OF THE BACK. 345 



The Cervicalis ascendens l is the continuation of the Accessorius upward into 

 the neck ; it is situated on the inner side of the tendons of the Accessorius, arising 

 from the angles of the four or five upper ribs, and is inserted by a series of slender 

 tendons into the posterior tubercles of the transverse processes of the fourth, fifth, 

 and sixth cervical vertebrae. 



The Longissimus dorsi is the middle and largest portion of the Erector spinas. 

 In the lumbar region, where it is as yet blended with the Ilio-costalis, some of the 

 fibres are attached to the vhole length of the posterior surface of the transverse 

 processes and the accessory processes of the lumbar vertebrae, and to the middle 

 layer of the lumbar fascia. In the dorsal region, the Longissimus dorsi is inserted, 

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

 tebrae, and into from seven to eleven of the lower ribs between their tubercles and 

 angles. This muscle is continued upward to the cranium and cervical portion of 

 the spine by means of two additional muscles, the Transversalis cervicis and Trach- 

 elo-mastoid. 



The Transversalis cervicis or colli, placed on the inner side of the Longissimus 

 dorsi, arises by long thin tendons from the summits of the transverse processes of 

 the six upper dorsal vertebras, and is inserted by similar tendons into the posterior 

 tubercles of the transverse processes of the cervical vertebras, from the second to the 

 sixth inclusive. 



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

 the Complex us muscle. It arises, by tendons, from the transverse processes of 

 the five or six upper dorsal vertebras, and 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 insertion into the mastoid process. 2 



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

 dorsal vertebrae together by a series of muscular and tendinous slips which are 

 intimately blended Avith the Longissimus dorsi. It is situated at the inner side of 

 the Longissimus dorsi, arising, by three or four tendons, from the spinous pro- 

 cesses of the first two lumbar and the last two dorsal vertebrae : these, uniting, 

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

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

 intimately united with the Semispinalis dorsi, which lies beneath it. 



The Spinalis colli is a small muscle, connecting together the spjnous processes 

 of the cervical vertebrae, and analogous to the Spinalis dorsi in the dorsal region. 

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

 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, sixth, and seventh cervical vertebrae, and occasionally 

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

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

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



Relations. The Erector spinas and its prolongations are bound down to the 

 vertebras and ribs in the lumbar and dorsal regions by the lumbar fascia and the 

 vertebral aponeurosis. The inner part of these muscles covers the muscles of the 

 fifth layer. In the neck they are in relation, by their superficial surface, with the 

 Trapezius and Splenius ; by their deep surface, with the Semispinalis dorsi et colli 

 and the Recti and Obliqui. 



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

 the neck, beneath the Splenius, and internal to the Transversalis cervicis and 



1 This muscle is sometimes called " Cervicalis descenders." The student should remember that 

 these long muscles take their fixed point from above or from below, according to circumstances. 



2 These two muscles (Transversalis cervicis and Trachelo-mastoid) are sometimes described as 

 one, having a common origin, but dividing above at their insertion. The Trachelo-mastoid is then 

 termed the Transversalis capitis. 



