1. To outline the normal anatomy of the fascial compartments of the head and neck (H&N). 2. To appreciate that knowledge of compartmental anatomy is essential for understanding the pathologies that arise in the different spaces, patterns of tumour propagation and the spread of infection.

Comprehension of the soft tissue spaces of the head and neck is often challenging. A brief overview of the anatomy is discussed before acompartmental approach is used. The neck is defined from the hard palate to the sternum & clavicles. It is divided into anterior and posterior compartments by sternocleidomastoid. The hyoid further divides it into supra and infrahyoid neck. The posterior compartment is divided by the inferior belly of omohyoid into: superior infraoccipital inferior subclavian The Aerodigestive Tract This is classically divided into the...

The Parapharyngeal Space (PPS) This space contains predominantly fat and is surrounded by several other important spaces. It is crescent shaped in its craniocaudal extent. It extends from the skull base to the superior cornu of hyoid thereby allowing spread of infection or tumour between surrounding compartments. The direction in which fat in PPS is displaced is important in identifying which space a lesion arises from and thereby helps to guide diagnosis. Borders Medial: pharyngeal mucosal spaces Lateral: masticator and parotid spaces Posterior: carotid space...

A knowledge of the anatomical spaces and understanding the patterns of disease are fundamental to guide to the diagnosis in imaging ofthe head and neck. Recognising the centre of a lesion and appreciating the direction of displacement of the fascial spaces, in particular the parapharyngeal space, leads to an accurate differentialdiagnosis and aids the localisation of the lesion.

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