Muscles of the Back

levatores costarum- origin

Origin: tips of transverse processes from C7 to T11

Obliquus Capitis Superior

Origin: transverse process of atlas (C1) Insertion: occipital bone (lateral part of area between superior and inferior nuchal lines) Nerve supply: suboccipital nerve Action: extension of head lateral flexion of head to same side of contracting muscle

Levator scapulae origin

Origin: transverse processes of upper 4 cervical vertebrae

what are other mm that are associated with the spine? slide 32

intertransversarii: extend between adjacent transverse processes best developed in cervical and lumbar regions interspinales: extend between adjacent spinous processes best developed in cervical and lumbar regions -levatores costarum

Semispinalis- location SLIDE 25-26

lacking below thoracic region has thoracis, cervicis and capitis subdivisions

Describe Transversospinalis

muscle fibers run superiorly and medially from transverse processes to spinous processes depending on length of muscle fibers, it is divided into 3 components (longest muscle fibers are more superficial within transversospinalis, shorter muscle fibers are deeper):

Multifidus-LOCATION

present along whole length of spine in sacral and lumbar regions lies deep to erector spinae (because there is no semispinalis in these areas) in thoracic and cervical regions it lies deep to semispinalis fibers insert into spinous processes of all vertebrae from L5-axis best developed in lumbar region

Other Muscles Associated with the Spine suboccipital muscles: describe

4 short muscles attaching to occipital bone, atlas and axis deepest muscles in upper part of posterior neck (lie deep to trapezius, splenius capitis and semispinalis capitis) components: rectus capitis posterior major rectus capitis posterior minor obliquus capitis inferior obliquus capitis superior all 4 muscles are supplied by suboccipital nerve (dorsal ramus of C1 spinal nerve)

What is the action of splenius capitis and splenius cervicis? slide 19

Action (both muscles): bilateral contraction > extension of head and neck, unilateral contraction > lateral flexion and rotation of head and neck to same side of contracting muscle

what is the action of the trapezius mm? refer to slide 6-7

Action: helps stabilize scapula upper fibers elevate scapula middle fibers pull scapula toward posterior midline (retract) lower fibers depress scapula acting together, superior and inferior fibers rotate scapula superiorly (inferior angle moves up and laterally) important movement in order to perform full abduction of arm (bring hand above head)

latissimus dorsi action

Action: extension, adduction and medial rotation of arm at shoulder joint when arms are raised above head, it pulls trunk upward

levator scapulae action

Action: helps stabilize scapula elevation of scapula inferior rotation of scapula

levatores costarum- insertion

Insertion: fibers run inferiorly and laterally and insert into rib immediately below (levator costarum brevis) or 2nd rib below (levator costarum longus)

serratus posterior superior insertion

Insertion: fibers run inferolaterally insert into 2nd to 5th ribs

Trapezius insertion

Insertion: lateral ⅓ of clavicle, acromion and spine of scapula

levator scapulae insertion

Insertion: medial border of scapula (above root of spine)

rhomboid minor insertion

Insertion: medial border of scapula (at level of root of spine)

rhomboid major insertion

Insertion: medial border of scapula (below root of spine)

Latissimus Dorsi insertion

Insertion: muscles fibers pass superiorly and laterally wrap around inferior border of teres major muscle tendon inserts into floor of intertubercular (bicipital) groove of humerus

serratus posterior superior nerve supply and action

Nerve supply: 2nd to 5th intercostal nerves (ventral rami of T2 to T5 spinal nerves) Action: elevation of ribs

nerve supply of erctor spinae slide 21

Nerve supply: dorsal rami of spinal nerves Action: bilateral contraction > extension of spine unilateral contraction > lateral flexion of spine to same side of contracting muscle

levatores costarum: nerve supply and action slide 34

Nerve supply: dorsal rami of spinal nerves Action: elevation of ribs lateral flexion of spine

what is the rhomboids nerve supply and action?

Nerve supply: dorsal scapular nerve (branch of brachial plexus) Action: help stabilize scapula, retraction of scapula, inferior rotation of scapula

latissimus dorsi nerve supply

Nerve supply: thoracodorsal nerve (branch of brachial plexus)

levator scapulae nerve supply

Nerve supply: ventral rami of C3 and C4 spinal nerves and dorsal scapular nerve (branch of brachial plexus)

Rectus Capitis Posterior Major: origin, insertion, nerve supply, action

Origin: spinous process of axis (C2) Insertion: lateral part of inferior nuchal line Nerve supply: suboccipital nerve Action: extension of head rotation of head to same side of contracting muscle

rhomboid minor origin slide 13

Origin: lower part of ligamentum nuchae and spinous processes of C7 and T1

splenius capitis origin

Origin: lower part of ligamentum nuchae and spinous processes of C7 to T3 vertebrae

Obliquus Capitis Inferior: location , origin, insertion, nerve supply, action

Origin: spinous process of axis (C2) Insertion: transverse process of atlas (C1) Nerve supply: suboccipital nerve Action: rotation of head to same side of contracting muscle

rhomboid major origin

Origin: spinous processes from T2 to T5

Trapezius origin

Origin: medial part of superior nuchal line, external occipital protuberance, ligamentum nuchae, spinous processes (C7 to T12)

serratus posterior superior origin slide 16

Origin: lower part of ligamentum nuchae and spinous process of C7 to T2 or T3

Rotatores- slide 29-30

deepest muscles located in groove between spinous and transverse processes best developed in thoracic region extend from a transverse process to spinous process of vertebra located immediately above (rotator brevis) or to spinous process of 2nd vertebra above (rotator longus

what is the nerve supply and action of transversospinalis?

dorsal rami of spinal nerves Action: bilateral contraction > extension of spine unilateral contraction: lateral flexion of spine to same side of contracting muscle rotation of spine to opposite side of contracting muscle shorter muscles main function is to stabilize vertebral column

Greater Occipital nerve slides 42-43

dorsal ramus of C2 spinal nerve curves around inferior border of obliquus capitis inferior ascends superficial to suboccipital triangle pierces semispinalis capitis and trapezius to reach scalp (does not pierce splenius capitis) divides into branches that supply skin of posterior part of scalp (run with branches of occipital artery)

serratus posterior inferior insertion

fibers run superolaterally > insert into lower 4 ribs

splenius capitis insertion

fibers run superolaterally and insert into lateral part of superior nuchal line (occipital bone) and mastoid process (temporal bone)

what innervates the deep mm of the back?

innervated by dorsal rami of spinal nerves

Semispinalis Capitis- Location KNOW IN DETAIL

large muscle on back of neck originates from transverse processes of T1 to T6 vertebrae and articular processes of lower 3 or 4 cervical vertebrae muscle fibers ascend deep to splenius and insert into occipital bone, in medial part of area between superior and inferior nuchal lines Action extend head and neck and rotate to opposite side

Suboccipital Triangle boundaries: laterally

laterally: obliquus capitis superior

Suboccipital Triangle boundaries: medially

medially: rectus capitis posterior major

name the 3 components of transversospinalis

semispinalis: muscle fibers span 6 or more vertebrae between origin and insertion multifidus: muscle fibers span 3 to 5 vertebrae between origin and insertion rotatores: muscle fibers span 1 or 2 vertebrae between origin and insertion

Name the two intermediate mm of the back

serratus posterior superior serratus posterior inferior

serratus posterior inferior origin

spinous processes from T11 to L2 or L3

muscles are divided into 3 groups, what are they?

superficial group: muscles insert into bones of upper limb (clavicle, scapula, humerus) intermediate group: muscles insert into ribs (accessory muscles of respiration) deep group: muscles involved with movements of vertebral column and head (proper/intrinsic muscles of back)

Name the 4 superficial mm of the back

superficial muscles: trapezius latissimus dorsi levator scapulae rhomboid minor and major

serratus posterior inferior nerve supply and action

Nerve supply: 9th, 10th, 11th intercostal nerves and subcostal nerve (ventral rami of T9 to T12 spinal nerves) Action: depression of ribs

Trapezius nerve supply

Nerve supply: accessory nerve (CN XI) and ventral rami of C3 and C4 spinal nerves latter nerves probably provide sensory innervation (proprioception)

Splenius Cervicis origin and insertion

Origin: spinous processes of T3 to T6 vertebrae Insertion: fibers run superolaterally and insert into transverse processes of upper 3 to 4 cervical vertebrae

Latissimus Dorsi origin slides 9-10

Origin: spinous processes of lower 6 thoracic, lumbar and sacral vertebrae, posterior part of iliac crest, lower 3 or 4 ribs, and sometimes inferior angle of scapula (attachments to vertebrae and iliac crest are established via thoracolumbar fascia)

Suboccipital Triangle boundaries :Inferiorly and what are the contents of the Suboccipital Triangle

inferiorly: obliquus capitis inferior covered by semispinalis capitis (roof) floor: posterior arch of atlas and posterior atlanto-occipital membrane contents: vertebral artery (3rd part) and suboccipital nerve (nerve emerges between vertebral artery and posterior arch of atlas)

Erector Spinae large muscular mass with an extensive inferior tendinous origin (erector spinae aponeurosis) Name the 3 columns they are divided into

lateral column: iliocostalis intermediate column: longissimus (largest component) medial column: spinalis (smallest component)

location of serratus posterior inferior

lies deep to latissimus dorsi

location of serratus posterior superior

lies deep to rhomboid mm

Rectus Capitis Posterior Minor location , origin, insertion, nerve supply, action

located medial and partly under rectus capitis posterior major Origin: posterior tubercle of atlas (C1) Insertion: medial part of inferior nuchal line Nerve supply: suboccipital nerve Action: extension of head

name the 3 groups the deep mm divide into: hint: superficial layer intermediate layer deep layer

superficial layer: only present in cervical and upper thoracic regions consists of SPLENIUS CAPITUS and SPLENIUS CERVICISmuscles fibers run superiorly and laterally intermediate layer: extends whole length of spine formed by ERECTOR SPINAE muscle fibers are more or less vertically oriented deep layer: extends whole length of spine formed by TRANSVERSOSPINALIS muscle fibers run superiorly and medially