McClung J R, Goldberg S J
Department of Anatomy, Virginia Commonwealth University, Richmond, Virginia 23298, USA.
Anat Rec. 2000 Dec 1;260(4):378-86. doi: 10.1002/1097-0185(20001201)260:4<378::AID-AR70>3.0.CO;2-A.
This anatomical investigation in the rat was designed to illustrate the detailed organization of the tongue's muscles and their innervation in order to elucidate the actions of the muscles of the higher mammalian tongue and thereby clarify the protrusor subdivision of the hypoglossal-tongue complex. The hypoglossal innervated, extrinsic styloglossus, hyoglossus, and genioglossus and the intrinsic transversus, verticalis and longitudinalis linguae muscles were observed by microdissection and analysis of serial transverse-sections of the tongue. Sihler's staining technique was applied to whole rat tongues to demonstrate the hypoglossal nerve branching patterns. Dissections of the tongue demonstrate the angles at which the extrinsic muscles act on the base of the tongue. The Sihler stained hypoglossal nerves demonstrate branches to the styloglossus and hyoglossus emanating from its lateral division while branches to the genioglossus muscle exit from its medial division. The largest portions of both XIIth nerve divisions can be seen to enter the body of the tongue to innervate the intrinsic muscles. Transverse sections of the tongue demonstrate the organization of the intrinsic muscle fibers of the tongue. Longitudinal muscle fibers run along the entire circumference of the tongue. Alternating sheets of transverse lingual and vertical lingual muscles can be observed to insert into the circumference of the tongue. Most importantly in clarifying tongue protrusion, we demonstrate the transversus muscle fibers enveloping the most superior and inferior portions of the longitudinalis muscles. Longitudinal muscle fascicles are completely encircled and thus are likely to be compressed by transverse muscle fascicles resulting in elongation of the tongue. We discuss our findings in relation to biomechanical studies, that describe the tongue as a muscular hydrostat and thereby define the "elongation-protrusion apparatus" of the mammalian tongue. In so doing, we clarify the functional organization of the hypoglossal-tongue complex.
本对大鼠的解剖学研究旨在阐明舌肌的详细组织结构及其神经支配，以阐释高等哺乳动物舌肌的作用，从而厘清舌下-舌复合体的前突肌细分。通过对舌的系列横切片进行显微解剖和分析，观察了由舌下神经支配的外在的茎突舌肌、舌骨舌肌和颏舌肌，以及内在的舌横肌、舌垂直肌和舌纵肌。将席勒染色技术应用于大鼠全舌，以显示舌下神经的分支模式。对舌的解剖显示了外在肌作用于舌根的角度。经席勒染色的舌下神经显示，其外侧分支发出至茎突舌肌和舌骨舌肌的分支，而至颏舌肌的分支则从内侧分支发出。可见舌下神经两个分支的最大部分进入舌体以支配内在肌。舌的横切片显示了舌内在肌纤维的组织结构。纵肌纤维沿舌的整个周长走行。可观察到交替的舌横肌和舌垂直肌片插入舌的周长。在阐明舌前突方面最重要的是，我们展示了横肌纤维包裹着纵肌的最上部和最下部。纵肌束被完全环绕，因此很可能被横肌束压缩，导致舌伸长。我们结合生物力学研究讨论了我们的发现，生物力学研究将舌描述为一种肌肉流体静力结构，从而定义了哺乳动物舌的“伸长-前突装置”。通过这样做，我们厘清了舌下-舌复合体的功能组织。
