Deep Intrinsic Back Muscles

Question 0

Multifidus

Answer 0

O: post sacrum, post sup iliac spine, aponeurosis of erector spinae, sacroiliac ligaments, mammillary processes of L vertebrae, transverse processes of T1-T3, articular processes of C4-C7
I: spinous processes of entire length of vertebral column 2-4 segments above origin
N: post rami of spinal nerves
A: unilateral contraction rotates to contralateral side, stabilize vertebrae

Question 1

Semispinalis

Answer 1

O: transverse processes of C4-T10
I: occipital bone and spinous processes in upper T and c regions, spanning 4-6 segments
N: post rami of spinal nerves
A: extends head and T and C regions of vertebral column, contralateral rotation

Question 2

rotatores (brevis and longus)

Answer 2

O: transverse processes of vertebrae (best developed in T region)
I: junction of lamina and transverse processes, OR spinous processes of vertebra immediately sup to origin (brevis) or 2 segments sup to origin (longus)
N: post rami of spinal nerves
A: may function as organs of proprioception, possibly stabilize vertebrae and assist w/ local extension and rotatory movements of vertebral column