HEAD AND NECK
Fig. 1. 38 Lateral radiograph of the neck: soft-tissue view showing pharynx and larynx. 1. Nasopharynx 2. Oropharynx 3. Laryngopharynx 4. Soft palate 5. Tongue G. Epiglottis 7. Base of tongue 8. Vallecula 9. Aryepiglottic fold 10. Ventricle 1 1 . Irregular calcification in superior cornu of thyroid cartilage 12. Calcification in lamina of thyroid cartilage 13. Inferior cornu of thyroid cartilage 14. Cricoid cartilage 15. Calcification in arytenoid cartilage 16. Body of hyoid bone 1 7 . Greater cornu of hyoid bone 18. Anterior arch of C, 19. Odontoid process of C2 2 0 . Body of C2 2 1 . Prevertebral space 2 2 . Prevertebral space 2 3 . Trachea
Palatal studies and videofluoroscopic feeding studies The movement of the palate during phonation can be imaged by radiography in the lateral projection, where the position of the soft palate can be seen outlined by air. Movement of the palate during complex speech is studied by videofluoroscopy with or without coating the nasal and oral surfaces of the palate with barium. Videofluoroscopy is also used to study the movement of the tongue, palate and pharynx during feeding by using foods and liquids of various consistencies mixed with barium. Cross-sectional imaging CT and MRI provide excellent detail of the pharynx, its fascial planes and its related spaces (see Figs 1. 34, 1. 35). Pathology in this region tends to cause asymmetry, which is readily detected. Images are usually obtained in the axial plane and a good understanding of the cross-sectional anatomy is therefore required. Coronal images may also be obtained by both modalities but are easier to obtain using MRI, as this may be performed without moving the patient. Pathology, especially carcinoma, of the nasopharynx spreads along the fascial planes and may extend intracranially through the many
foramina described. For this reason, imaging in both axial and coronal planes is necessary to evaluate the base of the skull. CT yields excellent axial images of the base of the skull and provides good bone detail. Both CT and MRI demonstrate the muscles and soft-tissue planes and the examinations are complementary. THE LARYNX (Figs 1. 38-1. 42) The larynx forms the entrance to the airway and is responsible for voice production. It extends from the base of the tongue to the trachea, lying anterior to the third to sixth cervical vertebrae. It lies between the great vessels of the neck and is covered anteriorly by the strap muscles of the neck, fascia and skin. It is lined by mucosa, which is continuous with that of the pharynx above and the trachea below. Its framework is composed of three single and three paired cartilages, which articulate with each other and are joined by muscles, folds and connective tissue. The anchor cartilage of the larynx is the cricoid cartilage This is shaped like a signet ring, with a flat, wide lamina posteriorly and an arch anteriorly. It is joined to the thyroid cartilage above by the cricothyroid membrane, and to the trachea below by the cricotracheal membrane. The paired pyramidal arytenoid cartilages sit on the superolateral
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