MUSCLES OF THE TRUNK. 253 



by fhroe fleshy portions; but they aio voluminous, and are in* rted, one into the atlas, another 

 into the naastoid crest, and the third into tiie occipital protuberance. In the complexus, the 

 two portiond are completely separated from each other, except at their upper extremity, by 

 the interspace lodging the superior cervical artery. The aponeurosis attaching the muscle to 

 the spinous processes of the first dorsal vertebraj is not confounded with that of the splenius 

 or tlie t-erratus anticus respiratory muscle. The atloidean fli shy body of the trachelo- 

 masf()deu!< is scarcely distinct from the superior branch of the iongissimmo dorsi and the 

 iiitertransversalcs. Lastly, it is ditticult to distinguish the small posterior gtrairjht muscle Imm 

 the deep fasciculus of tlie great strairfht rnnsclf. 



3. Carnivora, — In these animals the mus-Ies of the superior cervical region are nearly all 

 voluminous, as in the Pig. The rhomhoideus is bifid at its origin, and its anterior branch arises 

 from the mastoid crest. The nngularis is also attached to the last six cervical vertebrae. Very 

 tiiick and broad, the splenius only passes to the atlas and mastoid crest. The oblique and 

 straight posterior muscles of the head are also remarkably thick. 



B. Inferior Cervical or Trachelian Region. 

 The muscles composing this region are situated in front of the cervical 

 vertebrae, and are, for the most part, grouped around the trachea, which they 

 envelop as in a kind of sheath. They are eleven in number, and are : the cervical 

 panniculus, mastoido-hiimeralis, sterno-maxillaris, sterno-thijro-hyoideus, subsctt' 

 pulo-hyoideus, rectus capitis anticus major, rectus capitis anticus minor, rectus 

 capitis lateralis, scalenus, and the longus colli. 



Preparation. — 1. Place the animal in the first position. 2. Remove the skin of this region, 

 in order to expose and study the cervical panniculus. 3. Remove that muscle and the parotid 

 gland to prepare the mastoido-humeralis,' the stylo-maxillaris, and sterno-thyro-hyoideus. 4. 

 Transversely cut through the mastoido-humeralis near the angle of the shoulder, and isolate it 

 from the subscapnlo-hyoideus to expose this muscle ; taking care to preserve the jugular vein 

 and parotid gland, in order to study their relations with it. 5. Remove the fore limb.s ; open 

 tile thoracic cavity by sawing through the eight first ribs near their superior extremity ; take 

 out the viscera contained in this cavity, as well as the trachea, oesophagus, pharynx, and 

 larynx, to expose the longus colli, the scalenus, and the straight muscles of the jjead. 



1. Subcutaneous Muscle of the Neck (Cervical Panniculus) 

 (Figs. 159, 12 ; 174, 1). 



Synonyms.— It has been described by Bourgelat, and tlie majority of veterinary anatomists 

 who have followed him, as two muscles : the cuticularis of the neck and the face. (Percivall 

 includes this muscle in his description of tiie panniculus carnosus. It is the platysma myoidea 

 of Man.) 



This is a membraniform expansion, partly fleshy, partly aponeurotic, which 

 covers the muscles of the neck, the subma.xillary space, and the face. 



The fleshy fibres form, in front of the neck, a thin band, which is united, 

 through the medium of a fibrous raplie, to that of the opposite side. This band 

 is in contact with the sterno-maxillaris, sterno-thyro-hyoideus, and subscapulo- 

 hyoideus, as well as the jugular vein — enveloping them all as in a sort of furrow. 

 It gradually becomes thinner from below upwards, in such a manner that around 

 the upper part of the throat it is only composed of some scattered fibres. In the 

 submaxillary space, and on the expanding borders of the inferior maxilla, the fleshy 

 fibres appear again of a certain tliickness, but only to become attenuated on the 

 external surface of the cheeks. 



These fleshy fibres leave the cariniform cartilage of the sternum ^ and inter- 



' The mastoido-humeralis may be dissected at the same time as the trapezius, the subject 

 being placed in the second position. This conveniently permits the superior insertions of the 

 muscle to be studied (see Fig. 159). 



* It will be seen, on referring to Fig. 159 and its legend, that we restore to the cervical 

 19 



