Intrinsic Back Muscles (Quiz 1) Flashcards
What is the 1 muscle in the superficial layer of intrinsic back muscles?
splenius
What is the origin/proximal attachment of the splenius?
-nuchal ligament
-SP of C7-T6 vertebrae
What is the insertion/distal attachment for the splenius capitis?
-fibers run superolaterally to mastoid process of temporal b.
-lateral 3rd of superior nuchal line of occipital bone
What is the insertion/distal attachment for the splenius cervicis?
tubercles of TPs of C1-C3 or C4 vertebrae
What innervates the splenius?
posterior rami of spinal nerves
What are the actions of the splenius?
acting alone
-laterally flex neck
-rotate head to side of active muscles
acting together (splenius capitis and splenius cervicis)
-extend head and neck
What are the 3 muscles in the intermediate layer of the intrinsic back muscles?
Together they’re called “erector spinae”
1) iliocostalis
2) longissumus
3) spinalis
What do the erector spinae muscles do?
chief extensors of the vertebral column, generally act bilaterally
What are the origin/proximal attachments of the iliocostalis, longissumus, and spinalis (erector spinae muscles)?
theres a lottttttttt
-arises from a broad tendon from the posterior part of the iliac crest
-posterior surface of sacrum
-sacro-iliac ligaments
-sacral and inferior lumbar SP’s
-supraspinous ligament
What are the insertion/distal attachments of the iliocostalis?
-lumborum
-thoracis
-cervicis
these 3 fibers run superiorly to angles of lower ribs and cervical TP’s
What innervates the iliocostalis, longissumus, and spinalis (erector spinae muscles)?
posterior rami of spinal nerves
What are the main actions of the iliocostalis?
acting bilaterally
-extend vertebral column
-as back is flexed, control movement via eccentric contraction
acting unilaterally
-laterally flex vertebral column
What are the insertion/distal attachments of the longissumus?
-thoracis
-cervicis
-capitis
these 3 fibers run superiorly to ribs between tubercles and angles to TPs in thoracic and cervical regions, and to mastoid process of temporal bone
What are the actions of the longissumus?
acting bilaterally
-extend head
-as back is flexed, control movement via eccentric contraction
acting unilaterally
-laterally flex vertebral column
What are the insertion/distal attachments for the spinalis?
-thoracis
-cervicis
-capitis
these fibers run superiorly to SPs in the upper thoracic region and to cranium
What are the main actions of the spinalis?
acting bilaterally
-extend vertebral column and head
-as back is flexed, control movement via eccentric contraction
acting unilaterally
-laterally flex vertebral column
What are the 3 muscles of the deep layer of intrinsic back muscles?
together they are called transversospinalis
1) semispinalis
2) multifidus
3) rotatores (brevis and longus)
What are the 3 muscles of the minor deep layer of intrinsic back muscles?
1) interspinales
2) intertransversarii
3) levatores costorum
The transversospinalis muscles originate from _____ and attach to the __________________
TPs, SPs and lamina
What is the origin/inferior attachment of the semispinalis?
TPs of C4-T12 vertebrae
What is the insertion/superior attachment of the semispinalis?
SPs of more superior vertebrae
thoracis, cervicis, and capitis fibers run superomedially to occipital bone and SPs in thoracic and cervical regions, spanning 4-6 segments above
What are the actions of the semispinalis?
extends head, thoracic, and cervical regions of vertebral column and rotates them contralaterally
What are the origin/inferior attachments of the multifidus?
theres a lottttttttt
TPs
Arises from
-posterior sacrum
-posterior superior iliac spine of ilium
-aponeurosis of erector spinae
-sacro-iliac ligaments
-MPs of lumbar vertebrae
-TPs of T1-T3
-articular processes of C4-C7
What are the insertion/superior attachments of the multifidus?
SPs of more superior vertebrae
Thickest in lumbar region- fibers pass obliquely superomedially to entire length of SPs, located 2-4 segments superior to proximal attachment
What are the actions of the multifidus?
-extension
-stabilizes vertebrae during local movements of vertebral column
What is the origin/inferior attachment of the rotatores?
arise from TPs of vertebrae (best developed in thoracic region)
What are the insertion/superior attachments of the rotatores?
SPs of more superior vertebrae
fibers pass superomedially to attach to LPJ and TP of SP of vertebrae immediately (brevis) or 2 segments (longus) superior to vertebrae of attachment
What are the actions of the rotatores?
-extension
-stabilize vertebrae and assist with local extension and rotary movements of vertebral column
-may function as organs of proprioception
What is the origin/inferior attachment for the interspinales?
superior surfaces of SPs of cervical and lumbar vertebrae
What is the insertion/superior attachment of the interspinales?
inferior surfaces of SPs of vertebrae superior to vertebrae of proximal attachment
What is the main action of the interspinales?
aid in extension and rotation of vertebral column
What is the origin/inferior attachment of the intertransversarii?
TPs of cervical and lumbar vertebrae
What is the insertion/superior attachment of the intertransversarii?
TPs of adjacent vertebrae
What are the actions of the intertransversarii?
-aid in lateral flexion of vertebral column
-acting bilaterally- stabalize vertebral column
What is the origin/inferior attachment of the levatores costorum?
tips of TPs of C7-T11 vertebrae
What is the insertion/superior attachment of the levatores costorum?
pass inferolaterally and insert on rib between tubercle and angle
What are the main actions of the levatores costorum?
-elevate ribs (assisting respiration)
-assist with lateral flexion of vertebral column
