Muscles of back Flashcards
list the two categories of back muscles:
- intrinsic
- extrinsic
list extrinsic classifications and why:
- superficial
- intermediate
originate from locations other than the back
list intrinsic classifications and why:
- deep
originate in the back
superficial muscles: general
- move upper limb
intermediate muscles:
- attach to the ribs -> respiratory function
- 2 thin muscles sheets in sup/inf regions of back
deep muscles:
- move vertebral column and head
list muscles of superficial extrinsic
- trapezius
- latissimus dorsi
- rhomboid major
- rhomboid minor
- levator scapulae
list muscles of intermediate extrinsic
- serratus posterior superior
- serratus posteror inferior
list organisations of muscles in deep group:
superficial -> deep
- spinotransversales
- erector spinae
- transversospinales
- suboccipital
- segmental
name muscles in spinotransversales:
- splenius capitis
- splenius cervicis
name muscles in erector spinae:
- longissimus
- iliocostalis
- spinalis
name muscles in transversospinales:
- semispinalis
- multifidus
- rotatores
name muscles in suboccipital:
- rectus capitis posterior major/ minor
- obliquus capitis superior/ inferior
name muscles in segmental:
- intertransversarii
- interspinales
- levatores costarum
where can the thoracolumbar fascia be found:
btw extrinsic intermediate and deep groups of muscles
superficial muscles: extrinsic features
- immediately deep to skin and superficial fascia
- primarily involved in movement of appendicular skeleton (clavicle, scapula, humerus)
trapezius: origin
- superior nuchal line
- ligamentum nuchae
- spinous processes C7-T12
- supraspinous ligs
trapezius: insertion
- superior edge of spine of scapula
- post border of lateral 1/3 of clavicle
- acromion
trapezius: innervation
- accessory n
- C3-4
trapezius: action
- elevate
- depress
- retract
- rotate scapula
latissimus dorsi: origin
- spinous processes T6-T12
- interspinous ligs
- thoracolumbar fascia - SP of lumbar vertebrae and interspinous ligs
- iliac crest
- lower 3-4 ribs
latissimus dorsi: insertion
- floor of bicipital groove
latissimus dorsi: innervation
thoracodorsal n
latissimus dorsi: action
- adduction
- medial rotation
- ext of arm at the shoulder
levator scapulae: origin
TVP C1-4
levator scapulae: insertion
- medial border of scapula from superior angle to root of spine
levator scapulae: innervation
- dorsal scapular n
- C3-4
levator scapulae: action
elevates scapula
rhomboid minor: origin
- ligamentum nuchae
- SP C7- T1
rhomboid minor: insertion
- medial border at root of spine
rhomboid minor: innervation
- dorsal scapular n
rhomboid minor: action
elevates and retracts scapula
rhomboid major: origin
SP T2-5
rhomboid major: insertion
- medial border from spine root to inferior angle
rhomboid major: innervation
- dorsal scapular n
rhomboid major: action
elevates and retracts scapula
serratus posterior superior/ inferior: innervation
anterior rami thoracic nerves (lower and upper)
serratus posterior superior/ inferior: action
- elevates ribs 2-5: superior
- depresses ribs 9-12: inferior
thoracolumbar fascia: general features
- covers deep muscles of back and trunk
- organises layers
- contributes to integrity
thoracolumbar fascia orientation: superiorly
- ant to serratus post/ sup
- continuous with superficial lamina of investing layers of cervical fascia
thoracolumbar fascia orientation: medially
attaches to SP thoracic vertebra
thoracolumbar fascia orientation: laterally
angles of ribs
intrinsic muscles: deep features
- extend from pelvis to skull
- innervated by segmental branches of post rami of spinal nerves
muscles: extensors/ rotators of head and neck
spinotransversales:
- splenius capitis
- splenius cervicis
muscles: extensors and rotators of vertebral column
- erector spinae
- transversospinales
muscles: short segmentals
- interspinales
- intertranversarii
spinotransversales: features and eg
both:
- bilateral contraction = ext
- ipsilateral contraction = head rotation to same side
- splenius capitis
- splenius cervicis
erector spinae: general features
- largest group of intrinsic back muscles
- covered in thoracic/ lumbar region by thoracolumbar fascia, serratus post inferior, rhomboids, splenius muscles
erector spinae: classifications
columns
- lateral
- middle
- medial
regions: (by superior attachment)
- lumborum
- thoracis
- cervicis
- capitis
erector spinae: muscles of each column
- lateral: iliocostalis
- middle: longissimus
- medial: spinalis
erector spinae: regions of lateral muscle
- iliocostalis lumborum
- ilicostalis thoracis
- iliocostalis cervicis
erector spinae: regions of middle muscle
- longissimus thoracis
- longissimus cervicis
- longissimus capitis
erector spinae: regions of medial muscle
- spinalis thoracis
- spinalis cervicis
- spinalis capitis
transversospinales: general features
- start laterally and TVP -> oblique and upward to SP
- fill grove btw TVP and SP
major subgroups:
- semispinalis
- multifidis
- rotatores
transversospinales: semispinalis
- most superficial
- thoracic and cervical regions
- cross 4-6 verteral segments
transversospinales: multifidis
- deep to semispinalis
- entire length of vertebral column
- most developed in lumbar
- cross 2-4 vertebral segments
transversospinales: rotatores
- smallest, deepest
- span entire length of vertebral column
- most developed in thoracic
- short rotator: cross 1 vertebral segment
long rotator; - cross 2 vertebral segments
transversospinales: common muscles action
- bilateral contraction: extension
- unilateral contraction: contralateral rotation (trunk/ head rotation to OPPOSITE side to contraction)
transversospinales: muscles action exception
except semispinalis capitis:
- more lateral attachment to skull
- bilateral contraction
- unilateral contraction: extension and ipsilateral rotation (chin superiorly and rotates same side)
segmental: features
- deep in back
- span one motion segment
2 groups:
- levatores costarum
- interspinales + intertransversarii
segmental: group 1
- levatores costarum
- oblique lateral and down
- inserts into rib below vertebra og
- elevate ribs
segmental: group 2
- true segmental muscles
- postural muscles
- stabilise adjoining vertebra during movements of spine
- allow more effective movement of larger muscles group
segmental: group 2 muscles found where
interspinales:
- btw adjacent SP
intertransversarii:
- btw adjacent TVP
suboccipital: features
- small group of muscles
- btw C1/2 and occiput
- move the head
segmental: muscles
bilaterally
- rectus capitis post major
- rectus capitis post minor
- obliquus capitis inferior
- obliquus capitis superior
suboccipital triangle: formed by
subocciptal muscles
suboccipital triangle: medial border
rectus capitis posterior major
suboccipital triangle: lateral border
obliquus capitis superior
suboccipital triangle: inferior border
obliquus capitis inferior
suboccipital triangle: contents
- post ramus C1
- vertebral artery and veins
name prevertebral muscles: scalenes
scalenes:
- post scalene
- middle scalene
- anterior scalene
name prevertebral muscles: others
- rectus capitis anterior
- rectus capitis lateralis
- longus colli superior/ inferior
- longus capitis
arteries that supply vertebra arise from:
- vertebral and ascending cervical aa
- segmental aa in trunk
segmental aa detailed:
- thorax: post intercostal aa
- abdomen: subcostal and lumbar aa
- pelvis: iliolumbar and lateral and median sacral aa
what branches arise from segmental arteries once crossing ext surface of vertebra:
- periosteal
- equatorial branches
spinal branches enter IVF and divide:
- segmental (radicular) medullary aa
- ant vertebral canal branch
- post vertebral canal branch
venous drainage:
- internal vertebral venous plexus
- external vertebral venous plexus
basivertebral veins:
- form within vertebral bodies
- emerge through foramina
- drain into ant external/ internal vertebral venus plexuses -> large longitudinal sinuses
interverterbral veins:
- receive veins from spinal cord, vertebral venous plexus
drain into:
- neck (vertebral v)
- trunk (intercostal/ lumbar/ sacral)
