462 



(A) Mmcles of the Leg and Foot. 



1. Gastrocnemius, 3^ oz. 



2. Plantaris, 0^ ,, 



3. SolfBus, . . . • 5| 17 



4. Poplitseus, 0,| ,, 



5. Peronasus longus et brevis, I5 n 



6. Flexor proprius hallicis, Of 



7. Tibialis posticus, If 



8. Flexor communis digitorum, u 



9. Tibialis anticus, • 1? 57 



10. Extensor communis digitorum, et perinseus tertius, Of ,, 



11. Extensor proprius hallicis, Oi ?j 



Posterior Muscles of Hip Joint. 

 The posterior muscles, or glutm, act on the hip joint in the manner 

 represented in the annexed diagram (Fig. 1), which shows the innomi- 

 nate bone of the left side. 



Fig. 1. 



The glutmus maximus produces a rotation round the centre of the 

 acetabulum in a plane passing through the line a ; the glutcBus medim 

 in a plane passing through h ; and the glutceus minimus in a plane 

 through c. 



The angle between a and h, measured at the centre of the sphere, is 

 49° ; and the angle between a and c is 64°. 



Taking the moments of the three muscles, with respect to the 

 centre of the sphere, we find, by corollary 2, the resultant of all sup- 

 posed to be in action together, as follows : — Measuring X along a, and 

 Y at right angles to it, ayc obtain — 



X= 11-5 + 7-5 cos 49° + 2-75 cos 64°, 

 7-5 sin 49°+ 2-75 sin 64°; 



