The =psoas minor= begins at the disc between the twelfth and thirteenth
thoracic vertebræ.
The =psoas major= has a fleshy origin on the posterior border of the
last rib, and a thin tendon attached to the twelfth rib.
The =iliacus= begins under the body of the sixth lumbar vertebra, and is
more closely united with the psoas major than in the horse.
The =quadratus lumborum= extends as far forward as the body of the tenth
or eleventh thoracic vertebra.