Bersu E T, Ramirez-Castro J L
Am J Med Genet. 1977;1(2):173-93. doi: 10.1002/ajmg.1320010204.
This paper describes the anatomical variations observed in the head and neck in eight infants with the 18-trisomy syndrome that were dissected and studied in detail. Of the usual muscles of facial expression, occipitofrontalis and the auricular and nasal muscles were hypolastic in all eight bodies and each subject showed extensive fusion of the muscles around the corner of the mouth. In each body there was a supernumerary muscle band that extended from the region near the corner of the mouth to the occipital attachment of trapezius. The otomandibular region in each body showed a variable spectrum of muscular, skeletal, arterial, and salivary gland variations bilaterally. Three of the bodies had infrahyoid muscle variations. The sum of these observations provides a more complete delineation of the variations that occur in the 18-trisomy syndrome. Tentative pathogenetic hypotheses for several of the defects are discussed, based on observations from human descriptive embryology. Poswillo's teratological model [1973] implicating hemorrhaging as a causal mechanism in human first and second branchial arch malformations is suggested as a possible mechanism to explain the bilateral otomandibular defects.
本文描述了对8例18 - 三体综合征婴儿的头颈部进行解剖并详细研究后观察到的解剖变异情况。在所有8具尸体中，常见的面部表情肌、枕额肌以及耳部和鼻部肌肉均发育不全，且每例受试者的口角周围肌肉都有广泛融合。每具尸体中都有一条多余的肌带，从口角附近区域延伸至斜方肌的枕部附着点。每具尸体的耳下颌区域双侧均表现出肌肉、骨骼、动脉和唾液腺的多种变异。其中3具尸体有舌骨下肌变异。这些观察结果汇总起来，更完整地描绘了18 - 三体综合征中出现的变异情况。基于人体描述性胚胎学的观察结果，讨论了几种缺陷的初步发病机制假说。有人提出，Poswillo的致畸模型[1973年]认为出血是人类第一和第二鳃弓畸形的致病机制，这可能是解释双侧耳下颌缺陷的一种机制。
