Deep Back Flashcards
What are the functions of deep back muscles?
- maintain posture and balance (majority of the weight is anterior so these muscles prevent us from falling forward)
- flexion, extension, rotation of the back
What allows for the entire vertebral column to move smoothly during flexion, extension and rotation?
due to the origins and insertions of different muscles overlapping
What intrinsic muscles are in the superficial layer?
all three subgroups of erector spinae and splenius muscles
What intrinsic muscles are in the intermediate layer?
two parts of transversospinalis (semispinalis and multifidus)
What intrinsic muscles are in the deep layer?
segmental muscles and suboccipital muscles
Which intrinsic muscles are the most superficial of the posterior part of the neck?
splenius group
- bandage wrapped around the neck
- muscle fibers arise from midline and run superiorly and laterally
Which two muscles are in the splenius group?
splenius capitis
spleius cervicis
Name this muscle:
broad flat muscle of the neck, partly covered by trapezius and SCm, upper and larger of the two splenius muscles
Splenius capitis
Name this muscle:
narrow muscle located below and parallel to the splenius capitis, no fibers attach to the skull
Splenius cervicis
How do the muscle fibers of splenius capitis run?
superiolaterally from their origin (ligamentum nuchae, spines of upper thoracic vertebrae) to attach to the skull (occipital bone an mastoid process)
How do the muscle fibers of splenius cervicis run?
extend superiorly and laterally from spinous processes of upper thoracic vertebrae (T3-T6) and insert at the transverse processes of upper cervical vertebrae (C2-C4)
Which intrinsic muscle group has the largest muscle mass of the back?
erector spinae group (sacrospinalis)
What is the common tendon of origin?
attached to sacrum, iliac crest, spinous process of lumbar and last two thoracic vertebrae
What is the origin of erector spinae group?
common tendon of origin
In which region does the erector spinae group divide into 3 groups?
lumbar region
Which 3 groups do erector spinae group divide into?
1) iliocostalis
2) longissimus
3) spinalis
(I Love Spaghetti)
What are the three parts to iliocostalis of the erector spinae group?
1) iliocostalis lumborum
2) iliocostalis thoracis
3) iliocostalis cervicis
What are the attachments of iliocostalis lumborum?
common tendon to ribs 6-12
What are the attachments of iliocostalis thoracis?
lower 6 ribs to upper 6 ribs
What are the attachments of iliocostalis cervicis?
ribs 3-6 to transverse process of C4-C6
What are the three parts to longissimus of the erector spinae group?
1) longissimus thoracis
2) longissimus cervicis
3) longissimus capitis
What are the attachments of the longissimus thoracis?
common tendon to lower 9 ribs
*largest part of the three longissimus
What are the attachments of the longissimus cervicis?
transverse process of T1-T5 to transverse process of C2-C6
What are the attachments of the longissimus capitis?
tendon of insertion of longissimus cervicis to mastoid process
Which of the three division of erector spinae group is the intermediate division?
longissimus
Which of the three division of erector spinae group is the most lateral column?
iliocostalis
Which of the three division of erector spinae group is the most medial and smallest division?
spinalis
Briefly describe the spinalis division
- poorly developed, usually only thoracic part is visible
- some who have well developed contain thoracics, cervical and lumbar segments
- extends from spinous processes of lumbar vertebrae to the spinous processes of upper thoracic vertebrae
What is the action of erector spinae group?
- bilaterally extend the head and vertebral column
- unilaterally flex head and vertebral column laterally
- *chief extensor of the vertebral column
Briefly describe transversospinalis muscle group
- lies deeper to the erector spinae group
- shorter than erector spinae
- slant inward from origin to their insertion
- have 3 muscle masses
- originate from transverse processes and proceed to spinous processes of more superiorly located vertebrae
What are the three groups of transversospinalis muscle group?
1) semispinalis
2) multifidus
3) segmental muscles
What are the three parts to semispinalis?
1) semispinalis thoracis
2) semispinalis cervicis (inserts at C2)
3) semispinalis captitis (inserts on occipital bone)
Briefly describe the muscle fibers of semispinalis
- muscle fibers arranged longitudinally like erector spinae group
- muscle fibers span over about 4-6 vertebrae
- lacking lumbar region
- lie superficial to multifidus
Briefly describe mulifidus
- deeper to semispinalis
- thickest in lumbar area, but present throughout the back
- muscle fibers go from transverse to spinous processes
- ends in cervical region
- different parts are not usually distinct
- covered by erector spinae in sacral and lumbar regions
- covered by semispinalis in thoracic and cervical regions
Briefly describe the segmental muscles
- deepest part of the transversospinalis group
- better developed in cervical and lumbar regions
- lie deep to multifidus
What are the three sets of segmental muscles?
1) interspinalis
2) intertransversarii
3) rotators
Briefly describe the interspinalis group
- well developed in cervical and lumbar regions
- muscles are seperated by interspinous ligaments
- stretch between adjacent spinous processes from C2 to T1
- lack thoracic region
Briefly describe the intertransversarii group
- run vertically between adjacent transverse processes
- well developed in cervical and lumbar regions
- lack thoracic region
Briefly describe the rotators
- have single origin and single insertion unlike most other back muscles
- span one or two vertebrae
- best developed in thoracic region
What are the two sets of rotators?
long rotatores (longus) short rotatores (brevis) - both found in lumbar, thoracic, and cervical areas - longus skips a vertebra - brevis does not skip
What muscles connects the skull to the atlas and axis?
suboccipital muscles
What are the suboccipital muscles?
1) oblique capitis inferior
2) oblique capitis superior
3) rectus capitis posterior major
4) rectus capitis posterior minor
Which of the four suboccipital muscles does not lie within the suboccipital triangle?
rectus capitis posterior minor
Which artery can be seen in the suboccipital triangle?
vertebral artery can be seen coursing across the floor of the triangle entering the skull through the foramen magnum
What is the nerve supply to suboccipital muscles?
all fours muscles are innervated by the dorsal ramus of C1 (suboccipital) nerve
What is the dorsal ramus of C2 also known as? What is its significance in this triangle
greater occipital nerve
- no significance, does not provide innervation to any of the muscles, it just passes through to innervate the scalp
What are the movements of the vertebral column?
1) flexion
2) extension
3) lateral flexion (side to side)
4) rotation
How do the back muscles work to flex vertebral column?
- anterior trunk muscles, helped by gravity
- they act as antagonists, relax gradually to produce a smooth movement
How do the back muscles work to extend the vertebral column?
all deep back muscles except intertransversarii
- erector spinae acts as the chief extensor muscle
How do the back muscles work to lateral flex vertebral column?
- intertransversarii
- splenius capitis and cervicis rotate the head to the same side and laterally flex the neck
- erector spinae initiates lateral flexion unilaterally
- all muscles on the opposite side control flexion by relaxing gradually
How do the back muscles work to rotate the vertebral column?
- multifidi, rotatores, semispinalis muscles rotate trunk to opposite side
- splenius muscles and erector spinae extend the trunk and help to rotate it to the same side
Which muscles rotate the atlas and turn the face to the same side?
oblique capitis inferior and rectus capitits posterior major and minor
Which muscles extend the head bilaterally and flex it to the same side unilaterally?
oblique capitis superior and rectus capitis posterior major and minor
