Anatomy of Spinal Column Flashcards
Function of spinal column
protect spinal cord and nerves support weight of body rigid/flexible axis for body pivot for head posture and locomotion
What is the spinal column composed of
Cervical Thoracic Lumbar Sacral Coccygeal
How many cervical vertebrae
7
How many thoracic vertebrae
12
How many lumbar vertebrae
5
How many sacral vertebrae
5 (Fused)
How many coccygeal bones
4 (variable) fused
How many Vertebrae total in human
33
How do some anatomist describe the spinal column
26 separate bones (24 movable + sacrum +coccyx)
Why are spinal curves good
Better ability to withstand stress
What are the primary curvatures
- thoracic kyphosis
- sacral kyphosis
Convex posterioly
What are the secondary curvatures
- cervical lordosis
- lumbar lordosis
Convex anteriorly
When and why are secondary curves developed
Developed later in life due to our posture
Which come first, cervical or lumbar lordosis
Cervical
What are the features of a TYPICAL vertebrae
- body
- pedicles
- laminae
- vertebral/neural arch
- vertebral foramen (spinal canal)
- spinous process
- transverse process
- superior + inferior articular process
- superior + inferior vertebral notches
- intervertebral foramen (between 2 vertebrae)
What are the regional characteristics of a typical cervical vertebrae
- bifid spinous process
- presence of the transverse process foramina
- anterior + posterior tubercles on TP
- Large V. foramen
- uncinate process (uncus) (upper body)
Why do cervical vertebrae exhibit several different directions of movement?
articular processes and position of articular facets of cervical vertebra are closest to the transverse anatomical plane
What are the atypical cervical vetebrae
Atlas (C1)
Axix (C2)
vertebra prominens (C7)
What are the characteristics of C1
anterior arch
posterior arch
anterior and posterior tubercles on TP
lateral masses
superior articular surfaces (condyles) make joint with occipital bone
articular surface for dens on anterior arch
groove for vertebral artery
What are the characteristics of C2
Dens axis (odontoid process) two facets on dens axis: anterior- joint between dens and anterior arch of atlas posterior: transverse ligament of axis
What makes C7 different
longest spinous process which is easily palpated on the posterior surface of neck
What group of THORACIC vertebrae are the most typical
T5-T8
What are the characteristics of a typical THORACIC vertebrae
- large heart shaped Vertebral body
- long/point spinous process
- circular VF
- TP easily palpable
- facet joints are directed downward
- Costal facets- two half facets on body (ribs) ; one whole facet on TP (ribs)
What movement is generally seen in thoracic vertebrae
rotation
some extension/flexion
What at the ATYPICAL thoracic Vertebrae
T1, T10, T11, T12
What are the characteristics of T1
- body- one full facet for the 1st rib, two 1/2 facet for head of Rib2
- TP has full facet for Rib1
What are the characteristics of T10
- one 1/2 facet on superior margin of vertebral body
- TP may/maynot have the facet for Rib10
What are the characteristics of T11 & T12
- Each has full facet on body for ribs 11 + 12
- lack facets on TP
- Spinous process- short and rectangular ( more lumbar)
What are the characteristics of a Lumbar vertebrae
- largest vertebral bodies (kidney shaped)
- short
- regtangular and horizonatlly oriented spinous process
- two additional processes : mammillary and accessory
- facet joints are directed medially and vertically
- no costal facets
What are the position and orientation of facets on articular processes
approx the sagittal plane
What is the principle movement allowed by the sagittal plane?
flexion/extension
some lateral flexion
no rotation
Atypical LUMBAR verterbea
L5
What are the characteristics of L5
Wedge shaped body, which is thicker anteriorly than posteriorly
Why is the body of L5 wedge shaped
to accomodate the transition of lumbar spin to sacrum (which is nearly horizontal)
What are the characteristics of the PELVIC surface of sacrum
- transverse lines
- sacral pelvic foramina
- base of the sacrum
- apex
- ala
What are the characteristics of the DORSAL surface of the sacrum
- dorsal sacral foramina
- medial, intermediat and lateral sacral crests
- sacral canal as continuation of spinal canal
- sacral hiatus
- sacral conua
- auricular surface
- sacral tuberosity
What is in the sacral canal
spinal sacral nerves
What is the auricular surface of the sacrum for
sacro-iliac joint
what is the sacral tuberosity for?
attachment of ligaments that reingorce the sacro-iliac joint
What is the coccyx composed of?
4 coccygeal segments
coccygeal cornua
What are the two types of ossification centers?
primary and secondary
How many osssification centers are on the vertebrae
8
Where are the ossification centers located
Primary: on the body, on the pedicles
secondary: Transverse process, spinous process, and the superior and inferior surface of the body
How would one write out LUMBARIZATION
7C + 12T + 5L + 1S + S(4) + Co
How would one write out SACRALIZATION
7C + 12T + 4L + L5 on S + S + Co
What is LUMBARIZATION
when an extra sacral bone is fused to lumbar instead of sacrum
How many intervertebral discs are there
23
What is an anterior intervertebral joint
joints between bodies of adjoining vertebrae
What is an intervertebral disc made of
nucleus pulposus
annylus fibrosus
What is a nucleus pulposus
gelatinous central core of disc, attracts water
highly elastic
What is a annulus fibrosus
an external ring of fibrous tissue
What sections of the spine dont have an intervertebral disc?
occipital bone-axis
atlas-axis
What are the functions of the intervertebral disc
resistance to compression
connection between vertebral bodies
What are the steps in an intervertebral disc herniation
protrusion
prolaps
extrusion (sequestration of extruded discs)
Describe the anterior longitudinal ligament
wider than posterior long. ligament
attached to anterior surface of Vertebral body
resists extensions of spinal column
maintain joint stability
describe the posterior longitudina ligament
narrow, band-like within the spinal column
attached to posterior surface of vertebral bodies
prevent posterior protrusion of nucleus pulposis of disc
resists flexion of spinal column
What are posterior intervertebral joints
joints between superior and inferior articular processes between adjoining vertebrae
What type of movement is allowed in the cervical spine
flexion/extension
lateral flexion (side bending)
rotation
What type of movement is allowed in the Thoracic spine
rotation
limited flexion/extension
What type of movement is allowed in the lumbar spine
flexion /extension
lateral flexion
What are the four ligaments of the posterior intervertebral joints
Ligamentum flavum
Interspinous ligament
Intertransversarii ligaments
Supraspinous ligaments
What happens to the supraspinous and interspinous ligaments superior to C7?
Merge fibers, then follow nuchal ligament to occipital bone
What are the important characteristics of the occipital bone
basilar portion (squama) foramen magnum codyles of the occipital bone external occipital protuberance superior and inferior nuchal lines
Where is the atlanto-occipital joint? And what movement does it allow
between the occipital bone and atlas
permits flexion/extension
Where is the atlanto axial joint? and what movement does it allow
between the atlas and axis
allows rotation
What is the tectorial membrane
upward continuation of posterior longitudinal ligament, superior to C2
What is the Cruciate ligament
composed of two individual bands; Transverse ligament, attached to atlas,
superior/inferior band attach to the margin of Foramen Magnum and to posterior surface of C2
what is the alar ligament
dens to lateral margin of foramen magnum
what is the apical ligaments
dens axis to foramen magnum
What are the tree groups if intrinsic muscle of the spinal cord
- spinotransverse
- sacrospinalis
- transversospinalis
Where is the spinotransverse located
superficially
where is the sacrospinalis located
middle
where is the transversospinalis located
deep
Where do the fibers in the spinotransverse group run
fibers run from spinous process to the transverse process
What muscle(s) are in the spinotransverse group
Splenius capitis
Splenius cervicis
What is the O and I of Splenius capitis
O: Spinous process of C7-T4 and ligamentm nuchae
I: lateral third of the superior nuchal line and mastoid process
What is the O and I of the Splenius cervicis
O: spinous process of T3 to T6 vertebrae
I: posterior tuberles of TVPs of vertebrae C1-C4