1. Thoracic and Lumbar Spine Anatomy Dr.S.Nizamudeen

3. Anatomy Vertebral Column: Vertebral Column: Cervical Spine: Cervical Spine: Lordotic curvature Lordotic curvature Greatest ROM Greatest ROM Most vulnerable to injury Most vulnerable to injury Thoracic Spine: Thoracic Spine: Greatest protection Greatest protection Least ROM Least ROM Lumbar Spine: Lumbar Spine: Balance between protection/ROM Balance between protection/ROM

4. 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)

5. 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

6. 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

7. 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

8. 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

9. 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

10. 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

11. 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

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

14. Anatomy Bony Anatomy: Vertebral Foramen: Vertebral Foramen: Opening Opening Pedicles: (2) Sides of vertebral arch “Little feet” project posteriorly from body Laminae: (2) Flat roof plates Complete arch posteriorly Thoracic Vertebrae

15. 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

16. Cervical Vertebrae

18. Thoracic Vertebrae

20. Lumbar Vertebrae

24. Anatomy Facet Joints: Facet Joints: Articulations between superior articular facet (bottom vertebrae) and inferior articular facet (above vertebrae) Articulations between superior articular facet (bottom vertebrae) and inferior articular facet (above vertebrae) Contribute to ROM Contribute to ROM ↓ Weight-bearing stress through vertebral body and disc ↓ Weight-bearing stress through vertebral body and disc Synovial joints Synovial joints

25. Anatomy Pars Interarticularis: Pars Interarticularis: Area between the superior and inferior facets Area between the superior and inferior facets Common site for stress fractures (lumbar spine) Common site for stress fractures (lumbar spine) Spondylolysis - refers to the defect (black arrows) present when the pars interarticularis (green arrow) is fractured Spondylolysis - refers to the defect (black arrows) present when the pars interarticularis (green arrow) is fractured

26. Anatomy Intervertebral Foramen: Intervertebral Foramen: Space where spinal nerve roots exit the vertebral column Space where spinal nerve roots exit the vertebral column Size variable due to placement, pathology, spinal loading, and posture 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) Can be occluded by arthritic degenerative changes and space-occupying lesions (tumors, spinal disc herniations)

27. LevelVertebral BodyTransverse ProcessSpinous Process CervicalSmall; 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) ThoracicDiameter 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 ↓ LumbarVery broadLong for leverageSuperior borders are posteriorly projected with a large inferior flare Vertebral Anatomy

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

29. Anatomy Costotransverse Joint Costovertebral Joint

30. Anatomy Thoracic Segment: Thoracic Segment: Costovertebral Joint: Costovertebral Joint: Articulation between vertebral bodies and ribs Articulation between vertebral bodies and ribs Superior and Inferior Costal Facets Superior and Inferior Costal Facets Superior Costal Facet Inferior Costal Facet

31. Anatomy Sacrum: Curved, triangular shaped 5 fused vertebrae Fixes the spinal column to the pelvis Stabilizes the pelvic girdle

32. 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)

33. Anatomy

34. SI Ligaments: Anterior Sacroiliac Ligament: Connects the anterior surface of the lateral part of the sacrum to the ilium Note: Black Arrow

35. 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 PSLLong PSL

36. Anatomy SI Ligaments: Sacrotuberous Ligament: Arises from ischial tuberosity to blend in with inferior fibers of posterior SI ligaments Ischial Tuberosity Sacrotuberous Ligament

37. Anatomy SI Ligaments: Sacrospinous Ligament: Originates from the ischial spine and attaches to the coccyx Sacrospinous Ligament

39. 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

40. 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

41. 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

42. 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

43. Anatomy Lumbar and Sacral Plexus: Lumbar: Formed by 12 th 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

45. 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

47. Anatomy

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

49. 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

50. 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

51. Anatomy Lower Trapezius: O: Spinous processes of T8 – T12 I: Scapular spine (medial portion) A: Scapular depression and retraction; fixation of thoracic spine

52. 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

53. 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)

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

55. Anatomy External Oblique: O: 5 th through 12 th ribs I: Iliac crest and linea alba A: Bilaterally: trunk flexion; compression of abdomen; Unilaterally: lateral bending; rotation to opposite side

56. 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

57. 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

58. 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