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 Partr. 178 A N A T O M Y. the pofterior cavity are flretched out into two procefles, gus, brevis, and brachioeus externus, are inferted. The one on each fide: Thefe are called condyles ; from each olecranum makes it unneceffary that the tendons of the of which a ftrong ligament goes out to the bones of the extenfor mufcles ftiould pafs over the end of the os humeri; which would-have been of ill confequence in the fore-arm.—The external condyle, which has an oblique -great fledtions of this joint, or when any confiderable direction alfo forwards in refpeft of the internal, when the arm is in the molt natural pofture, is equally broad, external force is applied to this part.—The anterior proand has an obtufe fmooth head'rifing from it forwards.— cefs is not fo large, nor does it reach fo high as the one From the rough part of the condyle, the inferior head behind; but is (harper at its end, and therefore is named of the bicornis, the extenfor digitorum communis, ex- coronoid.—Between thefe two procefits, a large femicirtenfor carpi ulnaris, anconceus, and fome part of the fu- cular or figmoid concavity is left; the furfacd of which, pinator radii brevis, take their rife; and on the fmooth on each fide of a middle rifing, is flanting, and exadlly head the upper end of the radius plays.—Immediately adapted to the pully of the bone of the arm. Acrofs on the outfide of this, there is a finuofity made by the the middle of it, there is a fmall finuofity for lodging fliorter head of the bicornis mufcle, upon which the muf- mucilaginous glands ; where, as well as in a fmall hollow cular nerve is placed. The internal condyle is more on the internal fide of it, tbe cartilage that lines the reft pointed and protuberant than the external, to give origin of its furface is wanting.— Round the brims of this conto fome part of the flexor carpi radialis, pronator radii cavity the bone is rough, where the capfular ligament teres, palmaris longus, flexor digitorum fublimis, and of the joint is implanted. Immediately below the oleflexor carpi ulnaris.—Between the two condyles, is the cranon, on the back-part of the ulna, aflat, triangular, trochlea or pully, which confifts of two lateral protube- fpongy furface appears, on which we commonly lean.— rances, and ^middle cavity, that are fmooth, and co- At the internal fide of this, there is a larger hollow furvered with cartilage.—Wheij the fore-arm is extended, face, where the mufcidus anconoeus is lodged; and the the tendon of the internal brachioeus mufcle is lodged in ridge at the infide of this gives rife to the mufculus futhe fore-part of the cavity of this pully.—The external pinator radii brevis. Between the top of the ridge protuberance, which is lefs than the other, has a (harp and the coronoid procefs, is the femijunated fmooth caedge behind; but forwards, this ridge is obtufe, and on- vity, lined with cartilage, in which, and a ligament exly feparated from the little head, already defcribed, by tended from the one to the other end of this cavity, the a fmall fofla, in which the joined edges of the ulna and . round head of the radius plays.—Immediately below it, radius move.—The internal protuberance of the pully is a rough hollow gives lodging to mucilaginous glands.— largeft and higheft; and therefore, in the motions of the Below the root of the coronoid procefs, this bone is fcaulna upon it, that bone would be inclined outwards, was brous and unequal, where the brachiceus internus is init not fupported by the radius on that fide. Between ferted.—On the outfide of that, we obferve a fmooth conthis internal protuberance and condyle, a finuofity may cavity, where the beginning of the flexor digitorum profundus fprouts out. be remarked, where the ulnar nerve pafies. The round head at the upper end of this bone is arti- The body of the ulna is triangular.—The internal anculated with the glenoid cavity of the fcapula; which gle is very (harp where the ligament that connects the being fuperficial, and having long ligaments, allows the two bones is fixed;—the fides, which make this angle, are flat and rough, by the aftion and adhefion of the maarm a free and extenfive motion. The motions which the arm enjoys by this articulation, ny mufcles which are fituated here.—At the diftance of are to every fide; and by the fucceffion of thefe differ- one third of the length of the ulna from the top, in. its ent motions, a circle may be defcribed. Befides which, fore-part, the paffage of the medullary veffels is to be the bone performs a fmall rotation round its own axis. remarked flanting upwards.—The external fide of this The Fore-arm confills of two long bones, the ulna bone is fmooth, fomewhat convex, and the angles at and radius ; whofe fituation, in refpett of each other, is each edge of it are blunted by the preffure of the mufoblique in the leaft firaining or moft natural pofture ; that cles equally difpofed about them. is, the ulna is not dire&ly behind, nor on the outfide of As this bone defcends, it becomes gradually fmaller; the radius, but in a middle fituation between thefe two, fo that its lower end termihates in a little head, ftanding and the radius croffes it.—In the following defcription, on a fmall neck. Towards the fore but outer part by the term pojlerier is meant that part which is in the of which laft, an oblique ridge runs, that gives rife to the fame diredtion with the back of the hand; by anterior, pronator radii quadratus. The head is round, fmooth, that anfwering to the palm; by internal, that on the and covered with a cartilage on its internal fide, to be fame fide with the thumb; by external, the fide neareft received into the femilunar cavity of the radius ; while a the little finger. ftyloid procefs rifes from its outfide, to which is fixed a Ulna, fo named from its being ufed as a meafure, is ftrong ligament that is extended to the os cuneiforme and the longeft of the two bones of the fore-arm, and fitua- pififorme of the wrift.—Betveen the back-part of that ted on the outfide of the radius. fmooth fide and this procefs* a finuofity is left At the upper end of the ulna are two proceffes.—The internal for the tendon of the extenfor carpi ulnaris, —On the pofterior is the largeft, and formed like a hook, whofe fore-part of the root of the procefs, fuch another deprefconcave furface moves upon the pully of the os humeri, fion may be remarked for the paffage of the ulnar arteand is called olecranon, or top of the cubit.—The con- ry and nerve.—The end of the bone is fmooth, and covex back-part of it is rough and fcabrous, where the lon- vered with a cartilage.—Between it and the bones of