Transcript Back handoutx

The Back
• Bony anatomy of the vertebral column or
spine
• General vertebral joints or articulations
• Specific vertebral articulations
• Physiological curves of the back
• Muscles of the back
• Suboccipital Region
Vertebral column
• Total vertebrae
– Movable vertebrae
– Fused vertebrae
• Sacrum
• Coccyx
Numbers of vertebrae
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Cervical:
Thoracic:
Lumbar:
Sacral:
Coccygeal:
Variations in numbers of vertebrae
• Number of cervical vertebrae is very
constant in all mammals, including man
• Variations in numbers of thoracic, lumbar
and sacral vertebrae occur in about 5% of
otherwise average people
Common variations
• Sacralization of the 5th lumbar vertebrae
– The 5th lumbar vertebrae is partly or
completely incorporated into the sacrum
– X-Ray: only 4 lumbar vertebrae
– L5/S1 joint is strong
– L4/L5 level can degenerate – often producing
painful symptoms
• Lumbarization of the 1st sacral vertebrae
– 1st sacral vertebrae is separated from the
sacrum, and incorporated into the lumbar
spine
• In general, the relationship between these
variations and back symptoms in the clinic
is NOT clear
Intervertebral discs
• Resilient fibrocartilaginous structures
– Type of joint – Secondary cartilaginous joint
• Anterior articulation
• Connect presacral vertebrae (C2 to S1)
– No disc between:
• Occiput and C1
• C1 and C2
– No discs in sacrum or coccyx
Role of discs
• Strongest connection between vertebrae
• Important role in shock absorption
Posterior connection between
vertebrae
• For presacral vertebrae
– Zygapophyseal joints
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Gliding/sliding/planar type synovial joints
Zygo: yoke
-apo-: upon
-physeal: growth
Ligaments of the spine
• There are ligaments that strengthen the
connections between the vertebrae
– Some extend all or most of the length of the
vertebral column
– Some are specific to certain joints between
select vertebrae
Ligaments that extend the length of
the vertebral column
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Anterior longitudinal ligament
Posterior longitudinal ligament
Ligamentum flavum
Interspinous ligaments
Ligamentum nuchae and supraspinous
ligament
• Intertransverse ligaments
Anterior Longitudinal Ligament
• Anterior 1/3 to ½ of anterior surface of
body of vertebrae
• Runs length of vertebral column from:
– Sacrum
– C1 (atlas) anterior tubercle
– Occipital bone of skull, anterior to the foramen
magnum
• Firmly attached to the intervertebral discs
and the periosteum of the vertebral bodies
• Broader and stronger than posterior
longitudinal ligament
• Function
– Maintain stability of joints between vertebral
bodies
– Help prevent what movement of vertebral
column?
Posterior Longitudinal Ligament
• Wraps around 1/3 to ½ of posterior
surface of vertebral body
– Runs along posterior aspect of vertebral
bodies within the vertebral canal
• Thicker than ALL, but narrower and
weaker
• Attachment of posterior longitudinal
ligament
– sacrum to C2
– C1
– Superiorly is continuous with tectorial
membrane, which attaches to occipital bone
on internal part of foramen magnum
• Function
– Help prevent posterior protrusion of the
nucleus pulposus of the intervertebral discs
– What movement of the vertebral column will
this ligament limit?
Ligamentum Flavum
• Yellow ligament
• Location of ligament
• Function
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Interspinous ligament
• Location
• What is the ligament like?
Ligamentum nuchae and the
supraspinous ligament
• Supraspinous ligament
– Attachments
– Strength
– Location
• Ligamentum nuchae
– Superior extension of supraspinous ligament
– Location
Intertransverse ligaments
• Location
• Description
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– Lumbar region
Anatomy of the vertebrae
• Body - anterior
• Vertebral Arch - posterior
– Pedicle
– Lamina
– 7 Processes
The body of the vertebrae
• Anterior part of vertebrae
• AKA centrum (anatomical center)
• Primary function of the body is to bear
weight
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Vertebral Arch
• On posterior part of the vertebrae
• Function: Protect the spinal cord from
injury
• Formed from:
– 2 pedicles (little feet) – attach to body
– 2 lamina (thin plates) – attach to pedicles.
Attach to each other at posterior
Vertebral Foramen
• Vertebral arch encloses the vertebral
foramen
• Vertebral canal: formed by the successive
vertebral foramen
• Contents of vertebral canal
– Spinal cord
– Meninges
– Nerve roots
– Blood vessels
Pedicles
• Anterior attachment
• Posterior attachment
• Superior vertebral notch
• Inferior vertebral notch
• Intervertebral foramen
How are neural structures located
within the vertebral canal and
intervertebral foramen
• Dorsal and ventral roots
• Dorsal root ganglia
• Spinal nerve
Processes on vertebral arch
• 7 processes
– 3 lever-like
• 1 spinous process
• 2 transverse processes
– 4 articular processes
• 2 superior articular processes and facets
• 2 inferior articular processes and facets
Processes
• Serve as attachment sites for muscles and
ligaments to facilitate and help movement
of the vertebrae
• Spinous processes
– Project :
– From union of:
• Transverse processes
– Project:
– From union of:
Articular processes
• Superior and inferior articular processes
arise from the junction of the lamina and
pedicle
• The superior articular process of one
vertebrae articulates with the inferior
articular process of the above vertebrae
• Processes help prevent forward moving of
an upper vertebrae on a lower one,
especially in thoracic and lumbar regions
• The articular processes allow flexion and
extension, as well as varying degrees of
lateral bending and rotation in the different
regions of the spine
How do we tell the vertebrae apart
from the different levels of the
spinal cord
• Size of body
• Size and shape of processes
• Special features
Cervical vertebrae
• Main distinguishing
characteristics
– Transverse
foramen
– Bifid spinous
processes
– Vertebral foramen triangular
Transverse Foramen
• Oval foramen
• Where are they on the vertebrae?
• What travels through them?
Vertebral artery
• Comes off subclavian artery
• Travels through the transverse foramen of
C6 through C1
• The artery then bends backward above
C1, pierces the meninges, and enters the
skull through the foramen magnum
• Supplies rostral spinal cord, brainstem,
cerebellum, and posterior cerebral cortex
Transverse Foramen
• In C7, smaller and occasionally absent
– The vertebral artery DOES NOT travel
through the transverse foramen of C7
– If the transverse foramen is present, small
accessory vertebral arteries will travel through
it
Bifid Spinous Processes
• From C2 to C6, the spinous process is
often split at the end into a fork-like
structure
Atlas
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First Cervical Vertebrae
NO spinous process
NO body
Supports the skull (Atlas in mythology)
Superior articular facets
– Kidney-shaped
– Concave
– Articulate with occipital condyles of the skull
Axis
• Second cervical vertebrae
• Superior articular facets
– Atlas rotates on these facets
• Dens (odontoid process)
Dens
• Location: Anterior
• Articulates with facets on anterior arch of
atlas
• Held in place
– Transverse ligament
• Prevents horizontal displacement of atlas
• Skull and atlas rotate on axis as a unit
7th Cervical vertebrae
• Very long spinous process
• Recognizable through skin
– Neck flexion
• AKA vertebrae prominens
Review of characteristics of
cervical vertebrae
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Transverse foramen
Bifid spinous processes
C1 – unique
C2 – unique
C7 – long spinous process
Thoracic vertebrae
• Long, slender spinous processes which
face downward, especially in the
midthoracic region
• Middle thoracic vertebrae have circular
vertebral foramen
• All have facets on vertebral bodies for
articulation with the head of a rib
• Upper 10 have facets on transverse
processes to articulate with tubercle of a
rib
• First thoracic
vertebrae
– Similar to cervical in
that the spinous
process is almost
horizontal
– How would you
then tell C7 from T1
• Thoracic vertebral superior articular
processes
– Face posterior and slightly upward
– Would this restrict any movements?
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Lateral bending
Flexion/Extension
Rotation
Anterior/Posterior shift
Summary of thoracic vertebrae
• Spinous processes that face down
• Rib facets
– All have on sides of body
– Upper 10 have on both body and transverse
processes
• Round vertebral foramen or canal
• Heart-shaped body
• Superior articular facets that face posterior
and slightly upward
Lumbar vertebrae
• Spinous processes which are squared off
• Large bodies compared to cervical and
thoracic
• Vertebral canal is more oval-shaped
– Where does spinal cord end, and cauda
equina begin?
– L1/L2 canal more rounded than L5
• Articular facets face each other in sagittal
plane
– How would this affect movement?
Sacrum
• 5 fused sacral
vertebrae in the
adult
• Many of the
vertebral structures
exist, but they are
fused together
• Foramina
– 4 pairs on both the ventral and dorsal
surfaces of the sacrum
– For exit of the anterior and posterior primary
divisions of the sacral nerves
– Note that the ventral foramina are larger than
the dorsal sacral foramina
• 4 transverse lines on the pelvic (ventral)
surface that indicate where fusion of the
vertebrae occurred after the 20th year
• Base of the sacrum
– Superior surface of 1st sacral vertebrae
• Superior articulating processes of the
sacrum
– Articulate with inferior articulating facets of the
L5
• Sacral promontory
– Projecting anterior edge of the body of the
first sacral vertebrae
• Sacral hiatus
– Inverted V-shaped structure
– On dorsal surface
– Formed on each side by the sacral cornua
(horns)
• The sacrum
– Supports the vertebral column
– Forms the posterior part of the pelvis
• Sacrum is tilted
• Articulates with L5 at an angle
– Lumbosacral angle
Coccyx
• Degenerated remnant of embryonic tail
• 4 rudimentary vertebrae
– Lower three vertebrae are just a body
– 1st cervical
Ribs
• Usually 12 on each side of the thorax
• Each rib has a head, neck, tubercle and
shaft
• Head
– 2 facets
• Vertebrae of same number
• Vertebrae above
• Neck – between head and tubercle
Ribs 1, 3 and 8
• Tubercle
– Posterior surface of rib
– Facet: which ribs?
• Articulates with
• Shaft
– Superior border
– Inferior border
– Angle of Rib
• True ribs
• False Ribs
• Floating Ribs