Layer 6 Back Muscles Flashcards
Which muscles are in the 6th layer of the back?
Semispinalis group, multifidus muscle, rotatores longus and brevis muscles
Which muscles are in the semispinalis group?
Semispinalis thoracis, cervicis and capitis
Extend 5 or more spinal segments
What is the origin of semispinalis thoracis?
TP T6-12
What is the insertion site for semispinalis thoracis?
Spinous processes C6-T4
What is the action of semispinalis thoracis?
Extend spine and rotate spine away
What is the innervation of this entire group?
Posterior rami
What is the origin of semispinalis cervicis?
TP T1-6
What is the insertion site for semispinalis cervicis?
Spinous processes C2-5
What is the action of semispinalis cervicis?
Extend spine and rotate spine away
What is the origin of semispinalis capitis?
TP C7-T6, articular processes C4-6
What is the insertion of semispinalis capitis?
Between superior and inferior nuchal lines of the occipital bone
What is the action of semispinalis capitis?
Extend head and rotate face away
The multifidus muscle extends to how many spinal segments?
3 or 4
Best developed in lumbar region
What is the origin of the multifidus muscle?
Mamillary processes of lumbar vertebra, TP of thoracic vertebra and articular processes of C4-7
What is the insertion for the multifidus muscle?
Spinous processes three numeric segments superior, does not insert onto the atlas
What is the action of the multifidus muscle?
Extend the spine, rotate the spine away
What is the origin of both rotatores longus and brevis muscle’s?
Transverse processes
What is the insertion for rotatores longus muscle?
Roots of spinous processes 2 numeric segments superior
What is the insertion for rotatores brevis?
Roots of spinous processes 1 numeric segment superior
What is the action of both rotatores longus and brevis muscles?
Extend spine, rotate the spine away (primarily propioceptive)
