Which muscles are identified as transversospinalis muscles?
- semispinalis
- multifidis
- rotators
Transversospinalis muscles represent what layer of the true back?
layer 5
Based on the name of this group, what is the origin-insertion of the transversospinalis?
- transverse process origin
- spinous process insertion
How many vertebrae can be attached to a single segment by transversospinalis muscles?
as many as nine vertebrae
What muscles are classically identified as semispinalis muscles?
- semispinalis thoracis
- semispinalis cervicis
- semispinalis capitis
What osseous parts of the vertebral column serve as an origin to the semispinalis thoracis?
transverse tubercles of T6-T10 or as low as T12
What segment will represent the lowest attachment site for the semispinalis thoracis?
T12
What is the insertion for the semispinalis thoracis?
spinous processes of C6-C6 and T1-T4
Contraction of the semispinalis thoracis will result in what movements?
- extension, lateral flexion, and rotation of upper thoracic and lower cervical spine
- bilaterally they act to extend the thoracic spine
What is the innervation of the semispinalis thoracis?
dorsal rami of T1-T6 spinal nerves (cord levels T1-T6)
What osseous parts of the vertebral column serve as an origin to the semispinalis cervicis?
- transverse tubercles of T1-T5 or T6
- articular processes of C4-C7
What is the insertion for the semispinalis cervicis?
spinous processes of C2-C5
Contraction of the semispinalis cervicis will result in what movements?
- extension, lateral flexion, and rotation of the cervical spine
- bilaterally they act to extend the neck
What is the innervation of the semispinalis cervicis?
dorsal rami of C6-C8 spinal nerves (cord levels C6-C8)
What osseous parts of the vertebral column serve as an origin to the semispinalis capitis?
- transverse tubercles of C7, T1-T6 or T7
- articular processes of C4-C6
What is the insertion for the semispinalis capitis?
below the superior nuchal line of occipital bone
Contraction of the semispinalis capitis will result in what movements?
- turns the face to the ipsilateral side of rotation
- bilaterally they act to extend the head (the neck inadvertently)
What is the innervation of the semispinalis capitis?
dorsal rami of C1-C6 spinal nerves (cord levels C1-C6)
The semispinalis capitis and spinalis capitis may fuse to form what muscle?
biventer cervicis
What regional subdivisions are now identified with the multifidis muscles? What are their Latin names?
- lumbar multifidis - multifidis lumborum
- thoracic multifidis - multifidis thoracis
- cervical multifidis - multifidis cervicis
What osseous parts of the vertebral column serve as an origin to the classic multifidis?
- articular process of C4-C7
- transverse processes of T1-T12
- mammillary processes of L1-L5
- dorsal surface of S1-S4 or S5
What non-vertebral column site serves as an origin to the classic multifidis?
posterior superior iliac spine (PSIS) of the innominate bone
What is the insertion for the classic multifidis?
spinous process of 3-5 segements above the origin
What transversospinalis muscle attaches to articular and mammillary processes along the spine?
multifidis
Contraction of the classic multifidis will result in what movements of the vertebral column?
- lateral flexion and rotation of the spine
- maintains the lumbar lordotic curve
- prevents entrapment of zygapophyseal capsular ligament during movement
What is the innervation of the classic multifidis?
dorsla rami of C3-C8, T1-T12, L1-L5 and S1 spinal nerves (cord levels C3-C8, T1-T12, L1-L5, and S1)
What osseous parts of the vertebral column serve as an origin to the multifidis cervicis?
articular process of C4-C7
What is the attachment site and most cranial vertebra of insertion for the multifidis?
spinous process of C2
Contraction of multfifidis cervicis will result in what movements?
- alters the zygapophyseal capsular ligament response to load distribution
- determines the cervical spine response to injury as evidenced by neck pain
- a significant contributor to postural control of the head and neck
What osseous parts of the vertebral column serve as an origin to the multifidis lumborum?
spinous processes of L1-L5
What is the insertion for multifidis lumborum?
mammillary process and zygapophyseal capsular ligaments and dorsal surface of S1-S4 or S5
Which subdivision of multifidis may demonstrate a reversal of origin-insertion?
multifidis lumborum
Contraction of multfifidis lumborum will result in what movements?
- lateral flexion and rotation of the lumbar spine
- maintains the lumbar lordotic curve
- prevents entrapment of lumbar zygapophyseal capsular ligament during movement
The thoracic rotators are replaced in the lumbar spine by what muscles?
deep laminar fibers of the multifidis
What is characteristic of multifidis innervation?
all fascicles attaching to a specific spinous process are innervated by the nerve of that segement
- example: the L2 spinal nerve terminates on fascicles attaching to the L2 spinous process
Which muscles of the spine exhibit a reversal of the expected origin-insertion combination?
- iliocostalis lumborum pars lumborum
- longissimus thoracis pars lumborum
- multifidis lumborum
Rotator muscles are typically identified in what region of the spine?
thoracic region
What will replace muscles spanning one or two segmental levels in the cervicals and lumbars?
deep layers of the multifidis
What is the classic origin of rotator brevis or its homolog?
transverse processes from C3 and each lower vertebra to the dorsal surface of sacrum (C3-C7, T1-T12, L1-L5, sacrum)
What is the classic insertion of rotator brevis or its homolog?
spinous process one segmental level above, from C2-C7, T1-T12, L1-L5
Where does the rotator brevis originating at C3 insert?
the spinous process of C2
What muscle connects a transverse process to the spinous process of the segment above?
rotator brevis
Contraction of rotator brevis will result in what movements?
- rotation of the segment of insertion
- bilaterally acts to weakly extend spine
What is the classic origin of rotator longus or its homolog?
transverse processes from C4 and each lower vertebra to the dorsal surface of sacrum
What is the classic insertion of rotator longus or its homolog?
spinous process two segmental levels above, from C2-C7, T1-T12, L1-L5
What muscle connects a transverse process to the spinous process two segments above?
rotator longus
Contraction of rotator longus will result in what movements?
- rotation of the segment of insertion
- bilaterally acts to weakly extend spine
What innervates the rotators?
dorsal rami at the level of insertion