MUSCLES OF THE TBVNK. 



231 



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inferior maxilla, and is carried upwards to the 

 commissure of the lips. By its contraction it 

 gives the faxje an expression of melancholy or 

 contempt. 



12. The quadratus menti, which, after being 

 attached to the maxilla within the mental fora- 

 men, passes upwards on the skin of the lower 

 lip, which it depresses, and thus contributes to 

 the expression of fear or dismay. 



13. The transversalis nasi (compressor nasi), 

 a muscle which is fixed into the supermaxilla 

 and on the bridge of the nose, where it is con- 

 founded with the opposite muscle. 



14. The dilator of the ala of the nostril, a 

 very small triangular fasciculus applied to the 

 external part of the nostril, which, by contract- 

 ing, it elevates. 



C. Muscles of the Lower Jaw. 



There is nothing remarkable to be noted in 

 the masseter, temporal, or pterygoid muscles. 

 The upper beUy of the digastricus is not at- 

 tached directly to the inferior maxilla. 



D. Hyoid Muscles. 



These are only three in number : — 



1. The myki-hyoideus. 



2. The stylo-hyoideus, which commences at 

 the styloid process of the temporal bone, and 

 shows a ring for the tendon of the digastricus. 



3. The genio-hyoideus. 



We do not find in Man the oocipito-styloideus, 

 kerato-hyoidetM, or the transversalis-hyoideus. 



Axillary Region. 



This comprises two muscles, pairs, 

 placed beneath the sternum, in the arm- 

 pit, which terminate on the anterior limb. 

 These are the superficial and deejp pec- 

 torals.^ 



Fig. 113. 



MUSCLES or THE HUMAN HEAD ; 

 SUPEEMCIAL LAYER. 

 Frontal portion of the occipito-fronta- 

 lis ; 2, Its occipital portion ; 3, Its 

 aponeurosis ; 4, Orbicularis palpebra- 

 rum ; 5, Pyramidalis nasi ; 6, Com- 

 pressor nasi ; 7, Orbicularis oris ; 8, 

 Levator labii superioris alffique nasi ; 



9, Levator labii superioris proprius; 



10, Zygomaticus minor; 11, Zygo- 

 maticus major; 12, Depressor labii 

 inferioris ; 13, Depressor anguli oris ; 

 14, Levator labii inferioris; 15, Super- 

 iicial portion of masseter; 16, Its deep 

 portion; 17, Attrahens aurem; IS, 

 Buccinator ; 19, AttoUens aurem ; 20, 

 Temporal fascia covering temporal 

 muscle ; 21, Retrahens aurem ; 22, 

 Anterior belly of the digastricus, with 

 tendon passing through pulley ; 23, 

 Stylo-hyoid muscle; 24, Mylo-hyoi- 

 deus ; 25, Upper part of sterno-mas- 

 toid ; 26, Upper part of trapezius — ■ 

 the muscle between 25 and 26 is the 

 splenius. 



Freparation. — 1. Place the animal in the 

 first position. 2. Unfasten one of the fore-limbs, 

 and allow it to hang, so as to separate it from 

 the opposite one. 3. Eemove the skin with 

 care, and dissect, on the side corresponding to 

 the detached limb, the two muscles which form 

 the superficial pectoral. 4. Prepare the deep 

 pectoral on the opposite side. To do tliis, 

 remove the pannieulus cautiously, so as not to injure the muscle about to be examined ; 

 clivide the superficial pectoral transversely, and turn back the cut portions to the right and 

 left; divide also the masfoido-humeralis (levator humeri) and cervical trapezius ne^r 

 their insertion into the limb, and reflect them upon the neck. 



1. Superficial Pectoral. (Fig. 114, 9, 10.) 



Synonyms.— -Muscle common to the arm and fore-arm — Bourgelat. Pectoralis magnua 

 of Man. {Pectoralis transversus — Fercivall. Leyh divides this muscle into two portions, 

 which he designates the sterno-radialis and small sternohumeralis). 



F. r a justification of the employment of these new denominations, see the note 

 at p. 177. 



