82 ANATOMY. 



LUMBAR FASCIA, or vertebral aponeurosis of the transversalis, divides into 3 

 leaflets, the anterior and middle being attached to the apices of the transverse 

 processes of the lumbar vertebras, the posterior leaflet to the apices of their 

 spines. The anterior and middle leaflets enclose the quadratus lumborum 

 muscle, the middle and posterior enclose the erector spinse. 



Rectus Abdominis, 16 by 2 tendons from the pubic crest and the ligaments 

 covering the symphysis, into the cartilages of the 5th, 6th, and yth ribs. It 

 lies in a sheath formed by the aponeuroses of the internal oblique and trans- 

 versalis muscles for its upper three-fourths, and is crossed by 2 to 5 tendinous 

 lines, the Linea Transverse. At its outer border is a similar line placed 

 vertically, the Linea Semilunaris, formed by the aponeurosis of the internal 

 oblique at its point of division. Action, to flex the thorax on the pelvis and 

 vice versa, also to compress the abdominal viscera. Nerves, same as the 

 external oblique. 



Pyramidalis, 17 lies in front of the rectus, but in the same sheath, arises from 

 the front of the pubic bone and the anterior pubic ligament, into the linea 

 alba, half-way to the umbilicus. Action, a tensor of the linea alba. Nerves, 

 same as the external oblique. 



Quadratus Lumborum, 19 P1 - < from the ilio-lumbar ligament, adjacent 2 inches 

 of the crest of the ilium, and transverse processes of the lower 3 lumbar ver- 

 tebrae, into one-half of the lower border of the last rib, and the transverse 

 processes of the last 3 lumbar vertebrae. Action, to flex the thorax laterally 

 on the pelvis and vice versa. Nerves, anterior branches of the lumbar. 



MUSCLES OF THE THORAX. 



External Intercostals (n), each from the outer lip of the groove in the in- 

 ferior costal border, into the upper border of the next rib below, directed 

 obliquely downwards and forwards. Action, to raise and evert the ribs in 

 inspiration. Nerves, intercostal. 



Internal Intercostals (n), each from the inner lip of the groove in the in- 

 ferior costal border, into the upper border of the rib below, directed 

 obliquely downwards and backwards. Action, at sides of thorax to depress 

 the ribs in expiration; anteriorly they raise the costal cartilages. Nerves, 

 intercostals. 



Infra-costales (10), obliquely from inner surface of I rib, into the inner 

 surface of the ist, 2d, or 3d rib below. Action, muscles of inspiration. 

 Nerves, intercostal. 



Triangularis Sterni, from the inner surface of the ensiform cartilage, inner 

 surfaces of costal cartilages of 3 or 4 lower true ribs, and lower sides of the 



