1. DR FADEL NAIM IUG Anatomy of The Back I Dr. Fadel Naim Orthopedic Surgeon Faculty of Medicine IUG

2. DR FADEL NAIM IUG Functions Of Vertebral Column 1) Support weight Transmits weight to pelvis and lower limbs 2) Houses and protects spinal cord spinal nerves leave cord between vertebrae 3) Permits movements 4) Provides for muscle attachments muscles of back muscles of head Neck upper extremity thorax

3. DR FADEL NAIM IUG Regions and Normal Curvatures Formed from 33 bones in the adult Formed from 33 bones in the adult Divided into five major regions Divided into five major regions 1. Cervical vertebrae 7 vertebrae of the neck region 7 vertebrae of the neck region 2. Thoracic vertebrae 12 vertebrae of the thoracic region 12 vertebrae of the thoracic region 3. Lumbar vertebrae 5 vertebrae of the lower back 5 vertebrae of the lower back 4. Sacrum Inferior to lumbar vertebrae Inferior to lumbar vertebrae Articulates with coxal bones Articulates with coxal bones 5. Coccyx Most inferior region of the vertebral column Most inferior region of the vertebral column

4. DR FADEL NAIM IUG LEVEL CORRESPONDING STRUCTURE C2-3Mandible C3Hyoid bone C4-5Thyroid cartilage C6Cricoid cartilage C7Vertebra prominens T3Spine of scapula T8Point of inferior vena cava pierces diaphragm T10Xiphisternal junction T10Point of esophagus entering stomach T12Point of aorta entering abdomen L1End of spinal cord L3Subcostal plane L3-4Umbilicus L4Bifurcation of aorta L4Iliac crests S2End of dural sac

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6. DR FADEL NAIM IUG General Structure of Vertebrae

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8. DR FADEL NAIM IUG body Vertebral Parts spinous process vertebral foramen transverse process lamina pedicle rib facet

9. DR FADEL NAIM IUG Regions Vertebral Characteristics Specific regions of the spine perform specific functions Specific regions of the spine perform specific functions Types of movement that occur between vertebrae Types of movement that occur between vertebrae Flexion and extension Flexion and extension Lateral flexion Lateral flexion Rotation in the long axis Rotation in the long axis

10. DR FADEL NAIM IUG Cervical Vertebrae

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12. DR FADEL NAIM IUG Cervical Vertebrae Seven cervical vertebrae (C1 – C7) Seven cervical vertebrae (C1 – C7) smallest and lightest vertebrae smallest and lightest vertebrae C3 – C7 are typical cervical vertebrae C3 – C7 are typical cervical vertebrae Body is wider laterally Body is wider laterally Spinous processes are short and bifid (except C7) Spinous processes are short and bifid (except C7) Vertebral foramen are large and triangular Vertebral foramen are large and triangular Transverse processes contain transverse foramina Transverse processes contain transverse foramina Superior articular facets face superoposteriorly Superior articular facets face superoposteriorly

13. DR FADEL NAIM IUG The Atlas C1 is termed the atlas C1 is termed the atlas Lacks a body and spinous process Lacks a body and spinous process Supports the skull Supports the skull Superior articular facets receive the occipital condyles Superior articular facets receive the occipital condyles Allows flexion and extension of neck Allows flexion and extension of neck Nodding the head “yes” Nodding the head “yes”

14. DR FADEL NAIM IUG The Atlas

15. DR FADEL NAIM IUG The Axis Has a body and spinous process Has a body and spinous process Dens (odontoid process) projects superiorly Dens (odontoid process) projects superiorly Formed from fusion of the body of the atlas with the axis Formed from fusion of the body of the atlas with the axis Acts as a pivot for rotation of the atlas and skull Acts as a pivot for rotation of the atlas and skull Participates in rotating the head from side to side Participates in rotating the head from side to side

16. DR FADEL NAIM IUG Cervical Vertebrae Axis (C2) Atlas (C1) transverse foramen Dens (odontoid process) bifid process

17. DR FADEL NAIM IUG Transitions to thoracic vertebrae Transitions to thoracic vertebrae has a long spinous process with a broad tubercle has a long spinous process with a broad tubercle Not bifid Not bifid Vertebra prominens (C7)

18. DR FADEL NAIM IUG Thoracic Vertebrae (T 1 – T 12 ) All articulate with ribs All articulate with ribs Have heart-shaped bodies from the superior view Have heart-shaped bodies from the superior view Each side of the body of T2 – T10 bears hemifacts for articulation with ribs Each side of the body of T2 – T10 bears hemifacts for articulation with ribs T1 has a full facet for the first rib T1 has a full facet for the first rib T11 – T12 only have a single facet T11 – T12 only have a single facet

19. DR FADEL NAIM IUG Thoracic Vertebrae Spinous processes are long and point inferiorly Spinous processes are long and point inferiorly Vertebral foramen are circular Vertebral foramen are circular Transverse processes articulate with tubercles of ribs Transverse processes articulate with tubercles of ribs Superior articular facets point posteriorly Superior articular facets point posteriorly Inferior articular processes point anteriorly Inferior articular processes point anteriorly Allows rotation and prevents flexion and extension Allows rotation and prevents flexion and extension T10–T12 transition to lumbar vertebrae T10–T12 transition to lumbar vertebrae

20. DR FADEL NAIM IUG Lumbar Vertebrae (L 1 – L 5 ) Bodies are thick and robust Bodies are thick and robust Transverse processes are thin and tapered Transverse processes are thin and tapered Spinous processes are thick, blunt, and point posteriorly Spinous processes are thick, blunt, and point posteriorly Vertebral foramina are triangular Vertebral foramina are triangular Superior and inferior articular facets directly medially Superior and inferior articular facets directly medially Allows flexion and extension – rotation prevented Allows flexion and extension – rotation prevented

21. DR FADEL NAIM IUG Lumbar Vertebrae

22. DR FADEL NAIM IUG Vertebral Column intervertebral foamen intervertebral disk

23. DR FADEL NAIM IUG Thoracic & Lumbar Vertebrae lumbar vertebrae thoracic vertebrae

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25. DR FADEL NAIM IUG Sacrum (S 1 – S 5 ) Shapes the posterior wall of pelvis Shapes the posterior wall of pelvis Formed from 5 fused vertebrae Formed from 5 fused vertebrae Superior surface articulates with L5 Superior surface articulates with L5 Inferiorly articulates with coccyx Inferiorly articulates with coccyx Sacral promontory Sacral promontory Where the first sacral vertebrae bulges into pelvic cavity Where the first sacral vertebrae bulges into pelvic cavity Center of gravity is 1 cm posterior to sacral promontory Center of gravity is 1 cm posterior to sacral promontory Important in female Important in female

26. DR FADEL NAIM IUG Sacrum Sacral foramina Sacral foramina Ventral foramina Ventral foramina Passage for ventral rami of sacral spinal nerves Passage for ventral rami of sacral spinal nerves Dorsal foramina Dorsal foramina Passage for dorsal rami of sacral spinal nerves Passage for dorsal rami of sacral spinal nerves

27. DR FADEL NAIM IUG sacrum sacrum Characteristics : Characteristics : is curved, more in males than in females is curved, more in males than in females protects reproductive, urinary, and digestive organs protects reproductive, urinary, and digestive organs Attaches the axial skeleton to pelvic girdle of appendicular skeleton Attaches the axial skeleton to pelvic girdle of appendicular skeleton Together ith iliac bone SI joint Together ith iliac bone SI joint

28. DR FADEL NAIM IUG The Sacrum The adult sacrum: The adult sacrum: consists of 5 fused sacral vertebrae consists of 5 fused sacral vertebrae fuses between puberty and ages 25–30 fuses between puberty and ages 25–30 leaving transverse lines leaving transverse lines

29. DR FADEL NAIM IUG Sacral hiatus: Sacral hiatus: opening at the inferior end of the sacral canal opening at the inferior end of the sacral canal formed by ridges of sacral cornua formed by ridges of sacral cornua covered by connective tissues covered by connective tissues Sacral cornua: Sacral cornua: horn-shaped horn-shaped formed by laminae of the 5th sacral vertebra formed by laminae of the 5th sacral vertebra which do not meet at midline which do not meet at midline Sacral canal: Sacral canal: replaces the vertebral canal replaces the vertebral canal

30. DR FADEL NAIM IUG Median sacral crest: Median sacral crest: fused spinous processes fused spinous processes Sacral tuberosity: Sacral tuberosity: attaches ligaments of the sacroiliac joint attaches ligaments of the sacroiliac joint Lateral sacral crest: Lateral sacral crest: attach to muscles of lower back and hip attach to muscles of lower back and hip Auricular surface: Auricular surface: articulates with pelvic girdle (sacroiliac joint) articulates with pelvic girdle (sacroiliac joint)

31. DR FADEL NAIM IUG 4 Regions of the Sacrum 4 Regions of the Sacrum Base Base the broad superior surface the broad superior surface Ala-wings Ala-wings at either side of the base to attach muscles at either side of the base to attach muscles Sacral promontory Sacral promontory at the center of the base at the center of the base Apex Apex the narrow inferior portion articulates with the coccyx the narrow inferior portion articulates with the coccyx

32. DR FADEL NAIM IUG sacral foramen sacral hiatus sacral canal medial sacral crest Sacrum (5 fused vertebrae)

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34. DR FADEL NAIM IUGCoccyx Is the “tailbone” Is the “tailbone” Formed from 3 – 5 fused vertebrae Formed from 3 – 5 fused vertebrae Offers only slight support to pelvic organs Offers only slight support to pelvic organs attaches ligaments and a constricting muscle of the anus attaches ligaments and a constricting muscle of the anus

35. DR FADEL NAIM IUG Coccyx

36. DR FADEL NAIM IUG IMPORTANT VARIATIONS IN THE VERTEBRAE The seventh cervical vertebra may possess a cervical rib The first lumbar vertebra, which may have a rib. Sacralization of 5 th lumbar vertebra Lumberalization of 1 st sacral vertebra A large extent of the posterior wall of the sacral canal may be absent The coccyx may have three or five vertebrae. The first coccygeal vertebra may be separate.

37. DR FADEL NAIM IUG Joints between vertebrae in the back A typical vertebra has a total of six joints with adjacent vertebrae: A typical vertebra has a total of six joints with adjacent vertebrae: four synovial joints (two above and two below) four synovial joints (two above and two below) two symphyses (one above and one below). two symphyses (one above and one below). Each symphysis includes an intervertebral disc. Each symphysis includes an intervertebral disc.

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40. DR FADEL NAIM IUG Movements of the spine are a function of the following features: Movements of the spine are a function of the following features: Size and compressibility of intervertebral discs Size and compressibility of intervertebral discs Tightness of joint capsules Tightness of joint capsules Orientation of articular facets Orientation of articular facets Muscle and ligament function Muscle and ligament function

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42. DR FADEL NAIM IUG Regions and Normal Curvatures Four distinct curvatures give vertebral column an S-shape Four distinct curvatures give vertebral column an S-shape Cervical and lumbar curvature Cervical and lumbar curvature concave posteriorly concave posteriorly Thoracic and sacral curvatures Thoracic and sacral curvatures convex posteriorly convex posteriorly Curvatures increase the resilience of the spine Curvatures increase the resilience of the spine

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44. DR FADEL NAIM IUG The Axial Skeleton Throughout Life Curvatures of the vertebral column Curvatures of the vertebral column Primary curvatures Primary curvatures thoracic and sacral curvatures thoracic and sacral curvatures An infant's spine is C-shaped at birth An infant's spine is C-shaped at birth Secondary curvatures Secondary curvatures cervical and lumbar curvatures cervical and lumbar curvatures Develop when a baby begins to walk Develop when a baby begins to walk Redistributes weight of the upper body over the lower limbs Redistributes weight of the upper body over the lower limbs

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51. DR FADEL NAIM IUG TypePossible Cause IdiopathicUnknown Infantile (before 3 years of age) Juvenile (3 to 10 years of age) Adolescent (onset after age 10 years) CongenitalFailure of segmentation Failure of formation NeuromuscularCerebral palsy Myelomeningocele Muscular dystrophy Spinal muscular atrophy Friedreich ataxia Vertebral conditionsBenign bony tumors Bone infections Metabolic bone disease Spinal cord conditionsSyringomyelia Tethered cord syndrome Neurofibromatosis type 1 Connective tissue disordersMarfan syndrome Ehlers-Danlos syndrome

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61. DR FADEL NAIM IUG Intervertebral Discs Cushion-like pads between vertebrae Cushion-like pads between vertebrae Act as shock absorbers Act as shock absorbers Compose about 25% of height of vertebral column Compose about 25% of height of vertebral column Composed of: Composed of: 1. Nucleus pulposus 2. Annulus fibrosis

62. DR FADEL NAIM IUG Intervertebral Discs Nucleus pulposus Nucleus pulposus The gelatinous inner sphere of intervertebral disc The gelatinous inner sphere of intervertebral disc Enables spine to absorb compressive stresses Enables spine to absorb compressive stresses

63. DR FADEL NAIM IUG Intervertebral Discs Annulus fibrosis Annulus fibrosis An outer collar of ligaments and fibrocartilage An outer collar of ligaments and fibrocartilage Contains the nucleus pulposus Contains the nucleus pulposus Functions to Functions to Bind vertebrae together Bind vertebrae together Resist tension on the spine Resist tension on the spine Absorb compressive forces Absorb compressive forces

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70. DR FADEL NAIM IUG Disc Problems Slipped disc vs. herniated disc Slipped disc vs. herniated disc Most common sites for disc problems: Most common sites for disc problems: C5 - C6 C5 - C6 L4 - L5 L4 - L5 L5 - S1 L5 - S1 Laminectomy Laminectomy: ( surgical removal vertebral arch by shaving laminae to access disc) ( surgical removal vertebral arch by shaving laminae to access disc)

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