MUSCLES OF THE TRUNK. 187 



anterior border descends from the superior extremity of the shoulder on to 

 the muscles of the fore-arm. 



Structure Attachments. The fleshy fibres entering into the composition 

 of this muscle are directed forward for its posterior two-thirds ; but on 

 arriving on the shoulder they gradually straighten and become vertical. 

 They are continued, on the margins of the muscle, by aponeuroses which 

 attach it either to the internal surface of the skin or to the fibrous fascire 

 of the superficial muscles. 



This muscle has, besides, a very remarkable insertion into the humerus, 

 which was noticed by G. Cuvier, in his 'Legons d'Anatomie Comparee/ 

 and which appears to have been omitted, at least so far as Solipeds are 

 concerned, in every treatise on Veterinary Anatomy. The following is what 

 we have often observed in this respect : On reaching the posterior border of 

 the ulnar mass of muscles, the panniculus divides into two superposed 

 layers : one, superficial, is carried to the muscles of the anterior member ; 

 the other, deep, soon terminates by an aponeurosis which is united to the 

 great pectoral muscle, and is bordered at its upper margin by a nacrous 

 aponeurotic band, which penetrates between the thorax and the muscles of 

 the arm to be fixed to the small trochanter. 



Relations. By its superficial face, with the skin, to which it closely 

 adheres ; by its deep face, with the great dorsal, the dorsal portion of the 

 trapezius, the abdominal tunic, the great oblique muscle of the abdomen, the 

 great serratus, some external intercostals, the spur vein, and the superficial 

 muscles of the shoulder and arm. 



Action. The animal, in contracting this muscle, shakes the whole of the 

 cutaneous integument which covers it ; thus preventing insects from alighting 

 on the surface of the body, or tormenting by their bites or stings. 



In the Dog, the panniculus carnosus is prolonged over the croup, and is united along 

 the dorse-lumbar spine to that of the opposite side. It is very developed in the Cat. 



CERVICAL REGION. 



This region comprises all the muscles grouped around the cervical 

 vertebrae muscles which are conspicuous by their volume and the important 

 part they play in the animal economy. There are described a superior and 

 an inferior cervical. 



A. Superior Cervical, or Spinal Region of the Neck. 



This includes seventeen pairs of muscles, which are : the cervical portion 

 of the trapezius? rhomboideus, angularis of the scapula, splenius, great complexus, 

 small complexus, transverse spinous of the neck, the six intertransverse muscles of 

 the neck, areat oblique muscle of the head, great posterior rectus, and small pos- 

 terior rectus. These form four superposed layers on each side of the cervical 

 ligament, and occupy the triangular space circumscribed by the upper 

 border of that ligament, the transverse processes of the vertebrae of the neck, 

 and the spinous process of the second dorsal vertebra. 



Preparation. Place the subject in the second position and dissect in succession the 

 four layers of the region. To study the first layer, which is formed by the cervical portion 

 of the trapezius, remove the skin, cellular tissue, and the fibrous fascia covering that 

 muscle (See fig. 102). The preparation and study of the second layer, composed of the 

 rhomboideus, angularis. and splenius, is carried out in two stages. In Ihe first, the 

 trapezium and the mastoido-humeralis is removed, leaving only the cervical insertions 



For the description of this muscle, see the SPINAL REGION of the back and loins. 



