OF THE BACK. 2TT 



processes, and to the layer of lumbar fascia connected with the apices of the 

 transverse processes. In the dorsal region, the Longissirnus dorsi is inserted, 

 by long thin tendons, into the tips of the transverse processes of all the dorsal 

 vertebras, and into from seven to eleven ribs between their tubercles and angles. 

 This muscle is continued upwards to the cranium and cervical portion of the 

 spine, by means of two additional fasciculi, the Transversalis colli, and Trachelo- 

 mastoid. 



The Transversalis Colli, placed on the inner side of the Longissimus dorsi, arises, 

 by long thin tendons, from the summit of the transverse processes of the third, 

 fourth, fifth, and sixth dorsal vertebra, and is inserted, by similar tendons, into 

 the posterior tubercles of the transverse processes of the five lower cervical. 



The Traclielo-mastoid lies on the inner side of the preceding, between it and 

 the Complexus muscle. It arises, by four tendons, from the transverse processes 

 of the third, fourth, fifth, and sixth dorsal vertebra, and by additional separate 

 tendons from the articular processes of the three or four lower cervical ; the fibres 

 form a small muscle, which ascends to be inserted into the posterior margin of 

 the mastoid process, beneath the Splenius and Sterno-mastoid muscles. This 

 small muscle is almost always crossed by a tendinous intersection near its inser- 

 tion into the mastoid process. 



The Spinalis Dorsi connects the spinous processes of the upper lumbar and 

 the dorsal vertebras together by a series of muscular and tendinous slips, which 

 are intimately blended with the Longissimus dorsi. It is situated at the inner 

 side of the Longissimus dorsi, arising, by three or four tendons, from the spinous 

 processes of the first two lumbar and the last two dorsal vertebra : these, uniting, 

 form a small muscle, which is inserted, by separate tendons, into the spinous 

 processes of the dorsal vertebrae, the number varying from four to eight. It is 

 intimately united with the Semi-spinalis dorsi, which lies beneath it. 



The Spinalis Osrvicis is a small muscle, connecting together the spinous pro- 

 cesses of the cervical vertebras, and analogous to the Spinalis dorsi in the dorsal 

 region. It varies considerably in its size, and in its extent of attachment to the 

 vertebra, not only in different bodies, but on the two sides of the same body. It 

 usually arises by fleshy or tendinous slips, varying from two to four in number, 

 from the spinous processes of the fifth and sixth cervical vertebras, and occasionally 

 from the first and second dorsal, and is inserted into the spinous process of the 

 axis, and occasionally into the spinous process of the two vertebras below it. 

 This muscle has been found absent in five cases out of twenty-four. 



The Complexus is a broad thick muscle, situated at the upper and back part of 

 the neck, beneath the Splenius, and internal to the prolongations from the 

 Longissimus dorsi. It arises, by a series of tendons, about seven in number, from 

 the tips of the transverse processes of the upper three dorsal and seventh cervical, 

 and from the articular processes of the three cervical above this. The tendons 

 uniting form a broad muscle, which passes obliquely upwards and inwards, and 

 is inserted into the innermost depression between the two curved lines of the occi- 

 pital bone. This muscle, about its middle, is traversed by a transverse tendinous 

 intersection. 



The Biventer Cervicis is a small fasciculus, situated on the inner side of the 

 preceding, and in the majority of cases blended with it ; it has received its name 

 from having a tendon intervening between two fleshy bellies. It is sometimes 

 described as a separate muscle, arising, by from two to four tendinous slips, from 

 the transverse processes of as many upper dorsal vertebras, and is inserted, on 

 the inner side of the Complexus, into the superior curved line of the occipital bone. 



Relations. By their superficial surface, with the Trapezius and Splenius. By 

 their deep surface, with the Semi-spinalis dorsi and Semi-spinalis colli and the 

 Eecti and Obliqui. The Biventer cervicis is separated from its fellow of the 

 opposite side by the ligamentum nuchas, and the Complexus from the Semi- 

 spinalis colli by the profunda cervicis artery, the princeps cervicis, a branch of 

 the occipital, and by the posterior cervical plexus of nerves. 



