Intrinsic Back Muscles Flashcards
What muscles make up the intermediate layer of the intrinsic back muscles? What is this group called?
Erector spinal group
Iliocostalis, longissumus and spinalis
What is the superficial layer of the intrinsic back muscles ?
Splenius
What muscles make up the deep layer of the intrinsic back and what is this group called?
Transversospinalis.
Semispinalis, multifidus, rotatores (brevis and longus).
What muscles make up the minor deep layer of the intrinsic back muscles ?
Interspinales, intertransverii, and levatores costarum.
Proximal and distal attachment of the splenius
P: Nuchal ligament and spinous processes of C7-T6 (including capitis and cervicis)
D: splenius capitis- fibers run to the mastoid process and Nuchal line
splenius cervicis- tubercles of transverse processes of C1-C3 or C4 vertebrae.
Nerve supply for splenius
Posterior rami of spinal nerves
Action of splenius
Acting alone and together
Alone : laterally flex head and rotate head to side of active muscle (ipsilateral).
Together: extend head and neck
Origin of erector spinae muscles ( iliocostalis, longissimus, spinalis)
Arise from iliac crest tendon, posterior part of sacrum, sacro-iliac ligaments, sacral and inferior lumbar spinous processes and supraspinous ligament
Distal attachment of iliocostalis
Lumborum thoracis cervicis - fibers run to angles of lower ribs and cervical transverse processes
Distal attachment of longissimus
Thoracis cervicis capitis- fibers run to ribs between tubercles and angles to transverse processes in thoracic and Cervicle regions and to mastoid process
Distal attachment of spinalis
Thoracis, cervicis, capitis, fibers run to spinous processes in upper thoracic region and to cranium
Nerve supply to erector spinae muscles
Posterior rami of spinal nerves
Main actions of erector spinae acting alone and unilaterally
Bilaterally: extend VC and head. Control movement via eccentric contraction
Unilaterally: laterally flex VC
Origin and insertion if the Semispinalis (part of Transversospinalis-deep later)
O: rises from transverse processes of C4-T12
I: thoracis cervicis capitis- fibers run superomedially to occipital bone and spinous processes in thoracic and spinal regions
Innervation of the Transversospinalis muscles (deep layer- Semispinalis, multifidus, rotatores)
Posterior rami of spinal nerves (Semispinalis by Cervicle and upper thoracic posterior rami)
Action of Semispinalis
Extension- head and thoracic and cervical region of vertebral column and rotates head controlaterally
Action of multifidus (Transversospinalis) - deep
Stabilises vertebrae during local movement of VC
Origin and insertion of the multifidus
O: arises from sacrum and transverse processes of c2-l5
I: fibers pass obliquely superiomedially to entire length of spinous processes superior to their origins.
Main action of the rotatores (brevis and longus) part of Transversospinalis deep layer
Stabilise vertebrae and assist in local extension and rotational movements of VC - proprioception as we’ll
Origin and insertion rope rotatores (brevis and longus)
O: arise from transverse processes of vertebrae
I: superiomedially to lamina of vertebrae above or spinous processes immediately above (brevis) or 2 segments up (longus)
Muscles of the minor deep layer
Interspinales
Intertransverii
Levatores costarum.
Origin and insertion of Interspinales
O: superior surfaces of spinous processes of cervical and lumbar vertebrae.
I: inferior surfaces of spinous processes of vertebrae superior
Innervation of Interspinales
Posterior rami of spinal nerves
Main action of Interspinales
Air in extension and rotation of VC
Origin and insertion of intertransverii
O: transverse process of cervical and lumbar vertebrae
I: transverse process of adjacent vertebrae
Innervation of intertransverii
Posterior and anterior rami of spinal nerves
Action of intertransversii
Aid in lateral flex ion of vertebral column
Bilaterally- stabilise VC
Origin and insertion of levatores costarum
O: tips of transverse processes of C7 and T1-T11.
I: inferno laterally insert on rib between tubercle and angle of ribs 1-12
Innervation of levator costarum
Posterior rami of C8- T11 spinal nerves
Action of levator costarum
Elevate ribs assisting in respiration, assists with lateral flexion of VC
