Cervical MR Imaging in Postural Headache: MR Signs and Pathophysiological Implications

A, Posterior view of venous structures in suboccipital and upper cervical region. A, rectus capitis posterior major muscle; B, obliquus capitis superior muscle; C, obliquus capitis inferior muscle; D, semispinalis cervicis muscle; E, splenius cervicis muscle; F, atlantooccipital membrane; G, atlantoaxial membrane; H, dura;

SOVP, suboccipital venous plexus (note: slightly pulled up to visualize upper suboccipital triangle);

sPEVVP, superficial posterior external vertebral venous plexus;

DCV, deep cervical vein; PIVVP, posterior internal vertebral venous plexus; VA, vertebral artery; VV, vertebral veins; dPEVVP, deep posterior external vertebral venous plexus; VAVP, vertebral artery venous plexus; SOCS, suboccipital cavernous sinus; CEV, condylar emissary vein; MEV, mastoid emissary vein; I, atlas (posterior arch); II, axis (spinous process in A, body in B); asterisk, anastomotic vein.

B, Transverse section at the C1–C2 level. G, atlantoaxial membrane; H, dura; AIVVP, anterior internal vertebral venous plexus; IVV, intervertebral vein; PIVVP, posterior internal vertebral venous plexus; DCV, deep cervical vein; sPEVVP, superficial posterior external vertebral venous plexus; NL, nuchal ligament; dPEVVP, deep posterior external vertebral venous plexus; VA, vertebral artery; VAVP, vertebral artery venous plexus; LAAJ, lateral atlantoaxial joint; asterisk, anastomotic vein (between PIVVP and dPEVVP through G).