Zerin M, Van Allen M I, Smith D W
Pediatrics. 1982 Jan;69(1):91-3.
Plical folding of the cartilagenous ear plate is largely determined by the insertions of four extrinsic and seven intrinsic auricular muscles. Dissection of ten external auricles from anencephalic fetuses of six or more months' gestation was done. The transversus and obliquus auricular muscles found in association with the antihelical fold were evaluated. Four auricles were of normal form and had the transversus and obliquus auricular muscles with typical insertions in the cartilage. Six of the ten auricles had a simplified form, with no antihelical folding in five and minimal development in one. Fibers from neither the transversus nor the obliquus auricular muscles were identified in these six ears. The results of these dissections strongly suggest that antihelical folding is determined by the presence of functioning transversus and obliquus auriculae muscles. Similarly it is proposed that normal folding of the auricular cartilage is dependent on the presence of functioning auricular muscles. In evaluation of the child with absence of normal ear form, these findings suggest that the unusual shape is due to abnormal placement and/or function of the intrinsic and extrinsic auricular muscles. These changes may be a subtle sign of neuromuscular weakness, abnormal muscle insertion or absence of muscle.
软骨耳板的皱襞折叠在很大程度上由四条外在耳肌和七条内在耳肌的附着决定。对来自妊娠六个月或以上无脑儿胎儿的十个外耳进行了解剖。对与对耳轮皱襞相关的耳横肌和耳斜肌进行了评估。四个耳形态正常，耳横肌和耳斜肌在软骨中有典型的附着。十个耳中有六个形态简化，五个没有对耳轮折叠，一个发育极少。在这六个耳中未发现耳横肌和耳斜肌的纤维。这些解剖结果有力地表明，对耳轮折叠由正常发挥功能的耳横肌和耳斜肌的存在决定。同样，有人提出耳软骨的正常折叠取决于正常发挥功能的耳肌的存在。在评估耳部形态异常的儿童时，这些发现表明异常形状是由于内在和外在耳肌的位置异常和/或功能异常。这些变化可能是神经肌肉无力、肌肉附着异常或肌肉缺失的微妙迹象。
