Thoracic and Lumbar Spine Anatomy

1
Thoracic and Lumbar Spine Anatomy

• Orthopedic Assessment III Head, Spine, and
  Trunk with Lab
• PET 5609C

2
Clinical Anatomy

• Vertebral Column
• Cervical Spine
• Lordotic curvature
• Greatest ROM
• Most vulnerable to injury
• Thoracic Spine
• Greatest protection
• Least ROM
• Lumbar Spine
• Balance between protection/ROM

3
Clinical Anatomy

• Vertebral Column
• Extends from skull to the pelvis
• 33 total vertebrae
• Superiorly 24 individual vertebrae (separated
  by intervertebral discs)
• Inferiorly 9 fuse to form 2 composite bones
• Sacrum (5)
• Coccyx (4)

4
Clinical Anatomy

• Vertebral Column
• 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

5
Clinical Anatomy

• Vertebral Column Major Supporting Ligaments
• Anterior Longitudinal Ligament runs vertically
  along anterior surface of vertebral bodies
• Neck - Sacrum
• Attaches strongly to both vertebrae and
  intervertebral discs (very wide)
• Prevents back hyperextension

6
Clinical Anatomy

• Vertebral Column Major Supporting Ligaments
• Posterior Longitudinal Ligament - runs vertically
  along posterior surfaces of vertebral bodies
• Narrower, weaker
• Attaches to intervertebral discs
• Prevents hyperflexion

7
Clinical Anatomy

• Vertebral Column Major Supporting Ligaments
• Ligamentum Flavum - strong ligament that connects
  the laminae of the vertebrae
• 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

8
Clinical Anatomy

• Vertebral Column Supporting Ligaments
• Intertransverse Ligament - located between the
  transverse processes
• 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

9
Clinical Anatomy

• Vertebral Column Supporting Ligaments
• Interspinal Ligament - connect spinous processes
  (spans the entire process)
• Meets the ligamentum flavum in front and the
  supraspinal ligament behind

10
Clinical Anatomy

• Vertebral Column Supporting Ligaments
• Supraspinal Ligament -connects together the
  apexes of the spinous processes
• 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
11
(No Transcript)
12
Clinical Anatomy

• Bony Anatomy
• Body Centrum
• Anterior part
• Weight-bearing segment
• Vertebral Arch Neural Arch
• Posterior part
• Formed by pedicle and lamina on each side

13
Clinical Anatomy

• Bony Anatomy
• Vertebral Foramen
• Opening
• Pedicles (2)
• Sides of vertebral arch
• Little feet project posteriorly from body
• Laminae (2)
• Flat roof plates
• Complete arch posteriorly

Thoracic Vertebrae
14
Clinical Anatomy

• Bony Anatomy
• Transverse Processes
• Project laterally from each pedicle-lamina
  junction
• Attachment site for intrinsic ligaments and
  muscles
• Spinous Processes
• Prominent posterior projections
• Attachment site for intrinsic ligaments and
  muscles

15
Cervical Vertebrae
16
Cervical Vertebrae
17
Thoracic Vertebrae
18
Thoracic Vertebrae
19
Lumbar Vertebrae
20
Lumbar Vertebrae
21
(No Transcript)
22
Clinical Anatomy

• Facet Joints
• 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

23
Clinical Anatomy

• Pars Interarticularis
• 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

24
Clinical Anatomy

• Intervertebral Foramen
• 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)

25
Vertebral Anatomy
Level Vertebral Body Transverse Process Spinous Process
Cervical Small Vertebral body absent in C1 remaining bodies progressively ? in size Short Processes contain the transverse foramen for passage of vertebral artery Small and short, except for C7 (characteristics of thoracic vertebrae)
Thoracic Diameter and thickness ? as spine continues inferiorly Attachment of muscles and costovertebral ligaments Processes of T1-T12 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
26
Clinical Anatomy

• Thoracic Segment
• Wider/thicker help support torso weight
• Spinous Processes
• Downward projection
• Limit extension
• Attachment for thoracic muscles/ligaments
• Transverse Processes
• Costotransverse Joints
• Articulation with ribs
• Ribs 1 10
• Ribs 11 and 12
• No articulation with transverse processes

27
Clinical Anatomy
Costovertebral Joint
Costotransverse Joint
28
Clinical Anatomy

• Thoracic Segment
• Costovertebral Joint
• Articulation between vertebral bodies and ribs
• Superior and Inferior Costal Facets

Superior Costal Facet
Inferior Costal Facet
29
Clinical Anatomy

• Sacrum
• Curved, triangular shaped
• 5 fused vertebrae
• Fixes the spinal column to the pelvis
• Stabilizes the pelvic girdle

30
Clinical Anatomy

• Sacroiliac Joint (SI)
• Between the sacrum (base of the spine) and the
  ilium of the pelvis
• Strong, weight bearing synovial joints (2)
• Covered by 2 different kinds of cartilage
• Sacral surface (hyaline cartilage)
• Iliac surface (fibrocartilage)
• Functions
• Shock absorption (spine)
• Allows the transverse rotations (lower extremity)
  to be transmitted up the spine.
• Motions
• Anterior innominate tilt
• Posterior innominate tilt
• Sacral flexion (or nutation)
• Sacral extension (or counter-nutation)

31
Clinical Anatomy
32
Clinical Anatomy

• SI Ligaments
• Anterior Sacroiliac Ligament
• Connects the anterior surface of the lateral part
  of the sacrum to the ilium

Note Black Arrow
33
Clinical Anatomy

• SI Ligaments
• Posterior Sacroiliac Ligament
• Forms the chief bond of union between the bones
• Upper part (short PSL)
• Nearly horizontal in direction
• Ilium to upper sacrum
• Lower part (long PSL)
• Oblique in direction
• Lower sacrum to PSIS

Short PSL
Long PSL
34
Clinical Anatomy

• SI Ligaments
• Sacrotuberous Ligament
• Arises from ischial tuberosity to blend in with
  inferior fibers of posterior SI ligaments

Sacrotuberous Ligament
Ischial Tuberosity
35
Clinical Anatomy

• SI Ligaments
• Sacrospinous Ligament
• Originates from the ischial spine and attaches to
  the coccyx

Sacrospinous Ligament
36
(No Transcript)
37
Clinical Anatomy

• Coccyx Tailbone
• Consists of 4 (in some cases 3 or 5) vertebrae
  fused together
• Attachment site for muscles of pelvic floor and
  sometimes portions of gluteus maximus

38
Clinical Anatomy

• Intervertebral Discs
• 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
• Shock absorbers
• walking, jumping, running
• Allow spine to bend
• At points of compression, the discs flatten out
  and bulge out a bit between the vertebrae

39
Clinical Anatomy

• Nucleus Pulposus Core
• Gelatinous, acts like a rubber ball (enables
  spine to absorb compressive forces)
• 60-70 water
• Annulus Fibrosus Outer rings
• Multilayered fibers (cross from opposite
  directions)
• Rings absorb compressive forces themselves

40
Clinical Anatomy

• 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
• Flattens out (height is 1-2 centimeters less at
  night than when we awake in morning)
• Aging Process Permanent dehydration (ages 40
  60)
• Decreased ROM
• Narrowing intervertebral foramen

41
Clinical Anatomy

• Lumbar and Sacral Plexus
• Lumbar
• Formed by 12th thoracic nerve and L1-L5 nerve
  roots
• Innervation
• 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

42
(No Transcript)
43
Clinical Anatomy

• Lumbar and Sacral Plexus
• Sacral
• Formed by L4, L5 and lumbosacral trunk
• Innervation
• Muscles of buttocks, posterior femur, and lower
  leg
• Sciatic Nerve 3 sections
• Tibial nerve
• Common peroneal nerve
• Tibial nerve

44
(No Transcript)
45
Clinical Anatomy
46
Clinical Anatomy

• Lumbarization
• 1st sacral vertebrae does not unite with sacrum
• Becomes a 6th lumbar vertebrae
• Sacralization
• 5th lumbar vertebrae becomes fused to sacrum

47
Clinical Anatomy

• Extrinsic Muscles primarily function to provide
  respiration and movement associated with the
  upper extremity and scapula
• Indirectly influence the spinal column
• Intrinsic Muscles lie close to spinal column
• Directly influence the spinal column

48
Clinical Anatomy

• Middle Trapezius
• 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

49
Clinical Anatomy

• Lower Trapezius
• O Spinous processes of T8 T12
• I Scapular spine (medial portion)
• A Scapular depression and retraction fixation
  of thoracic spine

50
Clinical Anatomy

• Rhomboid Muscles
• 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

51
Clinical Anatomy

• Latissimus Dorsi
• 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)

52
Clinical Anatomy

• Rectus Abdominis
• O Pubic crest and symphysis
• I Xiphoid process and costal cartilages of 5th,
  6th, and 7th ribs
• A Trunk flexion compression of abdomen

53
Clinical Anatomy

• External Oblique
• 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

54
Clinical Anatomy

• Internal Oblique
• 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

55
Clinical Anatomy

• Erector Spinae 3 muscle pairs
• Iliocostalis
• Iliocostalis Lumborum
• Iliocostalis Thoracis
• Iliocostalis Cervicis
• Longissimus
• Longissimus Thoracis
• Longissimus Cervicis
• Longissimus Capitis
• Spinalis
• Spinalis Thoracis
• Spinalis Cervicis
• Spinalis Capitis

56
Clinical Anatomy

• Transversospinal Muscles
• Deep intrinsic layer
• Fibers run from 1 transverse process to the
  spinous process superior to them
• Group formed by
• Semispinalis
• Multifidus
• Rotators

57
(No Transcript)