80 MUSCLES OF THE BACK. 



thoracic duct, the azygous vein, and the great splanchnic nerve. 

 Use ; widens the thoracic, and diminishes the abdominal cavity. 



Quadratus Imnhorum. — Origin,^^ from the crest of the ilium. 

 Insertion^ into the transverse processes of the last dorsal and all 

 the lumbar vertebrce, and also into the last rib beneath the ligamen- 

 tum arcuatum. Use ; bends the loins to one side. 



Psoas parvus. — Not always present. Origin^ from the last dorsal 

 and first lumbar vertebrse. Insertion, by a long tendon, into the 

 crest qfthejmhcs and fascia iliaca. 



Psoas ??iagnus.^* — Origin, from the transverse processes of all 

 the lumbar vertebree, and from the bodies of the four upper lumbar 

 and last dorsal vertebrae. Insertion, into the lesser trochanter of 

 the femur, and into one inch below it. 



Iliacus internus. — Origin, from the transverse process of the 

 last lumbar vertebra, from the costa and crest of the ilium, and from 

 the capsule of the hip joint. Insertion, into the tendon of the psoas 

 magnus. Use ; the action of the last two muscles is the same, to 

 bend the body forwards and draw the thigh upwards. 



MUSCLES OF THE BACK. 



Trajpezivs} — Origin, from the superior semicircular ridge of 

 the occiput, from all the spinous processes of the neck, by means 

 of the ligamentum nuchce, and from all those of the back. Inser- 

 tion, into the external third of the clavicle, into the acromion pro- 

 cess, and spine of the scapula. Use ; draws the scapula towards the 

 spine. 



Latissirnus dorsi.* — Origin, from the seven inferior spinous pro- 

 cesses of the back, and from all those of the loins and sacrum, also 

 from four inferior ribs, which heads interdigitate with those of the 

 external oblique. Insertion, by a thick flat tendon, in common with 

 the teres major, into the posterior ridge of the bicipital groove. Use; 

 draws the humerus downwards and backwards. 



Serratus posticus inferior .^^ — Origin, from the two inferior spi- 

 nous processes of the back, and the three superior of the loins. In- 

 sertion, into the last four ribs. Use ,• draws the ribs downwards. 



Rhomboideus minor}^ — Origin, from the three inferior spinous 

 processes of the neck. Insertion, into the base of the scapula oppo- 

 site the spine. 



Rhomboideus 'major }^ — Origin, from the spinous processes of 

 the last cervical, and of the four superior dorsal vertebras. Insertion, 

 into the base of the scapula below the spine. Use; the last two 

 draw the scapula upwards and backwards. 



Serratus posticus sujierior. — Origin, from the three inferior spi- 

 nous processes of the neck, and the two superior of the back. In- 

 sertion, into the second, third, and fourth ribs. Use ; it draws the 

 ribs upwards. 



