BACK. 



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times happens that this muscle has no connexion 

 with the eleventh and twelfth dorsal vertebra. 

 The long tendinous fibres of the two trapezii, 

 at the junction of the cervical and dorsal re- 

 gions, form an oval aponeurosis of considerable 

 size, called the cervical aponeurosis, which is 

 supposed to give greater strength to this part. 

 All the spinal origin has its fibres blended with 

 those of the opposite muscle, and supraspinal 

 ligament. The insertion is by a mixture of 

 tendinous and fleshy slips, except at the extre- 

 mity of the spine of the scapula, where a little 

 tendon is formed which glides over a small 

 triangular surface to be inserted into the top of 

 the tubercle. The plane which this muscle 

 forms is curved on the side of the neck, and its 

 fibres are there a little twisted. Instead of three 

 sides this muscle has actually five: 1st, a 

 superior; 2nd, an internal- these are its ori- 

 gins; 3rd, an external, which is its insertion, 

 and two others which are unconnected, viz. 

 4th, an inferior external, and 5th, a superior 

 external. Of these the first is so short that it 

 attracts no notice ; the other four are of un- 

 equal lengths hence the name trapezius. But 

 the third and fourth sides are so nearly in one 

 continuous line that the whole muscle appears 

 triangular. 



The trapezius covers the complexus, the 

 splenii, the levator anguli scapulae, the serratus 

 posticus superior, the rhomboidei, the supra- 

 spinat'JS, a small portion of the infra-spinatus, 

 the latissimus dorsi, the sacro-lumbalis and 

 longissimus dorsi. It touches all these mus- 

 cles, and glides on them by means of a fine 

 cellular tissue, which contains little or no fat 

 except over the supra-spinatus. The anterior 

 superior edge forms the posterior boundary of 

 the great lateral triangle of the neck, and at its 

 upper extremity is often connected witli the 

 steruo-mastoid. The two trapezii have some 

 resemblance to the monk's cowl hanging over 

 the neck, hence the name cucullares often given 

 to them. 



By its superior fibres this muscle raises the 

 clavicle and scapula; by its middle it draws 

 the scapula towards the vertebral column, and 

 by its inferior it pulls the tubercle of the spine 

 of the scapula downwards. If all the fibres act 

 together, it will cause, the scapula to rotate on 

 the thorax, so as to elevate the shoulder-joint, 

 and in this it is powerfully assisted by the in- 

 ferior portion of the serratus magnus, as in 

 carrying heavy burthens on the shoulder. It 

 serves to keep the head from falling forwards, 

 and will, by its superior fibres, draw the head 

 to the shoulder and turn the face to the other 

 side. We use it in shrugging up the shoulders. 

 It becomes a muscle of inspiration by raising 

 and fixing the clavicle and scapula, so that the 

 subclavius, the lesser pectoral, part of the ser- 

 ratus magnus, &c. may elevate the ribs. The 

 spinal accessory nerve (the superior external 

 respiratory of the trunk) terminates in this 

 muscle, and, according to Sir Charles Bell, 

 associates it with the other respiratory muscles. 



The ligamentum nuchec, from which the chief 

 part of the cervical portion of the muscle arises, 

 is a line of dense cellular tissue, extending from 



VOL. I. 



the external tuberosity of the os occipitis to the 

 spine of the seventh cervical vertebra. It is 

 interposed between the two trapezii. A thin 

 septum extends from it to the spines of all the 

 cervical vertebra. In no part does it deserve 

 the name of ligament in the human subject. 

 In quadrupeds, however, especially where the 

 neck is long or the head very heavy, as in the 

 horse, stag, elephant, &c. it is a powerful elastic 

 ligament, resembling in structure the ligamenta 

 subflava of the spine, and is of great impor- 

 tance by supporting the head without much 

 muscular effort. In man it is quite rudimental. 



The trapezius presents much variety in differ- 

 ent animals. In the carnivoraand rodentia the 

 clavicular portion joins with the masto-humeral, 

 (a muscle not found in man,) and is separated 

 from the scapular portion by the levator anguli 

 scapula-. In the horse the only part of the muscle 

 developed is that which corresponds to the as- 

 cending fibres in man, and which are inserted into 

 the tubercle at the extremity of the spinous pro- 

 cesses. In the dolphin it is thin, covers all the 

 scapula, and is inserted into that bone near its 

 neck. In the mole a fleshy bundle coming 

 from the loins replaces it. In birds it consists 

 of two portions, one for the furca, the other for 

 the scapula. In reptiles there is no trapezius. 



LattS'imus dorsi. This muscle is also thin, 

 triangular, and very extensive, covering the 

 lumbar region, a part of the dorsal and of the 

 side of the thorax, and contributing to form the 

 posterior boundary of the axilla. It is exposed 

 by raising the integuments, superficial fascia, 

 and lower angle of the trapezius. Then we 

 find it arising from the tops of the spinous pro- 

 cesses of six, (sometimes of four or five, some- 

 times of seven or eight,) of the inferior dorsal 

 vertebra, of all the lumbar vertebra and from 

 the supraspinal ligament, from the spines and 

 other eminences of the sacrum, from nearly the 

 whole posterior half of the crest of the ilium, and 

 from the three or four lowest false ribs. The 

 fibres all converge, the uppermost running 

 transversely, the lowest vertically. It is in- 

 serted into the posterior edge of the bicipital 

 groove of the humerus. 



The costal origin of this muscle is fleshy, all 

 the rest is tendinous. The tendinous fibres on 

 the vertebrae are blended with those of the 

 opposite muscle, and on the sacrum and ilium 

 with the glutaeus maximus. They form a tendon 

 of great extent, narrow on the sacrum, \ery 

 broad on the lumbar region, and again becoming 

 narrow as we ascend to the dorsal. It is to this 

 tendinous expansion that the name of liunlxir 

 fascia is given; its fibres are for the most part in 

 the direction of the fleshy fibres which succeed, 

 but they are crossed irregularly by some others. 

 Tins fascia covers and binds down the lumbar 

 muscles, giving great strength to the loins ; it 

 is intimately connected with the tendon of the 

 serratus posticus inferior, the internal oblique 

 of the abdomen, and the posterior tendon of 

 the transversal is, all of which are inseparably 

 connected with its anterior surface. The costal 

 origin is by fleshy slips which indigitate with 

 similar slips of the obliquus extenuis abdominis; 

 these are so disposed that the inferior almost 



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