MUSCLES OF THE TRUNK. 73 



This muscle lies near the m. serralus or trausv. neap, tertius (Fig. 

 68 ts"), and has an analog-ous position. It would, therefore, possibly 

 be more correct to regard it also as a m. sermtus. It arises 

 from parts which represent ribs, and is inserted into the scapula. 

 It has^ at any rate, no analogy to the m. cuculJarh, with which 

 Dug-es connects it, nor with the vi. rlionihoideus, which Klein holds 

 it to be, as it does not arise from spinous processes. 



B. Long 3Iuscles of the Back. 



34. M. extensor dorsi comntimis (Fig. 67 Ig.d.). 



Dugès, n. 33-40, masse des muscles surspinaux devisee en huit faisceaux 

 principaux: 1. vertebro-sus-occîpital, 2-5. transverso-spinaux, 6. 

 trans verso-coccyg., 7. sacro-coccygien, 8. ileo-coccygien. The muscles 

 1-7 form the lombo-costal, 8 the ischicoccyg., Cuv. — Zenker, m. sa- 

 croliimharis. — Klein, longiss. dorsi, coccygeo-liimib., coccy(j. -iliac. 



This muscular mass is covered by \hQ fascia dorsalis, the m. cncid- 

 laris and retrahens scapula, and the suprascapula : it corresponds with 

 (i) the m. ileo-costalis and longissimus dorsi, dorsi and cervicis (Henle) ; 

 (2) the semupinalis and spinalis (Henle). 



The following sej)arate portions may be made out : — 



35. (i) M. longiss. dorsi {Fi<r. 67 Ig.d.). 



This muscle arises from the most anterior part of the urostyle, runs 

 forwards near the middle line, separated from the muscle of the 

 opposite side by the spinous processes of the vertebrae. The inner 

 portion passes over the 2)osterior spinous processes without being 

 connected with them, as far as the fifth, it is then inserted into the 

 succeeding spines as far as the exoccipital bone. The lateral portion 

 runs outwards and forwards to be attached to the transverse pro- 

 cesses and oblique processes of all the vertebrae, from the sixth 

 forwards, while accessory muscular slips arise from the transverse 

 processes and from the anterior spinous processes which, merging 

 in the general muscle-mass, are inserted with this into the occiput. 



The muscle is subdivided by a series of wavy, tendinous par- 

 titions (Fig. 67), which arise from the transverse processes, and 

 traverse the muscle in planes, the upper surfaces of which are 

 directed upwards and forwards. This arrangement of the muscle 

 indicates its relation with the lateral trunk muscles of fish and- 

 fish-like amphibians. 



36. (2) M. coccijfjeo-sacralis (Fig. 67 c.l^. 



This muscle is partially covered by the preceding, it arises from 

 the lateral surfaces of the anterior half of the urostyle ; from this 



