An anatomical basis for blocking of the deep cervical plexus and cervical sympathetic tract using an ultrasound-guided technique.

BACKGROUND: A selective blocking method for the cervical plexus and the cervical sympathetic trunk has not yet been established. METHODS: We performed a detailed examination of the neck anatomy using 28 cadavers. The pattern of local anesthetic distribution after injection in 2 healthy volunteers was imaged using computed tomographic scan. RESULTS: The deep cervical plexus was located in the groove between the longus capitis and scalenus medius muscles. The cervical sympathetic trunk was located on the anteromedial surface of the longus capitis. Although anesthetic injected into the longus capitis was confined to the muscle, it infiltrated into neighboring structures including the C2 to C5 roots and sympathetic trunk. CONCLUSIONS: The longus capitis muscle is a suitable landmark for blocking the cervical plexus and trunk.