Tamatsu Yuichi, Gasser Raymond F
Department of Cell Biology and Anatomy, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112, USA.
Clin Anat. 2004 Mar;17(2):99-106. doi: 10.1002/ca.10212.
To determine in selected, staged human embryos the time period and manner of formation of the sensory nerves to the mucosa on the dorsum of the tongue, cranial nerves V(3) and IX and their lingual branches were traced microscopically. These two cranial nerves along with cranial nerve VII are present in the dorsal part of their respective pharyngeal arch 1, 2, and 3 at Stage 13. All three nerves grow ventrally at Stage 16, and the lingual branches of V(3) and IX become closer to the developing tongue region. The lingual fibers begin to enter the tongue substance at Stage 17 when they appear as large short branches that terminate 100-400 microm from the dorsal mucosal basement membrane; of the fibers that are in the tissue deep to the surface mucosa, those in the posterior tongue segment terminate the closest and those in the anterior segment the farthest. Chorda tympani nerve fibers are joined with V(3) at Stage 20. At this stage nerve fibers reach the basement membrane in the posterior tongue segment and by Stage 23 they terminate at the basement membrane throughout the tongue, being sparsest in the anterior segment. Primordial papillae appear as small mucosal projections throughout the tongue at Stage 20 and are innervated by Stage 23. The study found that innervation to the dorsum of the tongue develops during the second month of prenatal life. During the 4-week period, Stages 13-23, an innervation pattern was observed based on the relative time fibers terminate at the basement membrane. The pattern begins caudally in the root, then moves rostrally lateral to the middle tongue segment, proceeding then to the tip of the tongue. The last area to become innervated is the medial part of the middle segment or central portion of the tongue.
为了确定在选定的分期人类胚胎中，舌背黏膜感觉神经的形成时间段和方式，对三叉神经下颌支（V(3)）、舌咽神经（IX）及其舌支进行了显微镜下追踪。在第13阶段，这两条颅神经与面神经（VII）一起出现在各自咽弓1、2和3的背侧部分。在第16阶段，所有三条神经都向腹侧生长，V(3)和IX的舌支变得更靠近发育中的舌区。在第17阶段，舌纤维开始进入舌实质，此时它们表现为大的短分支，在距背侧黏膜基底膜100 - 400微米处终止；在表面黏膜深层组织中的纤维，后舌段的纤维终止位置最靠近基底膜，前舌段的纤维终止位置最远。鼓索神经纤维在第20阶段与V(3)相连。在此阶段，神经纤维到达后舌段的基底膜，到第23阶段，它们在整个舌的基底膜处终止，在前舌段最为稀疏。原始乳头在第20阶段表现为遍布整个舌的小黏膜突起，并在第23阶段获得神经支配。研究发现，舌背的神经支配在产前生命的第二个月发育。在第13 - 23阶段的4周时间内，观察到一种基于纤维在基底膜处终止的相对时间的神经支配模式。该模式从舌根尾部开始，然后向头侧移动到舌中段外侧，接着延伸到舌尖。最后获得神经支配的区域是舌中段的内侧部分或舌的中央部分。
