Download Thoracic and Lumbar Spine Anatomy

Thoracic and Lumbar
Spine Anatomy
Orthopedic Assessment III – Head,
Spine, and Trunk with Lab
PET 5609C
Clinical Anatomy
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Vertebral Column:
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Cervical Spine:
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Thoracic Spine:
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Lordotic curvature
Greatest ROM
Most vulnerable to injury
Greatest protection
Least ROM
Lumbar Spine:
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Balance between
protection/ROM
Clinical Anatomy
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Vertebral Column:
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Extends from skull to
the pelvis
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33 total vertebrae:
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Superiorly: 24
individual vertebrae
(separated by
intervertebral discs)
Inferiorly: 9 fuse to
form 2 composite bones
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Sacrum (5)
Coccyx (4)
Clinical Anatomy

Vertebral Column:
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Functions:
Transmits weight of
the trunk to the lower
limbs
 Surrounds/protects
spinal cord
 Attachment point for
the ribs and muscles
of neck and back
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Clinical Anatomy
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Vertebral Column: Major
Supporting Ligaments
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Anterior Longitudinal
Ligament – runs vertically
along anterior surface of
vertebral bodies
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Neck - Sacrum
Attaches strongly to both
vertebrae and intervertebral
discs (very wide)
Prevents back
hyperextension
Clinical Anatomy
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Vertebral Column:
Major Supporting
Ligaments
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Posterior Longitudinal
Ligament - runs vertically
along posterior surfaces of
vertebral bodies
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Narrower, weaker
Attaches to intervertebral
discs
Prevents hyperflexion
Clinical Anatomy
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Vertebral Column: Major
Supporting Ligaments
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Ligamentum Flavum - strong
ligament that connects the
laminae of the vertebrae
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Protects the neural elements
and the spinal cord
Stabilizes the spine to prevent
excessive vertebral body motion
Strongest of the spinal
ligaments
Forms the posterior wall of the
spinal canal with the laminae
Stretches with forward bending
/ recoils in erect position
Clinical Anatomy
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Vertebral Column:
Supporting Ligaments
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Intertransverse
Ligament - located
between the transverse
processes
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Cervical region: consist of
a few irregular, scattered
fibers
Thoracic region: rounded
cords connected with deep
muscles of the back
Lumbar region: thin and
membranous
Clinical Anatomy
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Vertebral Column:
Supporting Ligaments
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Interspinal Ligament connect spinous
processes (spans the
entire process)
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Meets the ligamentum
flavum in front and the
supraspinal ligament
behind
Clinical Anatomy
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Vertebral Column:
Supporting Ligaments
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Supraspinal Ligament connects together the
apexes of the spinous
processes
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Extends from 7th cervical
vertebra to sacrum
Strong fibrous cord
At points of attachment
(tips of the spinous
processes) fibrocartilage is
developed in the ligament
Supraspinal
Ligament
Clinical Anatomy
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Bony Anatomy:
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Body : Centrum
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Anterior part
Weight-bearing segment
Vertebral Arch: Neural
Arch
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Posterior part
Formed by pedicle and
lamina on each side
Clinical Anatomy
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Bony Anatomy:
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Vertebral Foramen:
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Pedicles: (2)
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Opening
Sides of vertebral arch
“Little feet” project
posteriorly from body
Laminae: (2)
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Flat roof plates
Complete arch
posteriorly
Thoracic Vertebrae
Clinical Anatomy
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Bony Anatomy:
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Transverse Processes:
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Project laterally from each
pedicle-lamina junction
Attachment site for intrinsic
ligaments and muscles
Spinous Processes:
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Prominent posterior
projections
Attachment site for intrinsic
ligaments and muscles
Cervical Vertebrae
Cervical Vertebrae
Thoracic Vertebrae
Thoracic Vertebrae
Lumbar Vertebrae
Lumbar Vertebrae
Clinical Anatomy
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Facet Joints:
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Articulations between
superior articular facet
(bottom vertebrae) and
inferior articular facet
(above vertebrae)
Contribute to ROM
↓ Weight-bearing stress
through vertebral body
and disc
Synovial joints
Clinical Anatomy
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Pars Interarticularis:
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Area between the
superior and inferior
facets
Common site for stress
fractures (lumbar spine)
Spondylolysis - refers to
the defect (black arrows)
present when the pars
interarticularis (green
arrow) is fractured
Clinical Anatomy
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Intervertebral Foramen:
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Space where spinal nerve
roots exit the vertebral
column
Size variable due to
placement, pathology,
spinal loading, and posture

Can be occluded by arthritic
degenerative changes and
space-occupying lesions
(tumors, spinal disc
herniations)
Vertebral Anatomy
Level
Vertebral Body
Transverse Process Spinous Process
Cervical
Small;
Vertebral body
absent in C1;
remaining
bodies
progressively ↑
in size
Short; Processes
Small and short, except
contain the
for C7 (characteristics of
transverse foramen thoracic vertebrae)
for passage of
vertebral artery
Thoracic
Diameter and
thickness ↑ as
spine
continues
inferiorly
Attachment of
muscles and
costovertebral
ligaments;
Processes of T1T12 have articular
surfaces for the
ribs
Long and slender;
downward projections –
overlap of spinous
processes of inferior
vertebrae; gradually
thicken in size as you
move ↓
Lumbar
Very broad
Long for leverage
Superior borders are
posteriorly projected with
a large inferior flare
Clinical Anatomy
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Thoracic Segment:
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Wider/thicker – help support
torso weight
Spinous Processes:
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Downward projection
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Limit extension
Attachment for thoracic
muscles/ligaments
Transverse Processes:
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Costotransverse Joints:
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Articulation with ribs
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Ribs 1 – 10
Ribs 11 and 12
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No articulation with
transverse processes
Clinical Anatomy
Costovertebral
Joint
Costotransverse
Joint
Clinical Anatomy
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Thoracic Segment:
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Costovertebral Joint:
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Articulation between vertebral bodies and ribs
Superior and Inferior Costal Facets
Superior Costal Facet
Inferior Costal Facet
Clinical Anatomy
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Sacrum:
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Curved, triangular
shaped
5 fused vertebrae
Fixes the spinal
column to the pelvis
Stabilizes the pelvic
girdle
Clinical Anatomy
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Sacroiliac Joint (SI):
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Between the sacrum (base of the spine) and the ilium of the pelvis
Strong, weight bearing synovial joints (2)
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Covered by 2 different kinds of cartilage
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Functions:
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Sacral surface (hyaline cartilage)
Iliac surface (fibrocartilage)
Shock absorption (spine)
Allows the transverse rotations (lower extremity) to be transmitted up
the spine.
Motions:
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Anterior innominate tilt
Posterior innominate tilt
Sacral flexion (or nutation)
Sacral extension (or counter-nutation)
Clinical Anatomy
Clinical Anatomy
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SI Ligaments:
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Anterior Sacroiliac
Ligament:
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Connects the anterior
surface of the lateral
part of the sacrum to
the ilium
Note: Black Arrow
Clinical Anatomy
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SI Ligaments:
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Posterior Sacroiliac
Ligament:
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Forms the chief bond of
union between the bones
Upper part: (short PSL)
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Nearly horizontal in
direction
Ilium to upper sacrum
Lower part: (long PSL)
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Oblique in direction
Lower sacrum to PSIS
Short PSL
Long PSL
Clinical Anatomy
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SI Ligaments:
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Sacrotuberous
Ligament:
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Arises from ischial
tuberosity to blend in
with inferior fibers of
posterior SI ligaments
Sacrotuberous
Ligament
Ischial Tuberosity
Clinical Anatomy
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SI Ligaments:
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Sacrospinous
Ligament:
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Originates from the
ischial spine and
attaches to the coccyx
Sacrospinous
Ligament
Clinical Anatomy
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Coccyx: Tailbone
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Consists of 4 (in some
cases 3 or 5) vertebrae
fused together
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Attachment site for
muscles of pelvic floor
and sometimes
portions of gluteus
maximus
Clinical Anatomy
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Intervertebral Discs:
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23 intervertebral discs
No disc between skull and C1 or
between C1-C2
Discs are thickest in the lumbar
vertebrae and cervical regions
(enhances flexibility)
Functions:
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Shock absorbers
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walking, jumping, running
Allow spine to bend
At points of compression, the
discs flatten out and bulge out a
bit between the vertebrae
Clinical Anatomy
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Nucleus Pulposus: Core
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Gelatinous, acts like a
rubber ball (enables spine to
absorb compressive forces)
60-70% water
Annulus Fibrosus: Outer
rings
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Multilayered fibers (cross
from opposite directions)
Rings absorb compressive
forces themselves
Clinical Anatomy
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Intervertebral Discs: Dehydration Process
Collectively, the discs make up about 25% of the
height of the vertebral column
 Nucleus pulposus becomes dehydrated during
course of day
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Flattens out (height is 1-2 centimeters less at night
than when we awake in morning)
 Aging Process = Permanent dehydration (ages 40 –
60)
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Decreased ROM
Narrowing intervertebral foramen
Clinical Anatomy
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Lumbar and Sacral
Plexus:
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Lumbar:
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Formed by 12th thoracic nerve
and L1-L5 nerve roots
Innervation:
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Anterior and medial
muscles of thigh
Dermatomes of medial leg
and foot
Femoral Nerve – formed by
branches of L2, L3, L4 nerve
roots
Obturator Nerve – anterior
branches of L2, L3, L4
Clinical Anatomy
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Lumbar and Sacral
Plexus:
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Sacral:
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Formed by L4, L5 and
lumbosacral trunk
Innervation:
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Muscles of buttocks,
posterior femur, and
lower leg
Sciatic Nerve – 3
sections
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Tibial nerve
Common peroneal nerve
Tibial nerve
Clinical Anatomy
Clinical Anatomy
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Lumbarization:
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1st sacral vertebrae does
not unite with sacrum
Becomes a 6th lumbar
vertebrae
Sacralization:
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5th lumbar vertebrae
becomes fused to
sacrum
Clinical Anatomy
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Extrinsic Muscles – primarily function to
provide respiration and movement associated
with the upper extremity and scapula
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Indirectly influence the spinal column
Intrinsic Muscles – lie close to spinal column
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Directly influence the spinal column
Clinical Anatomy
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Middle Trapezius:
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O: Lower portion of
ligamentun nuchae and
spinous processes of C7
and T1 – T5
I: Acromion process,
scapular spine
A: Scapular retraction
and fixation of thoracic
spine
Clinical Anatomy
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Lower Trapezius:
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O: Spinous processes of
T8 – T12
I: Scapular spine
(medial portion)
A: Scapular depression
and retraction; fixation
of thoracic spine
Clinical Anatomy
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Rhomboid Muscles:
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Rhomboid Major and
Minor
O: Spinous processes of
C7 through T5
I: Vertebral border of
scapula between the spine
and inferior angle
A: Scapular retraction,
elevation, and downward
rotation; Fixation of
thoracic spine
Clinical Anatomy
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Latissimus Dorsi:
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O: Spinous processes of
T6 through T12 and the
lumbar vertebrae via the
thoracodorsal fascia,
posterior iliac crest
I: Intertubercular groove
of humerus
A: Extension of spine,
anterior rotation of pelvis,
stabilization of lumbar
spine (depression of
shoulder girdle, humeral
extension)
Clinical Anatomy
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Rectus Abdominis:
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O: Pubic crest and
symphysis
I: Xiphoid process and
costal cartilages of 5th,
6th, and 7th ribs
A: Trunk flexion;
compression of
abdomen
Clinical Anatomy
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External Oblique:
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O: 5th through 12th
ribs
I: Iliac crest and linea
alba
A: Bilaterally: trunk
flexion; compression
of abdomen;
Unilaterally: lateral
bending; rotation to
opposite side
Clinical Anatomy
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Internal Oblique:
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O: Inguinal ligament,
iliac crest,
thoracolumbar fascia
I: Tenth, eleventh, and
twelfth ribs; linea alba,
crest of pubis
A: Bilaterally: Trunk
flexion, compression of
abdomen; Unilaterally:
lateral bending and
rotation to same side
Clinical Anatomy
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Erector Spinae: 3
muscle pairs
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Iliocostalis:
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Longissimus:
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Iliocostalis Lumborum
Iliocostalis Thoracis
Iliocostalis Cervicis
Longissimus Thoracis
Longissimus Cervicis
Longissimus Capitis
Spinalis:
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Spinalis Thoracis
Spinalis Cervicis
Spinalis Capitis
Clinical Anatomy
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Transversospinal
Muscles:
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Deep intrinsic layer
Fibers run from 1
transverse process to
the spinous process
superior to them
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Group formed by:
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Semispinalis
Multifidus
Rotators