall and pharyngeal tonsil toward the midline and may cause lateral displacement of the parotid gland. Only when a lesion is very large does it manifest as a fullness near the angle of the mandible. Thus, clinical evaluation of the space is quite limited.