196 TBE MUSCLES. 



Freparation.—l. Place the animal in the first position. 2. Eemove the skin of this 

 region, in order to expose and study the cuticular muscle. 3. Eemove that muscle 

 and the parotid gland to prepare the mastoido-humeralis,' the stylo-maxillaris, stevno'- 

 hyoideus, and sterno-thyroideus. 4. Transversely cut through the mastoido-humeralis 

 near the angle of the shoulder, and isolate it from the subscapulo-hyoideus to expose 

 this muscle ; taking care to preserve the jugular vein and parotid gland, in order to study 

 their relations with it. 5. Kemove the fore limbs ; open the 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, cesophagus, pharynx, and larynx, to expose the 

 long muscle of the neck, the scalenus, and the straight muscles of the head. 



1. Subcutaneous Muscle of the Nech. (Figs. 102, 12 ; 114, 1.) 



Synonyms. — It has been described by Bourgelat, and the 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 the pamiiculus carnosus.) 



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

 which covers the muscles of the neck, the intermaxillary 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 raphe, to that of the opposite side. This 

 band is in contact with the sterno-maxiUary, sterno-hyoid, subscapulo-hyoid, 

 and stern o-thyroid muscles, as well as the jugular vein : enveloping them 

 all as in a sort of gutter. It gradually thins 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 intermaxillary space, and on the expanding borders 

 of the maxillary branches, the fleshy fibres appear again of a certain 

 thickness, but only to become attenuated on the external surface of the 

 cheeks. 



These fleshy fibres leave the anterior prolongment of the sternum^ and 

 intermediate middle raph^ of the two muscles, and directing their course 

 outwards and upwards, soon become confounded with the aponeurosis. The 

 latter, extremely thin, is spread over the mastoido-lnuneralis, the superior 

 cervical muscles, parotid region, and the cheeks, and is finally attached to 

 the zygomatic crest. On arriving near the commissui-e of the lips, the 

 cuticular muscle is united to the alveolo-labialis (or buccinator muscle) by 

 a fleshy fasciculus named, in Man, the risorius santorini (Fig. 110, 24). 



The cuticularis colli braces the muscles it covers during their contraction 

 and pulls backwards the commissures of the lips. We doubt very much 

 whether it has, in the cervical region at least, any action on tjie skin, for it 

 adheres but very slightly to its inner surface. 



2. Mastoido-humeralis. (Figs. 102, 105, 106, 114.) 



Synonyms. — The muscle common to the arm, neck, and head — Bourgelat. Eepre- 

 senting the cleido-mastoid, and the clavicular portions of the trapezius and deltoid of 



■ 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. 102). 



" It will be seen, on referring to figure 111 and its legend, that we restore to the 

 cuticular muscle of the neck the sternal band attributed until now to the mastoido- 

 humeralis. These are the considerations which induce us to make this modification : 

 1, This band is not distinct from the cuticularis of the neck ; a separation between the 

 two muscles can only be artificially obtained. 2, In dissecting this band with care, we 

 can see that its fibres, like those of the cuticularis, are not mixed with those of the 

 mastoido-humeralis (superficial portion) ; they pass along the external surface of that 

 muscle, to which they intimately adhere, it is true, but they can easily be separated, afld 

 are continuous with the aponeurosis of the first. 



