Deep Muscles Of Back

Question 1

Semispinalis (transversospinalis)

Answer 1

Attachments: from transverse processes to distant superior spinous processes

Actions: extension & contralateral rotation of vertebral column

Innervation: dorsal rami of spinal nerves

Blood supply: dorsal branches of intercostal, subcostal, lumbar, & lateral sacral aa.

Question 2

Erector spinae

Answer 2

Attachments: from sacrum, lumbar, & thoracic supraspinous lig., sacrotuberous lig. to costal angles (iliocostalis), ribs & transverse processes (longissimus), and spinous processes (spinalis)

Actions: extension and lateral flexion of vertebral column

Innervation: dorsal rami of spinal nerves

Blood supply: dorsal branches of intercostal, subcostal, lumbar, & lateral sacral aa.

Question 3

Multifidus and rotatores

Answer 3

Attachments: from transverse processes to more superior spinous processes

Actions: stabilizes vertebrae, and assists with extension & rotation of the vertebral column

Innervation: dorsal rami of spinal nerves

Blood supply: dorsal branches of intercostal, subcostal, lumbar, & lateral sacral ateries