舌下神经襻之形成及其变异

A STUDY OF THE FORMATION OF THE ANSA HYPOGLOSSI AND ITS VARIATIONS

导言关於舌下神经襻的构成、位置及联属,在多数解剖书刊上,叙述欠详,而且大致相同,易使初学者误认舌下神经襻真是一个联属简单,固定不变的结构。关於舌下神经襻之位置,仅Deaver及Grant等氏之著作,稍有所述,他们说有时包藏在颈动脉鞘以内,甚或有深於颈内静脉者,而Morris教本上指出襻之藏在鞘内,尚属可能,至於在颈内静脉之深面者,当属少见云。

The form and position of the ansa hypoglossi and the course of its components,the descending branch of the hypoglossal nerve and the communicatingbranches of the cervical nerves,were studied in 128 Chinese cadavers.It wasfound that only in half of the cases(55.7%)the ansa showed loop formationwhile in the other half the component nerves either joined each other at anacute angle or came together more gradually.The ansa may be found on thesurface of the carotid sheath or inside it.The point of union in percentageswas 48.2 half way between the mandible and the clavicle and 32.7 below thatlevel.In the majority of the cases(80.3%)the descending branch of thehypoglossal nerve ran down on the antero-lateral surface of the internal carotidartery,while in the rest it appeared in between the internal carotid artery andthe internal jugular vein.