MYOLOGY. 61 
symphysis and upper edge of the pubes, as also into the —— 
The use of this muscle is to assist the external oblique in expiration by 
depressing the ribs; also to bend the trunk forwards or to one side. 
The cremaster or suspensorius testis, hardly a distinct muscle, and only 
rudimental in the female, consists of a fasciculus of pale fleshy fibres which 
‘arise from the internal surface of the external third of Poupart’s ligament, 
and from the lower edge of the obliquus internus; the fibres pass downwards 
and forwards around the spermatic cord, and are inserted into the tunica 
vaginalis; a few fibres are lost in the scrotum. Use: to support, compress, 
and raise the testicle and its vessels. 
Transversalis, a somewhat square muscle, arises from the fascia lumborum 
and the posterior part of the crest of the illum, and from the iliac third of 
Poupart’s ligament; also from the two last ribs, and by fleshy slips from 
the inner side of the succeeding five. All the fibres end in a flat tendon, 
which near the linez semi-lunares joins the posterior lamina of the internal 
oblique, and is inserted along with it into the whole length of the linea 
alba, into the upper edge of the pubes, and also into the linea innominata. 
Its use is to compress the abdominal viscera in the circular direction, and 
to assist In expiration. 
The rectus abdominis is a long and flat muscle situated in the anterior 
part of the abdomen. Ht arises by a flat tendon, which is sometimes double, 
from the upper and anterior part of the pubes, between the spine and 
symphysis; it ascends parallel with its fellow, and is inserted into the 
anterior part of the thorax by three fasciculi. Of these, the internal is fixed 
to the cartilage of the seventh rib and costo-xiphoid ligament; the middle 
to the cartilage of the sixth rib; and the external to the cartilage of the 
fifth rib. It use is to bend the chest towards the pelvis, and to compress 
the abdomen. . 
The pyramidalis, sometimes wanting, arises from the symphysis pubis, 
and from the upper edge of the bone external to it, and is inserted into the 
linea alba, midway between the umbilicus and pubes. Use: to assist the 
rectus and make tense the linea alba. 
The diaphragm, the first of the deep muscles of the abdomen, is one of 
the most important in the body, second only to the heart. It is the prin- 
cipal agent in respiration, and is in a measure only under the influence of 
volition. It is usually divided into two portions, one superior, large, and 
broad transversely (the true or costal diaphragm); the other is inferior and 
posterior, small, thick, and narrow (the appendix, crura, or vertebral 
diaphragm). These two portions, although separate at their osseous 
attachments, are yet blended together in the common central tendon and 
' present a fan-shaped expansion, bent at their junction, the broad superior 
portion being nearly horizontal, while the posterior inferior is vertical and 
joined to the former at nearly aright angle. The superior arises. The 
central or cordiform tendon of the diaphragm is of considerable extent, and 
is entirely.surrounded by fleshy fibres. Below this tendon are the two 
crura or appendices, nearly parallel to the spine. There are three large 
openings in the diaphragm: one for the aorta (Adatus aorticus), of a semi- 
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