MUSCLES OF THE ANTERIOR LIMBS. 323 



The antibrachial aponeurosis is made tense by the contraction of the annexed 

 muscle of the latissimus dorsi, and that of the flexor brachii. With reference to 

 the pectoralis transversiis, which has hitherto been regarded as intended to play 

 the same part, it can only act on the fascia which covers, externally, the anti- 

 brachial aponeurosis. 



Preparation of the muscles of the forearm.— The preparation of these muscli-s is extremely 

 flimplf, as it suffices to remove the antibrachial aponeurosis and the interstitial ceilulo-adipose 

 tissue, to expose and to isolate them from each other. No special recommendations need there- 

 fore be given, as a glance at Figs. 179, 181, 182, and 183 will guide the student in his dissec- 

 tion, and supplement the manual details which would be superfluous here. 



Nevertheless, as the terminal insertions of some of these muscles are enclosed within the 

 hoof, and as it is indispensable, in order to expose them, to remove this horny case, some 

 explanation will be given as to the manner in which this should be effected, particularly as 

 the apparent difficulty and labour too frequently cause this part to beomitteil in the dissecting- 

 rooms. 



1. The ins-truments necessary to remove the hoof are : a scalpel, toe-knife, hammer, and a 

 pair of pincers. 



2. The limb should be in a vertical position, held by one or two assistants, and the foot 

 placed on a table, stool, or very solid block of wood. 



3. Pass the scalpel as deeply as possible around the coronet, to separate the wall of the 

 hoof from the organized tissues. 



4. With the knife and hammer, split the wall into four or five pieces by vertical incisions. 



5. When the wall is thus divided, it is sufficient to insert the knife under the fragments, 

 and, making it serve as a lever, tear them off; pincers may also be used for this purpose, each 

 of tiie pieces being twisted from the sole. 



6. To remove the sole, the blade of the scalpel should be passed between its upper face and 

 the plantar surface of the third phalanx ; afterwards the toe-knife may be inserted in the 

 interval at the bulbs of the frog, so as to slightly raise the external border of the sole. This is 



.then seized by the pincers and pulled off, along with the frog, in a single piece, by a powerful 

 twisting movement, aided by the assistants, who press on the limb in a contrary direction. 



A. Anterior Antibrachial Region. 



In Solipeds, this region includes four extensor muscles. Two act on the 

 entire foot ; these are the anterior extensor and the oblique extensor of the meta- 

 carpus. Two others — the anterior and the lateral extensor of the phalanges — 

 terminate in the digital region. 



1. Anterior Extensor of the Metacarpus (Extensor Metacarpi Magnus) 

 (Figs. 179, 11 ; 181, 15 ; 182, 9). 



Synonyms — Epicon<lylo-premetacarpeus — Girard. It represents the two external radiala 

 of Man. (Humero-metacarpeus —Leyh.) 



Situation — Direction — Form — Structure. — This muscle, situated in front of 

 the radius, in an almost vertical direction, is composed of a muscular body and 

 a tendon. The first has the form of an inverted cone, is intersected by some 

 aponeurotic layers, and is composed of muscular fibres slightly arciform at their 

 superior extremities. The tendon, at first rounded, then flattened, commencea 

 below the middle third of the radius, and succeeds the inferior extremity of the 

 muscular portion. 



AttacJtments. — This muscle has its fixed insertion : 1. By the upper extremity 

 of its fleshy fibres, on the crest that limits, behind and below, the musculo-spiral 

 groove of the humerus. 2. Above and in front of the Inferior articular surface 

 of the humerus, by means of a strong fibrous band common to it and the 

 anterior extensor of the phalanges, and which expands on the deep face of these 



