418 MYOLOGY 



If the thorax be fixed, the muscles, acting together, draw the pelvis upward, as in climbing; 

 or, acting singly, they draw the pelvis upward, and bend the vertebral column to one side or the 

 other. The Recti, acting from below, depress the thorax, and consequently flex the vertebral 

 column ; when acting from above, they flex the pelvis upon the vertebral column. The Pyramidales 

 are tensors of the linea alba. 



The Transversalis Fascia. The transversalis fascia is a thin aponeurotic membrane 

 which lies between the inner surface of the Transversus and the extraperitoneal 

 fat. It forms part of the general layer of fascia lining the abdominal parietes, and 

 is directly continuous with the iliac and pelvic fasciae. In the inguinal region, 

 the transversalis fascia is thick and dense in structure and is joined by fibers from 

 the aponeurosis of the Transversus, but it becomes thin as it ascends to the dia- 

 phragm, and blends with the fascia covering the under surface of this muscle. 

 Behind, it is lost in the fat which covers the posterior surfaces of the kidneys. 

 Below, it has the following attachments: posteriorly, to the whole length of the iliac 

 crest, between the attachments of the Transversus and Iliacus; between the ante- 

 rior superior iliac spine and the femoral vessels it is connected to the posterior 

 margin of the inguinal ligament, and is there continuous with the iliac fascia. 

 Medial to the femoral vessels it is thin and attached to the pubis and pectineal 

 line, behind the inguinal aponeurotic falx, with which it is united; it descends in 

 front of the femoral vessels to^orm the anterior wall of the femoral sheath. Beneath 

 the inguinal ligament it is strengthened by a band of fibrous tissue, which is only 

 loosely connected to the ligament, and is specialized as the deep crural arch. The 

 spermatic cord in the male and the round ligament of the uterus in the female 

 pass through the transversalis fascia at a spot called the abdominal inguinal ring. 

 This opening is not visible externally, since the transversalis fascia is prolonged on 

 these structures as the infundibuliform fascia. 



The Abdominal Inguinal Ring (annulus inguinalis abdominis; internal or deep 

 abdominal ring). The abdominal inguinal ring is situated in the transversalis 

 fascia, midway between the anterior superior iliac spine and the symphysis pubis, 

 and about 1.25 cm. above the inguinal ligament (Fig. 401). It is of an oval form, 

 the long axis of the oval being vertical; it varies in size in different subjects, and 

 is much larger in the male than in the female. It is bounded, above and laterally, 

 by the arched lower margin of the Transversus; below and medially, by the inferior 

 epigastric vessels. It transmits the spermatic cord in the male and the round 

 ligament of the uterus in the female. From its circumference a thin funnel-shaped 

 membrane, the infundibuliform fascia, is continued around the cord and testis, 

 enclosing them in a distinct covering. 



The Inguinal Canal (canalis inguinalis; spermatic canal). The inguinal canal 

 contains the spermatic cord and the ilioinguinal nerve in the male, and the round 

 ligament of the uterus and the ilioinguinal nerve in the female. It is an oblique 

 canal about 4 cm. long, slanting downward and medialward, and placed parallel 

 with and a little above the inguinal ligament; it extends from the abdominal 

 inguinal ring to the subcutaneous inguinal ring. It is bounded, in front, by the 

 integument and superficial fascia, by the aponeurosis of the Obliquus externus 

 throughout its whole length, and by the Obliquus internus in its lateral third; 

 behind, by the reflected inguinal ligament, the inguinal aponeurotic falx, the trans- 

 versalis fascia, the extraperitoneal connective tissue and the peritoneum; above, 

 by the arched fibers of Obliquus internus and Transversus abdominis; below, by 

 the union of the transversalis fascia with the inguinal ligament, and at its medial 

 end by the lacunar ligament. 



Extraperitoneal Connective Tissue. Between the inner surface of the general 

 layer of the fascia which lines the interior of the abdominal and pelvic cavities, 

 and the peritoneum, there is a considerable amount of connective tissue, termed 

 the extraperitoneal or subperitoneal connective tissue. 



