Deep Back Flashcards
Which germ layer does the muscular system of the deep back develop from?
Mesoderm
What does each somite differentiate into?
a sclerotomes and a myo - dermatome
What does the myotome region of myo - dermatome region give rise to in the deep back?
myoblast cells (embryonic muscle cells)
What do the myoblast cells (embryonic muscle cells) in the deep back form?
muscles of the trunk
What are the two divisions that the myotomes divide into?
epaxial (dorsal) division
hypaxial (ventral) division
WHICH nerves supply the epaxial division muscles?
DORSAL primary rami of spinal nerves
WHICH nerves supply the hypaxial division muscles?
VENTRAL primary rami of spinal nerves
Even though most of the myoblasts migrate away from their specific myotome level of origin, what do they always maintain from that segment?
their original nerve supply
What muscles are derived from the epaxial division?
deep extensor muscles of the back
What muscles are derived from the hypaxial division?
Infrahyoid
Flexor muscles of vertebral column
Quadratus lumborum
Originally, these muscles have a segmental arrangement and only extend from one vertebra (segment) to the next
Muscles of the deep back
As a group, these muscles extend from the skull (cranium) to the pelvis covered by the deep fascia
Muscles of the deep back
During development, fusion between adjacent segments takes place to form larger muscle masses covering more than one segment (in this muscle group)
Muscles of the deep back
Sequential splitting of muscles takes place later to form different superimposed layers in this muscle group.
Muscles of the deep back
In this muscle group, because the origins and insertions of different muscles overlap, the entire vertebral column moves smoothly during flexion, extension, and rotation.
Muscles of the deep back
In the muscles of the deep back, the entire vertebral column moves smoothly during flexion, extension, and rotation because the origins and insertions of different muscles do what?
overlap
The deep back muscles produce various movements (extension, flexion, rotation) of the back and act to maintain what two qualities of the erectly standing or sitting human?
posture and balance
What various movements do the muscles of the deep back produce?
flexion, extension, and rotation
Since most of the body weight is anterior to the vertebral column, many deep back muscles function to support the body weight be doing what?
extending the vertebral column
The transvers and spinous processes of the vertebrae proved places for what?
attachment of the muscles
THE INTRINSIC back muscles are the only muscles of the body innervated by this.
DORSAL primary rami of spinal nerves
Why do deep back muscles cross more than one segment of the vertebral column and are innervated by more than one spinal cord level?
Because many of the deep back muscles are very long
What do the majority of deep back muscles have multiple of?
origins and insertions
What are back strains the result of?
microscopic tearing of muscle cells or ligaments from extensive extension and rotation.
Which muscles of the back are mainly involved in extension of the spine?
intrinsic muscles of the back
How much of the back do the intrinsic muscles of the back span?
the entire back from the skull to the sacrum
How are the intrinsic muscles of the back often grouped?
according to the direction of muscle fibers and length of muscle bundles
WHAT are the four groups of the intrinsic back muscles?
Splenius group
Erector spinae group
Transversospinalis group
Suboccipital group
WHICH intrinsic back muscle group’s muscles arise from the posterior midline of the back and proceed laterally and superiorly to their insertion
Splenius group
WHICH intrinsic back muscle group’s muscles arise from the posterior midline of the back, or more laterally, and run up longitudinally?
Erector spinae group
WHICH intrinsic back muscle group’s muscles arise laterally but travel toward the midline to their insertion?
Transversospinalis group
WHICH intrinsic back muscle group’s muscles are responsible for movement of the head and neck only? (they do not follow the pattern of the other intrinsic back muscles)
Suboccipital muscles
Which groups of intrinsic back muscles are found in the back of the neck and mainly assist with head movements?
Splenius group
Suboccipital group
What are the three well-defined layers in which the intrinsic back muscle groups are arranged?
Superficial layer
Intermediate layer
Deep layer
What muscles does the superficial layer of the intrinsic back muscles include?
all three subgroups of erector spinae and splenius muscles
What muscles does the intermediate layer of the intrinsic back muscles include?
two parts of Transversospinalis: Semispinalis and Multifidus
What muscles are involved in the deep layer of the intrinsic back muscles?
Segmental muscles and Suboccipital muscles
Which back muscle group contains the most superficial intrinsic muscles of the posterior part of the neck?
Splenius group
What does the word "splenius" refer to?
a Band-Aid like structure
Which muscle group represents a bandage around the neck?
Splenius group
Which intrinsic back muscle group’s muscle fibers arise from the midline and run superiorly and laterally?
Splenius group
How many muscles are in the Splenius group?
2
Which muscle of the Splenius group is a broad flat muscle of the neck?
splenius capitis
Which muscle of the Splenius group is partly covered by the trapezius and the sternocleidomastoid?
splenius capitis
Which is the upper and larger of the two splenius muscles?
splenius capitis
Which muscle’s fibers proceed superiolaterally from their origin (ligamentum nuchae, spines of upper thoracic vertebrae) to attach to the skull (occipital bone, mastoid process)
splenius capitis
What is the narrow muscle located below and parallel to the splenius capitis?
splenius cervicis
Which muscle from the splenius group has fibers that 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)
splenius cervicis
Which of the splenius muscles has no muscles that attach to the skull?
splenius cervicis
What is another name for the Erector spinae group?
Sacrospinalis
What is the largest muscle mass of the back?
Erector spinae group (Sacrospinalis)
Which group of intrinsic back muscles forms a prominent bulge on each side of the lower part of the vertebral column between the spinous process and the angle of ribs?
Erector spinae group (Sacrospinalis)
Which group of intrinsic back muscles takes its origin from a very extensive <b>common tendon of origin</b>?
Erector spinae group (Sacrospinalis)
What is the common tendon of origin attached to?
Sacrum
Iliac crest
Spinous process of lumbar and last to thoracic vertebrae
Which group of intrinsic back muscles is the chief extensor of the vertebral column?
Erector spinae group (Sacrospinalis)
In the lumbar region, what 3 vertical columns does the erector spinae group (sacrospinalis) divide into?
Iliocostalis
Longissimus
Spinalis
Each vertical column (iliocostalis, longissimus, and spinalis) divide into 3 parts according to its what?
superior attachments
The muscle of each part (iliocostalis, longissimus, and spinalis) is made up of what in order to provide smooth controlled action?
overlapping short muscle fibers
Associated with the ribs, the iliocostalis has what three parts?
Iliocostalis lumborum
Iliocostalis thoracis
Iliocostalis cervicis
Which part of the iliocostalis goes from common tendon to ribs 6 - 12?
iliocostalis lumborum
Which part of the iliocostalis goes from the lower 6 ribs to the upper 6 ribs?
iliocostalis thoracis
Which part of the iliocostalis goes from ribs 3 - 6 to the transverse process of C4 - C6
iliocostalis cervicis
Which vertical column of the lumbar region is the most lateral column of the erector spinae group?
Iliocostalis
All 3 parts of which vertical column of the lumbar region have their origin and/or insertion on the ribs?
Iliocostalis
Which vertical column muscle of the lumbar region is associated with the transverse processes of vertebrae?
Longissimus
Which part of the Longissimus is the longest part?
Longissimus thoracis
Where does the longissimus thoracis go from and to?
common tendon to lower 9 ribs
Which part of the longissimus goes from the transverse process of T1 - T5 to transverse process of C2 - C6?
Longissimus cervicis
Which part of the longissimus goes from the tendon of insertion of longissimus cervicis to the mastoid process?
Longissimus capitis
Which vertical column of the erector spinae group is the intermediate division?
Longissimus
What is the lowest section in the longissimus?
longissimus thoraces (there is no lumborum part)
The lower part of which muscle blends with iliocostalis lumborum?
Longissimus
What is the most medial and smallest division of erector spinae?
Spinalis
Which division of the erector spinae is poorly developed in most individuals?
Spinalis
In a well developed individual, what part of the erector spinae extends from the thorax to the skull and contains a thoracic, cervical, and lumbar segment?
Spinalis
Usually, only the thoracic part of this division of the erector spinae is present
Spinalis
What part of the erector spinae lies medially to the longissimus thoracis
Spinalis
What part of the erector spinae extends from the spinous processes of lumbar vertebrae to the spinous processes of upper thoracic vertebrae?
Spinalis
Bilaterally, what is the action of the erector spinae group?
extend the head and vertebral column
Unilaterally, what is the action of the erector spinae group?
flex the head and vertebral column
What is the <b>chief</b> extensor of the vertebral column?
erector spinae
Which muscle group lies deeper to but is shorter than the erector spinae group?
Transversospinalis muscle group
Which group of intrinsic back muscles slants inward from origin to insertion?
Transversospinalis muscle group
Which group of intrinsic back muscles consist of these three muscle masses?: Semispinalis, Multifidus, Segmental muscles?
Transversospinalis muscle group
What three muscle masses does the Transversospinalis muscle group consist of?
Semispinalis
Multifidus
Segmental muscles
Which group of intrinsic back muscles originates from transverse processes and proceeds to spinous processes of more superiorly located vertebrae?
Transversospinalis muscle group
The Semispinalis muscle mass of the Transversospinalis muscle group consists of what three subdivisions?
Semispinalis thoracis
Semispinalis cervicis
Semispinalis capitis
What is the highest level of insertion of the Semispinalis cervicis?
C2 spine
Where does the Semispinalis capitis insert?
the occipital bone
How are the muscles arranged in the Semispinalis muscle mass?
longitudinally, like the erector spinae group
About how many vertebrae do the muscle fibers of Semispinalis span over?
4 to 6
Where is the Semispinalis group lacking?
lumbar region
Which muscle mass of the Transversospinalis group lies superficial to the Multifidus?
Semispinalis
Which muscle mass of the Transversospinalis group lies deeper to the Semispinalis?
Multifidus
Which muscle mass is the thickest in lumbar area?
Multifidus
Which muscle mass of the Transversospinalis group is present throughout the back?
Multifidus
Which muscle mass of the Transversospinalis group has its muscle fibers going from transverse to spinous processes?
Multifidus
In the Transversospinalis group, which muscle mass’s individual segments are not known by separate names?
Multifidus
Where does the Multifidus muscle mass end?
In the cervical region
The different parts are not usually distinct in this muscle mass of the Transversospinalis group
Multifidus
The sacral and lumbar areas of this muscles mass is covered by erector spinae
Multifidus
In the thoracic and cervical regions, this muscle mass is covered by Semispinalis
Multifidus
How many vertebrae do the muscle fibers of Multifidus cover?
2 - 4
What muscle mass is the deepest part of the Transversospinalis group?
Segmental muscles
What muscle mass is better developed in the cervical and lumbar regions?
Segmental muscles
What muscle mass lies deep to the Multifidus?
Segmental muscles
What are the three sets of segmental muscles?
Interspinalis
Intertransversarii
Rotatores
Which set/s of segmental muscles is/are well developed in cervical and lumbar regions?
Interspinalis and Intertransversarii
Which set of segmental muscles are separated by interspinous ligaments?
Interspinalis
Which set of segmental muscles stretch between adjacent spinous processes from C2 to T1?
Interspinalis
Which set of segmental muscles is/are lacking in thoracic region?
Interspinalis and Intertransversarii
Which set of segmental muscles run vertically between adjacent transvers processes?
Intertransversarii
Which set of segmental muscles have a single origin and a single insertion unlike most other back muscles?
Rotatores
How many vertebrae do Rotatores span?
one or two
Where are Rotatores best developed?
thoracic region
What are the two sets of rotatores?
Long rotatores (Longus) Short rotatores (Brevis)
Where are long rotatores found?
lumbar, thoracic, and cervical areas
Where are short rotatores found?
lumbar, thoracic, and cervical areas
Which rotatores skip a vertebra?
long rotatores (Longus)
Which rotatores attach to the vertebra above (do not skip a vertebra)?
short rotatores (Brevis)
This muscle group connects the skull to the atlas and axis
Suboccipital muscles
This muscle group has two obliquely oriented and two straight muscles
Suboccipital muscles
What are the four muscles in the Suboccipital muscle group?
Oblique capitis inferior
Oblique capitis superior
Rectus capitis posterior major
Rectus capitis posterior minor
The oblique capitis inferior, oblique capitis superior, and rectus capitis posterior describe which triangle?
the suboccipital triangle
which suboccipital muscle is a part of the suboccipital muscle group but does not form a boundary of the suboccipital triangle?
rectus capitis
What artery originates at the base of the neck from the subclavian artery and passes superiorly through the transverse foramina of cervical vertebrae. It enters the suboccipital triangle and by coursing across the floor of the triangle enters the skull though the foramen magnum.
vertebral artery
What is the nerve supply to ALL FOUR suboccipital muscles?
the dorsal ramus of C1 (suboccipital) nerve
What nerve emerges from below the oblique capitis inferior muscle (outside the suboccipital triangle)?
the greater occipital nerve (dorsal ramus of C2)
What nerve crosses the oblique capitis inferior muscle and travels obliquely across the suboccipital triangle to the back of the skull?
the greater occipital nerve (dorsal ramus of C2)
The greater occipital nerve (dorsal ramus of C2) is what kind of nerve to the posterior part of the scalp?
sensory
Does the greater occipital nerve (dorsal ramus of C2) provide innervation to any of the muscles of the suboccipital triangle?
no
What is the action of the deep back muscles?
No individual discrete action for any of the deep back muscles.
They function together as large groups because the origins and insertions of the muscle fibers overlap.
What are the movements of the vertebral column?
Flexion
Extension
Lateral flexion (from side to side)
Rotation (same side or opposite side)
Anterior trunk muscles + gravity are involved in which type of vertebral column movement?
Flexion
In which of the vertebral column movements do back muscles act as antagonistic – relaxing gradually to produce a smooth movement?
Flexion
Which deep back muscles are involved in extension?
All deep back muscles EXCEPT Intertransversarii
Which group of back muscles acts as the chief extensor muscle?
erector spinae
In what vertebral column movement are the Intertransversarii involved?
lateral flexion
Which muscles rotate the head to the same side and laterally flex the neck?
splenius capitis and splenius cervicis
Which muscle group initiates lateral flexion unilaterally?
erector spinae
How do muscles on the opposite side of the flexing side of the neck control lateral flexion?
by relaxing gradually
Which back muscles rotate the trunk to the opposite side?
Multifidi, Rotatores, and Semispinalis
Which back muscles extend the trunk and help to rotate it to the same side?
Splenius muscles and the Erector spinae
Which muscles rotate the atlas and turn the face to the same side?
oblique capitis inferior and rectus capitis posterior major and minor muscles
Which muscles extend the head bilaterally and flex it to the same side unilaterally?
the oblique capitis superior and rectus capitis posterior major and minor muscles
Which of the following muscles are derived from the epaxial division?
A. Infrahyoid B. Flexor muscles of the back C. Deep extensor muscles of the back D. Quadratus lumborum E. B and C
C. Deep extensor muscles of the back
The fibers of the following muscle/muscle groups proceed superiorly and medially:
A. Erector spinae B. Rotators C. Transversospinalis D. Splenius E. B and C
E. Rotators AND Transversospinalis
What muscle represents the lateral division of sacrospinalis?
A. Iliocostalis
B. Longissimus capitis
C. Longissimus cervicis
D. Spinalis
A. Iliocostalis
Which of the following muscles is/are attached at the mastoid process?
A. Splenius capitis B. Longissimus thoracis C. Longissimus capitis D. Semispinalis capitis E. A and C
E. Splenius capitis AND Longissimus capitis
