Dalley, 10th Edition

Chapter 2 ■ Back

102

Margins of foramen magnum #

Tectorial membrane

Apical ligament

Anterior atlanto occipital membrane

Vertebral artery

Anterior arch of atlas (C1)

#

Articular cavity between dens and anterior arch (median atlantoaxial joint)

#

Posterior atlantooccipital membrane Posterior arch of atlas (C1) Posterior atlantoaxial membrane Superior longitudinal band Transverse ligament of atlas

D

Anterior atlantoaxial membrane

C2

Becomes

Becomes

Anterior longitudinal ligament

Cruciate ligament

Posterior longitudinal ligament

Inferior longitudinal band Ligamentum flavum

Becomes

(A) Medial section

Anterior articular cavity of median atlantoaxial joint

Anterior arch of atlas

Alar ligament

Superior articular facet of atlas

Dens of axis

Posterior articular cavity of median atlantoaxial joint

Transverse ligament of atlas

Vertebral canal Posterior arch of atlas

(B) Superior view Spinous process of axis

Cranium and atlas rotate left around pivot of dens

AA AT C1–C4 D

Anterior arch of C1 Anterior tubercle of C1 Cervical vertebrae Dens (odontoid) process of C2 Zygapophysial (facet) joint Lamina Posterior arch of C1 Posterior tubercle of C1 Superior articular facet of C1 Spinous process Foramen transversarium Vertebral canal

AT

AA

AA

D

Head turned left

T

FJ La PA PT SF

T

C1

SF

VC

PA

PA

PT

C2 SP T VC Copyright © 2027 Wolters Kluwer. Unauthorized reproduction of the article is prohibited. C3

La

La

C4

FJ

SP

(C) 3D CT reconstruction, posterosuperior view

Cranium and atlas rotate right around pivot of dens

FIGURE 2.23. Structure and function of median atlantoaxial joint. A. Continuity of craniovertebral membranes. B. Superior view of articulated atlas and axis. C. Three-dimensional reconstructed CT image of upper cervical spine. D. Motion at atlantoaxial joints. The cranium and atlas move as a unit around the pivot of the dens of axis.

Head turned right

(D) Superior views