| XXX | (194) | XXX |
Part II. 194 ANA T O M Y. This whole raufcle is covered by the trapezius, and increafes gradually in breadth, and is inserted in all the covers immediately the ferratus pofticus fuperior, being true ribs, and often in one or two of the falfe ribs, by the joined to each of thefe mufcles by a filamentary or cellu- fame number of digitations. lous fubftance. S U B*C L A V I U S. Angularis, vulgo LEVAraa Scapula Proprius. Th i s is a fmall oblong mufcle, lying between the claThis is a long, and pretty thick mufcle, about two vicle and firft rib. It is fixed by one end in all the midfingers in breadth, lying above the fuperior angle of the dle lower portion of the clavicle, at the diftance of about fcapula, along the poflerior lateral part of the neck of an inch from each extremity; and by the other in the that bone. cartilage and a fmall part of the bone of the firft rib. It is inferred above in the extremities of the tranfverfe It feems likewife to adhere to the extremity of the claapophyfes of the four firlf vertebrae of the neck, by four vicle next the fternum, by a kind of broad thin ligament. flefliy branches, ending in Ihort tendons; fometimes the fecond, fometimes the third, or both, and fometimes the Uses of the Muscles 'which move Bones of the fourth of thefe branches, is wanting; thefe defedls being Shoulder on the Trunk. made up by the largenefs of the rett. From thence thefe branches run down a little oblique- The mechanifm of the fcapula, in relation to its moly, and then uniting together, they are inferred in the tions and changes of fituation, is very different from that fuperior angle of the fcapula, and in the edge of its ba- of all the other bones of the body, except the os hyfis, from thence to the finall triangular fpace, being there oides. AH the other bones have fohd fulcra or fixed points, on which they are either moved or fixed by the covered a little by the rhomboides. This mufcle is eafily divided into two through its mufcles; but the motions of the fcapula, its changes of whole length. It is covered by the trapezius, and its fituation, and its continuance in any one given attitude, infertions in the neck are fometimes mixed with thofe of are brought about without the help of any folid fulcrum. The mufcles alone fuflain it and brace it down, in all its the neighbouring mufcles. different motions and fituations. The fcapula has this peculiarity likewife belonging to PECTORALIS MINOR. it, that it is the fulcrum and bafis of all the motions of This is a fmall flelhy mufcle, fomething of a triangu- the os humeri, of fome motions of the fore-arm, and lar fhape, fituated at the fuperior, lateral, and anterior even of all the moft violent efforts made with thefe bones, without being itfelf either moved or fixed on any part of the thorax. By its bafis it is inferred in the external labium of the folid bafis. upper edge of the fecond, third, fourth, and fifth true The ufe of the trapezius is to raife the fhoulder, and ribs ; near their union with the cartilages, by the fame to keep it from finking. number of digitations or feparate flefhy portions, becaufe The ferratus major raifes the fhoulder or top of the of the intervals between the ribs ; and for that reafon it fcapula, brings it forward, and hinders it from finking. In all thefe, it is the principal adlor; and it is impoffible has been called ferratus minor anticus. From thence thefe portions run up, more or lefs, ob- to conceive how labourers raife and fupport, by the liquely toward the Ihoulder, and form a flefhy belly, fhoulder alone, the heavy burdens with which they are which contrails as it paffes before the two firft ribs, and loaded, without the affiftance of this mufcle. then becoming a fhort, flat, and broad tendon, is infert- According to the infertions and dire&ion of the rhomt d in the upper part of the apophyfis coracoides of the boides, its general ufe muft be, to draw backward and fcapula, reaching all the way to the point of that upward the fub-fpinal portion of the bafis fcapuias. It is likewife a moderator to the trapezius and ferratus procefs. This mufcle is covered by the pefloralis major, and major, when they raife the fhoulder, or carry the aeroadheres very clofely to the external interccflal mufcles. mium upward; and it brings the fcapula back to its natural fituation, when the aftion of thefe mufcles ceafes. The angularis, by its infertion in the fuperior angle of SERRATUS MAJOR. the fcapula, moderates the defeent of that angle, while This is a broad, flefhy, and pretty thick mufcle, ly- the trapezius and ferratus major raife the acromium. ing on the lateral part of the thorax, between the ribs Afterwards, when thefe two mufcles ceafe to ail, the and fcapula, hy which it is covered. Its figure is that of angularis raifes the fuperior angle, and by that means dethe acromium. an irregularwhere fquare, its greateftby breadth in the prefies hack-part, it terminates digitationsbeing of unequal The pe&oralis minor aflifts the rhomboides and angulengths, in a radiated difpofition, their extremities de- laris, as moderators of the aflion of the trapezius and scribing an arch or curve; and from thefe digif'ations its ferratus major, in turning the point of the acromium upward, the fuperior angle downward, and the inferior name is taken. It is inferred backward in the internal labium of all the angle forward. bafis of the fcapula, from the fuperior to the inferior It is likewife an a flirtant to the rhomboides arid anguangle. Front thence running forward wholly flefhy, it laris, in rertoring the fcapula to its natural fituation, when
