Extrinsic muscles of the back
associated with the ribs or upper limbs superficially, not true back muscles
Intrinsic back muscles
deep and involved with axial skeleton
Intrinsic back muscle properties
- Action-move spine
- Location-hollow space b/w vertebral spinous processes and angles of ribs
- They are contained in a tube of fascia which extends whole vert column
- In the neck- called prevertebral fascia
- Inferior to the neck- called thoraco-lumbar fascia
Intrinsic back muscle nerve supply
dorsal rami of spinal nerves
Muscle which runs form cervical and thoracic spinous processes to upper ribs and can pull these ribs upward
Serratus posterior superior
Muscles which runs from thoracic and lumbar spinous processes to lower ribs, and can pull these ribs downward
Serratus posterior inferior
Intrinsic back muscle which passes from one spine to the next and assist in extending the vertebral column
Two most basic movements of the skeleton
flexion and extension
- flexion=fetal position
- extension=opposite direction
Intrinsic back muscle which passes from one transverse process tothe next and assist in laterally flexing the vertebral column
Intrinsic back muscle which passes from transverse processes to ribs and assist in elevation of the ribs during respiration and lateral flexion of the vertebral column
levatores costarum mm.
What is proprioception?
sensing force and position, allow stabilization; this is the function of the intrinsic back muscles
What is the transversospinalis?
Group of mm which run from transverse to spinous processes
Name the transversospinalis
- rotatores-attach inferiorly on transverse processes and superiorly on spinous processes (pass 1-2 intervert spaces)
- multifidus- attach same as above, extended over more invert spaces, more prominent on lower spine
- semispinalis-attach same as above, superior half of vert column, span more spaces (4-6), IMPORTANT in holding head up and neck straight
Name the two parts of the semispinalis
Semispinalis capitis-connects b/w transverse processes of upper thoracic vert and skull
Semispinalis cervicis- inferiror attachments are on cervical and thoracic tranverse processes
Name the muscles in the Erector spiane (also called sacrospinalis)
iliocostalis- most lateral fibers, attaches superiorly to transverse processes and the angles of the ribs
longissimus (the longest)- extends all the way to the skull
spinalis- most medial, attaching superiorly and inferiorly on spinous processes
Muscle which attaches spines of vert T6 and higher to the skull or to transverse processes of upper cervial vert. Acting bilaterally they extend the head and end, unilaterally they head/neck to the side
Splenius capitis et cervicis
ventral root carry?
motor (efferent) signals
Dorsal root carry only
sensory (afferent) signals
rami of spinal nerves carry
both sensory and motor
Describe signal transmission in somatic nervous system
- 1)signal travels dorsol root-
- 2)in gray matter of the cord synaptic transmission conveys the stim to a motor (efferent) nerve cell in ventral horn of g-matter
- 3)signal passes through ventral root to skeletal
- *Brain intervention is not necessary
segment of skin recieving branches from one parin of spinal nerves is called
dermatome- remember spinal nerves overlap in these areas
Number of pairs of spinal nerves
Cervical spinal nerves emerge
above the number of the same vert; e.g. C1 emerges above C1(atlas) and skull except C8 emerges below C7 and above T1
- Remember- each thoracic, lumbar, and sacral nerve pass through the intervert formamen below the vert the the same number
- Remmeber- there are no intervert foramen below the last sacral vert, so S5 and Co1 pass through the sacral hiatus
What is the posterior ramus of C1 called?
suboccipital nerve- emerges in the center of the triangle and supplies the 3 muscles that form the suboccipital triangle, plus the rectus capitis minor m
What is the posterior ramus of C2 called?
greater occipital nerve- it passes throgh the superificial aspect of the suboccipital triangel en route to the skin on the back of the head.
Waht is a spinal cord segment?
is that part of the cord that gives rise to a particular spinal nerve (so there are 31 segments in the cord, numbered like the nerves), but the spinal cord level does not equal vertebral level