In Revelation 4:8, this signifies that what the Word continually teaches is that the Lord Jesus Christ alone is God, and is alone to be worshipped. (Apocalypse Explained 285, Apocalypse Revealed 247)

'The neck' signifies influx and the communication of interior and exterior levels and their conjunction. The inmost or third heaven has reference to the head and the middle or second heaven has reference to the body. Therefore, because it is in the middle, 'the neck' signifies influx, and the communication of celestial things with spiritual things.

(Reference: Arcana Coelestia 3603, 5328)