Anatomy - Muscles of Back and Thorax

The aorta is relatively _ and close to the _

Posterior; spine

The abdominal aorta bifurcates at roughly the level of the

ASIS

Before it reaches the diaphragm, the thoracic aorta gives off

Intercostal (3-11) and one subcostal artery

The subcostal and posterior intercostal arteries are

Posterior

The subclavian artery gives off the _ trunk, which gives off the _ artery that becomes the _

Costocervical trunk; supreme intercostal artery; 1st and 2nd posterior intercostal arteries

The first branch off of the subclavian artery is the

Internal thoracic artery

The internal thoracic artery is an _ structure

Anterior

At which space does the internal thoracic artery branch into musculophrenic and superior epigastric

6th intercostal space

At the 6th intercostal space, the internal thoracic artery branches into the _ and continues as the _

Musculophrenic artery; superior epigastric artery

The musculophrenic artery ends up in the

9th intercostal space

The internal thoracic artery gives off the

1st-6th anterior intercostal artery

The musculophrenic artery gives off the

7th-9th anterior intercostal artery

The anterior and posterior intercostal arteries will

Anastomose

After giving off the 7th-9th anterior intercostal arteries, the musculophrenic artery will

Directly supply the 10th intercostal artery

The dorsal scapular artery supplies the

- Rhomboids

- Levator

- Trapezius

The subclavian artery directly gives off the

- Costocervical trunk

- Thyrocervical trunk

- Internal thoracic artery

- Dorsal scapular artery

What is the benefit of having spinal curvature?

Shock absorption that allows for movement

What is disadvantageous of excessive spinal curvature

There will be abnormal force distribution

What ligaments limit spinal flexion

Posterior longitudinal, supraspinous, interspinous, intertransverse

What motion closes the intervertebral foramen?

Extension and lateral flexion

What motion opens up the intervertebral foramen?

Flexion

Facet joint pain will likely be caused by _ and relieved by _

Long periods of standing; sitting down

Superficial extrinsic back musculature includes the

- Traps

- Latissimus dorsi

- Levator

- Rhomboids maj/min

Intermediate extrinsic back musculature includes the

Serratus posterior superior and inferior

The extensors, rotators and lateral flexors of the head and neck include the

Splenius capitis/cervicis

The extensors, rotators, and lateral flexors of the vertebral column includes the

Erector spinae and transversospinalis

The interspinales and intertransversarii are

Short segmental muscles

Intrinsic back muscles primarily act on the

Spine

The thoracolumbar fascia has relatively low

Elasticity

What is the main purpose of the thoracolumbar fascia

Transfer of kinetic energy

In the thoracic region, the thoracolumbar fascia covers the _ and _

Deep muscles and separates them from the superficial and intermediate groups

PPRs supple nerve fibers to the _ of the vertebral column

Synovial joints

One defining factor of PPRs is that they

Remain separate from each other and do not merge to form plexuses

The superficial intrinsic back muscle is the

Splenius

What is a function of the splenius other than motion

It tacks down the musculature underneath

The intermediate layer of intrinsic back musculature includes the

Erector spinae muscles

The erector spinae muscle lie in a _ on each side of the vertebral column

Groove

The chief extensors of the vertebral column are the

Erector spinae

From lateral to medial, the erector spinae muscles are

Iliocostalis > Longissimus > Spinalis

The common origin of the three erector spinae muscles is through a broad tendon that attaches to the

- Posterior part of the iliac crest

- Posterior aspect of the sacrum

- Sacro-iliac ligaments

- Sacral and inferior lumbar spinous processes

The action of the iliocostalis muscles are

Unilaterally, ipsilateral lateral flexion and rotation

Bilaterally, extension

The action of the longissimus muscles are

Unilaterally, Ipsilateral lateral flexion and rotation, except for the cervicis which only laterally flexes

Bilaterally, extension

The action of the spinalis muscles are

Unilaterally, ipsilateral lateral flexion

Bilaterally, extension

Why do the spinalis muscles not cause rotation?

They exist too close to the spinal column

The transversospinalis muscles include the

Semispinalis capitis, multifidus, rotatores

The deep back intrinsic muscles are the

Transversospinales muscles

What are the actions of the semispinalis muscles

Unilaterally, contralateral rotation

Bilaterally, extension

The semispinalis muscles span how many vertebrae

6-8

Of the transversospinalis muscles, the semispinalis is the most

Superficial

The multifidus spans how many vertebrae

2-4

The rotatores spans how many vertebrae

1-2

The multifidus and rotatores provide

Stability to the vertebrae during movement of the spinal column

From most superficial to deep of the transversospinalis muscles

Semispinalis < Multifidus < Rotatores

The rotatores is best developed in the

Thoracic region

The multifidus is thickest in the

Lumbar region

The multifidus and rotatores do not cause motion, rather, they _

Provide stability for the movement that is being performed

The minor deep back muscles include the

- Interspinales

- Intertransversarii

- Levator costarum

The minor deep back muscles are relatively sparse in the

Thoracic region

Like the multifidus and rotatores, the minor deep back muscles do not

Produce motion, but provide stability during movement

Principle muscles that cause TS and LS flexion are

- Rectus abdominis

- Psoas major

- Gravity

Principle muscles that cause TS and LS extension are

- Erector spinae

- Multifidus

- Semispinalis thoracis

Principle muscles that cause TS and LS lateral flexion are

Unilateral action of:

- Iliocostalis thoracis and lumborum

- Longissimus thoracis

- Multifidus

- External and internal oblique

- Quadratus lumborum

- Rhomboids

- Serratus anterior

Principle muscles that cause rotation of the LS and TS are

Unilateral action of:

- Rotatores

- Multifidus

- Iliocostalis

- Longissimus

- External oblique with opposite internal oblique

- Splenius thoracis

What are the contents of the suboccipital triangle

Vertebral artery and suboccipital nerve

Primary flexors of the OA joint are the

- Longus capitis

- Rectus capitis anterior

- Anterior fibers of the SCM

- Suprahyoid and infrahyoid muscles

Primary extensors of the OA joint include the

- Rectus capitis posterior major/minor

- Obliques capitis superior

- Splenius capitis

- Longissimus capitis

- Trapezius

Primary lateral rotators of the OA joint include the

- SCM

- Obliquus capitis superior

- Rectus capitis lateralis

- Longissimus capitis

- Splenius capitis

Primary ipsilateral movers of the AA joint include the

- Obliquus capitis inferior

- Rectus capitis posterior major/minor

- Longissimus capitis

- Splenius capitis

Primary contralateral movers of the AA joint include the

- SCM

- Semispinalis capitis

Primary CS flexors are

- Longus coli

- Scalene

- SCM

Primary CS extensors are

- SCM

- Traps

- Deep neck muscles

Primary CS lateral side bending muscles are

Unilateral action of:

- Iliocostalis cervicis

- Longissimus capitis and cervicis

- Splenius capitis and cervicis

- Intertransverasraii and scalenes

- SCM

Principle CS rotators are the

Unilateral action of

- Rotatores

- Semispinalis capitis and cervicis

- Multifidus

- Splenius cervicis

The suboccipital nerve originates from the

PPR of spinal nerve C1

What is the course of the suboccipital nerve

Runs between cranium and C1 vertebrae to reach suboccipital triangle

The greater occipital nerve originates from the

Posterior ramus of spinal nerve C2

The course of the greater occipital nerve

Emerges inferior to obliquus capitis inferior and ascends to posterior scalp

The distribution of the greater occipital nerve is

The skin over the neck and occipital bone

The origin of the lesser occipital nerve is the

Anterior rami of spinal nerves C2-C3

The course of the lesser occipital nerve

Passes directly to the skin

The posterior rami nerves C3-C7 innervates

Intrinsic muscles of back and overlying skin

The true muscles of the thoracic wall are the

- Serratus posterior

- Levatores costarum

- Intercostals

- Subcostals

- Transversus thoracis

The intercostal spaces lie between

Adjacent ribs and are filled by intercostal muscles

The intercostal nerves and associated major arteries and veins lie in the

Costal groove along the inferior margin of the superior rib

A secondary function of the innermost intercostal muscles are

Tacking down the neurovascular structures underneath it

The most active intercostal muscles during inspiration are the

External intercostals

The fiber direction of the external intercostals move

Inferiorly towards your "pockets"

The most active intercostal muscle during expiration are the

Internal intercostals

The fiber direction of the internal intercostal move

Superior towards the heart

The fiber direction of the innermost intercostal is the same as the

Internal intercostals

The neurovascular bundles that are associated with the intercostal space passes

In a plane between the innermost and internal intercostal

The subcostals are the most numerous in the

Lower regions of the posterior thoracic wall

The transversus thoracis exists on the

Deep surface of the anterior thoracic wall

The Transversus thoracis lies deep to the

Internal thoracic vessels and secure these vessels to the wall

Thoracic wall is innervated by

APRs through the intercostal nerves

The intercostal nerves travel between the

Internal and innermost intercostal muscles

What supplies sensation to the lateral and anterior thoracic skin

The lateral and anterior cutaneous branches of the intercostal nerves

The spinal cord terminates at approximately _ in adults and _ in children

L1; L3

The Filum terminale descends from the

Conus medullaris and attaches to coccyx

What is the function of the Filum terminale

Tacks down the spinal cord