Anatomy of the Spine #2 PDF

Functional Human Anatomy Spine #2 D R. D O N AL M U R R AY PH D H E AV Y C O N T R IBU T I O N S BY: D R. E LLE N C O S T E LLO, PT, PH D By the end of the session: Describe the components of the IV disc Describe the process associated with degeneration of the IV disc Explain what forces are produc...

Functional Human Anatomy Spine #2 D R. D O N AL M U R R AY PH D H E AV Y C O N T R IBU T I O N S BY: D R. E LLE N C O S T E LLO, PT, PH D By the end of the session: Describe the components of the IV disc Describe the process associated with degeneration of the IV disc Explain what forces are produced during spinal movements Identify the attachments, action and innervation associated with the deeper back muscles Identify the borders & content of suboccipital triangle Explain general signs/symptoms associated with identified low back related pathology Cervical X-Ray Cervical X-Ray Intervertebral Disc Found between adjacent vertebral bodies Shape corresponds to vertebral body shape Generally thicker ant than post in C & L region Disc adherent to thin layers of hyaline cartilage which cover the surfaces of the body Essentially avascular b/c sustained pressure ( if there was blood supply) would impede blood flow Rec’s nutrition by diffusion through the spongy bone of adj vertebra; requires motion to move fluid Intervertebral Disc cont. Each disc consists of: Annulus Fibrosis  Annulus Fibrosis Nucleus  AF=inner layer of fibrocartilage; Pulposus outer layer of collagenous fibers  Annular fibers-12-18 concentrically arranged rings running obliquely  Many mechanoreceptor & sensory receptors in outer layer  Peripheral aspect of annulus receives some blood supply from arteries supplying boney structures (e.g. vertebral bodies)  function-contains nucleus; permit deformation; resist tensile forces  Nucleus Pulposus Annulus Fibrosis Anterior Intervertebral Disc Nucleus Pulposus (inner core)  high percentage of H2O  composed of collagen within a mucoprotein jell; rich in hydrophilic Glycosaminoglycans (GAGS)  lies slightly posterior in the disc Disc function=redistribute forces “Herniated Disc”  Protrusion : mildest form: annular fibers still intact  Prolapsed : nuclear material reaches edge of disc and creates a bulge  Extrusion: annual fibers rupture; some nuclear material escapes  Sequestration: nuclear material free to roam Disc Degeneration Movements of Spinal Column In part guided and directed by the facet joints Facet joints innervated (sensory) by branches of dorsal rami Flexion ant disc compression tightening of PLL movement between inf artic process of vertebra above with sup articulating process of vertebra below Extension post disc compression tautness of ALL approximation of spinous processes Movements of the Spinal Column Sidebending lat disc compression Consensus clinically although literature is not overwhelming (Cook et al, 2006; see notes) Facet joint: SB associated with rotation (aka coupled motion behavior) Cervical region-SB & rotation occur to same side Thoracic & Lumbar region-SB & rotation to opposite sides Rotation Creates a shear stress on the IV disc Load and movement change the shape of the nucleus pulposus Thoracolumbar fascia (or lumbar fascia) Covers deep muscles of the back In thoracic region it is a thin covering for vertebral extensors; attached medially to T spines & laterally to costal angles At lumbar levels it is trilaminar  post layer attached to L & S spines & supraspinous ligaments  middle layer attached to tips of L transverse processes & ligaments, to iliac crest & 12th ribs  ant layer-covers quadratus lumborum m.  Anterior Layer TL fascia Middle Layer TL fascia Post layer TL fascia Muscles of the back The superficial extrinsic back muscles (trapezius, latissimus dorsi, levator scapulae, and rhomboids) The intermediate extrinsic back muscles (serratus posterior) are thin, weak muscles, commonly designated as superficial resp The intrinsic back muscles (muscles of back proper, deep back muscles) are innervated by the posterior rami of spinal nerves and act to maintain posture and control movements of the vertebral columniratory muscles Serratus Posterior Ms. (Intermediate Layer of Muscles) Serratus Posterior superior  From nuchal ligament, spinous processes of CV7 to TV3  To the superior borders of ribs 2-4  Axn: Elevate rib  Innervation: Intercostal nerves T2- T5 Serratus Posterior Inferior  Spinous processes of TV11 to LV2  To inferior borders of ribs 8-12 near angles  Axn: Depress ribs  Innervation: Intercostal nerves T9- T11 and subcostal nerve  Serratus posterior superior muscle Thoracolumbar fascia Deep Muscles of the Back Intrinsic Complex organization from pelvis to skull Includes the following:  extensors & rotators of head & neck  (splenius capitis & splenius cervicis)  short segmental muscles  (interspinales & intertransversarii)  spinal extensors: erector spinae  (iliocostalis, longissimus, spinalis)  & spinal rotators (transversospinales)  (semispinalis, rotatores, & multifidi) Complex organization from pelvis to skull includes the following: extensors & rotator of head & neck (splenius capitis & cervicis) Erector short segmental muscles spinae (interspinales & muscle intertransversarii) group spinal extensors: erector spinae (iliocostalis, longissimus, spinalis) & spinal rotators (transversospinales) (semispinalis, rotatores, & multifidi) Erector Spinae (aka sacrospinalis) Common distal attachment  Arises from a broad, thick tendon attached to the median sacral crest  Spines of TV11,12 and all LV,  and their supraspinous ligaments  The medial, dorsal ilium & lateral aspect of sacral crests Erector Spinae cont.  Subdivides into the following:  (iliocostalis, longissimus, spinalis groups)  Use common distal attachment for iliocostalis lumborum….. To the proximal attachment as follows…  Iliocostalis Lumborum-to the inferior borders of the lower 6 or 7 costal angles  Iliocostalis Thoracis- from the upper borders of the lower costal angles; ascends to the sup borders of the upper costal angles & the back of the 7th C transverse process  Iliocostalis Cervicis-ascends from the 3rd-6th costal angles to the post tubercles of the 4th to 6th C transverse process  Iliocostalis nerve supply-dorsal rami of C, T & upper L nerves  Iliocostalis axn-extension & lateral flexion of vertebral column Common distal attachment Ilocostalis: costal angles a major attachment Longissimus Group Longissimus thoracis-to the tips of all thoracic transverse processes & the lower 9 or 10 ribs between their tubercles & angles Longissimus cervicis-from long tendons attached from TV1-TV4 or T5 transverse processes to tendons attached to CV2-CV6 transverse process post tubercles Longissimus capitis-from tendons of TV1-TV4 or T5 transverse processes & lower 3 or 4 cervical articular processes to the post margin of mastoid process Longissimus nerve supply-dorsal rami of lower C, T & L spinal nerves Action-thoracis & cervicis-extend & SB vertebral column; capitis-ext the head & rot face to the same side Spinalis Group Spinalis thoracis-from TV11-LV2 spines to TV4 - TV8 spines Spinalis cervicis-(inconstant) from lower ligamentum nuchae, CV7 spine to spine of CV2 Spinalis capitis-blended with semispinalis capitis Spinalis nerve supply-dorsal rami of lower Cervical & Thoracic spinal nerves Spinalis Axn-ext of vertebral column Transversospinalis Muscle Group Ascends obliquely & medially from transverse processes to adjacent vertebral spines  Transversospinalis includes:  semispinalis thoracis, cervicis & capitis  multifidi  rotatores lumborum, thoracis & cervicis  Nerve Supply-dorsal rami C & T spinal nerves  Action:  semispinalis thoracis & cervicis-ext T & C vertebral regions, rot head contralaterally  capitis-ext the head, minimal rotation Semispinalis cervicis Rotatores thoracis Transversospinalis Group cont.  Multifidi-found in the groove lat to the vertebral spines from sacrum to axis; ascend medially the whole length of spine to the adj 3rd or 4th vertebrae above  Rotatores Cervicis, Thoracis, Lumborum-irregular, variable ms with similar attachments as the multifidi  Interspinales-short paired ms between adj vertebral spines  Intertransversarii-small ms between transverse processes  AXN-short dorsal ms are probably postural, steadying adjoining vertebrae & controlling them during motion of the column Suboccipital Triangle Subocciptal Triangle Borders Rectus capitis posterior minor ms.  Rectus capitis posterior major and minor  Superior oblique  Inferior oblique  AA membrane and post arch of CV1 (floor) Contents  Vertebral artery and suboccipital nerve (dorsal ramus of C1)  Suboccipital nerve innervates all 4 muscles of triangle Epidural Anesthesia Regional anesthesia resulting from injection of an anesthetic into the epidural space of the spinal cord Results in temporary anesthesia to abdominal and genital region and lower extremities Insertion usually LV3-4 or LV4-5 interspace… why? Osteoporosis Spine Decreased bone mass & microdamage to bone structure: bone now susceptible to fracture Primary: affects males and females:  Two types:  Postmenopausal/estrogen deficient  Age related  50% of females over 50 will experience fragility fracture  25% of males over 50 will experience fragility fracture Secondary: related to medication side effects or other diseases  Prolonged corticosteroid, heparin, anticonvulsant therapy Typical fracture sites: vertebral bodies, hip, ribs, radius, and femur (in that order) Vertebral compression fractures symptoms: severe back pain at site of fracture which may radiate, posture change, loss of height, functional impairment, disability, decreased QOL Compression Fracture Spinal Stenosis General term referring to a narrowing of the vertebral foramen  usually secondary to intervertebral disc degeneration causing encroachment of the foramen or  Osteophyte formation on vertebral bodies or  Calcification of ligamentous material Can result in compression of neural tissue resulting in sensory and motor dysfunction Common in those > 65 Spinal Stenosis Spondylolysis (posterior arch defect) Interruption of the pars interarticularis of the vertebra causing a unilateral or bilateral stress fracture Pars=portion of the posterior arch between sup & inf artic process Most likely an acquired abnormality due to abnormal vertebral stress between infancy and early adulthood Diff Dx: for adolescent/teenager active in sports with LBP Spondylolisthesis Spondylolysis can persist & develop into Spondylolisthesis One vertebral body slips forward in relation to an adjacent vertebra Most common LV4-5 & LV5- S1 interspace Spondylolisthesis is almost never due to trauma; usually 2’ overuse in young athletes Radiograph: ID Scottie dog with slippage at neck Let’s Recap Can you describe the components of an IV disc and disc function? How does the disc differ in shape as you move from the cervical region down to the lumbar region? Can you describe what happens to the ligaments and the IV discs during spinal flexion, extension, SB and rotation? Can you ID and provide general muscle attachments and innervation for the intermediate and deep muscles of the back? Can you ID and describe innervation for muscles of the suboccipital triangle? Can you describe the general pathology associated with osteoporosis, spinal stenosis, spondylolysis and spondylolisthesis?