ANATOMY OF THE HOUSE. 
425 
Form . —Similar to that of the preceding muscle. 
Attachment. —Anteriorly and superiorly, within the pelvis, to 
the sacro-sciatic ligament, and to the body of the sacrum; pos¬ 
teriorly and interiorly, to the inferior parts of the bodies of the 
coccygeal bones. 
Relations . —Superiorly, with the erector; interiorly and exter¬ 
nally, with the skin; internally, with the coccyx. 
Structure .—Like the preceding muscle, it has, exteriorly, a 
flattened tendon; but it is a much smaller one, and does not 
detach any lateral slips, until it has descended to near the middle 
of the coccyx. Its fleshy belly, on the whole, is more bulky than 
that of the erector; it grows contracted in passing out of the 
pelvis, but afterwards forms a rounded prominence along the 
under part of the tail. Its posterior attachments are made by 
strong and detached tendons, issuing from the broad one travers¬ 
ing its middle, which are concealed within the fleshy belly. Its 
tendons increase in number, but diminish in size, as the muscle 
proceeds backward : near the tip of the tail, they surpass in 
strength those of the erector. It is the principal one of these 
tendons which commonly project within the section made in the 
operation of nicking, and requires excision. 
Action. —To depress the tail and retain it against the rump. 
If one muscle act alone, it will at the same time incline the tail 
to one side; in which case it may co-operate with the erector of 
the same side. The power of action possessed by the depressors 
may be roughly estimated, by the force it requires with the hand 
to raise the docks of horses that are said to be “ shy about the 
tail.” 
curvator coccygjs .—( Sacro-coccygeus lateralis.) 
Situation .—Upon the side of the dock, between the two former. 
Form. —Smaller than either of the afore-described muscles; 
though it bears a close similarity to them in the appearance and 
disposition of its fibres. 
Attachment. —Anteriorly, within the pelvis, to the lateral parts 
of the sacrum; and, commonly, to the fourth and fifth lumbar 
vertebrae ; posteriorly, to the transverse processes of all the bones 
of the coccyx. 
Relations. —Superiorly, with the erector ; inferiorly, with the 
depressor; externally, with the skin; internally, with the coccyx. 
Structure. —Anteriorly, it consists of tw T o parts, which have 
been regarded as separate muscles : one portion accompanies the 
erector; the other the depressor. Posteriorly, it consists of ten¬ 
dinous and fleshy parts intimately and inseparably interwoven 
with each other. 
