Lumbar vertebrae

Normal anatomy and clinical correlation of lumbar vertebrae

1. Lumbar Vertebrae Dr. Mathew Joseph MBBS,MD(2 nd Year),BCCPM Junior Resident Department of Anatomy All India Institute of Medical Sciences - Rishikesh

2. Learning Objectives General Features. Classification: Typical and Atypical Ossification Applied anatomy

3. General Features Lumbar vertebrae have Massive body . Vertebral foramen is Triangular . Spine is quadrangular . Superior articular facet is concave . Inferior articular facet is convex . Posterioinferior part of root of transverse process has a rough elevation called accessory process .

4. Classification Total number of Lumbar Vertebrae : 5 Typical : First to Fourth Atypical : Fifth

5. Typical Lumbar Vertebrae Body Vertebral foramen Vertebral arch i. Pedicles ii. Laminae iii. Spine iv. Transverse processes v. Articular processes

6. Body

7. Body Large Transverse diameter > Anterio -posterior diameter Upper and lower surfaces: Hyaline Cartilages Anterior surface: Anterior longitudinal ligament (ALL) in midline. Crura of diaphragm: Either side of ALL Right crus : Upper 3 Left crus : Upper 2 Psoas major and tendinous arches: Upper and lower margins of sides of body. Posterior surface: Posterior longitudinal ligament .

8. Vertebral Foramen Triangular in cross section Dura matar and Arachnoid matar : L1-L5 Conus medullaris with pia matar : L1 Cauda equina : L2-L5

9. Vertebral Arch Pedicles: Short and Strong Inferior vertebral notches are deeper than superior. Formation of intervertebral foramen . Traversed by spinal nerves and radicular vessels.

10. ii. Laminae : Short and Thick. Directed postero -medially. Ligamentum flavum : Upper border and lower half of its anterior surface. Posterior surface of lamina: Deep muscles of back

11. iii. Spine : Quadrilateral. Posterior border: Supraspinatus ligament (Midline), Posterior lamella of thoracolumbar fascia . Superior and Inferior borders: Interspinous ligaments (midline), Interspinalis muscles ( each side) Sides of spine: Deep muscles of back.

12. iv. Transverse Process(TP): Tapering and Thin. Homologous with ribs. Medial and lateral arcuate ligaments: Tip of TP of L1. Iliolumbar ligament: Tip of TP of L5 Middle lamella of thoracolumbar fascia: L1-L5

13. Anterior surface : Faint ridge: Anterior lamella of thoracolumbar fascia. Medial to ridge: Psoas major Lateral to ridge: Quadratus lumborum Upper and lower borders of TP : Intertransversarii muscles. Accessory process : Medial intertransverse muscle. Posterior surface of TP: Deep muscles of back.

14. v. Articular process: Superior articular facet: Concave , Medially Inferior articular facet: Convex , Lateraly Distance between the superior articular process is relatively more than inferior articular process in L1-L3 Relation is reversed in L5 Equal distant: L4

15. Posterior border of superior articular process : Mamillary process : Medial intertransverse muscles and deep muscles of back.

16. Atypical Vertebra Thick and short transverse process : Connected to whole of pedicles and part of body. The distance between inferior articular process is more than superior articular process. The body is very much deeper anteriorly than posteriorly .

17. Fawcetts’s rule for identification of individual lumber vertebrae. Trapezium : L1/L2 Vertical rectangle : L3 Square : L4 Horizontal Rectangle : L5

18. Ossification Of Lumbar Vertebrae Primary centers : 3 [1 Body, 1 for each half of vertebral arch] Appearance : 9-16 weeks IUL Fusion : Each half of vertebral arch with each other: 1 year : Vertebral arch with body: 3-6 years

19. Secondary centers : 5 1 each :Annular epiphyseal ring(upper and lower surface of body). 1 each: Tip of transverse process. 1: Tip of spine Appearance : Puberty Fusion : 25 years

20. 2 additional centers appear , 1 for each Mamillary process .

21. Applied anatomy Anomalies of vertebral coloumn . Sacralization of 5 th lumbar vertebra. Fusion of L5 with sacrum. Complete/Incomplete. Transverse process of L5 may articulate with ala of sacrum and compress the L5 spinal nerve.

22. Spina bifida: It occurs due to non-fusion of two halves of the vertebral arch. Meninges and spinal cord are exposed and may herniate out in midline through the gap.

23. Lumbar disc prolapse :

24. Lumbar Spondylolysis : Degenerative conditions affecting the discs, vertebral bodies, and associated joints of the lumbar vertebrae.

25. Cauda equina syndrome: Due to compression of cauda equina (L2-S1) Clinical presentation : Flaccid paraplegia Saddle – shaped anesthesia Bladder and bowel involvement Impotence Absence of knee and ankle reflex