Deeper Back Muscles

Question 0

Multifidus

Answer 0

Origin: 1)Posterior sacrum, 2)posterior superior iliac spine of ilium, 3)aponeurosis of erector spinae, 4)sacro-iliac ligaments, 5)mammillary processes of lumbar vertebrae, 6)transverse processes of T1-T3, and 7)articular processes of C4-C7

Insertion: Thickest in lumbar region, fibers pass obliquely superomedially to entire length of spinous processes of vertebrae located 2-4 segments superior to origin

Innervation: Posterior rami of spinal nerves

Question 1

Semispinalis (thoracis, cervicis, capitus)

Answer 1

Origin: Transverse processes of C4-T10

Insertion: Fibers run superomedially to 1)occipital bone and 2)spinous processes in upper thoracic and cervical regions, spanning 4-6 segments

Innervation: Posterior rami of spinal nerves

Question 2

Rotatores (Longus, Brevus)

Answer 2

Origin: Transverse processes of vertebrae, best developed in thoracic region

Insertion: Fibers pass superomedially to attach to junction of lamina and transverse process or spinous process of vertebra immediately (brevis) or 2 segments (longus) superior to vertebra of origin

Innervation: posterior rami