Back Muscles Flashcards
thoracolumbar fascia explain
- deep fascia
- thin in thoracic
- thick in lumbar
- strengthen lumbar area and surround intrinsic back muscles
trapezius innervation
spinal accessory nerve (Cranial nerve XI)
sensory: ventral rami of C3 and C4
levator scapulae action
- elevation of scapula
- rotates inferiorly
action of erector spinae muscles
- bilateral: extension of spine
- unilateral: lateral flexion of spine to same side of contracting muscle
- Contracts during flexion of spine to control movement against gravity
Where are the intermediate back muscles found and what are they called?
- they are located on entire length of spine
- erector spinae muscles (iliocostalis, longissimus, spinalis)
semispinalis insertion
-occipital bone, in the medial part of area between superior and nuchal lines
latissimus dorsi innervation
-thoracodorsal nerve
latissimus dorsi actions
- adduction of arm at shoulder
- extension of arm at shoulder
- medial rotation of arm
Where are the superficial intrinsic back muscles found and what are they?
only found in cervical and upper thoracic regions
splenius capitis and splenius cervicis
trapezius insertion
- lateral 1/3rd of clavicle
- acromion
- spine of scapula
semispinalis capitis origin
-transverse processes of C4-T12
describe the occipital region (where antomically located/surrounded/near what structures)
- deep to trapezius
- roof is the semispinalis muscle
- floor is the posterior atlanto-occipital membrane and the posterior arch of the atlas
- contains the vertebral artery and suboccipital nerve
action of splenius capitis
bilateral contraction- extension of head and neck
unilateral contraction- lateral flexion and rotation of head and neck to same side of contracting muscle
splenius cervicis origin
-spinous processes of T3-T6 vertebrae
What are and what is purpose of intrinsic back muscles. What is the subdivision of the intrinsic back muscles?
- extend from pelvis to skull
- act to maintain posture and control movements of vertebral column
- subdived into superficial, intermediate, and deep layers
splenius capitis innervation
dorsal rami of cervical spinal nerves
rhomboid major and minor action
- retract scapula
- inferiorly rotate
innervation of erector spinae muscles
innervated by dorsal rami of spinal nerves
serratus posterior inferior insertion
-lower 4 ribs (ribs 9-12)
What is the greater occipital nerve and where is it located?
- dorsal ramus of C2 spinal nerve
- curves around inferior border of obliquus capitis inferior-> ascends over suboccipital triangle->pierces semispinalis capitis and trapezius to reach scalp (it does not pierce splenius capitis)
- divides into branches that supply skin of posterior part of scalp (run with branches of occipital artery)
origin of erector spinae muscles(iliocostalis, longissimus, and spinalis)
all 3 columns originate from a broad tendon that attaches to:
- iliac crest
- sacrum
- sacroiliac ligaments
- inferior lumbar spinous processes
latissimus dorsi insertion
-floor of intertubercular groove of humerus
levator scapulae origin
-transverse processes of upper 4 cervical vertebrae (C1-C4)
rhomboid minor insertion
-medial border of scapula at level of root of spine
rhomboid major and minor innervation
dorsal scapular nerve
trapezius actions
elevation scapula
retraction scapula
(superiorly) rotates scapula and depresses
ERRAttach Sounds
What is the nerve innervation of intrinsic back muscles?
innervated by dorsal rami of spinal nerves
action of suboccpital triangle muscles
- mostly postural, acting directly or indirectly on head
- extension of head on C1
- rotation of head with C1 on C2
- also more proprioceptive in nature
serratus posterior superior origin
- ligamentum nuchae
- C7 to T2/T3 spinous processes
action of semispinalis
- extension of head, thoracic, and cervical regions of vertebral column
- rotates these regions contralaterally
what are the minor intrinsic back muscles?
- levatores costarum muscles
- interspinous muscles
- intertransverse muscles
serratus posterior inferior origin
-spinous processes of T11 to spinous processes of L2-L3
thoracolumbar fascia attachments (posterior layer, intermediate layer, anterior layer)
- posterior: attach to the spinous processes
- intermediate: attach to transverse processes
- anterior: forms quadratus lumborum (muscle of posterior abdominal wall) the fascia attaches to the the transverse processes
trapezius origin
superior nuchal line
external occipital protuberance
ligamentum nuchae
spinous processes C7-T12
action of splenius cervicis
bilateral contraction- extension of head and neck
unilateral contraction- lateral flexion and rotation of head and neck to same side of contracting muscle
(same as splenius capitis)
rhomboid minor origin
- (inferior portion) of ligamentum nuchae
- spinous processes C7 and T1
serratus posterior inferior innervation
ventral rami of T9-T12 spinal nerves
what nerve innervates the muscles of the suboccipital triangle?
innervated by suboccipital nerve (dorsal ramus of C1 spinal nerve)
serratus posterior inferior action
depresses ribs 8-12
where are the deep intrinsic back muscles found and what are they?
- run entire length of spine
- called the transversospinalis muscle group (semispinalis, multifidus, rotatores)
- group of muscles that generally run superomedially from transverse processes of inferior vertebrae to spinous processes of superior vertebrae
what muscles are contained within the suboccipital triangle?
- rectus capitis posterior major
- rectus capitis posterior minor
- superior oblique (obliquus capitis superior)
inferior oblique (obliquus capitis inferior)
serratus posterior superior innervation
-ventral rami of T2-T5 spinal nerves
splenius cervicis innervation
dorsal rami of cervical spinal nerves (same as splenius capitis)
splenius capitis insertion
- superior nuchal line
- mastoid process
serratus posterior superior insertion
-ribs 2-5
rhomboid major origin
-spinous processes T2-T5
describe orientation of semispinalis muscles (capitis, cervicis, thoracis)
capitis- more vertically oriented, run from transverse processes of cervical and upper thoracic vertebrae to the occipital bone
cervicis- deep to semispinalis capitis to cervical spinous processes
thoracis- to thoracic spinous processes
splenius capitis origin
- lower part of ligamentum nuchae
- spinous processes of C7-T3
semispinalis innervation
innervated by dorsal rami of spinal nerves
serratus posterior superior action
elevate ribs 2-5
innervation of transversospinalis muscles?
dorsal rami of spinal nerves
describe multfidus (orientation, where found)?
- present along entire length of spine
- best developed in lumbar region
levator scapulae innervation
- ventral rami of C3 and C4 spinal nerves
- dorsal scapular nerve (branch of brachial plexus)
latissimus dorsi origin
- spinous processes T7-T12
- inferior 3 or 4 ribs
- Lumbar, sacral vertebrae, and iliac crest via thoracolumbar fascia
name the deep transversospinalis muscles from superficial to deep
superfical: semispinalis (s for superficial)
intermediate: multifidus (m for middle)
deep: rotatores (row deep)
group of muscles that generally run superomedially from transverse processes of inferior vertebrae to spinous processes of superior vertebrae
ie transvers-o-spinalis
action of transversopinalis muscles
- bilateral contraction: extension of spine
- unilateral contraction: lateral flexion of spine to same side of contracting muscle AND rotation of spine to opposite side of contracting muscle
- shorter muscles main function to stabilize the spine
rhomboid major insertion
-medial border of scapula (root of spine to inferior angle)
levator scapulae insertion
-medial border of scapula (from superior angle to root of spine)
describe rotatores (where run and where found predominantly)?
- shortest and deepest of transversospinalis muscles
- best developed in thoracic region
splenius cervicis insertion
-transverse processes of C1-C3 vertebrae
