how many vertebras and IV disks?

Regions of VC

How many sacrum

How many coccyx

Held the smallest functional unit in the spine

Any 2 adjacent vertebrae, intervening IV disk and all the soft tissues that secure them together

Cylindrically shaped vertebral body

Irregularly shaped vertebral/neural arch

Portion of the neural arch that lie anterior to the articular processes on either side and serve as the connection between the posterior elements & vertebral bodies

Short, stout pillars with thick walls

Increase in size from the cervical to lumbar region

Neural arch is divided into

Centrally posterior elements

Region of the lamina wherein force transfers occurs, located between the superior and inferior articular process

Subjected to bending forces that are transmitted from the vertically oriented lamina to the more horizontally oriented pedicles

Pars interarticularis is most developed in what spine

Block of trabecular bone covered by a layer of cortical bone

Vertical plate that constitutes the central portion of the arch posterior to the pedicles

Lateral projections of bone that originate from the lamina

Posterior projection of bone that originates from the central portion of the lamina, dividing into two

Opening bordered by the posterior vertebral body and the nerual arch

Resist compressive loads

Transmit the bending forces from the posterior elements to the vertebral body

Transmit the forces from the articulat, transverse and spinous process to the pedicle

Serve as muscle attachments and provide mechanical lever

Serve ad muscle attachment and provides mechanical lever; may also serve as a bony block to motion

Combined with all segments, forms a passage and protection for the spinal cord

Separates two vertebral bodies

Transmit load from one vertebral body to the next

IV disk make up for 20-35% of tge length of the vertebral column

Ratio between the disc thickness abd vertebral body height determines the available motion

IV disc is composed of 3 parts

70-90% water content depending on age and time of the day

60-70% water content depending on age and time of the day

Nucleus pulposus

Annulos fibrosus

Between the vertebral bodies

Interbody joints

Joints between the zygapophyseal facets located on the superior and inferior processes of one vertebra which articular with adjacent vertebra

Connects anterior and lateral surfaces of the vertebral bodies from the sacrum to 2nd cervical vertebrae

Connects posterior aspect of the vertebral bodies from c2 to sacrum

Connects adjacent spinous process

Connects adjacent spinous process along with supraspinous lig.

First to be damaged with excessive flexion

Connects the tips of spinous processes from c7 to l3 or l4

Ligaments pass between the transverse processes and attach to the deep muscles of the back

ALL stretched

PLL stretched

ALL compressed

PLL compressed

Ligamentum flavum stretched

Ligamentum flavum compressed

Interspinous ligament stretched

Interspinous ligament compressed

Supraspinous ligament stretched

Supraspinous ligament compressed

Extended when stretched

Flexed when stretched

Neutral under constant tension when stretched

Flexed when compressed

Alternately stretched and compressed during lateral flexion

Extended when compressed

compressed: neutral when normal height of the disc is reduced

C2 to occiput

C1 and C2

Lower lumbar region

Limits extension

Limits forward flexion

Limits flexion

Limit rotation of the head to the same side and lateral flexion to the opposite side

Resists anterior sliding of the L5 and S1

Extension of the ligamentum flavum from C2 to occiput

Extension of the ligaments from c2 to the occiput

Flexed when stretched

Extended when compresed

Extended when stretched

Neutral position when stretched under constant tension

compressed: neutral when the normal height of the disc is reduced

Stretched across the ring of th atlas and divides the ring into a large posterior section for the spinal cord and a small anterior space for the dens

Has a thin layer of articular cartilage on its anterior surface for articulation with the dens

Its superior longitudinal band attaches to the occipital bone and its inferior longitudinal band attaches to posterior portion of the axis

Transver ligament and its longitudinal bands

Critical in maintaining stability at the C1/C2 segment

Dens would fracture before the ligament will tear

Limits anterior displacement of atlas

Prevents anterior displacement of C1 and C2

Help prevent distraction of C1 on C2

Specific to the cervical region

Paired ligaments aris from the axis in either side of the dens and extend laterally and superiorly to attach to roughened areas on the medial sides of the occipital condyles and lateral masses of the atlas

Connects the axis and occipital bone of the skull

Fan shaped arrangement from the apex of the dens to the anterior margin of the foramen magnum of the skull

Consistent association of one motion about an axis with another motion around a different axis

Kinematics of VC

Resist compression and transmit forces to laminae

Transmits compressive forces to vertebral end plates

Transmit forces to laminae

Resist shear, compression, tensile and torsional forces

Resists compression forces to vertebral end plates and translates vertical compression forces into circumferential tensile forces in annulus fibrosus

Resist tensile, torsional, and shear forces