Structure of the Vertebrae

Vertebrae

vertebrae share common features

body (centrum)

vertebral foramen

pedicles and laminae

superior and inferior articular processes

transverse processes

spinous process

memory trick for Vertebrae number:

Breakfast at 7, Lunch at 12, Dinner at 5

7 cervical, 12 thoracic, 5 lumbar

Body (centrum)

Most anterior structure

Weight bearing with vertebral discs between adjacent vertebral bodies

Vertebral Foramen

Space for spinal cord and associated structures

Collectively, make up the vertebral cavity

Pedicles and Laminae

Pedicles project laterally from the body and Laminae project posteriorly

Together they form the Vertebral Arch

The inferior side of the pedicles curves up to create an Inferior Vertebral Notch and the superior side curves down to create the Superior Vertebral Notch

Notches of successive vertebrae form the Intervertebral Foramina where spinal nerve roots pass

Superior and Inferior Articular Processes

Found at the junctions of the pedicles and laminae

Surfaces of both processes contain smooth Facets covered in hyaline cartilage

Superior articular facets of one vertebra form joints with the inferior articular facet of the vertebra above it

Transverse Processes

Project from the lateral sides of the vertebral arch

Attachment sites for muscles

Spinous Process

Posterior projection for muscle attachments and protect the posterior spinal cord

Cervical Vertebrae

Smallest vertebrae with Transverse Foramina in their transverse processes for the passage of vertebral arteries and veins

C1: Atlas

C2: Axis

C3-C7

C1: Atlas

Named for the Greek Titan that supported the world

No vertebral body or spinous process

Two Anterior Arches that meet at the Anterior Tubercle and two Posterior Arches that meet at the Posterior Tubercle

Lateral Masses contain the articular facets

Superior articular facet meets the occipital condyles at the atlanto-occipital joint

C2: Axis

The Dens (Odontoid Process) projects from the body and fits into the atlas’s vertebral foramen forming the atlantoaxial joint

held by the transverse ligament

C3-C7

Have oval bodies, large triangular vertebral foramina, and short, forked spinous processes

C7 (Vertebra Prominens)

Has a unique, longer spinous process that is not forked

This process is palpable and is used as a clinical landmark

Thoracic Vertebrae

Larger than cervical vertebrae and grow larger moving down the vertebral column

Heart-shaped bodies

Circular vertebral foramina

Long spinous processes that point inferiorly

Superior Costal Facets and Inferior Costal Facets on lateral sides of bodies provide points of articulation for the ribs

T10-T12 there is only one costal facet on each side

T1-T10 also have transverse costal facets, which articulate with another portion of the ribs

looks like the head of a giraffe

Lumbar Vertebrae

Largest and heaviest to bear the weight of the torso

Kidney-shaped bodies

Thick spinous processes that point posteriorly

Vertebral foramina shaped like a flattened triangle

Lumber pedicles and laminae are thicker and shorter than other vertebrae

looks like the head of a moose

Vertebral Compression Fracture

Fracture of the vertebral body that reduces the height of the vertebra by more than 20%

Typically result from trauma or diseases that destroy bone, such as osteoporosis and bone tumors

wedge fractures and burst fractures

Wedge Fractures

Involve the anterior portion of the vertebra

Common in elderly women with kyphosis and osteoporosis

Cause radiating pain

Burst Fractures

Involve the entire vertebral body

From severe trauma

Bone fragments may damage the spinal cord and nerves

Treatments include bed rest, bracing, physical therapy, and surgery if the injury is severe

Sacrum

S1-S5 form the posterior wall of the pelvic cavity;

Fuse by ages 20–25

Flattened Base on superior surface articulates with 5L at its superior articular processes

Apex at the inferior surface articulates with the coccyx

Auricular Surfaces on the lateral sides articulate with the pelvic bones

Sacral Promontory is a bony projection at the anterior margin of the base with smooth regions called Alae

Sacral Canal opening connects to the vertebral canal and terminates in the Sacral Hiatus

Bordered posteriorly by the Median Sacral Crest with 4 pairs of holes called the Sacral Foramina

Lateral to these are the Lateral Sacral Crests

Coccyx

Generally composed of 4 vertebrae

Fuse about age 25

Similar to the sacrum, has transverse ridges where the vertebrae fused

Coccygeal Cornu—Hornlike projections at the superior end

Intervertebral Discs

Pads between vertebrae; There are 23 discs from C2-S1

structure contains nucleus pulposus and anulus fibrosus

Ligaments and muscles also support the vertebral column

Nucleus Pulposus

Inner, jelly-like shock absorber

Anulus Fibrosus

Outer ring of fibrocartilage

Holds nucleus pulposus and vertebrae together

Herniated Disc

Tear in the anulus fibrosus allows the nucleus pulposus to protrude, usually on posterolateral side

Results from trauma, injuries from lifting, or longer-term damage from repeated motions

Nerve compression can cause significant pain, numbness, tingling, and muscle weakness

Treatments include physical therapy, anti-inflammatory steroid injections, and surgery