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 29* Part VI. ANA T O M Y. their infertions, which are in a contrary dire&ion to thofe pophyfis, and they diminilh unequally in length as they of the refti, their fixed points with relation to the mo- approach the apophyfes. tions of the globe being placed forward, and thofe of Thefe four mufcles feem always to a<St in concert, the occipitales being only auxiliaries or aflifiants to the fronthe refti backward, at the bottom of the orbit. The redhis externus, by being bent on the globe, not tales, the office of which is to raife the fupercilia, by only hinders it from being carried outward, but alfo pre- wrinkling the fldn of the forehead. vents the indiredt motions of the obliqui from thruiling The mufculi fuperciliares are fleftiy fafciculi, fituated behind the fupercilia, and behind the inferior portion of it out of the orbit toward the temples. the mufculi frontales, from the root of the nofe to above half of each fuperciliary arch. They are ftrongly'The Super.cii,*a, «k</Muscui,i Frontales, Occi- one inferted, partly in the fynarthrofis of the olfa nafi, with PITALES, and SUPERCILIARES. the os frontis, where they come very near the proper mufThe fupercilia, or eye-brows, are the two hairy arches cles of the nofe, and partly in a fmall neighbouring fituated at the lower part of the'forehead, between the portion of the orbit. From thence- they firfi run up a top of the nofe and temples, in the fame direction with little, and afterwards more or lefs in the diredtion of the the bony arches which form the fuperior edges of the eye-brows. They are made up of feveral finall fafciculi orbits. Their colour is different in different perfons, of oblique fibres, all fixed by one end in the manner aland often in the fame perfon different from that of the ready faid, and by the other partly in the lower extrehair on the head: the hairs of which they confift are mity of the mufcles by which they are covered, and ftrong and pretty fliff, and they lie obliquely, their roots partly in the fldn of the fupercilia. being turned to the nofe, and their points to the temples. The aftion of thefe mufcles is to deprefs the eyeThe fupercilia have motions common to them with brows, to bring them clofe together, and to contradt the thofe of the fkin of the forehead, and of the hairy fealp. fldn of the fore-head immediately above the nofe, into By thefe motions the eye-brows are lifi ed up, the fkin of longitudinal and oblique wrinkles, and the fldn which the forehead is wrinkled more or lefs regularly and tranf- covers the root of the nofe into irregular tranfverfe verfely and the hair and almolt the whole i'calp is mo- wrinkles. ved, but not in the fame degree in ail perfons. The eye-brows have likewife particular motions which con- The Palpe^r.® Membrana Conjunctiva, trad the fkin above the nofe;-and all thefe different moThe palpebne are a kind of veils or curtains placed' tions are performed by the following mufcles. The frontal mufcles are two thin, broad, fiefhy planes tranfverfely above and below the anterior portion of the of unequal lengths, lying immediately behind the fkin globe of the eye;: and accordingly- there are two eyeand membrana adipofa, on the anterior parts of the fore- lids to each eye, one fuperior, the other inferior. 7 he head, which parts they cover from the root of the r.ofe, fuperior is the largeft and moft moveable in man. They and through about two thirds of the arch of the eye- both unite at each-fide of the globe, and. the places of brows on each fide, all the way,to the lateral parts of the their union are termed angles, one large and internal, hair, on the forehead. At the root of the nofe they which is next the nofe, the other fmall ■ or external, touch each other as if they were but one mufcle; and at which is next the temples. this place their fibres are fhort and longitudinal, or ver- The palpebrse- are made up of common and proper tical. parts. The common parts are the fldn, epidermis, and Thefe mufcles are fixed by the inferior extremities of membrana adipofa. The proper .parts are the mufcles, their ffefhy fibres immediately in the ilcin, running thro’ the tarfi, the pundta or foramina lachrymalia, thejnemthe membrana adipofa. They cover the mufculi fuper- brana conjundtiva, the glandula lachrymalis, and -the parciliares, and adhere clofely to them by a kind of inter- ticular ligaments which fuftain the tarfi,- The tarfi and texture. By the fame fibres they feem to be inferted in their ligaments are in fome meafure the bafis of all thefe the angular apophyfes of the os frontis, and to be blend- parts-. ed a little with the mufcles of the palpebrae and nofe; The tarfi are thin cartilages forming the principal part The upper extremities of their flefhy fibres are fixed in of the edge of each palpebra; and they are broader at the external or convex furface of the pericranium. Each the middle than at the extremities. Thofe of the fupeof their lateral portions covers a portion of the temporal rior pal pebrje are fomething lefs than half an inch in mufcle on the fame fide, and adheres very clotely to it. breadth; but in the lower palpebras they are not above The occipital mufcles are tv/o fmall, thin, broad, and the fixth part of an inch ; and their extremities next the very Ihort flelhy planes,> fituated on the lateral parts of temples are more flender than thofe next the nofe. the occiput, at fome difiance from each other. They Thefe cartilages are fuited to the borders and curvaare inferted by the inferior extremities of their .flelhy fibres ture of the eye-lids. The lower edge, of the fuperior in the fuperior tranfverfe line of the os occipitis, and al- cartilage and- upper edge of the inferior, terminate efo a little above it. From thence they run up obliquely qually, and both may be termed the c/V/arji edges. The from behind forv/ard, and are fixed in the inner concave oppofite edge of the upper tarfus is fomething femi-cirfurface of the pericranium. cular between its two extremities; but that of the infeThe breadth of thefe mufcles reaches from the pofie- rior tarfus is more uniform, and both are thinner than riar middle part of the occiput, toward the. mafioid a- the ciliary edges.