Vertebral Column

The human vertebral column is built up of a series of vertebrae

7 Cervical, 12 Th., 5 Lumbar, 5 Sacral (Fused as Sacrum), 4 coccygeal (fused as coccyx).

Primary Curves:

–Thoracic and sacral curves - present during fetal development

• Secondary Curves:-Lumbar and –cervical curves-appear after birth

Vertebral Segments

Primary Curve

Secondary Curves Lateral

Vertebral Column

Typical Vertebrae

Body: central strong part. Size increases as we go down towards lumbar region• Superior and inferior surfaces of body (plateaus)• Its post. Surface showing one or more foramina for

basivertebral vein.

Vertebral Arch:• Pedicles, 2 Laminae.Seven processes:1) Transverse Processes(2)2) Spinous Process3) Facets – superior articular and inferior articular (2)

Vertebral Foramen: Intervertebral Foramen:

Typical Vertebrae

Typical Vertebrae

Cervical Vertebrae Contain 7 vertebrae – C1 – C7

• Smallest vertebrae

• Body upper surface is concave

• Spinous process – bifid, shorter than diameter of vertebral foramen

• Transverse process: Contain transverse foramina • Protect vertebral arteries & veins that go to the brain

• Formed of ant. Root, post.root, and costo transverse bar.

• Ant. And post. Roots have tubercles, the tubercle of 6th vertebra is called carotid tubercle.

• Ant. root.and tubercle ,costotransverse bar represent costal element while the post. root represent the true transverse process.

Cervical Vertebrae

-Atlas (C1):• articulates with occiptal condyles of skull• has no body or spinous process. -2 lateral masses from which

arise transverse processes.-has a large, round foramen with anterior and posterior arches.

– Axis (C2):• supports the atlas -has he dens or odontoid process.• has heavy spinous process• to attach muscles of head and neck

– Axis and atlas bodies fuse during development to form the dens

• Vertebra prominens (C7):

• transitions to thoracic vertebrae

• has a long spinous process ,can be felt.

• The foramen transverserium for vertebral vein

– a traumatic dislocation of cervical vertebrae

The Thoracic Vertebrae

Characteristics :• have heart-shaped bodies

• larger bodies than in C1–C7

• smaller vertebral foramen than in C1–C7

• long, slender spinous processes

• Dorsolateral surfaces of body have costal facets-which articulate with heads of ribs.

• Costal facets is present also on transverse processes to articulate with tubercle of ribs (except

11th and12th ribs)

• T1

• Has an upper circular complete facet on the body to articulate with 1st rib.

• Semilunar lower facet for 2nd rib. - spine thick ,horizontal

• T10:has no lower facet on the body.

• T11: kidney shaped body like lumbar vertebrae.

-single facet on the body close to upper border

-transverse process has no facet.

• T12:single facet away from upper border.

-the transverse process has no facet.

-the inf. Articular processes directed laterally like lumbar vertebrae

Atypical Thoracic

The Lumbar Vertebrae

Characteristics L1–L4:• largest vertebrae

• oval-shaped bodies

• thicker bodies than T1–T12

• no costal or transverse costal facets

• triangular vertebral foramen

• Sup. articular process directed backwards and medially. -mammillary process.

• Inf. Art. Process directed laterally.

• T. process: long, tapering, has accessory process on post. Surface.

-L5:large body. -T. process large bulky

Attached to whole side of the pedicle

Typical Lumbar

Sacrum and Coccyx

The Sacrum Composed of 5 fused sacral vertebrae

Triangular have base and apex.

• Anterior concave and post. Convex surfaces.

• It has lateral surface and sacral canal. Articulations:-by the base with 5th lumbar(2nd cartilagenous).-by apex with coccyx.(2nd cartilagenous).-by lateral surface ( auricular surface ) with ilium (sacroiliac joint). Ant sacral foramina: 4 pairs for ventral rami of upper 4 sacral

nerves .+lateral sacral arteries. Dorsal sacral foramina:4 pairs for dorsal rami of sacral nerves. Intermediate area between foramina show transverse ridges that

indicate fusion of vertebrae.

The Sacrum

Sacral Apex – narrow, inferior portion• Base – broad, superior surface

• Sacral Promontory• Important landmark in females –

• Used during pelvic exams and during labor & delivery

• A prominent bulge @ anterior tip of base

• Ala – a wing extending on either side of sacrum

The Sacrum

Auricular Surface

Sacral Tuberosity

Sacral Canal

Ala of sacrum

Sacral promontery

-lateral mass: part of sacrum lateral to foramina represents costal element ant. And T. processes post.

-Sacral canal

• Extends the length of sacrum – nerves & membranes are in this canal

-The auricular surface

• Thickened, flattened area (on lateral surface) – where articulation w/ pelvic girdle is (sacroiliac or SI joint)

-Sacral tuberosity

• Site of attachment for ligaments that stabilize the SI joint.

-median sacral crest…..fused spines.

-intermediate sacral crest……fused articular processes.

-lateral sacral crest………. fused T. processes.

-sacral hiatus: at lower end of median crest…. Lamina of 5th vertebra failed to fuse leaving a jap.

-sacral cornu: free inf. Art. Process of 5th vertebra

Sacral Promontory

Base

Ala

Sacral Apex

Vertebral Relationships

Intervertebral Discs-2nd cartilaginous joints. -number 23.

-Increase in size from C to L (3mm to 9 mm).

-Make up 20-30% of length of column.

-the 1st disc between C2 and C3 and the last betweenL5 and S1.

- discs are avascular except periphery supplied from adjacent vessels.

-disc prolapse commonly occur between L4,5 or between L5 and S1.

-PROLAPSE COMMONLY OCCUR IN POSTEROLATERAL DIRECTION WHERE IT IS NOT SUPPORTED BY POST. LONGTUDINAL

LIGAMENT.

Intervertebal Discs

Two Components Outer rim of fibrocartilage called the anulus fibrosus.

Connects vertebral bodies in a fibrocartilaginous joint (no capsule, little motion).

Anulus encloses a central mass called the nucleus pulposus.

N.P. About 80-90% water, less with increased age Contains a mucopolysaccharide matrix Neither blood vessels or nerves penetrate nucleus

Structure deforms when pressure is put on vertebral column as in weight bearing

Acts as a shock absorber Annulus totally encloses the nucleus and

keeps it under constant pressure As you get older, the H2O content decreases

and the nucleus becomes more fibrocartilaginous, therefore less easily deformable and more easily damaged

Nucleus, when under extreme pressure, can herniate or extrude from the disc in a posterior or posterior-lateral direction

Usually occurs in cervical or lumbar region Nucleus can put pressure on spinal nerve

causing refereed symptoms (motor and sensory)

Can cause pressure on cord itself if true posterior

Major Ligaments of the Spine

Anterior Longitudinal Ligament - ALL Dense band along anterior and lateral surface

of the vertebral bodies from C2 to sacrum• Superficial - bridge several vertebrae

• Deep – short, run from V to V, blends with fibers of anulus fibrosus

• Limits extension of V column

From C1 to skull, called anterior Atlanto-Occipital Membrane

ALL

A and P Longitudinal Ligament

Major Ligaments

Posterior Longitudinal Ligament• Runs along posterior surface of vertebral

bodies (anterior to spinal canal)

• C2 to Sacrum

• Short fibers attach ligament to posterior disc, reinforce disc posteriorly

Superiorly, continues to occiput, called Tectorial Membrane

Limits flexion

Ligaments

Supraspinous• Spinous process to spinous process – tip to

tip

• C7 to sacrum

Limits flexion In cervical region, becomes much thicker

with a greater elastic content Called Ligamentum Nuchae

Supraspinous

Ligaments

Interspinous Found between spinous processes Most well developed in lumbar region support

Interspinous

Ligaments

Ligamentum Flavum Connects lamina of one to lamina of the

other Found from axis to sacrum Limit flexion Continuation to the skull is called

Posterior Atlanto-Occipital membrane

Ligamentum Flavum

Ligaments

Intertransverse Between transverse processes Limit lateral flexion. PEDICLE IS HE ONLY PART OF VERTEBRAL

ARCH HAVE NO LIGAMENTS TO FORM INTERVERTEBRAL FORAMINA FOR SPINAL NERVES

Sacralization

Where 5th lumbar vertebrae takes on characteristics of the sacrum and may be partially or completely fused with sacrum

Lumbarization:Superior aspect of the sacrum assumes characteristics of the 5th lumbar vertebrae

Atlanto-Axial Joint

Atlas and Axis Pivot Two convex superior facets of axis with two

concave inferior facets of the atlas Atlas also posses a facet on the internal

surface of the anterior arch which articulates with the dens of the axis

Major ligaments from spine support – Ant. Atlanto-Occipital, Tectorial Membrane, Post. A-O

C1/C2

C1/C2

C1/C2

A-A Joint

Alar – from dens to occiput Transverse - around dens Cruciate

• Sup. Longitudinal Band

• Inferior Longitudinal Band

• Transverse

Atlanto-Occipital Joint

Two concave superior facets of atlas articulate with two convex surfaces of occipital condyles of the skull

Supported by major ligaments Small saddle joint Very limited motion – nodding type

motions in all directions.

Atlanto-Occipital