MUSCLES OF THE TRUNK. 209 



7. Transverse Spinous Muscle of the Back and Loins. (Fig. 106, 3.) 



Synonyms. Transverso-spinous Girard. Dorso-lumbar portion of the semispinalis 

 of Man. (The spinalis and semispinalis dorsi Percivall.} 



Situation Extent. This is a very long muscle, directly applied to the 

 supersacral and dorso lumbar spine, and continuous, in front, with the 

 transversales colli ; these two muscles, therefore, measure nearly the whole 

 length of the spine. 



Structure. It is formed of an assemblage of short fasciculi, which are 

 flattened on both sides, tendinous at their extremities, directed obliquely 

 forwards and downwards, and a little inwards, thus crossing at a right angle 

 the spinous processes they cover. 



Attachments. These fasciculi are attached, below, to the lateral lip of 

 the sacrum, the articular tubercles of the lumbar vertebrae, and the trans- 

 verse processes of the dorsal vertebrae origin. They are fixed, above, to the 

 spinous processes of the sacral, lumbar, and dorsal vertebras, and into that of 

 the last cervical vertebra termination. It is to be remarked that they do 

 not attain the summits of these spinous processes in the first half of the 

 dorsal region. 



delations. Outwards, with the lateral sacro-coccygeal and ilio-spinalis 

 muscles, which are confounded with it near its posterior extremity ; inwards, 

 with the sacral spine and the spines of the lumbar and dorsal vertebrae, and 

 with the interspinous ligaments of these three regions. 



Action. It is an extensor of the spine. 



DIFFERENTIAL CHARACTERS OF THE MUSCLES IN THE SPINAL REGION OF THE BACK AND 

 LOINS IN OTHER THAN SOLIPED ANIMALS. 



1. RUMINANTS. In the Ox, Sheep, and Goat, the trapezim is thick and very broad. 

 The anterior small serrated muscle is inserted, by its last digitation, into the ninth rib. 



The posterior serrated is fixed into the four last ribs. 



2. PIG. Its trapezius is well developed. The great dorsal is voluminous, and ia 

 attached to the surface of the ribs, which it covers by dictations from its fleshy portion. 

 It is fixed near the small trochanter to the lip of the bicipital groove. The inferior 

 branch of the ilio-spinalis of this animal is easily divided into two portions, traces of 

 which are found in the Horse: one is formed by the costal fasciculi, the other by the 

 transversal fasciculi. The latter constitutes the muscle to which Bourgelat has given the 

 name of short transversal. 



3. CARNIVORA. Several of the spinal muscles in the Dog resemble those of the Pig ; 

 such are the trapezium, the great dorsal, and the ilio-spinalis. In animals of this group, 

 it is remarked that the anterior serrated is very thick and very developed, and that it is 

 attached to the eight ribs succeeding the second by as many well-marked festoons. The 

 posterior has only three digitations, which are attached to the three last ribs. The common 

 intercostal exactly resembles the sacro-lumbalis of Man ; behind the last rib, it constitutes 

 a thick fleshy body, separated by a fissure from the ilio-spinalis, with which it is attached 

 to the coxa. Lastly, the transverse spinal muscle of the back and loins is very strong in 

 the lumbar region, and is prolonged on the coccygeal vertebrae. 



(According to Leyh, the interspinales muscles are absent in the Horse and Ruminants; 

 they are found in the Pig between the spinous processes of the dorsal and lumbar 

 vertebrae, and in Carnivora between the spinous processes of the cervical vertebrae.) 



COMPARISON OF THE MUSCLES OF THE BACK AND NECK IN MAN WITH THE ANALOGOUS 

 MUSCLES IN THE DOMESTICATED ANIMALS. 



It is usual, in human anatomy, to describe by the name of muscles of the back and 

 neck those which correspond to the superior cervical region, and those of the spinal region 

 of the back and loins of the domesticated animals. The muscles of the inferior cervical 

 region are described in Man as muscles of the neck, with the hyoid muscles and the 

 scalemis. 



