Muscles of the Back

What are the superficial muscles of the back? Are they intrinsic or extrinsic?

Trapezius, latissimus dorsi, levator scapulae, rhomboid major and minor; extrinsic

Extrinsic

located in the back region, but act to connect the upper limb to the trunk. Primary actions are NOT directly related to movements of the back

Trapezius

latissimus dorsi

levator scapulae

rhomboid major

rhomboid minor

What are the intermediate muscles of the back? Are they extrinsic or intrinsic?

serratus posterior superior and inferior; extrinsic

serratus posterior superior

serratus posterior inferior

What are the deep muscles of the back? Are they intrinsic or extrinsic?

splenius capitis, splenius cervicis, spinalis, longissimus, iliocostalis, semispinalis capitis, semispinalis cervicis, multifidus, rotatores; intrinsic

Splenius capitis

splenius cervicis

spinalis

longissimus

iliocostalis

semispinalis capitis

semispinalis cervicis

multifidus

rotatores

What are the suboccipital muscles?

rectus capitis posterior major, rectus capitis posterior minor, obliquus capitus superior, obliquus capitus inferior

Rectus capitis posterior major

rectus capitis posterior minor

obliquus capitis inferior

obliquus capitis superior

What muscles make up the suboccipital triangle?

medial - rectus capitis posterior major

inferior - obliquus capitis inferior

lateral - obliquus capitis superior

What is the roof of the suboccipital triangle (superficial layer)?

semispinalis capitis

what is the floor of the suboccipital triangle (deep layer)?

posterior atlanto-occipital membrane, posterior arch of C1

What are the contents of the suboccipital triangle (what’s inside)?

vertebral artery and suboccipital nerve (C1)

Trapezius - medial attachments

superior nuchal line, external occipital protuberance, ligamentum nuchae, SP C7-T12

Trapezius - lateral attachments

lateral 1/3 of the clavicle and acromion and spine of scapula

Trapezius - actions

scapular upward rotation, upper fibers produce scapular elevation, middle fibers produce scapular retraction, inferior portion produces scapular depression

unilaterally - ipsilateral lateral flexion/side bending of head and neck

bilaterally - extension of head and neck

what are the muscles of the erector spinae (lateral to medial)?

iliocostalis, longissimus, spinalis (I Like Standing)

latissimus dorsi - actions

shoulder extension, shoulder adduction, shoulder internal rotation

levator scapulae - actions

scapular elevation, scapular downward rotation

unilaterally - ipsilateral lateral neck flexion (side bending)

bilaterally - extension of neck

rhomboid major and minor - actions

scapular retractions, scapular downward rotation

serratus posterior superior - actions

elevates ribs 2-5

serratus posterior inferior

depresses ribs 9-12

splenius capitis and cervicis - actions

unilateral - ipsilateral side bending of head and neck, ipsilateral rotation of head and neck

bilateral - head and neck extension

iliocostalis - actions

unilateral - ipsilateral trunk flexion/side bending

bilateral - trunk extension

longissimus - actions

unilateral - ipsilateral trunk flexion/side bending

bilateral - trunk and head extension

spinalis - actions

unilateral - ipsilateral trunk flexion/side bending

bilateral - trunk and head extension

semispinalis capitis and cervicis - actions

ipsilateral - contralateral head (capitis) and neck (cervicis) rotations and ipsilateral side bending of head (capitis) and neck (cervicis)

bilateral - head extension (capitis) and neck extension (cervicis)

multifidus - actions

ipsilateral - spinal rotation (contralateral)

bilateral - spinal extension

rotatores - actions

ipsilateral - spinal rotation (contralateral)

bilateral - spinal extension

rectus capitis posterior major - action

extends head and rotates face to same side

rectus capitis posterior minor - action

extends head

obliquus capitis superior - actions

extends head

obliquus capitis inferior - actions

rotates face to same side

trapezius - innervation

motor: spinal accessory nerve (CN XI)

proprioception: C3-C4

Latissimus dorsi - medial attachments

SP T7-T12, thoracolumbar fascia, iliac crest, ribs 10-12, inferior angle of scapula

latissimus dorsi - lateral attachment

floor of intertubercular sulcus of humerus

latissimus dorsi - innervation

thoracodorsal nerve (middle subscapular nerve)

levator scapulae - medial attachments

TP C1-C4

levator scapulae - lateral attachments

superior part of medial border of scapula

levator scapulae - innervation

dorsal scapular nerve

rhomboid major - medial attachments

SP T3-T5

rhomboid major - lateral attachments

medial border of scapula to inferior spine

rhomboid major - innervation

dorsal scapular nerve

rhomboid minor - medial attachment

ligamentum nuchae, SP C7-T1

rhomboid minor - lateral attachment

medial border of scapula at spine

rhomboid minor - innervation

dorsal scapular nerve

serratus posterior superior - medial attachment

SP C7-T3

serratus posterior superior - lateral attachment

superior borders of ribs 2-5, lateral to their angles

serratus posterior superior - innervation

anterior rami T2-T5

serratus posterior inferior - medial attachments

SP T11-L2

serratus posterior inferior - lateral attachments

inferior border of ribs 9-12, lateral to their angles

serratus posterior inferior - innervation

anterior rami T9-T12

splenius capitis - medial attachments

ligamentum nuchae, SP C7-T4

splenius capitis - lateral attachments

mastoid process, lateral 1/3 of superior nuchal line

splenius capitis - innervation

posterior rami of middle cervical nerves

Splenius cervicis - medial attachment

SP T3-T6

splenius cervicis - lateral attachment

TP C1- C3

splenius cervicis - innervation

posterior rami of lower cervical nerves

spinalis - medial attachments

median sacral crest, posterior surface sacrum, SP L and lower T, medial part iliac crest

spinalis - lateral attachment

SP of T and C

spinalis - innervation

posterior rami of lower cervical nerves

longissimus - medial attachment

median sacral crest, posterior surface sacrum, SP L and lower T, medial part iliac crest (same as spinalis and iliocostalis)

longissimus - lateral attachment

between tubercles and angles of ribs, TP of T and C, mastoid process

longissimus - innervation

posterior rami of lower cervical nerves (same as spinalis and iliocostalis)

iliocostalis - medial attachment

median sacral crest, posterior surface sacrum, SP L and lower T, medial part iliac crest (same as spinalis and longissimus)

iliocostalis - lateral attachment

angles of lower ribs and TP of C

iliocostalis - innervation

posterior rami of lower cervical nerves (same as spinalis and latissimus)

semispinalis capitis - medial attachment

TP T1-T5/T6

semispinalis capitis - lateral attachment

SP C2-C5

semispinalis capitis - innervations

posterior rami of spinal nerves (same as cervicis)

semispinalis cervicis - medial attachment

TP T1-T5/T6

semispinalis cervicis - lateral attachment

SP C2-C5

Semispinalis cervicis - innervation

(same as capitis) posterior rami of spinal nerves

Multifidus - medial attachment

sacrum, ilium, TP T1-L5 and AP C4-C7

multifidus - lateral attachment

SP C2-L5

Multifidus - innervations

(same as capitis) posterior rami of spinal nerves

Rotatores - general location

arise btwn transverse processes, best developed in thoracic region

fibers pass superomedially to attach at the junction of the lamina and transverse process of one (brevis) or two (longus) segments superior to origin

rotatores - action/function

proprioception of spine, stabilization of vertebrae and local extension and rotation of the spinal column

rotatores - innervation

posterior (dorsal) rami of spinal nerves

Rectus capitis posterior major - general location

occipital bone to spinous process of C2

rectus capitis posterior major - innervation

suboccipital nerve (posterior ramus C1)

rectus capitis posterior minor - general location

occipital bone to tuberosity on posterior arch of C1

rectus capitis posterior minor - innervation

suboccipital nerve (posterior ramus C1)

obliquus capitis superior - general location

occipital bone to transverse process of C1