Thoracic and Lumbar Spine AnatomyOrthopedic Assessment III Head, Spine, and Trunk with LabPET 5609C

Clinical AnatomyVertebral Column: Cervical Spine:Lordotic curvatureGreatest ROMMost vulnerable to injuryThoracic Spine:Greatest protectionLeast ROMLumbar Spine:Balance between protection/ROM

Clinical AnatomyVertebral Column:Extends from skull to the pelvis33 total vertebrae:Superiorly: 24 individual vertebrae (separated by intervertebral discs)Inferiorly: 9 fuse to form 2 composite bonesSacrum (5)Coccyx (4)

Clinical AnatomyVertebral Column:Functions:Transmits weight of the trunk to the lower limbsSurrounds/protects spinal cordAttachment point for the ribs and muscles of neck and back

Clinical AnatomyVertebral Column: Major Supporting LigamentsAnterior Longitudinal Ligament runs vertically along anterior surface of vertebral bodiesNeck - SacrumAttaches strongly to both vertebrae and intervertebral discs (very wide)Prevents back hyperextension

Clinical AnatomyVertebral Column: Major Supporting LigamentsPosterior Longitudinal Ligament - runs vertically along posterior surfaces of vertebral bodiesNarrower, weakerAttaches to intervertebral discsPrevents hyperflexion

Clinical AnatomyVertebral Column: Major Supporting LigamentsLigamentum Flavum - strong ligament that connects the laminae of the vertebraeProtects the neural elements and the spinal cordStabilizes the spine to prevent excessive vertebral body motionStrongest of the spinal ligaments Forms the posterior wall of the spinal canal with the laminaeStretches with forward bending / recoils in erect position

Clinical AnatomyVertebral Column: Supporting LigamentsIntertransverse Ligament - located between the transverse processesCervical region: consist of a few irregular, scattered fibersThoracic region: rounded cords connected with deep muscles of the backLumbar region: thin and membranous

Clinical AnatomyVertebral Column: Supporting LigamentsInterspinal Ligament - connect spinous processes (spans the entire process)Meets the ligamentum flavum in front and the supraspinal ligament behind

Clinical AnatomyVertebral Column: Supporting LigamentsSupraspinal Ligament -connects together the apexes of the spinous processesExtends from 7th cervical vertebra to sacrumStrong fibrous cordAt points of attachment (tips of the spinous processes) fibrocartilage is developed in the ligamentSupraspinal Ligament

Clinical AnatomyBony Anatomy: Body : CentrumAnterior partWeight-bearing segmentVertebral Arch: Neural ArchPosterior partFormed by pedicle and lamina on each side

Clinical AnatomyBony Anatomy: Vertebral Foramen:OpeningPedicles: (2)Sides of vertebral archLittle feet project posteriorly from bodyLaminae: (2)Flat roof platesComplete arch posteriorly

Thoracic Vertebrae

Clinical AnatomyBony Anatomy:Transverse Processes:Project laterally from each pedicle-lamina junctionAttachment site for intrinsic ligaments and musclesSpinous Processes:Prominent posterior projectionsAttachment site for intrinsic ligaments and muscles

Cervical Vertebrae

Cervical Vertebrae

Thoracic Vertebrae

Thoracic Vertebrae

Lumbar Vertebrae

Lumbar Vertebrae

Clinical AnatomyFacet Joints:Articulations between superior articular facet (bottom vertebrae) and inferior articular facet (above vertebrae)Contribute to ROM Weight-bearing stress through vertebral body and discSynovial joints

Clinical AnatomyPars Interarticularis:Area between the superior and inferior facetsCommon site for stress fractures (lumbar spine)Spondylolysis - refers to the defect (black arrows) present when the pars interarticularis (green arrow) is fractured

Clinical AnatomyIntervertebral Foramen:Space where spinal nerve roots exit the vertebral columnSize variable due to placement, pathology, spinal loading, and postureCan be occluded by arthritic degenerative changes and space-occupying lesions (tumors, spinal disc herniations)

Vertebral Anatomy

LevelVertebral BodyTransverse ProcessSpinous ProcessCervicalSmall; Vertebral body absent in C1; remaining bodies progressively in sizeShort; Processes contain the transverse foramen for passage of vertebral arterySmall and short, except for C7 (characteristics of thoracic vertebrae)ThoracicDiameter and thickness as spine continues inferiorlyAttachment of muscles and costovertebral ligaments; Processes of T1-T12 have articular surfaces for the ribsLong 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

Clinical AnatomyThoracic Segment:Wider/thicker help support torso weightSpinous Processes:Downward projectionLimit extensionAttachment for thoracic muscles/ligamentsTransverse Processes:Costotransverse Joints: Articulation with ribsRibs 1 10 Ribs 11 and 12No articulation with transverse processes

Clinical AnatomyCostotransverseJointCostovertebralJoint

Clinical AnatomyThoracic Segment:Costovertebral Joint:Articulation between vertebral bodies and ribsSuperior and Inferior Costal Facets

Superior Costal FacetInferior Costal Facet

Clinical AnatomySacrum:Curved, triangular shaped5 fused vertebraeFixes the spinal column to the pelvisStabilizes the pelvic girdle

Clinical AnatomySacroiliac Joint (SI):Between the sacrum (base of the spine) and the ilium of the pelvisStrong, weight bearing synovial joints (2)Covered by 2 different kinds of cartilageSacral 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)

Clinical Anatomy

Clinical AnatomySI Ligaments:Anterior Sacroiliac Ligament:Connects the anterior surface of the lateral part of the sacrum to the ilium Note: Black Arrow

Clinical AnatomySI Ligaments:Posterior Sacroiliac Ligament: Forms the chief bond of union between the bonesUpper part: (short PSL)Nearly horizontal in directionIlium to upper sacrumLower part: (long PSL)Oblique in directionLower sacrum to PSIS

Short PSLLong PSL

Clinical AnatomySI Ligaments:Sacrotuberous Ligament:Arises from ischial tuberosity to blend in with inferior fibers of posterior SI ligamentsIschial TuberositySacrotuberous Ligament

Clinical AnatomySI Ligaments:Sacrospinous Ligament:Originates from the ischial spine and attaches to the coccyxSacrospinous Ligament

Clinical AnatomyCoccyx: TailboneConsists of 4 (in some cases 3 or 5) vertebrae fused togetherAttachment site for muscles of pelvic floor and sometimes portions of gluteus maximus

Clinical AnatomyIntervertebral Discs:23 intervertebral discsNo disc between skull and C1 or between C1-C2Discs are thickest in the lumbar vertebrae and cervical regions (enhances flexibility)Functions:Shock absorberswalking, jumping, running Allow spine to bendAt points of compression, the discs flatten out and bulge out a bit between the vertebrae

Clinical AnatomyNucleus Pulposus: CoreGelatinous, acts like a rubber ball (enables spine to absorb compressive forces) 60-70% water Annulus Fibrosus: Outer ringsMultilayered fibers (cross from opposite directions)Rings absorb compressive forces themselves

Clinical AnatomyIntervertebral Discs: Dehydration ProcessCollectively, the discs make up about 25% of the height of the vertebral columnNucleus pulposus becomes dehydrated during course of dayFlattens out (height is 1-2 centimeters less at night than when we awake in morning)Aging Process = Permanent dehydration (ages 40 60)Decreased ROMNarrowing intervertebral foramen

Clinical AnatomyLumbar and Sacral Plexus:Lumbar:Formed by 12th thoracic nerve and L1-L5 nerve rootsInnervation:Anterior and medial muscles of thighDermatomes of medial leg and footFemoral Nerve formed by branches of L2, L3, L4 nerve rootsObturator Nerve anterior branches of L2, L3, L4

Clinical AnatomyLumbar and Sacral Plexus:Sacral:Formed by L4, L5 and lumbosacral trunkInnervation: Muscles of buttocks, posterior femur, and lower legSciatic Nerve 3 sectionsTibial nerveCommon peroneal nerveTibial nerve

Clinical Anatomy

Clinical AnatomyLumbarization:1st sacral vertebrae does not unite with sacrumBecomes a 6th lumbar vertebraeSacralization:5th lumbar vertebrae becomes fused to sacrum

Clinical AnatomyExtrinsic Muscles primarily function to provide respiration and movement associated with the upper extremity and scapulaIndirectly influence the spinal columnIntrinsic Muscles lie close to spinal columnDirectly influence the spinal column

Clinical AnatomyMiddle Trapezius:O: Lower portion of ligamentun nuchae and spinous processes of C7 and T1 T5I: Acromion process, scapular spineA: Scapular retraction and fixation of thoracic spine

Clinical AnatomyLower Trapezius:O: Spinous processes of T8 T12 I: Scapular spine (medial portion)A: Scapular depression and retraction; fixation of thoracic spine

Clinical AnatomyRhomboid Muscles:Rhomboid Major and MinorO: Spinous processes of C7 through T5I: Vertebral border of scapula between the spine and inferior angleA: Scapular retraction, elevation, and downward rotation; Fixation of thoracic spine

Clinical AnatomyLatissimus Dorsi:O: Spinous processes of T6 through T12 and the lumbar vertebrae via the thoracodorsal fascia, posterior iliac crestI: Intertubercular groove of humerusA: Extension of spine, anterior rotation of pelvis, stabilization of lumbar spine (depression of shoulder girdle, humeral extension)

Clinical AnatomyRectus Abdominis:O: Pubic crest and symphysisI: Xiphoid process and costal cartilages of 5th, 6th, and 7th ribsA: Trunk flexion; compression of abdomen

Clinical AnatomyExternal Oblique:O: 5th through 12th ribsI: Iliac crest and linea albaA: Bilaterally: trunk flexion; compression of abdomen; Unilaterally: lateral bending; rotation to opposite side

Clinical AnatomyInternal Oblique:O: Inguinal ligament, iliac crest, thoracolumbar fasciaI: Tenth, eleventh, and twelfth ribs; linea alba, crest of pubisA: Bilaterally: Trunk flexion, compression of abdomen; Unilaterally: lateral bending and rotation to same side

Clinical AnatomyErector Spinae: 3 muscle pairsIliocostalis:Iliocostalis LumborumIliocostalis ThoracisIliocostalis CervicisLongissimus:Longissimus ThoracisLongissimus CervicisLongissimus CapitisSpinalis:Spinalis ThoracisSpinalis CervicisSpinalis Capitis

Clinical AnatomyTransversospinal Muscles: Deep intrinsic layerFibers run from 1 transverse process to the spinous process superior to themGroup formed by:SemispinalisMultifidusRotators