We attempted to synthesize the anatomy of the face and neck in this anatomy module. We used MRI images T2-weighted with axial, sagittal and coronal planes. 512 anatomical structures were dynamically labeled, and some structures have been redesigned or enhanced with a graphic tablet for better readability.

Cross-sectional anatomy: Magnetic Resonance Imaging of the head and neck

• An MRI of the face and neck was performed on a healthy patient, using T2 weighting, (image size: 320 * 320 pixels) (600 images). We did not select the T1 weighting because it provided a lower contrast. Unfortunately, during the MR exam, we discovered a thyroglossal duct cyst associated with ectopic thyroid behind the hyoid bone. We have didactically “cleared” this abnormal image in order to provide to users a normal exam; however anomalies can be seen in the pre-epiglottic fat body; please excuse us for this.
• After post-processing with Photoshop, DICOM images converted to JPEG have been included with Adobe Animate to create this dynamic module. Each anatomical element was labeled on the 3 space planes: axial, frontal and sagittal.

Anatomy of the face and neck: view anatomical labels

On the top menu, the user can select the labels to be displayed:

The bones of the face and neck were labeled using different colors to facilitate comprehension. The bone structures are rather more difficult to view on a weighted MRI T2 than on a CT-Scan: for more details on the bones of the face, please refer to the e-Anatomy module “Face-CT-Scan”.

• The teeth were numbered using the FDI World Dental Federation notation ISO-3950. 
• Due to the large number of muscle structures of the head and neck, we had to use several groups of muscles: muscles of the face, tongue, pharynx, larynx, neck, back and masticator muscles. 

• The fascias of the face and neck were labeled; however their complex structure could not be drawn.
• We tried to be as comprehensive as possible for the study of the nasal cavity, paranasal sinuses and oral cavity, however it is true that the descriptive anatomy of many structures is sometimes more difficult to see on MRI than as in the practice of other medical specialties (endoscopy, etc).
• We have distinguished the 3 parts of the pharynx (nasopharynx and oropharynx laryngopharynx) to limit the number of structures displayed on a single image.
• The tab larynx includes both the cartilage of the larynx but also all adjacent structures, including mucous membranes.
• The oesophagus, trachea and thyroid gland were grouped as they represent only few anatomical structures of this module.
• The arteries and veins of the face and neck were labeled focusing on large trunks emerging from the external carotid artery or draining into the jugular vein system.
• The peripheral nervous system is extremely complex as regards the otolaryngologic anatomy and was also segmented in several groups: first, the cranial nerves (trigeminal nerve (V) split into ophthalmic nerve (V1), nerve maxillary (V2) and mandibular nerve (V3 )); facial nerve (VII), vestibulo-cochlear nerve (VIII), glosso-pharyngeal nerve (IX), vagus nerve (X) (or pneumogastric), accessory nerve (XI) (Note that one of the roots was represented as cranial however recent studies suggest that it does not exist and that there is only a spinal root); hypoglossal nerve (XII); and secondly the autonomic nervous system and the system dependent on the spinal roots of the cervical and thoracic spinal cord (cervical plexus, brachial plexus and nervous system dependent branches after cervical). All these nerves and their branches were labeled according to their assumed position since they are very difficult to see directly on Magnetic Resonance Imaging. Only the cranial nerves at the emergence of the brainstem and spinal roots could be viewed directly. Other labels mainly followed the vessels to which they are most often joined.
• The lymphatic system was represented by green symbols to facilitate comprehension; indeed nodes from the face and neck were inconsistent, especially in healthy subjects. The terminology in practice uses a double nomenclature: anatomical names defined by the Terminologia Anatomica, but also a system of classification with numbers used by radiologists, oncologists and ENT surgeons (American Joint Committee on Cancer (AJCC) classification and American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) guidelines). We mainly used two publications: http://www.cancerimaging.org/2004/4/2/0020/ and http://archotol.ama-assn.org/cgi/content/full/125/4/388. Note that the supraclavicular nodes may be numbered V or IV, or simply referred to by their anatomical names. We decided to classify it VB.
• The deep spaces of the face and neck were completely redrawn for each image of each plane for direct viewing. Indeed there are already two e-Anatomy modules dedicated to this complex anatomy and we wanted to make it different by not using interactive areas. This last point in particular facilitates the teaching of deep spaces of the face and neck for students in medicine, anatomy or nurses and paramedics, who may directly study the limits and content of these spaces. Most of these spaces are not explained as such in the Terminologia Anatomica and their names vary among authors. To facilitate understanding and to avoid any controversy, we show different spaces on the right and left part of the axial and coronal slices. We welcome any comments on this critical point.

The anatomical structures were labeled by Antoine Micheau M.D. (Radiologist, Montpellier – France), using the Terminologia Anatomica. This module can be used as a medical dictionary. 

This atlas of otolaryngologic anatomy on an MRI of the face and neck was designed to facilitate the teaching by anatomists in different universities and medical schools, to facilitate the understanding of students preparing for medical exams (as well as exams for nurses, radiology technicians and physiotherapists), but also to facilitate medical practice common in radiology, radiotherapy, oncology, nuclear medicine, dental, ENT and maxillo-facial surgery and medicine in general.