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to the cnin cerebri, thalami, ti:bcrcula quadrigemina, 



ami pineal gianJ. 'I'lie dctrp-fcatcd artery of the brain 



is fcparatcJ tVotn the former branch by the nerve of 



the third pair. Afceniiiiig between the cerebellum and 



p'jilcrior lobe of the cerebrum, it fends off the connnuni- 



laliiig branch, which meeting and inofcnlating with a fimi- 



i.ir branch of the carotid, completes the circle of Willis. 



'J'iie rttl of the artery k dillributed to the back of the brain. 



'I'iic fuperior iutcrcoftal artei7 goes off from the back 



->f the fubdavian, and defcends over the heads of the hrll 



and fecond ribs. Jt gives fmall twigs to the ocfophagus ; 



two branches to the fpinal marrow ; two others which 



penetrate to the miifclesof the liack; and two branches for 



the firft and fecond intercollal fpaces, which communicate 



with the inferior intercoflal arteries. 



Tliefe four brar.ches are ufiially given off before the fvib- 

 cUvian paffes between the fcaleni ; the two following arile 

 while it is paffing, or immediately after it has pafled. 



The deep-feated cervical artery goes under the mufcles 

 of the neck, almoft touching the vertebiiE. It is entirely 

 dillributed to the furrounding mufcles, and reaches almoil 

 to the occiput. 



The fuperficial cervical artery is hidden under the brachial 

 nerves ; its lirll branches go to thofe nerves, and to the 

 fcaleni mufcles; the rcll of the trunk goes to the mufcles 

 behind the neck, as the fplcnius, complexus, trapezius, and 

 levator fcapula:. 



The artery, having left the fcaleni mufcles, recedes from 

 the trunk of the body, and affumes the name of axillary; 

 k bends obliquely downwirds over the middle of the firll 

 and fecond ribs, and under the clavicle into the axilla. 

 Emerging from under the clavicle, it is covered by the 

 brachial nerves, by the axillaiy vein and glands; externally 

 it is protected by the pcc\oral mufcles. It is fituated in the 

 axilla, between the fen-atus anticus and fubfcapularis muf- 

 cles ; at the lower margin of the tendon of the latiffimus 

 doi'ii, it changes its name for that of the humeral artery. 

 Branches of the Axillary Artery. 

 The firft or upper thoracic artery arifes near the upper 

 margin of the peAoralis minor mufcle, behind which it 

 defcends ; its branches fupply the ferralus anticus, pedloral, 

 and fome of the intercollal mufcles. 



The long or fecond thoracic artery, which is fometimes a 

 branch of the pofterior circumflex, or infra-fcapular arte- 

 ries, paffes alfo behind the pedloralis minor, fas ar as the 

 fixth rib. Its branches go to the axillaiy glands and 

 mammx, alfo to the feiratus, peftoralis minor, and intei- 

 , coflal mufcles. 



Thefe two thoracic arteries inofculatc with tbe inter- 

 coftals, and the internal mammary. 



The thoracic artery of the Ihoulder (arteria thoracica 

 humeraiia) comes off near the fecond rib, and penetrating 

 between the peftoralis major and deltoid, is diftributed 

 chiefly to the former mufcle, and the neighbouring integu- 

 ments. 



The deep or fourth thoracic branch (arteria thoracica 

 alaris), fupplies the axillaiy glands, the pedloralis minor, 

 and fubfcapularis. 



Ohfervation. The thoracic arteries are fubjedl to confider- 

 able variety in number, fize, and dilliibution. 



The infrafcapular or fubfcapular artery, which is a very 

 large trunk, comes off near the neck of the fcapula. Its 

 lirll branches go to the fubfcapularis, to the caplule of the 

 flioulder joint, and to the mufcles, which arile from the 

 coracoid proccfs. A very large mufcular branch is dif- 

 tributed to the teres major and minor, the ferratus, latilli- 

 tnus dorfi, fubfcapularis, &c. The principal part of the 

 6 



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trunk turns over the inferior collaof the fcapula, and rami- 

 fies on the dorfum of the bone, fupplying the infra-lpina- 

 tus, and teres minor, and comnuinicating with the (upra- 

 fcapular artery. 



'i'he pofterior circumflex artery goes off between the 

 teres major and fubfcapularis ; it paffes backwards between 

 thefe, and under the long head of the triceps, and is re- 

 flefted round the head of the humerus, being connected 

 with the deltoid. Its branches go to the deltoid and other 

 mufcles about the fcapula, and communicate with the pro- 

 funda humeri. 



The anterior circumflex artery is a much more (lender 

 brar.ch ; it goes under the biceps and coracobrachiahs, and 

 terminates on the deltoid. 



The brachial or humeral artery leaving the axilla, purfues 

 its courfe along the middle of the biceps mufcle ; it pafles 

 over the brachialis interuus, and advances gradually towards 

 the front of the arm. In tliis courfe the large median 

 nerve lies in front of it. Arriving at the bend of the elbow, 

 it goes under that produdliou which the tendon of the biceps 

 fends off to the fafeia of the fore -arm, and is lodged deep 

 in the hollow w'hich is left between the two maffes of miil- 

 cles on the fore -arm, where it divides into the radial and 

 ulnar arteries. The median nerve ftill remains in front of 

 the artery ; the cephalic vein is lituated conliderably on the 

 oullide of the artery ; and the median vein crolTes over it 

 to join the cephalic. 



Branches of the Brachial Artery. 

 Branches of little confequeuee go to the teres major, 

 latiffunus dorfi, triceps, coracobrachiahs, biceps, and nerves 

 of the arm. 



The larger deep-feated artery of the flioulder (profunda 

 humeri major or coUateralis magna) ariles high up in the 

 arm, and is frequently given oft by the inferior fcapular\', 

 or pofterior circumflex arteries. It bends backwards be- 

 tween the long and the external head of the triceps, giving 

 many large branches to that mufcle, and comes out at 

 the back of the arm, where it divides into two branches; 

 thefe communicate at the back oi the elbow with the 

 radial and ulnar recnnents. 



The nutrient artery of the humerus comes off near the 

 infertion of the coracobrachiahs, and having diftributed 

 branches to the neighbouring mufcles, enters the fubftance 

 of the bone. 



The fmaller deep-feated branch, or branches, go to the 

 outfide of the brachialis internus, fupinator radii longus, 

 extenfores carpi radiales, &c. and communicate with the 

 recurrents of the fore-arm. 



The great anaftomoling branch (ramus anaftomoticus 

 magnus) comes off from the infide of the trunk, within 

 a (hort diftance of the joint, and proceeds towards the 

 inner condyle ; its branches communicate above with the 

 profunda, below with the recurrents. 



Tiie two lall-mentioncd branches, with one or two more 

 which delcend along the triceps to communicate with the 

 arteries of the fore-arm, are fometinacs defcribed under the 

 name of coUaterales minores. 



The radial artery, which is fmaller than the ulnar, fecms 

 to be given off as a branch from the ulnar ; it paffes 

 along the furface of the pronator teres, and then 

 goes on the infide of the fupinator longus tox the 

 wrift. It bends under the extenfor tendons of the thumb, 

 and penetrates the abductor indicis to arrive in the palm 

 of the hand. Here it palFes along the heads of the nie- 

 tacai'pal bones, and having formed the arcus profundus 

 voLe, communicates on the oppolite fide of the hand with 

 a large branch of tlie ulnar. 



Branches 



