614 
DEPARTMENT OF SURGERY. 
still more frequently observed in the bitch ; in some instances 
these osteomata do not make delivery impossible, but difficult, 
although when they obstruct the passage and make parturition 
impossible the foetus must be removed otherwise. In the mare 
all other means of delivering the foetus must be attempted be¬ 
fore resorting to Caesarian section, but in no case should the 
operation be deferred until the patient is exhausted and un¬ 
able to withstand the surgical shock. 
(C) Pelvic Constrictions.— It is seldom that these con¬ 
strictions, without foetal complications, demand surgical inter¬ 
ference ; if all other conditions are normal delivery is generally 
. possible though difficult, but when complicated with malpresen- 
tations or monstrosities they are serious conditions. This con¬ 
formation is often confined to certain breeds and usually con¬ 
sists of a general reduction of all dimensions of the pelvis ; 
however, careful observations have revealed to the obstetrician 
several varieties of these constrictions, which for our purpose 
they shall be considered as follows, viz.: 
(a) General constriction of the lumen of the pelvic canal. 
ip) Constriction of sacro-pubic diameter. 
(c) Constriction of the transverse diameter. 
X a ) General Constriction of the lumen of the pelvic* canal is 
usually confined to certain strains of domestic animals and is 
marked by a reduction in the size and the change in the con¬ 
formation of the bones that form the skeleton of the pelvis ; the 
constriction is such that it uniformly reduces all the diameters 
of the pelvic canal and invariably is the cause of maternal dys- 
tokia and when associated with some foetal abnormality may 
make parturition impossible. 
(h) Constriction of the Sacro-Pnbic Diameter .—-The cause of 
this reduction may result from an abnormal position of the pel¬ 
vis ; such as in improper inclination ; or, a depression of the 
anterior portion of the ilium. The condition may also result 
from an abnormal conformation of the sacrum ; e. g., the pos¬ 
terior extremity of the sacral portion of the vertebra may be 
depressed ( kyphosis ) ; or the entire bone may be depressed; be¬ 
sides there is another, though not very common in domestic 
animals, but deserves to be mentioned in this connection ; this 
is a curvature of the sacrum which directs its posterior ex¬ 
tremity to one side ( scoliosis ) ; it may be caused by a contrac¬ 
tion of the muscles of one side and is generally of a rheumatic 
origin ( scoliosis rheumatica ), although in some cases the condi¬ 
tion is osteopathic. 
