Differential diagnosis of head and neck lesions based on their space of origin. 2. The infrahyoid portion of the neck.

The infrahyoid portion of the neck can be considered as a series of contiguous fascial planes and intervening spaces that lend themselves well to axial imaging. These spaces can serve as a basis on which to formulate differential diagnoses for diseases in this region. This pictorial essay describes the fascia and fascial spaces of the infrahyoid portion of the neck. The contents of each space, the common abnormalities affecting the space, and the characteristic displacements produced by disease in each space are reviewed.