1342 



SURFACE ANA'. 





of the posterior tibial artery becomes evident near the lower end of the back of the 

 tibia, and is easily detected behind the medial malleolus. 



Veins. By compressing the proximal trunks, the venous arch on the dorsum 

 of the foot, together with the great and small saphenous veins leading from it (see 

 page 669), are rendered visible. 



Nerves. The only nerve of the lower extremity which can be located by palpa- 

 tion is the common peroneal as it winds around the lateral side of the neck of the 

 fibula. 



SURFACE MARKINGS OF THE LOWER EXTREMITY. 



Bony Landmarks. The anterior superior iliac spine is at the level of the sacral 

 promontory the posterior at the level of the spinous process of the second sacral 

 vertebra. A horizontal line through the highest points of the iliac crests passes 

 also through the spinous process of the fourth lumbar vertebra, while, as already 

 pointed out (page 1315), the transtubercular plane through the tubercles on the 

 iliac crests cuts the body of the fifth lumbar vertebra. The upper margin of the 

 greater sciatic notch is opposite the spinous process of the third sacral vertebra, 

 and slightly below this level is the posterior inferior iliac spine. The surface mark- 

 ings of the posterior inferior iliac spine and the ischial spine are both situated in a 

 line which joins the posterior superior iliac spine to the outer part of the ischial 

 tuberosity; the posterior inferior spine is 5 cm. and the ischial spine 10 cm. below 

 the posterior superior spine; the ischial spine is opposite the first piece of the 

 coccyx. 



With the body in the erect posture the line joining the pubic tubercle tc the top 

 of the greater trochanter is practically horizontal; the middle of this line overlies 

 the acetabulum and the head of the femur. 



Sacrotuberous ligament 

 Savrospinous ligament 



Greater trocJianter 

 of femur 



Ischial tviberosity 



FIG. 1243. Nelaton's line and Bryant's triangle. 



A line used for clinical purposes is that of Nelaton (Fig. 1243), which is drawn 

 from the anterior superior iliac spine to the most prominent part of the ischial 



