FASCIA LUMBORUM. 



357 



tory muscle ; or they may assist the pectoralis major in drawing the 

 movable trunk towards the humerus, as in the act of climbing. 



* Dissection. The latissimus is to be divided about midway between 

 the spines of the vertebra aud the angle of the scapula, and the pieces are 

 to be reflected inwards and outwards. In raising the inner part of the 

 muscle, care must be taken not to destroy either the thin lower serratus 

 with which it is united, or the aponeurosis continued upwards from the 

 serratus. In the interval between the last rib and the iliac crest the latis- 

 simus is adherent to the aponeurosis^ the trans versalis abdominis muscle, 



tXi 



lie latissimus dorsi lies on the 

 the lower ribs with their 

 the scapula, it conceals 

 Its position to the 

 , it covers the posterior 

 i&jround the lower bor- 

 wetfn. the angle of the 

 *he interior boundary 



and should not be detached from it* 



* Parts covered by the 

 erector spinse, the serratus posticus inf 

 intercostal muscles. As it rests on th 

 the teres major, and part of the rhomboid 

 teres is worthy of note : at the angle of the < 

 surface of the teres, but nearer the humerus it 

 der, and is inserted in front of that muscle, 

 scapula and the humerus the latissimus forms part 

 of the axilla. 



Dissection of fascia lumborum. After the latissimu^d^si has been 

 reflected, the dissector of the abdomen can look to theVdjs position of the 

 posterior tendon of the trans versalis abdominis (fascia lunMrjJam) between 

 the last rib and the innominate bone. Q> 



In the spot referred to are portions of the external and ii<ywfcil oblique 

 muscles, left in the dissection of the wall of the abdomen. ^pUYer the 

 removal of those muscles the aponeurosis of the transversalis muscle (fas- 

 cia lumborum) appears, and perforating it are two nerves one, the last 

 dorsal with an artery near the last rib : and th other, the ilio-hypogastric 

 with its vessels, close to the iliac crest. i 



Two offsets are prolonged backwards from this fascia to the transverse 

 processes. To see the more superficial layer which passes beneath the 

 erector spinae to the apices of the processes, the latissimus dorsi is to be 

 cut through (both its aponeurosis and fleshy part) by a horizontal incision 

 directed outwards from the spinous processes, on a level with the third 

 lumbar vertebra. On raising the outer border of the erector spinae 

 muscle which comes into view, the strong process of the fascia will be 

 apparent. 



After dividing transversely this first prolongation, another muscle (quad- 

 ratus lumborum) will be seen; and on raising its outer border the second 

 thin offset of the fascia will be evident on the abdominal aspect of that 

 muscle. 



The fascia lumborum (fig. 136, c ) is the posterior aponeurosis or tendon 

 of the transversalis abdominis muscle, and occupies the interval between 

 the last two ribs and the. crest of the hip-bone. By its cutaneous surface 

 it gives attachment to the internal oblique muscle, and sometimes to the 

 external oblique. The last dorsal ( J ) and ilio-hypogastric ( 2 ) nerves, ac- 

 companied by vessels, pierce it in their course from the abdomen. From 

 the inner part of the aponeurosis two offsets are prolonged to the trans- 

 verse processes of the lumbar vertebrae, and inclose the quadratus lum- 

 borum in a sheath. 



The more superficial of the two is the strongest ; it lies beneath the 

 erector spinaj in this position of the body, and is connected to the apices 

 of the transverse processes, but it also fills the intervals between them : at 



