[Plate 152, Lumbar Vertebrae]page 84
page 85Cervical vertebrae
Permit forward/lateral flexion, extension, rotation
C1 (Atlas): No body or spinous process; articulates with occipital condyles via paired lateral masses and with the axis via the
superior articular facets and dens of the axis; groove on superior aspect of the posterior arch for vertebral arteries and dorsal ramus
of C1
C2 (Axis): Dens (odontoid process), large superior articular facets for C1
C3-C5: Short bifid spinous processes (anterior tubercle of C6 is the carotid tubercle, which the carotid artery can be compressed
against to control bleeding)
C6-7: long, nonbifid spinous processes
C7 (Vertebra prominens): long (nonbifid) spinous process; small transverse foramina that transmit accessory vertebral veins NOT
vertebral artery
Have transverse processes with anterior and posterior tubercles and foramina (foramina transversaria), which transmit vertebral
arteries and veins and sympathetic nerves plexuses
Thoracic vertebrae
Are relatively rigid, mainly allow rotation of the trunk
T1-T4: Atypical-have some features of cervical vertebrae
T5-T8: Typical
T9-T12: Atypical-have tubercles similar to mamillary and accessory processes of lumbar vertebrae
Have long transverse processes that extend posterolaterally
Lumbar vertebrae
Are relatively mobile, permit forward/lateral flexion and extension but little rotation
Have accessory process found on posterior surface of the base of each transverse process for attachment of medial intertransverse
lumborum muscle
Have mamillary process for attachment of multifidus and medial intertransverse muscles
L5: massive body and transverse processes and is thicker anteriorly-contributes to the lumbosacral angle (usually 130°-160°) and
carries the weight of the upper body
Sacrum (sacral vertebrae)
Composed of five vertebrae that fuse at about 20 years of age, inferior portion is nonweightbearing
Articulates with "hip" bones at sacroiliac joints
Has concave pelvic surface