DEEP BACK ANATOMY EXAM ACTUAL QUESTIONS AND
ANSWERS WITH COMPLETE SOLUTIONS VERIFIED GRADED A++
Describe the action of the Semispinalis, multifidus, and rotatores muscles.
Semispinalis - bilateral contractions extends the thoracic spine, cervical spine, and head
(stabliizes the craniocertebral joints). Unilateral contractions bends the head, cervical
and thoracic spine to the same side and rotates them to the opposite side.
Multifidus - Bilateral contraction extends the spine. Unilateral contraction flexes to the
same side and rotates to the opposite side.
Rotatores Muscles - Bilateral contractions Extends the thoracic spine. Unilateral
contractes rotates it to the opposite side. Also the many spindle finbers suggest this
group of muscles is a strain gauge for the brain to understand the position of the
individual vertebrae.
Describe the two parts of an intervertebral disk and name the function of the
middle one. Also name its functionality.
Anulus fibrosis - is the outer disk that holds together. It is fibrocartilagenous.
Nucleus pulposis - contains a gelatinous center - which acts as a pivotal center for
motion of the vertebral bodies. Allows the interior to maintain constant pressure on all
surfaces while vertebrae are in motion, reducing risk of splitting the anulus fibrosis
, open. (These degenerate as one ages - usually by 70's are replaced by fibrocartilage)
Functions to permit multiple motions of the back. Loses water during the day due to
pressure, also makes one's height decrease during standing hours. NOT shock
absorbers as once thought.
Describe where the Iliocostalis, Longissimus, and Spinalis MM are located
Iliocostalis (most lateral layer; from ilium to ribs) - The lowest part has an origin that is at
the iliac crest and lumbar spinous processes and inserts itself to the angle of the lowest
6 ribs
The upper parts has origins from the 12th-3rd Ribs and inserts itself on some of the
upper ribs and onto the transverse processess of C4-C6 vertebrae
Longissimus M (middle layer of group; long muscles) - The lowest part starts at iliac
crest and lumbar spinous proccesses and end by attaching to the thoracic transverse
processes. Origins blend with iliocostalis.
The Upper parts start from transverse processes of thoracic vertebrae, end on higher
transverse processes above, with the highest part ending on the mastoid process of the
skull.
Spinalis M. (Most medial layer; along the spines) - Goes from lower to higher spinous
processes. Capitus part ends on posterior portion of skull, just deep to Trapezius M.
Describe where the Rectus capitus poseterior major/minor, & Obliquus capitus
inferior/superior muscles are located.
ANSWERS WITH COMPLETE SOLUTIONS VERIFIED GRADED A++
Describe the action of the Semispinalis, multifidus, and rotatores muscles.
Semispinalis - bilateral contractions extends the thoracic spine, cervical spine, and head
(stabliizes the craniocertebral joints). Unilateral contractions bends the head, cervical
and thoracic spine to the same side and rotates them to the opposite side.
Multifidus - Bilateral contraction extends the spine. Unilateral contraction flexes to the
same side and rotates to the opposite side.
Rotatores Muscles - Bilateral contractions Extends the thoracic spine. Unilateral
contractes rotates it to the opposite side. Also the many spindle finbers suggest this
group of muscles is a strain gauge for the brain to understand the position of the
individual vertebrae.
Describe the two parts of an intervertebral disk and name the function of the
middle one. Also name its functionality.
Anulus fibrosis - is the outer disk that holds together. It is fibrocartilagenous.
Nucleus pulposis - contains a gelatinous center - which acts as a pivotal center for
motion of the vertebral bodies. Allows the interior to maintain constant pressure on all
surfaces while vertebrae are in motion, reducing risk of splitting the anulus fibrosis
, open. (These degenerate as one ages - usually by 70's are replaced by fibrocartilage)
Functions to permit multiple motions of the back. Loses water during the day due to
pressure, also makes one's height decrease during standing hours. NOT shock
absorbers as once thought.
Describe where the Iliocostalis, Longissimus, and Spinalis MM are located
Iliocostalis (most lateral layer; from ilium to ribs) - The lowest part has an origin that is at
the iliac crest and lumbar spinous processes and inserts itself to the angle of the lowest
6 ribs
The upper parts has origins from the 12th-3rd Ribs and inserts itself on some of the
upper ribs and onto the transverse processess of C4-C6 vertebrae
Longissimus M (middle layer of group; long muscles) - The lowest part starts at iliac
crest and lumbar spinous proccesses and end by attaching to the thoracic transverse
processes. Origins blend with iliocostalis.
The Upper parts start from transverse processes of thoracic vertebrae, end on higher
transverse processes above, with the highest part ending on the mastoid process of the
skull.
Spinalis M. (Most medial layer; along the spines) - Goes from lower to higher spinous
processes. Capitus part ends on posterior portion of skull, just deep to Trapezius M.
Describe where the Rectus capitus poseterior major/minor, & Obliquus capitus
inferior/superior muscles are located.
