Post on 22-Dec-2015
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VERTEBRAL COLUMN ANATOMYPatrick Elder
Basics• How do we divide the vertebrae of the vertebral
column, and how many are there?• 7 cervical, 12 thoracic, 5 lumbar, 5 sacral and the coccyx.
• From where do the spinal nerves originate, and how are they named?• Spinal nerves C1-C7 emerge from above their
corresponding vertebrae.• Spinal nerves C8-S5 emerge from below their
corresponding vertebrae (NB - there is a C8 spinal nerve, but no C8 vertebra.
Basics
7 x Cervical(C1-C7)
12 x Thoracic(T1-T12)
5 x Lumbar(L1-L5)
5 x Sacral(S1-S5)
Coccyx
Spinal nerves emerge above corresponding vertebrae (Spinal nerves C1-C7)
Spinal nerves emerge below corresponding vertebrae (Spinal nerves C8 to S5/Co)
C7
Vertebral Levels
7 x Cervical(C1-C7)
12 x Thoracic(T1-T12)
5 x Lumbar(L1-L5)
5 x Sacral(S1-S5)
Coccyx
Vertebrae and spinal nerves are named relative to each other
C7
C5
C6
C7
C8
T1
T2
C5C6
T1
Cervical spinal nerves exit above correspondingly numbered vertebrae
All spinal nerves from T1 down exit below correspondingly
numbered vertebrae
T2
R G Tunstall 2013
Name 5 functions of the vertebral column
Carries & protects spinal cord & nerves
Provides support to thoracic / rib cage
Transfers weight from upper body to lower limbs
Shock absorbing
Muscle attachment point
Label the vertebra
Body
Pedicle
Transverse process
Lamina
Spinous Process
Vertebral Canal
Articular facets
Which parts make up the neural arch?
= Neural arch
Where do the spinal nerves exit the vertebral column?• Spinal nerves emerge via the intervertebral foramen
• What are the borders of the intervertebral foramen?• Pedicle• IV disc• Articular processes & synovial joints
Spinal nerves are mixedMay contain somatic sensory, somatic motor, visceral sensory or autonomic nerves
Spinal nerves emerge via intervertebral foramen
• Pedicle• IV Disc• Articular processes & synovial joints
Issues/diseases affecting these structures can
affect/irritate/impinge the spinal nerve
Spinal Nerves & Intervertebral Foramen
R G Tunstall 2013
What are the names of the first 2 cervical vertebrae?• They are specialised vertebrae
• C1 = Atlas• C2 = Axis
• What are the distinguishing features of atlas?• Joins to occipital condyle on the base of the skull and permits
movement• Has anterior and posterior arches• Has specialised facets for occipital condyle
Joins to occipital condyle on base of skull and permits movement
C1 (Atlas) carries the weight cranium
Osteology: Cervical Vertebrae
R G Tunstall 2013
You can palpate the transverse process/lateral mass of axis via your lateral neck just deep to sternocleidomastoid
Excess compression can shatter the ring of
AtlasJefferson Fracture
What are the distinguishing features of axis?
• Odontoid peg• Forms pivot joint with atlas• Can be fractured and impinge spinal cord• Fractures may occur in car crashes
Odontoid process can be fractured & impinge spinal
cord# via car crashes
Name the type of vertebra
Lumbar Cervical
Sacral
Thoracic
Cervical vertebra• Small bodies: they do not have
to carry that much weight
• Large vertebral foramen: spinal column is large at this point
• Bifid spine
• Foramen transversarium: carries vessels and nerves – vertebral artery can be compressed here
• Spinous process of C7 is very prominent and can be easily palpated
Foramen transversarium(carry vertebral arteries, veins and
sympathetic nerves to CNS)
Thoracic vertebra• Progressively increase in size and
possess articulations for head and neck of ribs
• Heart-shaped body: don’t need to carry too much weight
Lumbar vertebra• Large kidney-shaped body
– they carry the majority of the weight
• Smaller vertebral canal: most of the nerves have already left the spinal cord
• Square spinous process
• Articulations are aligned in a different plane, in order to prevent rotational movements
Anterior Posterior
Osteology: Sacral Vertebrae
Anterior sacral foramen(Ventral rami of sacral nerves exit via these foramen)
Posterior sacral foramen(Posterior rami of sacral nerves exit via these foramen)
Sacral hiatus(Can perform sacral epidural via this foramen)
Sacrum consists of x5 fused vertebrae and transmits weight to pelvic girdle
R G Tunstall 2013
Where in the vertebral column would you find the IV discs?• Secondary
cartilagenous joints
• Present from beneath C2 to above S1
• What are the two parts?• Annulus fibrosus =
Layers of fibrocartilage• Nucleus pulposus =
Rubbery central core (GAG)
NP
AF
Located between articular facets of adjacent vertebrae
Simple synovial plane joints
Facets change orientation from superior-to-inferior
Joints can dislocate (vertebral bodies displaced)
Cervical
Thoracic
Lumbar
R G Tunstall 2013
How does the angle of the zygapophyseal joints change as you go down the vertebral column?
Which ligaments support the vertebral column? 5
• Anterior Longitudinal
• Posterior longitudinal – relatively incomplete, so IV discs can be displaced posteriorly
• Ligamentum flavum
• Interspinous ligament
• Supraspinous ligament
Strong ligaments support the column
Anterior Longitudinal Posterior Longitudinal Ligamentum Flavum
Ligaments
Note the relatively incomplete nature
of the posterior longitudinal ligament
Elastic ligament joining adjacent lamina. Pierced during lumbar puncture.
R G Tunstall 2013
Interspinous Ligament
Supraspinous Ligament
Ligaments
Ligamentum NuchaeCan be palpated in the midline posterior neck
R G Tunstall 2013
Which ligaments will be penetrated by a needle inserted in the midline?• Supraspinous
• Interspinous
• Ligamentum flavum
A midline (midvertebral line) needle insertion will penetrate the skin, supraspinous and interspinous ligaments and
ligamentum flavum
4 – Supraspinous ligament5 – Interspinous ligament6 – ligamentum flavum
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Lumbar Puncture & Vertebral Column Ligaments
Tunstall & Shah 2012 Pocket Tutor: Surface Anatomy
R G Tunstall 2013
Which spinal nerve will be affected by a posterolateral prolapse of an IV disc in the lumbar region?
• Affects the spinal nerve of the intervertebral foramen one level below.
• E.g. L4/L5 herniation affects L5 spinal nerve
• L5/S1 affects S1 spinal nerve
IV Disc Prolapse
Prolapse in lumbar region is commonDisc prolapse/herniation affects the spinal nerve of IVF one level below
Note lumbar nerves lateral and superior to disc forming IV foramen
Lateral prolapse affects nerve travelling to lower IV foramen
Where will your patient experience problems?
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R G Tunstall 2013
What happens if a disc herniates posteriorly?
• Cauda equina syndrome• Saddle anaesthesia• Loss of anal tone / wink on PR• Bladder and bowel incontinence• Lower limb sensory loss / changes• Reduced ankle jerk (S1/S2)• Weakness of pelvic floor
Important vertebral levels• At what level does the spinal cord terminate in adults?
• L1/L2
• At what level does it terminate at birth?• L3/L4
• What is the filum terminale, and at what level does it end?• Continuation of the pia mater, terminates at the coccyx
• At what level does the subarachnoid space end?• S2
L1/2Termination of adult spinal cord
L3/4Cord termination at birth
Filum TerminaleFibrous cord
Important Vertebral Levels
Subarachnoid spaceEnds at S2
Filum TerminaleTerminates at the coccyx
R G Tunstall 2013
L1
L2
L3
L4
L5
S1
Tunstall & Shah 2012 Pocket Tutor: Surface Anatomy
What is this? • Wedge / compression fracture
• May be traumatic or occur with osteoporosis
What is this?
Cause of lower back pain
Spondylolysis
• Fracture in region of articular facets without displacement
What is this? Spondylolisthesis
• Lumbar vertebrae body slips / moves anteriorly
• Can be traumatic, degenerative, dysplastic
• Often accompanies spondylolysis