Vertebrae

H. Smith

3

Spinous process

Transverse processBody

Vertebral foraman

Intervertebral foraman

4

Muscular Attachments• muscular attachments on spinous and

transverse processes

5

Vertebral column

• Extends from skull to pelvis• Consists of many vertebrae separated by

cartilaginous intervertebral disks that are connected by ligaments

• Forms central axis of the skeleton

• Supports the head and the trunk of the body

• Flexible to permit movements

• Protects the spinal cord

How many vertebrae do we have?

• Adult: 26

• Infant: 33 separate bones– Five vertebrae fuse to form the sacrum and four

others join to become the coccyx

Components of vertebral column

• Cervical vertebrae• Thoracic vertebrae• Lumbar vertebrae• Sacrum• Coccyx

3 parts of Vertebra• Body:– Transfers weight along the axis; separated by

intervertebral discs

• Arch: surrounds vertebral foramen

• Articular process: – Intervertebral foramina: gaps b/t each vertebra;

permits passage of nerves to or from spinal cord

Cervical Vertebrae• Comprise the bony axis of the neck• Total of 7• Allows for 180 degree range of motion

• Atlas: (C1) holds up head– Practically no body or spine– Pivots around the dens of axis

• Axis: (C2) during development fuses with atlas

Atlas, C1, cervical vertebrae

Inferior view

Transverse foramen

Inferiorarticular facet

Vertebral foramen

Transverse process

Anterior arch

Posterior arch

Anterior tubercle

Posterior tuberclesteven leeM.S. PathologyFTCC

Axis, C2 cervical vertebrae Dens (odontoid process)

Superiorarticularfacet

Vertebral foramen

Spinousprocess

steven leeM.S. PathologyFTCC

Distinctions of Cervical• Transverse processes of cervical are DISTINCT b/c of

transverse foramina– Passageways for arteries leading to the brain

• Spinous processes:Uniquely forked (bifid): provide attachment for muscles

Thoracic Vertebrae• Total of 12

• Larger than cervical

• Long pointed spinous process slopes downward

• Bear increasing loads of body weight due to the increase in the body size of the vertebra

Thoracic

• Demi facets: on side of body to articulate with ribs

Lumbar • Total of 5 in small of back

• Supports more weight b/c of larger and stronger bodies

• Transverse processes point backwards at sharp angles

• Large Bodies

Lumbar

• Short spinous processes, provide muscle attachement

• Longer transverse processes

Sacral Vertebraefig 7.39

• Originates as 5 vertebrae

• Complete fusion by age 25 (18-30)

Coccygeal

• Originates as 4 vertebra, fuses as 1 bone• Fusion of time varies