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25 r Part V. A N A r r O M Y. number is applied to each nerve. ; There are generally parts of the fuperior extremity. Seven of thefe branches faid to be thirty pair of them; feven of which come out we ftiall defcribe under particular names. between the vertebras of the neck, twelve between thofe x. Scapularis runs freight to the cavitas femiluof the back, five between thofe of the loins, and fix nata of the upper cofta of the fcapula, which is a hole, in the recent fubjeft, by a ligament being extended from one from the falfe vertebras. The First Cervical pair of nerves csmes out be- angle of the bone to the other, giving nerves in its way tween the firft and fecond vertebras of the neck; and ha- to the mufcles of the fcapula. When it has palled this ving given branches to join with the tenth pair of the hole, it fupplies the fupra-fpinatus mufcle; and then deat the anterior root of the fpine of the fcapula, head, the fecond cervical and intercoftal, and to ferve itfcending the mufcles that bend the neck, it fends its largeft is loft in the other mufcles that lie on the dorfum of branches backwards to the extenfor mufcles of the head that bone. and neck; fome of which piercing through thefe mufcles, 2. Articularis finks downward at the axilla, to run up on the occiput to be loft in the teguments here; get below the neck of the head of the os humeri, and and many fibres of it advance fo far forward as to be to mount again at the back-part of it; fo that it almoft the articulation, and is diftributed to the mufconnedted with the fibrils of the firft branch of the fifth furrounds pair of the head, and of the portio dura of the auditory cles that draw the arm back, and to thofe that raife it up. 3. Cutaneus runs down the fore-part of the arm, nerve. The Second Cervical is foon joined, by fome near the fkin, to which it gives off branches ; and then branches, to the ninth of the head and intercoftal, and divides, on the infide of the fore-arm, into feveral nerves, to the firft and third of the neck; then has a large which fupply the teguments there, and on the palm of branch that comes out at the exterior edge of the fter- the hand. no-maftoidasus mufcle, where it joins with the accefforius 4. Musculo-Cutaneu s, or perforans Cajferi, pafof the eighth pair; and is afterwards diftributed to the fes through the coraco-brachialis mufcle; and, after fupplatyfma myoides, teguments of the fide of the neck and plying the biceps flexor cubiti and brachiseus internus, head, parotid gland, and external ear, being connedted paffes behind the tendon of the biceps, and over the ceto the portio dura of the auditory nerve, and to the firft phalic vein, to be beftowed on the teguments on the outcervical. The remainder of this fecond cervical is fpent fide of the fore-arm and back of the hand. on the levator fcapulse and the extenfors of the neck and 5. Muscularis has a fpiral courfe from the axilla, head. Generally a large branch is here fent off to join under the os humeri, and backward 10 the external part the accefforius of the eighth pair, near the fuperior angle of that bone, fupplying by the way the extenfor mufcles of the fore-arm, to which it runs between the two braof the fcapula. The Third Pair of the neck paffes out between the chiaei mufcles, and within the fupinator radii longus.— third and fourth cervical vertebras; having immediately At the upper part of the fore-arm, it fends off a branch, a communication with the fecond, and fending down a which accompanies the fupinator longus till it comes near branch, which being joined by a branch from the fourth the wrift, where it paffes obliquely over the radius, to cervical, forms the Phrenic nerve. This defcending, be loft in the back of the hand and fingers. The princienters the thorax, between the fubclavian vein and ar- pal part of this nerve pierces through, the fupinator radii tery ; and then being received into a groove, formed for brevis, to ferve the mufcles that extend the hand and it in the pericardium, it has its courfe along this capfula fingers, whofe adtions are not injured when the fupinator of the heart, till it is loft in the middle part of the dia- adts. phragm. The right phrenic has a freight courfe; but 6. Ulnaris is extended along the infide of the arm, the left one is obliged to make a confiderable turn out- to give nerves to the mufcles that extend the fore-arm, W'ards, to go over the prominent part of the pericardium, and to the teguments of the elbow: Towards the lower^ where the point of the heart is lodged. The middle part of the arm, it llants a little back-ward, to come at of the diaphragm fcarce could have been fupplied by any the groove behind the internal condyle of the os humeri, other nerve which could have had fuch a freight courfe through which it runs to the ulna: In its courfe along this bone, it ferves the neighbouring mufcles and teguas the phrenic has. The other branches of the third cervical nerve are di- ments ; and as it comes near the wrift, it detaches a ftributed to the mufcles and teguments at the lower part branch obliquely over the ulna to the back of the hand, of the neck and top of the fhoulder. to be loft in the convex part of feveral fingers. The The Fourth Cervical nerve, after fending off that larger part of the nerve goes ftreighi forward to the inbranch which joins with the third to form the phrenic, ternal fide of the os pififorme of the wrift; where it fends and beftowing twigs on the mufcles and glands of the off a branch which finks under the large tendons in the neck, runs to the farm-pit, where it meets with the palm, to go crofs to the other fide of the wrift, ferving Fifth, Sixth, and Seventh cervicals, and First the mufculi lumbricales and interoffei, and at laft terDorsal, that efcape in the interftices of the mufculi minating in the fhort mufcles of the thumb and fore-finfcaleni, to come at the arm-pit, where they join, fepa- ger. What remains of the ulnar nerve, after fupplying rate, and rejoin, in a way fcarce to be rightly expreffed in the fhort mufcles of the little finger, divides into three words; and, after giving feveral confiderable nerves to branches; whereof two are extended along th« fides of the mufcles and teguments which Cover the thorax, they the flieath of the tendons of the flexors of the little findivide into feveral branches, to be diftributed to all the ger, to furnifli the concave fide of that fingeu-; and the third
