1216 SURFACE AND SURGICAL ANATOMY. 
fragment is lable to perforate the skin. The skin over the lower half of this 
surface is the commonest seat of varicose and callous ulcers, which are frequently 
prevented from healing by adhesion of the floor of the ulcer to the periosteum. 
The shaft of the fibula, situated on a plane posterior to that of the tibia, is, with 
the exception of the triangular subcutaneous surface above the external malleolus, 
deeply placed amongst the 
muscles. To examine the 
fibula, the surgeon should 
stand on the opposite side 
of the patient and manipu- 
late the bone along the line 
Quadriceps extensor Of the intermuscular septum 
~tendon between the peronei and 
__Vastus externus 
Se 
— 
NS 
Tlio-tibial band — S=& 
Biceps tendon 
External condyle VA the muscles of the ealf. 
Ae : ‘Je patella The greater fulness of the 
f j antero-external surface of 
ttn “uberosity the Jeg, as compared) with 
Ligamentum patel jt{s inner surface, is due to 
SSruberclacetibia the presence of the extensor 
and peroneal groups. of 
muscles. When _ these 
groups are thrown into 
action, the individual 
muscles are mapped out 
upon the surface by the 
grooves corresponding to 
FibialioeuLicus their intermuscular septa. 
The posterior peroneal sep- 
tum is seen as a well-marked 
furrow, extending from the 
posterior aspect of the head 
Peroneus tertius of the fibula to the hollow 
Head of fibula 
Gastrocnemius _ 
Soleus) 
Peroneus longus 
ace behind the external mal- 
leolus; in front of it are 
Tendo the peronei muscles, the 
Achillis - longus giving rise to a pro- 
minence on the upper half 
of the leg, while the brevis 
is prominent on the lower 
half; behind the septum is 
a prominence formed by 
the outer border of the 
soleus, which projects 
beyond that of the gastro- 
cnemius. 
It is along the lne of 
the posterior peroneal inter- 
muscular septum that 
incisions should be made to 
expose the fibula; to avoid the musculo-cutaneous nerve, however, the icision 
must not extend higher than 1 in. below the head of the fibula. 
The furrow between the extensors and the two peronei, the anterior peroneal 
septum, is much less distinct, and runs in a line from the anterior border of the 
head of the fibula to the anterior border of the external malleolus; the cutaneous 
portion of the musculo-cutaneous nerve corresponds to the lower half of this line. - 
At the junction of the middle and lower thirds of the leg the extensor muscles 
incline inwards over the anterior surface of the tibia. 
The anterior tibial artery reaches the front of the interosseous membrane 2 in. 
below the tubercle of the tibia; in the upper two-thirds of its course it les upon the 
External 
malleolus 
Tip of \ . 
external— 
malleolus 
Fic. 819.—OutErR ASPECT OF KNEE AND LEG. 
