翼状突起の硬化像について

SCLEROTIC CHANGES OF THE PTERYGOID PROCESS: A RADIOLOGICAL STUDY

　I．はじめに

　翼状突起は翼口蓋窩の後壁をなす構造であるが，翼口蓋窩の下縁において口蓋骨錐体突起あるいは上顎骨の上顎結節下面に連結する。翼状突起をX線的に観察するには普通撮影法（軸位）と断層撮影法（前頭断）とがある。鼻根部から6〜7cm後方の前頭断面のX線写真によつて翼状突起の基部と先端の内側板，外側板とが観察できる。その際に翼状突起の左右のX線透過度に差がみられ，いずれかの側で透過度が減少する（硬化像を呈する）ことは稀ではない（第1図）。この現象は腫瘍，炎症の疾患の別は問わず，副鼻腔の病変が一側性であるときにより判然とすることが多い。上顎癌において破壊を伴わない翼状突起の硬化像は，上顎洞や前頭洞にみる辺縁硬化像と同様に興味ある所見である。われわれはすでに副鼻腔疾患における辺縁硬化像^1），および中頭蓋窩底部の硬化像^2）について報告を行なつたが，今回は翼状突起における硬化像につき，疾患とその部位との関連を中心に，硬化像の意義とその発現機序につき検討する。

　Sclerotic changes (differences in the radiolucency between the right and left pterygoid processes) were investigated using posterior-cut PA polytomography. The paranasal lesions in this study included 15 cases of maxillary cancer, 20 unilateral sinusitis, 27 bilateral chronic sinusitis, 30 postoperative cysts of the maxilla, 3 caseous sinusitis, 4 maxillary papilloma, and 2 maxillary sarcoma. The sclerotic changes were seen in 60% of maxillary cancer, 75% of unilateral sinusitis, 25.9% of bilateral chronic sinusitis, 20% of post-operative cysts of the maxilla, all cases of caseous sinusitis, all cases of maxillary papilloma,and 50% of maxillary sarcoma. Both sex and average age were not related to the change. Among the radiological findings of the paranasal sinuses, diffuse opacity of the maxillary sinus showed highest coincidence (89.7%). Among the findings of the nasal meati, closure of the middle meatus showed highest coincidence (77.3%). The sclerotic reactions were seen in the other areas as the ethmoid-maxillary plate, inferior orbital wall, perpendicular plate of the palatine bone, and the middle cranial base, and the last one showed the highest coincidence (81.8%) of the sclerotic changes. The sclerotic reaction of the pterygoid process was caused primarily by lesions in the maxillary sinus filled either with secretion or soft tissue. This reaction was also one of the important radiological findings seen in maxillary cancer.