THE UPPER LIMB 



289 



Posterior Lamina of the Lumbar Aponeurosis.— The lumbar 

 aponeurosis is the posterior aponeurosis of the transversahs ab- 

 dominis muscle, and is composed of three laminae — anterior, middle, 

 and posterior, the latter of which is alone fully exposed in this 

 region. It is of considerable strength, and is attached to the spines 

 of the lumbar and sacral vertebrae, and the posterior fourth of the 

 outer lip of the iliac crest. It affords origin to a portion of the latis- 

 simus dorsi and to the serratus posticus inferior, and lies behind the 

 erector spinae, where it forms the posterior wall of its sheath. At 

 the outer border of that muscle it blends with the middle lamina, 

 which may be partially seen by raising the border. Superiorly it 

 is joined by the vertebral aponeurosis. 



Erector Spirut 



Transverse Process 



Posterior l-amina of Ltimbar Aponeurosis 



Middle lamina of Lombtur Aponeurosis 

 Qoadratus Lumborum 



Anterior Lamina of Lumbar 

 Aponeurosis 

 Lattssimus Dorsi 





Body of 3rd 

 Lumbar Vertebra 



Fascia Transversalis/ 



Psoas Magnus, covered 

 by Psoas Fascia 



I ; Obliquus Ext. Abd. 

 I Obliquus' Int. Abdominis 

 I'ransversalis Abdominis 



Fig. 168. —Diagram of the Lumbar Apokeurosis. 



Vertebral Aponeurosis. — This is a thin aponeurotic sheet v/hich 

 covers the erector spinae. Its fibres are chiefly arranged trans- 

 versely, being attached internally to the spines of the vertebrae, and 

 externally to the angles of the ribs. Superadded to the transverse 

 fibres there are a few which are longitudinal. Superiorly the 

 aponeurosis passes beneath the serratus posticus superior, and 

 becomes continuous with the deep cervical fascia as that ensheathes 

 the splenius. Inferiorly it blends with the posterior lamina of the 

 lumbar aponeurosis. 



Splenius. — This muscle is so named because it straps or binds 

 down the muscles beneath it. It is single at its origin, but at its 

 insertion it is divided into two parts — splenius capitis and splenius 

 colli. 



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