1. Mark Kozsurek, M.D., Ph.D. mark@kozsurek.hu
Composition of the vertebral column Atlanto-occipital and atlanto-axial joints
Mark Kozsurek, M.D., Ph.D.
ED I, 07/12/2016

2. I. The vertebral column
Strong but flexible axis of the human body providing attachment for the shoulder and pelvic girdles and many muscles.
Transmits body weight when standing and acts as a shock absorber during walking.
Protects spinal cord.
It is composed of 7 cervical, 12 thoracic, 5 lumbar, 5 sacral and 4-6 coccygeal vertebrae.

3. The vertebral column as a whole
primary: thoracic and sacral kyphotic curves
lifting the head: cervical lordotic curve
siting, standing: lumbar lordotic curve

4. Composition of the vertebral column
How vertebrae are connected together?
How these connections provide stiffness and/or flexibility?
synostosis
synchondrosis
syndesmosis
synovial joints

5. synostosis: sacrum, coccygeal bone

6. synchondrosis: intervertebral disks – shock absorbtion

7. Intervertebral disks have a gelatinous core (nucleus pulposus) surrounded by a fibrous ring (anulus fibrosus).

8. syndesmosis: ligaments – balance between stiffness and flexibility

10. interspinal, supraspinal and
intertransverse ligaments

11. Anterior longitudinal ligament: arrises from the occipital bone as the anterior atlanto-occipital membrane and descends along the vertebrae and is attached bot to the vertebrae and the intervertebral disks.
Posterior longitudinal ligament: originates anterior to the foramen magnum as the tectorial membrane and descends behind the vertebral bodies constituting the anterior wall of the vertebral canal. In contrast to the anterior longitudinal ligament it is only attached to the posterior rim of the disks.
Ligamentum flavum: fills the gaps among adjacent vertebral arches.

12. zygapophyseal joints: each vertebrae are connected to their upper and lower neighbours through a pair of superior and inferior articular processes (gliding or plane joints).

14. Movements of the backbone
Cervical part: the most flexible part with flexion-extension, lateral bending and rotation.
The neck is much slimmer then the trunk, and the soft tissues do not limit movement.
Intervertebral disks are relatively thick compared to the cervical vertebrae.
Zygapophyseal articular surfaces are big and capsules are loose.

15. Thoracic part: very limited movement (that also serves the protection of thoracic organs), mainly lateral bending.
Thoracic vertebrae are connected to the sternum via the ribs.
Lumbar part: lateral bending and extension mainly, but rotation is impossible.

16. II. The vertebral column – head junction
atlanto-occipital joint
atlanto-axial joint

17. The atlanto-occipital joint
Surfaces:
superior articular sfacets of atlas and the occipital condyle

18. Mechanizsm: elipsoid joint (biaxial with two perpendicular axes)
transverse axis: flexion - extension („yes-yes”)
sagittal axis: lateral bending („well-well”)

19. The atlanto-axial joint
Surfaces:
1. inferior facet of atlas and superior facet of axis
2. tooth process of axis and the atlas with related ligaments

20. ant. facet of dens – fovea dentis
post. facet of dens – transverse ligament of atlas

21. Mechanism:
trochoid joint: vertical axis with rotation („no-no”)

22. Putting together: Atlanto-occipital joint elipsoid joint
Atlanto-axial joint
trochoid joint
vertical axis
Atlanto-occipital joint
elipsoid joint
sagittal and transverse axes
2+1 axis≈ spheroid joint

23. lig. apicis dentis: remnant of notochord
TUMOR
posterior view
alar ligament: keeps the occipital bone, the atlas and the axis together and limits their movments.
lig. apicis dentis: remnant of notochord

24. Cruciform ligament of atlas: provides socket for the posterior facet of the tooth process, consists of the transverse ligament and the longitudinal fascicles.

25. dens axis
post. longitudinal lig.

26. post. longitudinal lig.
ant. longitudinal lig.
ligg. flava

27. III. Muscles acting upon the atlanto-occipital, atlanto-axial joints and the vertebral column

28. nape muscles neck muscles back muscles abdominal mucles
cervical vertebral column
atlanto-occipital joints,
atlanto-axial and
neck muscles
back muscles
abdominal mucles
thoracic and lumbar vertebral column

29. Muscles of the neck (ventrally)
→ see elsewhere!!!
Sternocleidomastoid
Rectus capitis lateralis
Rectus capitis anterior
Longus capitis and colli
prevertebral muscles

30. Prevertebral muscles

31. Muscles of the neck (ventrally)
→ see elsewhere!!!
Sternocleidomastoid
Rectus capitis lateralis
Rectus capitis anterior
Longus capitis and colli
Muscles of the nape (dorsally)
Trapezius (found in the nape but a dorsal thoracoappendicular muscle!)
Splenius capitis, Longissimus capitis
Semispinalis capitis
Rectus capitis posterior major and minor,
Obliquus capitis superior and inferior
prevertebral muscles
suboccipital muscles

32. 2. Splenius and longissimus capitis
1. Trapezius
3. Semispinalis capitis
4. Suboccipital muscles

33. Suboccipital muscles
Suboccipital trigone: vertebral artery , suboccipital nerve (from C1)

34. There is a substantial overlap between muscles acting upon the atlanto-occipital and atlanto-axial joints and the cervical vertebral column!

35. nape muscles neck muscles back muscles abdominal mucles
cervical vertebral column
atlanto-occipital joints,
atlanto-axial and
neck muscles
back muscles
abdominal mucles
thoracic and lumbar vertebral column

36. ABDOMINAL MUSCLES – see elsewhere!
BACK MUSCLES
Superficial back muscles (or dorsal thoracoappendicular muscles): are found on the back, but do not act upon the vertebral column, e.g.: Trapesius, Levator scapulae, Rhomboids, Latissimus dorsi.
Deep or intrinsic back muscles:
Erector spinae
Spinalis
Longissimus
Iliocostalis
Transversospinal muscles
Semispinalis
Multifidus
Rotatores
ABDOMINAL MUSCLES – see elsewhere!

37. Depending on their location cervical, thoracis and lumbar parts can be distinguished within the Erector spinae muscles (e.g. Iliocostalis lumborum, thoracis and cervicis, etc.)

38. Within the transversospinal group the most superficial Semispinalis is almost vertical, the intermediate Multifidus is oblique, while the deepest Rotatores are close to horizontal.

40. Clinical considerations

41. Lumbar punction

43. Spinal disk herniation

45. Abnormalities of spinal curves

46. I II
X-ray

47. MRI

48. Fractures
car accident,
young victims

49. Chordoma
Rare but malignant tumor arising from the remnant of the notochord typically around the clivus.

50. Thank you for your attention!