MUSCLES OF THE TRUNK. 243 



be too strong in the spring, for in that case it becomes so fatiguing to the hand that it is 

 impossible to continue its use for any lengtii of time. The forceps should be held lightly 

 between the thumb and the first and second fingers of the left hand, which may be steadied by 

 resting the little finger on a neighbouring part. 



" The chain-hooks should be strong, and bent in the direction of the thickness and not of 

 the breadth of the steel, as is sometimes done. These Litter are very inferior, being liable to be 

 unbent under any considerable strain. Care should be taken that tlie chains are firmly linked, 

 and that the central ring is sufficiently stout to bear any force that may be applied. The 

 scissors should be large and strong, and it will be found advantageous to have one curved pair, 

 which is very useful in preparing the ligaments. 



" The student will do well to bear in mind that he will probably be called upon in after life 

 to operate on the living body, the only preparation for which is careful dissection: he 

 should therefore, as far as possible, conduct all his dissections as methodically, and with as 

 much care, as if operating on the living body. 



"The student should bear in mind that his manual labour is only a part of his duty, and 

 will be thrown away, unless he at the same time study the description of the part upon which 

 be is engaged ; he should not, therefore, carry the dissection further than he can learn the 

 description on the same day, and at the subject, and should, if possible, re-peruse the description 

 in the evening, and always on the next morning, before carrying the dissection any further.") 



CHAPTEE II. 



THE MUSCLES OF MAMMALIA IN PARTICULAR. 



Article I. — Muscles of the Trunk. 



Subcutaneous Region. 



This only comprises a single muscle, the /leshi/ panniculus (panniculus cartiosus), 

 which moves the skin covering the trunk. Strictly speaking, however, we may 

 describe as dermal muscles all those which are attached to the inner surface of 

 the superficial integument — the muscles of the face, for example. 



Fleshy Panniculus (Panniculus Carnosus). 



Preparation. — Place the animal on its side, and carefully remove the skin, allowing the 

 panniculus muscle to remain on the subjacent muscles. It may also be easily prepared on 

 the subject placed in the first position. 



Situation — Form — Extmt. — Situated on the inner surface of the skin covering 

 the sides of the thorax and abdomen, this is an immense wide muscle, UTegularly 

 triangular in shape, thin at its borders, and thicker in the middle than elsewhere. 



The upper border corresponds to a curved line, convex superiorly, and 

 extending obliquely from the flank to the withers. The inferior border is carried 

 horizontally from the flank to the posterior border of the olecranian mass of 

 muscles, passing along the upper margin of the deep pectoral muscle, which it 

 covers, and to which it adheres somewhat closely. The anterior border descends 

 from the superior extremity of the shoulder on to the muscles of the forearm. 



Structure — Attachments. — The fibres of this muscle are directed forwards 

 for its posterior two-tliirds ; but on arriving on the shoulder they gradually 

 become vertical. They are continued, on the margins of the muscle, by aponeu- 

 roses which attach it either to the internal surface of the skin, or the fibrous 

 fascia of the superficial muscles. 



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



