SURGICAL AXATOMY OF THE LOWER EXTREMITY. 537 



EMELLUS SUPERIOR. 



OBTURATOR INTERNUS 



GEMELLUS INFERIOR. 



BTURATOR EXTERNUS 



UAORATUS FEMORIS. 



SURGICAL ANATOMY OF THE LOWER EXTREMITY. 



The student should now consider the effects produced by the action of the various muscles 

 in fractures of the bones of the lower extremity. The more common forms of fractures are 



selected for illustration and 

 description. 



In fracture of the neck 

 of the femur internal to the 

 capsular ligameiit (Fig. 338) 

 the characteristic marks are 

 slight shortening of the 

 limb and eversion of the 

 foot, neither of which symp- 

 toms occurs, however, in 

 some cases until some time 

 after the injury. The 

 eversion is caused by the 



-PYRIFORMIS. weight of the limb rotating 



it outward. The shorten- 

 ing is produced by the 

 action of the Glutei, and 

 by the Rectus femoris in 

 front and the Biceps, 

 Semitendinosus, and Serni- 

 membranosus behind. 



In fracture of the 

 femur just below thetrochan- 

 ters (Fig. 339) the upper 

 fragment, the portion chiefly 

 displaced, is tilted forward 



FIG. 338. Fracture of the neck of the femur within the capsular 

 ligament. 



almost at right angles with the pelvis by the combined action of 

 the Psoas and Iliacus. and. at the same time, everted and drawn 

 outward by the External rotator and Glutei muscles, causing a 

 marked prominence at the upper and outer side of the thigh, and 

 much pain from the bruising and laceration of the muscles. The 

 limb is shortened, in consequence of the lower fragment being 

 drawn upward by the rectus in front, and the Biceps. Semi- 

 membranosus. and Semitendinosus behind, and. at the same 

 time, everted, and the upper end thrown outward and the lower 

 inward by the Pectineus and Adductor muscles. This fracture 

 may be reduced in two different methods : either by direct relax- 

 ation of all the opposing muscles, to effect which the limb should 

 be placed on a double inclined plane ; or by overcoming the con- 

 traction of the muscles by continued extension, which may be 

 effected by means of the long splint. 



Oblique fracture of the femur immf-dintihi above the condyles 

 Fi-r. 34<i is a formidable injury, and attended with considerable 

 displacement. On examination of the limb the lower fragment 

 may be felt deep in the popliteal space, being drawn backward 

 by the Gastrocnemiua and Plantaris muscles, and upward by 

 the posterior Femoral and Rectus muscles. The pointed end 

 of the upper fragment is drawn inward by the Pectineus and Ad- 

 ductor muscles, and tilted forward by the Psoas and Iliacus, pierc- 

 ing the Rectus muscle and occasionally the integument. Relaxation 

 of these muscles and direct approximation of the broken frag- 

 ments are effected by placinsr the limb on a double inclined plane. 

 The greatest care is requisite in keeping the pointed extremity 

 of the upper frasnient in proper position ; otherwise, after union 

 of the fracture, the power of extension of the limb is partially 

 destroyed, from the Rectus muscle being held down by the frac- 

 tiirv'l end of the bone, and from the patella, when elevated, 

 beinsr drawn upward atrainst the projectins fragment. FIG. 339. Fracture of the femur 



In fracture of the paUUa (Fig. 341) the fragments are sepa- below the trochanters. 

 rated by the effusion which takes place into the joint, and 

 possibly by the action of the Quadriceps extensor; the extent of separation of the two 



MEMBRANOSUS. 



TENDINOSUS. 



