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Thoracic and Lumbar Spine Anatomy

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Presentation on theme: "Thoracic and Lumbar Spine Anatomy"— Presentation transcript:

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


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