MUSCLES OF THE FOOT. 



359 



are employed in the movements of the foot 

 and its several portions, and classify them ac- 



The motions of the ankle- 

 joint are 



The motions between the 

 first and second row of 

 tarsal bones* are . 



The motions of the toes arex 



'1. Downwards and in- I 2. 

 wards accomplished by . j 3. 



f 1 ' 



2. Upwards and outwards J 2. 



by Is. 



I 4. 



1. 



2. 

 3. 



1 . Flexion performed by .^ 4. 

 5. 



6. 

 7. 



2. Extension by 



3. Abduction by 



4. Adduction by 



In this table we are struck with the propor- 

 tion which the antagonist muscles bear to each 

 other, both in numbers and in individual as 

 well as collective power. This proportion is of 

 course regulated by the demand for muscular 

 force in the ordinaiy movements of the joints. 

 The extension of the ankle, in the most ordi- 

 nary mode of its performance, implies the lift- 

 ing of the whole weight of the body by the 

 elevation of the heel, the toes resting upon the 

 ground. This, owing to the unequal length 

 of the two levers, requires an immense power, 

 while the shortness of the moveable lever allows 

 of very little extent of motion. The gastro- 



* It is remarkable that so original and accurate 

 an observer as Dr. Barclay should attribute this 

 motion to the ankle-joint, and should deny any 

 motion, more than a mere yielding, to any of the 

 tarsal bones. But it is still more surprising that 

 he should make the same observation of the carpus, 

 when so very considerable a part of the ordinary 

 motion at the wrist is obviously between the two 

 rows of carj al bones. See Barclay on Muscular 

 Motion, pp. 404, 447. 



cording to the joints upon which they act and 

 the movements they produce. 



Tibialis anticus. 

 Peroneus tertius. 

 Extensor longus digitorum. 

 Extensor proprius pollicis. 

 Gastrocnemius externus. 

 Gastrocnemius internus. 

 Plantaris. 



I lexor longus digitorum. 

 Flexor longus pollicis. 

 Tibialis posticus. 

 Peroneus longus. 

 Peroneus brevis. 

 Tibialis posticus. 

 Extensor proprius pollicis. 

 Flexor longus digitorum. 

 Flexor longus pollicis. 

 Peroneus Longus. 

 Peroneus brevis. 

 Peroneus tertius. 

 Extensor longus digitorum. 

 Flexor longus pollicis. 

 Flexor brevis pollicis. 

 Flexor longus digitorum. 

 Flexor brevis digitorum. 

 Flexor accessorius digitorum . 

 Lumbricales. 



Flexor brevis minimi digiti. 

 Extensor proprius pollicis. 

 Extensor longus digitorum. 

 Extensor brevis digitorum. 

 Abductor pollicis. 

 Abductor minimi digiti. 



f Prior indicis. 

 Interossei< Prior medii digiti. 



L Prior tertii digiti. 

 Adductor pollicis. 

 Transversalis. 



f Prior minimi digiti. 

 . 1 Posterior indicis. 

 Interossei 1 Posterior medii digiti. 



l^ Posterior tertii digiti. 



cnemii are accordingly thick short muscles, 

 with a Ions: and powerful tendon. These are 

 assisted by the plantaris and five other muscles. 

 Flexion, on the contrary, which generally im- 

 plies merely the elevation of the foot, without 

 any other force to overcome, is adequately 

 provided for by only four muscles, and these 

 not large, indeed one of them very small. 

 The assistance rendered by the five auxiliary 

 muscles, which pass behind the malleoli, 

 though considerable on the whole, yet is small 

 individually in proportion to their size, owing 

 to the disadvantageous situation which their 

 tendons occupy at so very short a distance from 

 the centre of motion ; for this reason, when 

 the tendo Achillis is ruptured, the patient is 

 as incapable of walking as if all the extensor 

 muscles were divided, yet when the body is 

 resting ihe antagonism of the extensors is not 

 entirely lost. The foot is not permanently bent 

 upwards, and the simple act of extension can 

 be accomplished without great difficulty. One 

 of the most remarkable of all the extensor 

 muscles, both as to its course and its function, 



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