Ultrasound-Guided Third Occipital Nerve and Cervical Medial Branch Nerve Blocks

Abstract

Cervical zygapophyseal (facet) joints are diarthrodial joints formed by the superior articular process of one cervical vertebra articulating with the inferior articular process of the vertebrae above at the level of the junction of the lamina and the pedicle. The angulations of the facet joints increases caudally, being about 45° to the transverse plane at the upper cervical level to assuming a more vertical position at the upper thoracic level. The superior articular process also faces more posteromedial at the upper cervical level, and this changes to more posterolateral at the lower cervical level, with C6 being the most common transition level [1, 2].