480 



H. — Muscles of the Spine. 



The muscles of the spine may be divided into the Direct and Ob- 

 lique muscles, according as they pass from origin to insertion from and 

 to similar or different processes of the vertebrae. 



The Direct muscles are 



1. Interspinal, 



2. Intercostal, 



3. IntertransversaL 



The Oblique muscles are 



1. Spino-costal, or costospinal; 



2. Spino-transversal, or transversospinal ; 



3. Costo-transversal, or transversocostal. 



Direct Muscles of the Spine. 



I. Interspinal Muscles, passing from spinous process to spinous pro- 

 cess, along the line of vertebrae. There are interspinal muscles developed, 

 more or less, along the column, especially in the dorsal and lumbar por- 

 tions. 



II. Intercostal Muscles. — The costal processes of the cervical vertebrae 

 are, as usual, well developed ; and in the lumbar region they form broad 

 horizontal expansions, which are continued, with modifications down the 

 whole length of the tail. 



a, M. intercostalis lumharis (quadratus lumborum), 



I • 6,96 oz - 



This muscle takes its origin from the interior quadrate surface of 

 the ilium, Pig. 27 (quad, lurnb.), and from the crest of ilium; and is 

 inserted into the backs of the flat costal processes of all the lumbar ver- 

 tebrae, into the edge of last rib, and posterior surfaces of next two ribs 

 (extensor of lumbar spine). 



b, M. intercostalis dorsalo-cervicalis, c', . .2*071 , A<7 



c . . 1-27/ ' ' L ' bl oz ' 

 Prom the costal processes of all the dorsals into the backs of the 

 ribs (9 — 1), and of all the cervical costal processes (pleurapophyses), 

 terminating at the mastoid process (extensor of dorsal and cervical 

 spine). 



c, M. intercostalis caudalis superior, c\ . . 0*681 a <>& 



c, . . o-eaj- • 0-66 oz - 



This muscle is a horizontal wagger of the tail, and its origin is shown 

 in Fig. 26 (i. c. c) from a line on the posterior interior edge of the ilio- 

 ischium ; it is inserted into the back of the costal expansion of the 

 sacrum, and into the backs of the costal processes of the caudal vertebrae 

 (1 — 6) — (extensor of caudal spine). 



