Deep Back Flashcards
What is the innervation to deep back muscles? Are these muscles intrinsic or extrinsic? What is the overal function of these muscles?
- Posterior Rami of Spinal Nerves
- Intrinsic muscles
- Move vertebral column
What are the three component layers of the deep (intrinsic) back muscles?
- Most Superficial: Splenius
- Intermediate: Erector Spinae
- Deepest: Transversospinalis
Muscles are covered by thoracolumbar fascia (deep fascia)
What muscles comprise the most superficial of the deep back muscles?
- Splenius Capitis
- Splenius Cervicis
Splenius Capitis
Deep to serratus posterior superior
Origin:
- Ligamentum Nuchae
- Spinous Processes C7-T3
Insertion:
- Mastoid Process
- Superior Nuchal Line
- Head
Innervation:
- Posterior Rami of Spinal nn.
Action:
- Bilaterally: extend neck
- Unilaterally: flex/rotate head to same side
Blood Supply:
- Occipital a.
Splenius Cervicis
Deep to serratus posterior superior
Origin:
- Spinous processes T3-T6
Insertion:
- Transverse processes C1-C2
- Neck
Innervation:
- Posterior rami of spinal nn.
Action:
- Bilaterally: extend the neck
- Unilaterally: flex/rotate head to same side
Blood Supply:
- Occipital a.
What muscles comprise the intermediate deep back muscles?
Erector Spinae (Help stand upright)
Comprised of:
- Iliocostalis
- Longissimus
- Spinalis
“I love [your favorite S-word]”
Iliocostalis
Deep to serratus posterior inferior
Most lateral of erector spinae mm.
Attachments:
- Angles of Ribs
Innervation:
- Posterior rami of spinal nn.
Action:
- Bilateral: extends spine
- Unilateral: bends spine lateral to same side
Longissimus
Deep to serratus posterior inferior
Middle of erector spinae mm.
Attachments:
- Typically originate/insert on tranverse processes of vertebrae
Innervation:
- Posterior rami of spinal nn.
Action:
- Bilaterally: extends head and spine
- Unilaterally: flexes/rotates head/spine to same side
Spinalis
Deep to serratus posterior inferior
Most medial of erector spinae mm.
Attachments:
- Originate/insert on spinous processes
Innervation:
- Posterior rami of spinal nn.
Action:
- Bilaterally: Extends cervical and thoracic spine
- Unilaterally: Bends cervical/thoracic spine to same side
What muscles comprise the deepest of the deep back muscles? What direction do these fibers run?
Transversospinalis mm.
Run superomedially
Include:
- Multifidus
- Semispinalis
- Rotatores
Function:
- Stabilize Spine
Semispinalis Capitis
Deep to the splenius mm.
Attachments:
- See picture (not emphasized in class)
Innervation:
- Posterior rami of spinal nn.
Action:
- Bilaterally: extends thoracic/cervical spine
- Unilaterally: bends head/cervical/thoracic spine to same side
What nerve passes through semispinalis capitis?
Greater Occipital Nerve
Semispinalis Cervicis
Deep to semispinalis capitis
Attachments:
- See image (not emphasized in class)
Innervation:
- Posterior rami of spinal nn.
Action:
- Bilaterally: extends thoracic/cervical spine
- Unilaterally: bends head/cervical/thoracic spine to same side
Multifidus
Attachments:
- Between transverse and spinous processes, skipping two to four vertebrae
Innervation:
- Posterior rami of spinal nn.
Action:
- Bilaterally: extend spine
- Unilaterally: flex spine to same side
Rotatores
Attachments:
- Between transverse and spinous process of adjacent (or, skipping one vertebra)
Innervation:
- Posterior rami of spinal nn.
Action:
- Bilaterally: extends thoracic spine
- Unilaterally: rotates spine to opposite side
