Fig. 2
From: Non-neoplastic pathology at the crossroads between neck imaging and cardiothoracic imaging
Infrahyoid deep neck spaces. The carotid space (CS) contains the cranial nerves IX–XII, internal jugular vein, and the internal carotid artery. The retropharyngeal space (RPS) is anterior to the vertebral column. The suprahyoid RPS contains fat and medial and lateral RPS nodes whereas the infrahyoid RPS contains fat only. The danger space (DS) is a potential space in the posterior RPS, separated from the anterior RPS by a facial “trap door”, approximately at the level of T3. RPS infection or tumor may spread to the mediastinum via this route. The visceral space (VS) contains thyroid and parathyroid glands, trachea, esophagus, recurrent laryngeal nerves, and pretracheal and paratracheal nodes. The posterior cervical space (PCS) contains fat, CNXI, and level V nodes. The perivertebral space (PVS) includes the prevertebral PVS and the paraspinal PVS. The prevertebral PVS contains brachial plexus and phrenic nerve, vertebral body, veins, arteries, and prevertebral and scalene muscles within. The paraspinal PVS contains only posterior vertebra elements and paraspinal muscles [3]