Internal derangements of the temporomandibular joint: an assessment of condylar position in centric occlusion. 
Subjects experiencing painful dysfunction of the TMJ and diagnosed by arthrography to have displacements of the meniscus were compared to normal or asymptomatic subjects to assess condyle-fossa relationships.  The groups did not differ by linear or area determinations of the P/A ratio.  The use of plain film alone is not adequate for diagnosis or assessment of treatment if abnormalities of meniscus function are the primary etiology.