1. Thoracic and Lumbar Spine Anatomy
Orthopedic Assessment III – Head, Spine, and Trunk with Lab
PET 5609C

2. Clinical Anatomy Vertebral Column: Cervical Spine: Thoracic 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

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: Pedicles: (2)
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

15. Cervical Vertebrae

16. Cervical Vertebrae

17. Thoracic Vertebrae

18. Thoracic Vertebrae

19. Lumbar Vertebrae

20. Lumbar Vertebrae

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

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: Functions:
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 Annulus Fibrosus: Outer rings
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

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

45. Clinical Anatomy

46. Clinical Anatomy Lumbarization: Sacralization:
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