e 
tendo Achillis, of which it completes the 
fibrous canal, formed posteriorly by the super- 
ficial layer; the other remains applied over the 
osterior surface of the deep muscles, and both 
arrive at the heel. 
In its inferior third, this aponeurosis thus 
ircumscribes three spaces. One is filled by 
tendon of the muscles of the calf. The se- 
ond incloses the flexor muscles of the toes, 
ad the vessels. The third, which separates 
e two others, lies between the tendo Achillis 
nd the posterior surface of the last-named 
Muscles. The latter is remarkable, from being 
filled with fat and fibrous filaments, interlaced 
| various directions.* 
‘We have, for convenience of description, de- 
failed the anatomy of the superficial parts of 
le leg, without particular reference to the re- 
gional divisions, which become more defined, 
listinet, and practical as we investigate the re- 
ations of the deeper seated parts, and to which 
é shall therefore now limit ourselves. 
In the anterior region, comprising all those 
nuscles which rest upon the tibio-fibular fossa, 
ve find, on dissecting the fascia from the upper 
art, only two muscles exposed, viz. the tibialis 
nticus and extensor communis digitorum. 
ower down, we see in addition the extensor 
roprius pollicis coming out between the two 
fast, and the peroneus tertius a slip of the outer 
ide of the extensor communis. These four 
e, as it were, bound down in a canal, formed 
nteriorly by the aponeurosis, posteriorly by 
e tibia, fibula, and interosseous ligament. 
e direction of the tibialis anticus, its size, 
d boundaries should be borne in mind, as 
ese form the surest guide for cutting down 
on the anterior tibial artery. This muscle is 
a prismatic form, tapering downwards, and 
outer edge is indicated externally by a 
cus in the integuments made more apparent 
y extension of the foot. It is found more ac- 
rately by tracing a line from the middle of 
space between the crest of the tibia 
id the fibula to the middle of the instep ; and 
e, between this muscle and the extensor 
mmunis, the arteryruns. The external mus- 
sare the peronei longus and brevis; they 
enveloped in a sheath of the aponeurosis, 
d are applied, for some extent, to the exter- 
surface of the fibula. They are completely 
arated from the extensors and from all the 
nuscles of the posterior region by the two apo- 
neurotic septa attached to the anterior and 
sterior edges of the bone. The adherence of 
ié muscular fibres continuing until just above 
he outer malleolus, a transverse section, in the 
Wo superior thirds, does not entirely destroy 
heir action upon the foot, while, lower down, 
t would render abduction almost impossible. 
Ve have not heard of an instance of the entire 
upture of any of these muscles, nor is it an 
ccident likely to occur, as they are not, from 
neir Situation, likely to be called upon for any 
ery great exertion of power; but these muscles 
€ occasionally liable to the accidental rupture 
i 
i 
| 
} 
= 
; 
* See Velpeau’s Anatomy of Regions, translated 
dancock. 
ps 
4 
REGIONS OF THE LEG. 
131 
of some of their fibres, a circumstance attended 
with much more pain and distress in moving 
than the apparently slight nature of the accident 
might lead us to expect. We have had lately 
a case of this kind under our care, where the 
suffering and the injury to the movements of 
the foot were so great as at first to lead us to 
suspect a much more serious extent of injury 
than really existed. It was occasioned by at- 
tempting to push along a sack of corn with 
both knees, both feet being on the ground, and 
the heels raised, while the upper part of the 
sack was held in the arms. 
The only artery of importance in this region 
is the anterior tibial. It commences from the 
trunk of the popliteal nearly at right angles, 
traverses the opening in_the upper part of the 
interosseous ligament, cl®Se to the neck of the 
fibula, and below the head of the tibia. The 
angular curve which the artery makes at this 
part of its course, according to M. Ribes, ac- 
counts for the great retraction of it after ampu- 
tation of the leg.* It descends upon the inter- 
osseous ligament, in the direction of a line 
drawn from the middle of the space between 
the head of the fibula and the crest of the 
tibia, to the middle of the instep. Through 
the upper part of its course it lies upon the in- 
terosseous ligament; as it descends it gradually 
advances upon the tibia, and runs upon the 
anterior surface of this bone through its lower 
third. It is found at the upper third of the 
leg, between the tibialis anticus and extensor 
communis digitorum; in the middle third, its 
course is between the tibialis anticus and the 
extensor longus pollicis, and about four inches 
above the ankle-joint it passes obliquely under 
the tendon of this last muscle, and then is 
found between its tendon and that of the ex- 
tensor communis. It runs between two veins 
through its whole course. The nerve is on its 
outer side above ; in front in the middle; and 
internal below. An extensible but resistant 
cellular sheath unites the whole. It is evident, 
that in the upper part of its course the artery 
will be found much deeper than at the lower, 
when it is lying among the tendons, but in the 
living subject the natural state of tension of the 
muscles keeps these tendons more elevated 
than after death, and we shall consequently find 
the artery, even in this situation, deeper than 
from dissection we might have heen led to an- 
ticipate. The surgeon will find little difficulty 
in discovering this artery when it is required to 
be tied. The marks for his guidance are clear, 
and the situation of the vessel on the whole 
pretty uniform ; but owing to the depth of its 
situation above, and to the immediate vicinity 
of the veins and nerve, some difficulty will be 
experienced in excluding these from the liga- 
ture. The only branch from it of any surgical 
importance is the recurrent tibial. This arises 
just after the trunk has passed through the in- 
terosseous ligament, and passes upwaids in nu- 
merous branches to the ‘parts below and to the 
outer side of the knee-joint, anastomosing freely 
with the inferior external articular artery. These 
* See Velpeau’s Anatomy of Regions, p. 473, 
K 2 
