Lecture 14 Bones and Jts of the Axial Skeleton Flashcards
What is the primary location of the occipital bone?
Posterior inferior on the skull
What is another name for the external occipital protuberance?
Inion
What are the two nuchal lines associated with the occipital bone?
- Superior nuchal line
- Inferior nuchal line
Which structures do the occipital condyles articulate with?
Superior articular facets of C1
What is the foramen magnum?
Large hole located inferiorly through which the brainstem passes
List the primary functions of the vertebral column.
- Support
- Motion
- Protection of spinal cord
How many individual vertebrae are in the vertebral column before fusion?
33 individual vertebrae
What are the components of the vertebral column by type?
- 7 cervical
- 12 thoracic
- 5 lumbar
- 5 sacral
- 4 coccygeal
What is the function of the curves of the spine?
To absorb downward forces during activities like walking, jumping, etc.
What are the two types of spinal curves, and when do they develop?
- 1° curves: Present at birth (thoracic and sacrococcygeal kyphoses)
- 2° curves: Develop as the infant lifts his head and begins to stand/walk (cervical and lumbar lordoses)
What is the structure of a typical vertebra?
- Vertebral body (VB)
- Vertebral foramen
- Vertebral arch
- Pedicle
- Transverse process
- Lamina
- Spinous process
What is the anterior structure of a typical vertebra called?
Vertebral body (VB)
What does the vertebral foramen house?
The spinal cord
What connects the vertebral body to the articular pillar in a typical vertebra?
Pedicle
Which process extends laterally from the articular pillar?
Transverse process
Fill in the blank: The __________ extends posteriorly from the union of the lamina.
Spinous process
What passes through the intervertebral foramina?
spinal nerves
Does C1 have a vertebral body?
no
What do the superior articular facets of C1 articulate with?
Occipital condyles
What occupies each third of the vertebral foramen (divided according to Steele’s Rule of Thirds)?
Anterior 1/3: Dens
Middle 1/3: cord
Posterior 1/3: empty
The dens is on which cervical vertebrae?
C2
The certebral artery passes through which foramen from C6 to C1 (not C7)
Transverse foramen on the medial aspect of the TVP
These vertebrae have a bifid spinous process
C2-C6
Cervical TVPs point in what direction?
Anterior inferior
What is the orientation of cervical facets?
45 degrees to the horizontal with no lateral-medial orientation
Which vertebra have uncinate processes on the superior lateral VB projecting superiorly?
C3-T1
Which vertebra have full facets?
T1, T11, T12
Which vertebrae have demi-facets?
T1-T10
Which ribs articulate with their respective thoracic vertebrae?
ribs 1, 11 and 12
Which ribs articulate with their respective vertebrae and the one above?
ribs 2 to 10
eg. rib 3 articulates with T2 and T3 and with T3 TVP
How are the facets on thoracic vertebrae oriented?
60 degrees to horizontal with slight lateral facing
What is the orientation of facets on lumbar vertebrae?
vertically and medially
Where are the intervertebral discs found?
between the vertebral bodies from C2-3 to L5-S1
Where are intervertebral discs thinnest?
thoracic spine
The thicker the disc relative to VB height the greater what becomes?
flextion - extension
Intervertebral discs are strongly attached to what ligament?
posterior longitudinal ligament
Where is the weakest aspect of intervertebral disc?
posterior lateral
What is the inner aspect of the intervertebral disc called?
nucleus pulposus
What is the difference between disc herniation and disc protrusion?
Protrusion is bulging of the annulus fibrosis but it usually remains intact. Usually symmetrical
Herniation is when the nucleus pulposus ruptures through some or all of the annulus. Usually asymmetrical
What are the articulating surfaces of intervertebral joints?
sup and inf. end plates of vertebral bodies
sup. and inf. surfaces of intervertebral disc
C2-3 to L5-S1
What is the classification of intervertebral joints?
symphysis (cartilagenous, amphiarthrosis)
What are the movements permitted in the intervertebral joints?
limited translatory and rotary movements
flex/ex
lateral flexion
rotation
Where do the longitudinal ligaments run?
between adjacent vertebral bodies ant. and post. from C2 to the sacrum
This ligament is loosely attached to the IVDs and is the continuation of the anterior atlanto-occipital membrane
The anterior longitudinal ligament
This ligament is strongly attached to the IVDs and is a continuation of the tectorial membrane
The posterior longitudinal ligament
What is the blood supply to the intervertebral joints?
segmental arterial supply from aorta
What are the articulating surfaces of the zygappophyseal/facet jts?
right and left sup. articulating facets of the vertebra below
right and left inf. facets of the vertebra above
C1-2 to L5-S1
What are the facet joints classifed as?
nonaxial plane synovial
What are the movements permitted in the facet joints?
flex/ex: greatest in lumbar (60 degrees flex)
lateral flex: greatest in cervical spine (45 degrees)
rotation: greatest in cervical spine (80 degress, 45 degrees from C1-2)
What are the ligaments of the facet jts?
capsule
ligamentum nuchae
ligamentum flavum
interspinous ligament
supraspinous ligament
intertransverse ligament
What are the articular surfaces of the atlanto-occipital jt (C0-1)
occipital condyles of the occiput
superior articular facets of C1
The AO jt is classified as what type of jt?
Biaxial synovial condyloid jt
What are the movements permitted at the AO jt?
flex/ex
lateral flex and rotation (limited)
say “yes” before “no” (C0-1 flexion, C1-C2 rotation)
What are the ligaments of the AO jt?
capsule
atlanto-occipital membrane - posterior and anterior bands - ant. bands continues as the ALL inf. and posterior band continues as ligamentum flavum inf.
What are the articulating surfaces of the atlanto-axial facet joint and medial atlanto-axial jt (C1-2)?
atlanto-axial facet jts: inf. articular facets of C1 and sup. facets of C2
medial atlanto-axial jt: articular facet of C1 anterior arch and dens of C2
What are the atlanto-axial facet jts classifed as?
non-axial plane synovial
What is the medial atlanto-axial jt classifed as?
uniaxial synovial pivot jt
What movements are permitted at the atlanto-axial facet and medial atlanto-axial jts?
rotation: 45 degrees bilaterally (about half of rotation)
flex/ex and lateral flexion (limited due to dens)
What are the ligaments of the atlanto-axial facet jts and medial atlanto-axial jt?
capsule
cruciate ligament
tectorial membrane
alar ligament
apical ligament
What are the bands of the cruciate ligament in the medial atlanto-axial jt?
superior and inferior longitudinal bands and the transverse ligament
What are the articulating surfaces of the
