ANAT 102 Topic 8

state the number of vertebrae in the cervical column

7

state the number of vertebrae in the thoracic column

12

state the number of vertebrae in the lumbar column

5

state the number of vertebrae in the sacral column

5, which are fused to form the sacrum.

state the number of vertebrae in the coccygeal column

4, which are fused to form the coccyx.

state the 3 functions of the vertebral column

• support upper body weight  

• protect spinal cord and nerves  

• allow trunk movement

state the functions of the vertebral body

weight bearing and movement

state the functions of the vertebral arch 

protection, movement

state the functions of the vertebral foreamen/cannel

passageway for spinal nerves

what is the vertebral cannal bound by

•  IV disc in front  

•  bone of the pedicle above and below  

•  Z joints behind 

classify the intervertabral disk joint

modified fibrocartilaginous joint

what are the components of the intervertebral disk joint

• cartilage end plate (top and bottom) 

•  annulus fibrosis  

•  nucleus pulposus 

what is the annulus fibrosis in the intervertebral disk joint

 alternating layers of dense regular connective tissue 

describe the neucleus pulposus in the intervertebral disk joint

• toothpaste like consistency  

• End plate  

• cartilage disc 

what is the function of the cartilage end plate in the IV disk

• transmits weight to adjacent vertebral body  

• confines nucleus pulposus and annulus fibrosis  

•  role in securing nutrition for disc  

what is the function of the annulus fibrosis in the IV disk

• retain the nucleus pulposus  

•  allow and limit movement 

what is the function of the nucleus pulposus in the IV disk

• shock absorber – rapidly applied loads are temporarily diverted into bracing the annulus fibrosis – stiffens vertebrae 

•  force distributor

classify the interbody joints

Fibrous cartilaginous joint  

what is the thickest and thinnest interbody joint

• thickest in lumbar region (more weight goes through lumbar region) 

•  thinnest in upper thoracic region  

why is the interbody joint avasuclar

it has little blood flow therefor it gains nutrition viathe diffusion of nutrients from the surrounding vertebral bodies.

describe the function of determining movement in the interbody joints

oblique orientation of annulus fibres mean that shear movements are limited in every direction. the length of the annulus fibres allows rocking movements

describe the function of weight bearing in the interbody joints and what it results in

there is radial expansion of the nucleus pulposus which causes tension in the annulus fibrosis. Allows load transmission, shock absorption

ibe the function of the Contribution to normal vertebral column curvature   in the interbody joints and what it results in

• increase the shock absorbing function of the vertebral column  

which regions of the spine are kyphotic and lordotic

•  Thoracic/sacral regions = kyphotic (primary/structural) curve  

•  Cervical/lumbar regions = lordotic (secondary/functional) curve

describe the line of gravity in the spine

passes through junctions of normal vertebral column curves  

classify the Z joint

synovial multiaxial plane

describe the articular surfaces of the Z joint

 superior and inferior articular facets  

describe the joint capsule of the Z joint

 loose but reinforced by:  ligamentum flavum  multifidus  ligament

describe the functions of the Z joint

• to determine the direction of vertebral column movement  

•  to determine the range of vertebral column movement  

•  to bear weight (67% in cervical region, 15% in lumbar region) 

what are vertebral column movements determined by

articular triad: nterbody joint and zygapophyseal joints of each vertebral level

what movements are available in the whole vertebral column

•  flexion/extension  

•  right and left lateral flexion  

• right and left rotation  

•  Segmental range of movement small but total range large

what movements are available in the cervicale region of the vertebral column 

•  superior articular facets tipped forward from the coronal plane  

•  conjunct rotation - ipsilateral coupling with lateral flexion  

• large range of flexion/extension " intervertebral disc degeneration (fissures in annulus fibrosis)

what movements are available in the thoracic region of the vertebral column

• superior articular facets close to the coronal plane  

•  equal range movements in all directions  

•  all movements limited in range due to ribs 

what movements are available in the lumbar region of the vertebral column

J-shaped” superior articular facets in upper lumbar region (coronal and sagittal sections)  

• Therefore:  very, very limited rotation - sagittal portion  

• protection for intervertebral disc - coronal portion 

describe the anterior longitudinal ligament

• extends from C1 to sacrum attaching to anterior surfaces of vertebral bodies and discs  

• broad, strong  

•  outer fibres span 3-4 segments, inner fibres span 1 segment  

what does the anterior longitudinal ligament limit

extension of the vertebral column

describe the posterior longitudinal ligament

• extends from C2 to sacrum attaching to posterior surfaces of margins of vertebral bodies and discs  

•  separated from vertebral bodies by venous plexus • 

• weak and narrow in lumbar area  

what does the posterior longitudinal ligament limit

flexion of the vertebral column

describe ligamentum flavum

• contains a significant amount of elastic tissue  

•  connects laminae of adjacent vertebrae  

•  passes from the posterior surface of the lamina of one vertebra to the anterior surface of the lamina of the vertebra above (zig zag) 

•  attach to anterior part of capsule of zygapophyseal joints  

what does ligamentum flavum limit

• “brake” flexion  

•  protect zygapophyseal joint capsules  

• protect neural tissue 

describe the supraspinous ligament

• connects apices of spinous processes from C7 to sacrum  

•  may be absent in low lumbar area  

•  expands as ligamentum nuchae over cervical area  

what dos the supraspinous ligament limit

• limits flexion of the spine 

describe the interspinous ligament

connect transverse processes of adjacent vertebrae  

what does the interspinous ligament limit 

• limits lateral flexion

classify the atlanto occipital joints

synovial, biaxial, ellipsoid (often considered a single joint) 

describe the articular surfaces of the atlanto-occipital joints

•  Superior articular facets of C1  

•  Occipital condyles of skull

describe the articular capsule of the atlanto-occipital joint

thin and loose 

describe the movements available at the atlanto-occipital joints

• Flexion and extension  

•  Lateral flexion and rotation – coupled contralaterally 

what does the atlanto-occipital ligaments limit

 Limit all movements at atlanto-occipital joints  

classify the median atlanto-axial joint

synovial, uniaxial, pivot  

classify the 2 lateral atlanto-axial joints

synovial, multiaxial, plane (zygapophyseal joints) 

what are the articular surfaces of the median atlanto-axial joint

• Facet for dens on anterior arch of C1  

•  Dens of C2  

•  Transverse ligament of atlas 

what are the articular surfaces of the 2 lateral atlanto-axial joints

• Inferior articular facets of C1  

•  Superior articular facets of C2  

describe the atlanto-axial joint movements

rotation - C1 and the head rotate as a unit on C2 

describe the apical ligament of dens

From tip of dens to anterior margin of 
foramen magnum 
• Anterior to superior longitudinal band of 
cruciform ligament

describe the alar ligaments

• From tip of dens to medial sides of 
occipital condyles 

what is the function of the alar ligaments

limit flexion, lateral flexion and 
contralateral rotation of the head

describe the tectorial membrane

Superior continuation of posterior 
longitudinal ligament – from posterior 
surface of body of C2 to anterior margin 
of foramen magnum 
• Posterior to cruciform ligament and alar 
ligaments

what is the funciton of the tectorial membrane

limits flexion of the head 

describe ligamentum nuchae

• Not a “true” ligament of the neck 
• Fibroelastic septum in the 
midline of the posterior neck 
• From spinous process of C7 to 
occipital bone 
• Superior continuation/expansion 
of supraspinous ligament