ACUTE INFLAMMATION OF THE PODOPHYLLOUS MEMBRANE. 773 
(3) Septicaemia oftenest results from necrosis of the sensitive laminae 
or sole, especially when the disea 
veins are incapable of collapsm 
material penetrating their walls, 
Spinola drew attention to the 
frequent connection between 
necrosis of the pedal bone and 
attacks of septicaemia or pyaemia. 
The constant and severe pain 
also causes the patients to lie 
continually, and, further, pre¬ 
disposes to fatal blood-poisoning. 
Causes. With the exception 
of laminitis, which will later 
5e attacks the os pedis. As the pedal 
they offer little resistance to septic 
and reaching the general circulation. 
receive attention, acute inflam¬ 
mation of the sensitive struc¬ 
tures of the foot is due to 
external injurious influences. 
Mechanical injuries, like bruises, 
wounds by driven or picked-up 
nails, or separations of the wall 
Fra. 291.—Vertical cross section of a foot seen 
from behind. To illustrate the structures 
involved in surgical injuries of the foot. A, 
Coronet bone ; B, navicular bone ; 0, pedal 
bone ; a, lateral cartilage ; b, anterior portion 
of plantar cushion ; c, divided part of flexor 
pedis perforans tendon; cl, postero-lateral 
ligaments of navicular bone ; l, horn wall ; 
m, horn sole ; n, white line ; o, horn frog. 
allow of irritants reaching the sensitive parts directly; in other cases the 
injury is thermal, but as the horny box forms so excellent a protection 
against ordinary changes in temperature, and burns from hot-fitting of 
shoes are nowadays rare, such cases are much less frequent. 
Fig. 292. —-Vertical cross section of foot 
seen from behind (this section has 
been made nearer the heels than fig. 
291). To illustrate the structures 
involved in surgical injuries of the foot. 
ct, Posterior part of plantar cushion ; 
b , median ridge of frog; c, lateral 
cartilage ; d, horn wall; e, lateral face 
of frog; /, point of union between the 
bars and frog. 
Cold is more frequently injurious, 
especially when the horn is split. 
Pricks in shoeing or excessive paring 
of corns may be followed by irritation 
during winter weather, especially if 
the roads are very dirty. Frostbite of 
the heels has been seen. Chemical 
substances, like acids, employed by 
farriers in treating disease of the 
feet, sometimes cause inflammation. 
But by far the most frequent and 
important cause of acute inflammation 
is infection with pus cocci and other 
micro-parasites. Normally, the soft 
parts are protected by the horny wall, 
but as soon as a fissure exists, in consequence either of pricks in 
shoeing, picked-up nails, the formation of sand-cracks, or separation of 
the wall, a way is opened for infection, which is especially liable to 
