OCR Text |
Show 'liAl?. II. OBLIQUE EYEBROWS. 181 peculiar furrows formed on the forehead. Th o mu los, when thus in conjoint yet ppo ed action, may b called, for th sake of brevity, the grief-muscles. vVhen a person elevates hi eyebrows by the contraction of the whole frontal muscle, transv r ·e wrinkles extend aero ·s th whole breadth of the forehead; but in tho pre ent case the middle fasciro alone are contracted; cons . quently, transverse fnrrows are fortned across the middl part alone of the forehead. The skin over the exteri r parts of both eyebrows is at the same time drawn downwards and smoothed, by the contraction of the outer portions of the orbicular muscles. The eyebrows are likewise brought together through the simultaneous contraction of the corrugators; 3 and this latter action generat s 3 In tho for goino- r mark:3 n tho manner in which tho eyebrows arc mildo oblique, I have followed what seems to be tho universal opiniou of all tlw anatomist::~, whose works I have consulted on tho action of the nbove-namo(l muse! ::J, or with whom I have convers d. Hence throughout this work I shall taka a similar view of tho action of tho cmntgalor supercilii, orbicularis, 7Jyramid(tlis nasi, and fronlaliH muscles. Dr. Ducll.onne, however, boliovoi:!, and ovary conclusiou nt which he arrives dosorveH serious c nsidomtion, that it is tho corrugator, called by him tho sonrcilier, which mises tho inner corner of the eyebrows and is nnta.gonistic to the upper and inner part of the orbicular muscle, as well as to the pyramidal-is nctsi (seeM (co.nisme de 1a Phys. Humnino, 18G2, folio, art. v., toxt anrliigures 19 to 29: octavo edit. 1 U2, p. 43 text). llo admits, however, that the corrugator <.!raws together tho eyebrows, aul'ling vertical furrows above tho base of th nos , or a frown. IIo further believes that towards tho outer two-thirds of tho eyebrow the corrugator acts in conjunction with the upper orbicuLtr muscle; both here standing in n.ntu.gonism to th frontal muscle. I am unn.blo to nudcrstand, ju(lging from Henle's drawings (woodcnt, fig. 3), how tho corrugator can act in tho manner described by Duchonno. See, also, on this subject, Prof. Donders' r marks in tho 'Archives of Medicine,' 1870, ,ol. v. p. 31..1:. Mr. J. ·wood, who iH so well known for his careful study of tho muscles of tho human frame, informs me that ho bcliovos tho account which I have givcu of thu action of tho corrugator to be correct. But this is n t a point of nny importance with respect to tho expression which is cans d by the obli<luity of the oy brows, nor of mn h importance to the theory of its origin. |