ANATOMY. 



motion of the limbs, or their motion with 

 force in opposite directions, can only be 

 produced by the instrumentality of oppo- 

 site or antagonist muscles, of flexors and 

 extensors answering to each other. For 

 instance, the biceps and brachialis inter- 

 ims, placed in the front of the arm, by 

 their contraction, bend the elbow, and 

 with such degree offeree as the case re- 

 quires, or the strength admits of. The 

 relaxation of these muscles after the effort 

 would merely let the fore-arm drop down: 

 for the back stroke, therefore, and that 

 the arm may not only bend at the elbow, 

 but also extend and straigthen itself with 

 force, other muscles, as the triceps and 

 anconeus, placed on the hinder part of the 

 arm, fetch back the fore -arm into a straight 

 line with the humerus, with no less force 

 than that with which it was bent out of it. 

 It is evident, therefore, that the animal 

 functions require that particular disposi- 

 tion of the muscles which we call anta- 

 gonist muscles. 



It often happens that the action of mus- 

 clesis wanted, where their situation would 

 be inconvenient. In which case, the bo- 

 dy of the muscle is placed in some com- 

 modious position at a distance, and it com- 

 municates with the point of action by 

 slender tendo^. if the muscles which 

 move the fingers Viad been placed in the 

 palm or back of the \> an d, they would 

 have swelled that part to an awkward 

 and clumsy thickness. The l^autv, the 

 proportions of the part, would liav c " been 

 destroyed. They are therefore disposal 

 in the arm, and even up to the elbow, and 

 act by long tendons strapped down at the 

 wrist, and passing under the ligament to 

 the fingers, and to the joints of the fin- 

 gers, which they are severally to move. 

 In the same manner the muscles, which 

 move the toes and many of the joints of 

 the foot, are gracefully disposed in the 

 calf of the leg, instead of forming an un- 

 wieldy tumefaction in the foot itself. 



The great mechanical variety in the 

 figure of the muscles may be thus stated. 

 It appears to be a fixed law, that the con- 

 traction of a muscle shall be towards its 

 centre. Therefore the subject for me- 

 chanism on each occasion is, so to modify 

 the figure, and adjust the position of the 

 muscle, as to produce the motion requir- 

 ed, agreeably with this law. This can 

 only be done by giving to different mus- 

 r !( s a diversity of configuration, suited 

 fo their several offices, and to their situa- 

 tion with respect to the work which they 

 have to perform. On which account we 

 rind them under a multiplicity of forms . 



and attitudes; sometimes with double, 

 sometimes with treble tendons, some- 

 times with none ; sometimes one tendon 

 to several muscles, at other times one 

 muscle to several tendons. The shape of 

 the organ is susceptible of an incalcula- 

 ble variety, whilst the original property 

 of the muscle, the law and line of its 

 contraction, remains the same, and is 

 simple. Herein the muscular system may 

 be said to bear a perfect resemblance to 

 our works of art. An artist does not alter 

 the native quality of his materials, or 

 their laws of action. He takes these as 

 he finds them. His skill and ingenuity 

 are employed in turning them, such as 

 they are, to his account, by giving to the 

 parts of his machine a form and relation, 

 in which these unalterable properties may 

 operate to the production of the effects 

 intended. 



The muscular system would afford us 

 numerous examples of what may be call- 

 ed mechanical structure : i. e. of such 

 contrivances, employed to attain certain 

 objects, as a human artist would adopt on 

 similar occasions. One of the muscles of 

 the eye-ball presents us with a very per- 

 fect pulley ; by means of which the globe 

 of the eye is moved in a direction exactly 

 contrary to the original application of the 

 force. This muscle, which is called the 

 trochlearis, arises from the very back 

 part of the orbit it has a long and slen- 

 der tendon, running through a pulley in 

 the inner part of the front margin of the 

 orbit, and then going back to be fixed in 

 the hind portion of the eye-ball. Thus it 

 draws the globe obliquely upwards and 

 forwards, although the line of'the con- 

 traction of the muscle is directly back- 

 ward. 



In the toes and fingers, the long ten- 

 don, which bends the. first joint, pusses 

 through the short tendon, which bends 

 the second joint 



The foot is placed at a considerable 

 angle with the leg. It is manifest, there- 

 fore, that flexible strings, passing along 

 the interior of the angle, if left to them- 

 selves, would, when stretched, start from 

 it. The obvious preventive is to tie them 

 down, and this is done in fact. Across 

 the instep, or rather just above it, the 

 anatomist finds a strong ligament, under 

 which the tendons pass to the foot. The 

 effect of the ligament, as a bandage, can 

 be made evident to the senses; for if it 

 be cut, the tendons start up. The sim- 

 plicity, yet the clearness of this contri- 

 vance, its exact resemblance to establish- 

 ed resources of art, place it among the 



