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Axial Skeleton: Vertebral Column
Slides by Vince Austin;
figures from Marieb & Hoehn 7th & 8th eds.;
modifications and some slides by W. Rose
Portions copyright Pearson Education
Vertebral Column

26 irregular bones (vertebrae) connected to form a
flexible curved structure

Cervical vertebrae – 7 bones of neck

Thoracic vertebrae – 12 bones of torso

Lumbar vertebrae – 5 bones of lower back

Sacrum – bone inferior to the lumbar vertebrae that
articulates with the hip bones (fusion of 5, starts ~>
puberty, done mid-20s)
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Vertebral Column
Lordotic
Spinal nerves C1-C7 exit
above vertebrae C1-C7
Spinal nerve C8 exits above T1
Kyphotic
Spinal nerves T1-T12, L1-L5,
S1-S5 exit below vertebrae
T1-T12, L1-L5, S1-S5
Lordotic
Kyphotic
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Figure 7.13
Vertebral Column: Curvatures

Kyphosis = posteriorly convex curvature. Thoracic and sacral
normally kyphotic (but not too much).

Lordosis = posteriorly concave curvature. Cervical and lumbar
normally lordotic (but not too much).

Abnormal spinal curvatures
•
Scoliosis (lateral curve)
•
Excessive kyphosis (hunchback)
•
Excessive lordosis (swayback)
•
What happens in pregnancy?
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Vertebral Column: Ligaments


Anterior and posterior longitudinal ligaments –
continuous bands down the front and back of the
spine from the neck to the sacrum
Short ligaments connect adjoining vertebrae
together
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Vertebral Column: Ligaments
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Vertebral Column: Intervertebral Discs

Cushion-like pad composed of two parts


Nucleus pulposus – inner gelatinous nucleus that
gives the disc its elasticity and compressibility
Annulus fibrosus – surrounds the nucleus pulposus
with a collar composed of collagen and
fibrocartilage
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Vertebral Column: Intervertebral Discs
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General Structure of Vertebrae



Body or centrum – disc-shaped, weight-bearing
region
Vertebral arch – composed of pedicles and laminae
that, along with the centrum, enclose the vertebral
foramen
Vertebral foramina – make up the vertebral canal
through which the spinal cord passes
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General Structure of Vertebrae



Spinous processes project posteriorly, and
transverse processes project laterally
Superior and inferior articular processes – protrude
superiorly and inferiorly from the pedicle-lamina
junctions
Intervertebral foramina – lateral openings formed
from notched areas on the superior and inferior
borders of adjacent pedicles
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General Structure of Vertebrae
transverse costal facet
for tubercle of rib
part of the facet joint
superior demifacet;
must be a T
heart-shaped in Ts,
oval in Ls
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Cervical Vertebrae

Seven vertebrae (C1-C7): smallest, lightest
vertebrae

C3-C7: Distinguished by oval bodies, short spinous
processes, large, triangular vertebral foramina.
Articular facets (sup & inf) form joints with
vetrebrae above & below.

Each transverse process contains a transverse
foramen. (Only cervical have transverse
foramina.)
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Cervical Vertebrae
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Table 7.2.2
Cervical Vertebrae: Atlas (C1)

No body, no spinous process

Anterior and posterior arches, and two lateral
masses

Superior surfaces of lateral masses articulate with
occipital condyles
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Cervical Vertebrae: The Atlas (C1)
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Figure 7.16a, b
Cervical Vertebrae: Axis (C2)

Body, spine, and vertebral arches, like other
cervical vertebrae

Unique feature: dens, or odontoid process, projects
superiorly from body, cradled in the anterior arch
of the atlas

The dens is a pivot for the rotation of the atlas

The “missing body” of the atlas?
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Cervical Vertebrae: The Axis (C2)
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Figure 7.16c
Cervical Vertebrae: Atlas, Axis (C1, C2)
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Figure 7.17a
Regional Characteristics of Vertebrae
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Table 7.2.1
Regional Characteristics of Vertebrae
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Table 7.2.2
Thoracic Vertebrae

Twelve vertebrae (T1-T12), each of which articulates with one or
two of the twelve ribs

Major markings include:
•
•
Superior, inferior articular facets (vertebrae above, below)
Sup, inf costal facets (“demifacets”) on heart-shaped body (rib heads)
(T10, T11, T12 have single costal facets)
•
•
Circular vertebral foramen
Transverse processes with transverse costal facets (rib tubercles) (not T11,
T12)
•

Long spinous process
Location, orientation of articular facets prevents sagittal plane
flexion and extension, but allows rotation and limited lateral
flexion, of thoracic spine
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Thoracic Vertebrae
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Figure 7.17b
Lumbar Vertebrae

The five lumbar vertebrae (L1-L5) are located in
the small of the back and have an enhanced
weight-bearing function

They have short, thick pedicles and laminae, flat
hatchet-shaped spinous processes, and a triangularshaped vertebral foramen

Orientation of articular facets locks the lumbar
vertebrae together to provide stability
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Lumbar Vertebrae
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Figure 7.17c
Sacrum

Sacrum

Consists of five fused vertebrae (S1-S5), which
shape the posterior wall of the pelvis

It articulates with L5 superiorly, and with the
auricular surfaces of the hip bones

Major markings include the sacral promontory,
transverse lines, alae, dorsal sacral foramina, sacral
canal, and sacral hiatus
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Coccyx

Coccyx (Tailbone)

The coccyx is made up of four (in some cases three
to five) fused vertebrae that articulate superiorly
with the sacrum
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Sacrum and Coccyx: Anterior View
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Figure 7.18a
Sacrum and Coccyx: Posterior View
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Figure 7.18b