90 



motion of the knee joint, which is parallel to the brim of the acetabulum 

 in ordinary positions of the leg. 



They may be classed as follows : — 



1 . Extensors of Thigh. 



Ozs. 



1. Biceps femoris, 27-75 



2. Semitendinosus, ■ . 10*00 



3. Semimembranosus^ 26-25 



4. Gracilis, 9 00 



5. Adductor magnus,* 13-62? 



6. Adductor longus, 2-75 



7. Quadratus femoris, 1*58 



Total moment of Extension of Thigh, .... 90-95 oz. 

 2. Flexors of Thigh. 



Ozs. 



1. Tensor vaginse femoris, 6*50 



2. Sartorius, 11-75 



3. Psoadiliacus, 10-75 



Total moment of Flexion of Thigh, . .... 29-00 oz. 



From the preceding it appears that the total moment of extension ex- 

 ceeds that of flexion in the proportion of 91 to 29, nearly, or more than 

 three times. 



Let us now suppose the thigh flexed on the body at an angle of 45°, 

 as it would be preparatory to a spring, and consider the action of the 

 remaining muscles of the hip joint. They all tend to turn the femur in 

 planes pei-pendicular to the plane already considered, and which all pass 

 through the axis perpendicular to the brim of the acetabulum. 



I examined carefully the azimuths of the planes of motion of these 

 muscles on the rim of the acetabulum, in the position of the thigh 

 described, and found them to be as follows, counting from right to left, 

 on the left leg of the Lion: — 



Rotators of Thigh. 



Muscles. Azimuth, Moment. 



Ozs. 



1. Obturator externus, 0° 2-60 



2. Pectinajus, 60 0-75 



3. Ilio capsularis, 149 ..... 0 53 



4. Gluteus minimus, 167 2 '50 



5. Glutaeus medius, ,193 14-50 



6. Piriformis, 266 .... . 2 50 



7. Glutseus maximus, 266 3-50 



8. Obturator internus, 277 4-00 



9. Agitator caudae, 277 6-50 



10. Ad Juctor magnus, 360 13-62 ? 



Total moment of Muscles rotating the Thigh, . . 51-00 oz. 



* Half the force of the adductor magnus is here supposed to act in the plane of mo 

 tion of the knee joint. 



