Superficial & Intermediate layers of Intrinsic Back Muscles

Question 1

Splenius Capitis

Origin-2, Insertion-2, Innervation, Actions-3

Answer 1

Origin:

• Nuchal ligament
• Spinous processes C7-T3

Insertion:

• Mastoid process
• Lateral 1/3 of superior nuchal line

Innervation: Dorsal Rami of spinal nerves

Unilaterally: Ipsilaterally laterally flexes neck and ipsilaterally rotates head

Bilaterally: Extends head and neck

Question 2

Splenius Cervicis

Origin-2, Insertion, Innervation, Action-3

Answer 2

Origin:

• Nuchal Ligament
• Spinous processes of C7-T3

Insertion: Tubercles of transverse processes C1-C3

Innervation: Dorsal Rami of spinal nerves

Unilaterally: ipsilaterally Laterally flexes neck and ipsilaterally rotates head

Bilaterally: Extends head and neck

Question 3

Erector Spinae (and their origins-5)

Answer 3

Iliocostalis, Longissimus, Spinalis

Common origin:

• Posterior iliac crest
• Posterior surface of sacrum
• SI Ligament
• Spinous processes of sacral & inferior lumbar vert.
• Supraspinous Ligament

All innervated by Dorsal Rami of Spinal nerves

Question 4

Iliocostalis

Regions-3, Insertion-2, Actions-2

Answer 4

Regions: Lumborum, Thoracis, Cervicis

Insertion:

• Angle of lower ribs
• Cervical transverse processes

Bilaterally: Extends vertebral column and head

Unilaterally:Laterally flexes vertebral column

Question 5

Longissimus

Regions-3, Insertion-3, Actions-2

Answer 5

Regions: Thoracis, Cervicis, Capitis

Insertion:

• Ribs between angle & tubercle
• Transverse processes in thoracic and cervical vert.
• Mastoid process

Bilaterally: Extends vertebral column and head

Unilaterally: Laterally flexes

Question 6

Spinalis

Regions-3, Insertion, Actions-2

Answer 6

Regions: Thoracis, cervicis, capitis

Insertion: Spinous processes of thoracic vertebrae

Bilaterally: Extends vertebral column and head

Unilaterally: Laterally flexes vertebral column