Muscles of the back

What muscles are in layer I?

Trapezius and Latissimus dorsi

What muscles are in Layer II?

Levator scapulae, rhomboid minor and rhomboid major

What muscles are in Layer III?

Serratus posterior superior, serratus posterior inferior

What muscles are in Layer IV?

Splenius capitis, splenius cervicis

What muscles are in Layer V?

Iliocostalis (cervicis, thoracis, lumborum)

Longissimus (capitis,cervicis, thoracis)

Spinalis (capitis, cervicis, thoracis)

What muscles are in Layer VI?

Semispinalis (capitis, cervicis, thoracis), Multifidus, and Rotatores

What is the nerve supply and action(s) of the trapezius?

N: spinal accessory nerve (CN XI)

A: raises, lowers, adducts, and rotates scapula

What is the nerve supply and action(s) of the latissimus dorsi?

N: thoracodorsal nerve

A: extends, adducts, and internally rotates the humerus

What is the nerve supply and action(s) of the levator scapulae?

N: dorsal scapular nerve

A: elevates the scapula

What is the nerve supply and action(s) of rhomboid minor and major?

N: dorsal scapular nerve
A: retraction and elevation of scapula

What is the nerve supply and action(s) of serratus posterior superior?

N: ventral primary rami (T2-T5)

A: raises ribs during forced inspiration

What is the nerve supply and action(s) of serratus posterior inferior?

N: ventral primary rami (T9-T12)

What is the nerve supply and action(s) of splenius capitis?

N: dorsal primary rami (C4-C8)

A: bilat: extends head and neck unilat: rotates face to same side

What is the nerve supply and action(s) of splenius cervicis?

N: DPR (C4-C8)

A: bilat: extends neck, unilat: rotates neck same side

What is the nerve supply and action(s) of iliocostalis cervicis?

N: DPR

A: extension and lateral flexion of cervical spine

What is the nerve supply and action(s) of iliocostalis thoracis?

N: DPR
A: extension and lateral flexion of thoracic spine (and draws ribs up)

What is the nerve supply and action(s) of iliocostalis lumborum?

N: DPR

A:extension and lateral flexion of lumbar spine (also draws ribs down)

What is the nerve supply and action(s) of longissimus capitis?

N: DPR

A: bilat: extension of the head, unlit: lateral bending of head and rotation of face to same side

What is the nerve supply and action(s) of longissimus cervicis?

N: DPR
A: bilat: extension of cervical spine unilat: lateral flexion of the neck

What is the nerve supply and action(s) of longissimus thoracis?

N: DPR
A: extension of thoracic and lumbar vertebrae, unilat: laterally flexing the spine

What is the nerve supply and action(s) of spinalis capitis?

N: DPR

A: extension of head and neck vertebrae

What is the nerve supply and action(s) of spinalis cervicis?

N: DPR
A: extension of neck vertebrae

What is the nerve supply and action(s) of spinalis thoracis?

N: DPR

A:extension of thoracic vertebrae

What is the nerve supply and action(s) of all semispinalis muscles?

N: DPR

A: most powerful head extensor (also does some rotation to the opposite side)

What is the nerve supply and action(s) of the multifidus?

N: DPR
A: extension, lateral flexion, and rotation of vertebral column to opposite side

What is the nerve supply and action(s) of the rotatores?

N: DPR

A: extend the vertebral column and rotate it to the opposite side

What are the boundaries of the triangle of ausculation?

Medially: trapezius (lower part)

Laterally: medial border of scapula

Inferiorly: latissimus dorsi

What are the boundaries of the triangle of Petit?

Medially: latissimus dorsi

Laterally: medial border of scapula

Inferiorly: iliac crest

What is the thoracolumbar fascia?

Big piece of fascia that extends from thoracic region to sacrum

What are the layers of the thoracolumbar fascia?

Posterior layer: most superficial and attaches to lumbar SP’s, interspinous ligaments and median sacral crest

• Gives origin to erector spinae muscles

Middle layer: attaches to tips of TP’s and intertransverse ligaments and extends superiorly from the iliac crest to the last rib

• Covers the posterior surface of the QL

Anterior layer: covers the anterior surface of QL and attaches to the anterior surfaces of lumbar TP’s

What 4 muscles have an origin that includes the thoracolumbar fascia?

• Erector spinae

• Latissimus dorsi

• Transverse abdominis

• Internal oblique

What is another name for the erector spinae muscles?

Sacrospinalis

Which 3 muscles comprise the erector spinae from medial to lateral?

Iliocostalis (lateral), Longissimus (intermediate), Spinalis (medial)

What is the origin, insertion, nerve supply, and action of the interspinalis muscles?

O and I: adjacent SP’s

A: extend the vertebral column

N: DPR

What is the OIAN of the intertransversarii muscles?

O and I: adjacent TP’s

A: lateral flexion of vertebral column

N: Lateral C, T, L intertransversarii=VPR

Medial Lumbar intertransversarii=DPR

What is the OIAN of the levator costarum muscles?

O: TP’s

I: Brevis: angle of 1 rib below, Longus: angle of two ribs below

A: elevate ribs and help lat. flex and rotate trunk to same side

N: DPR

What is the OIAN of the rectus capitis posterior major?

O: Spinous process of C2

I: Lateral part of inferior nuchal line

A: bilat: extension of the head, unilat: rotation of the head to the same side

N: Suboccipital nerve

What is the OIAN of the rectus capitis posterior minor?

O: posterior tubercle of C1

I: medial part of inferior nuchal line
A: extension of the head
N: suboccipital nerve

What is the OIAN of the obliquus capitis inferior?

O: spinous process of C2
I: transverse process of C1
A: rotation of the head to the same side
N: suboccipital nerve

What is the OIAN of the obliquus capitis superior?

O: transverse process of C1
I: occiput between superior and inferior nuchal lines, lateral to semispinalis capitis
A: extension and lateral flexion of the the head
N: suboccipital nerve

What are the boundaries of the suboccipital triangle?

Superomedial: rectus capitis posterior major

Superolateral: obliquus capitis superior

Inferolateral: obliquus capitis inferior

What structures are found contained within the suboccipital triangle?

Vertebral artery

Suboccipital nerve 

Suboccipital plexus of veins

Posterior arch of Atlas