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Thoracic and Lumbar Spine Anatomy. Orthopedic Assessment III – Head, Spine, and Trunk with Lab PET 5609C. Clinical Anatomy. Vertebral Column: Cervical Spine: Lordotic curvature Greatest ROM Most vulnerable to injury Thoracic Spine: Greatest protection Least ROM Lumbar Spine:
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Thoracic and Lumbar Spine Anatomy Orthopedic Assessment III – Head, Spine, and Trunk with Lab PET 5609C
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
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) 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 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 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 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 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 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 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 Clinical Anatomy Supraspinal Ligament
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
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 Clinical Anatomy Thoracic Vertebrae
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 Clinical Anatomy
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
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
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)
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
Clinical Anatomy Costovertebral Joint Costotransverse Joint
Clinical Anatomy • Thoracic Segment: • Costovertebral Joint: • Articulation between vertebral bodies and ribs • Superior and Inferior Costal Facets Superior Costal Facet Inferior Costal Facet
Sacrum: Curved, triangular shaped 5 fused vertebrae Fixes the spinal column to the pelvis Stabilizes the pelvic girdle Clinical Anatomy
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)
SI Ligaments: Anterior Sacroiliac Ligament: Connects the anterior surface of the lateral part of the sacrum to the ilium Clinical Anatomy Note: Black Arrow
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 Clinical Anatomy Short PSL Long PSL
SI Ligaments: Sacrotuberous Ligament: Arises from ischial tuberosity to blend in with inferior fibers of posterior SI ligaments Clinical Anatomy Sacrotuberous Ligament Ischial Tuberosity
SI Ligaments: Sacrospinous Ligament: Originates from the ischial spine and attaches to the coccyx Clinical Anatomy Sacrospinous Ligament
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 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 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 Clinical Anatomy
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
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 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 Clinical Anatomy
Lumbarization: 1st sacral vertebrae does not unite with sacrum Becomes a 6th lumbar vertebrae Sacralization: 5th lumbar vertebrae becomes fused to sacrum Clinical Anatomy
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
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 Clinical Anatomy
Lower Trapezius: O: Spinous processes of T8 – T12 I: Scapular spine (medial portion) A: Scapular depression and retraction; fixation of thoracic spine 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 Clinical Anatomy