Hypopharynx and larynx anatomy

Transcription

1 Hypopharynx and larynx anatomy Poster No.: C-0786 Congress: ECR 2016 Type: Educational Exhibit Authors: A. I. Fernández Martín, N. Delgado Ronda, E. Dominguez Franjo, M. Martínez Martínez-Losa, N. Alegre Borge, J Martínez Salazar ; Arganda del Rey, MADRID/ES, Ávila/ES, Arganda del Rey/ES, Madrid/ES, San Sebastián de los Reyes/ ES Keywords: Education and training, elearning, Education, MR, CT, Head and neck, Anatomy DOI: /ecr2016/C-0786 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 24

2 Learning objectives Review the ct and mri anatomy of the hypopharynx and larynx Correlate the images with the findings at endoscopy Page 2 of 24

3 Background The thorough knowledge of Anatomy is crucial to read head and neck studies so we intend to catch up this subject centered on hypopharynx and larynx subsites. The correlation with the laryngoscopy images add an extra value to understand the Anatomy itself and the otorhinolaryngologist point of view. For example, so we realize that the laryngoscopy doesn t depict the "outer" tissues of the airway, then Radiology takes over. The approach to this subject from different points of views but complementaries involves an integral cooperative job. Page 3 of 24

4 Findings and procedure details HYPOPHARYNX The hypopharynx extends from the vallecula to the inferior cricoid carilage (cricopharyngeal muscle). It consists of three regions: pyriform sinus, postcricoid area or prharygoesophageal junction and posterior hypopharyngeal wall. The pyriform sinus consists of an invaginaion of the aryepiglottic folds and the thyroid cartilage. Its inferior tip (apex) is located at the level of the true vocal cords. The postcricoid area or pharygoesophageal junction is the anterior wall of the hypopharynx at the level of the cricoid and extends from the level of cricoarytenoid joints to the lower border of the cricoid cartilage. It is an area difficult to evaluate with CT or MRI. The posterior hypopharyngeal wall continuates the posterior oropharynx wall; it is composed of mucosa and the constrictor muscle. LARYNX The larynx is divided into three subsites: supraglottis, glottis and subglottis. The supraglottis extends from the tip of the epiglottis to the laryngeal ventricles. It contais the vestibule, epiglottis, pre-epiglottic fat, aryepiglottic folds, false vocal cords, paraglottic space, arytenoids cartilages and ventricles. The epiglottis is a leaf-shaped flexible cartilage situated into the anterosuperior part of the laryx. It is seldom calcified. The epiglottis acts as a lid, protecting the airway during swallowing and is divided into the free margin (suprahyoid) and the fixed portion (infrahyoid). The petiole or "stem of a leaf" attaches the epiglottis to the thyroid lamina in conjunction with the thyroepiglottic ligament. Other connecting structures are the glossoepiglottic fold, the hyoepiglottic ligament and the pharyngoepiglottic folds that attacht the epiglottis to the tongue in the midline, the hyoid bone and the oropharynx respendolectively. The pre-epiglottic space represents the fat tissue situated anterior to the epiglottis and posterior to the hyoid bone. Page 4 of 24

5 The aryepiglottic folds separate the epiglottis (supraglottis) from the piriform sinuses (hypopharynx). They project from the superior tip of arytenoid cartilages to inferolateral edge of epiglottis. The false vocal cords consist of mucosa lining the laryngeal vestibule. The aryepiglottic folds are continuated inferiorly by the false vocal cords, and these by the the paraglottic spaces. The paraglottic spaces contain the fat situated beneath false and vocal cords. Superiorly, they blend with the pre-epiglotic space. The glottis includes exclusively the true vocal cords and anterior and posterior commissures. The true vocal cords are formed by the thyroarytenoid muscles, whose medial fibers are named "vocalis muscle". The point in which both vocal cords meet anteriorly is the anterior commissure. The subglottis extends from the undersurface of the true vocal cords to inferior surfaces of cricoid cartilage. This site comprises the mucosal surface at the level of cricoid cartilage, which includes the conus elasticus and the quadrangular membrane. The cricoid, thyroid and arytenoids cartilages serve as a framework for the soft tissue structures of the larynx. The thyroid cartilage is composed of two laminae that meet anteriorly at an acute angle with a notch in the anterior superior aspect. It acts as a protective shield. The superior and inferior horns strecht out from the posterior part of the laminae to articulate with the hyoid and cricoid cartilages respectively. The thyrohyoid ligaments attacht to the superior horns. The cricoid cartilage has a ring shape, only completed at the level of endolarynx. It consists of a posterior lamina and an anterior arch and its lower border separates the larynx above and the trachea below. The paired pyramidal arytenoid cartilages sit on top of the posterior cricoid cartilage (lamina) and move the vocal cords during phonation. Their vocal processes serve for the attachement of the posterior part of vocal cords. Their ossification begins by the age of 20. And as a "picture is worth a thousand words"...let s convert into images the theoretical knowkedge! The CT and plain radiograph images: Fig. 1 on page 7, Fig. 2 on page 7, Fig. 3 on page 8, Fig. 4 on page 9, Fig. 5 on page 10, Fig. 6 on page 11, Fig. 7 on page 12 & Fig. 8 on page 13 Page 5 of 24

6 The laryngoscopy images: Fig. 9 on page 14, Fig. 10 on page 15, Fig. 11 on page 16, Fig. 12 on page 17, Fig. 13 on page 18 & Fig. 14 on page 19 And MR-laryngoscopy images correlation: Fig. 15 on page 20, Fig. 16 on page 21 Page 6 of 24

7 Images for this section: Fig. 1: Axial CT image of the neck at the level of high supraglottic level of larynx UCR Page 7 of 24

8 Fig. 2: Axial CT image of the neck at a lower level than the previous image. The aryepiglottic folds depict the border between larynx and hypopharynx. UCR Page 8 of 24

9 Fig. 3: Axial CT neck image at the level of the true vocal cords. UCR Page 9 of 24

10 Fig. 4: Axial CT image of the neck at the level of the subglottis. This level starts when the cricoid cartilage is visible and no arytenoid cartilages are noted. Any soft tissue density in the subglottis is pathological and therefore suspicious of tumor extension into this level. UCR Page 10 of 24

11 Fig. 5: coronal reformatted ct image of the airway from the nasopharynx to larynx-trachea. UCR Page 11 of 24

12 Fig. 6: Saggital reformation obtained from CT images. UCR Page 12 of 24

13 Fig. 7: Plain film that depicts the airway. We usually tend to feel unconfortable with this technique, however it is exactly the same as the reformatted ct previous image! UCR Page 13 of 24

14 Fig. 8: A serie of axial CT images of the neck that depict the position of the nasogastric tube (as a marker of the hypopharynx and esophagus). The NGT is highlighted with a red arrow. For a better understanding, the hypopharynx-larynx crossroad can be conceptualised as a pair of trousers, in wich both share a common part and then each one takes its own way. UCR Page 14 of 24

15 Fig. 9: Image obtained from laryngoscopy. "Department of Otorhinolaryngology, Hospital del Sureste/Spain 2015 " Page 15 of 24

16 Fig. 10: Image (same image as the previous one) obtained from laryngoscopy, but with the signs. "Department of Otorhinolaryngology, Hospital del Sureste/Spain 2015 Page 16 of 24

17 Fig. 11: Image obtained from laryngoscopy at the level of epiglotis. "Department of Otorhinolaryngology, Hospital del Sureste/Spain 2015 Page 17 of 24

18 Fig. 12: Image obtained from laryngoscopy that depicts the level of the false and true vocal cords. "Department of Otorhinolaryngology, Hospital del Sureste/Spain 2015 Page 18 of 24

19 Fig. 13: Image obtained from laryngoscopy that depicts the true vocal cords abducted. "Department of Otorhinolaryngology, Hospital del Sureste/Spain 2015 Page 19 of 24

20 Fig. 14: Image obtained from laryngoscopy during phonation (adducted true vocal cords). "Department of Otorhinolaryngology, Hospital del Sureste/Spain 2015 Page 20 of 24

21 Fig. 15: Axial T2 image - laryngoscopy image correlation. This latter image is turned "upside-down" regarding the position the otorhinolaryngologist sually would see it. - Arganda del Rey/ES Page 21 of 24

22 Fig. 16: Axial T2 image - laryngoscopy image correlation. This latter image is turned "upside-down" regarding the position the otorhinolaryngologist sually would see it. - Arganda del Rey/ES Page 22 of 24

23 Conclusion The anatomy landmarks are the mainstay to read a head and neck study, so its deepest knowledge is needed to make the correct diagnosis. Furthermore, the correlation between the ct/mri images and those seen by the otorhinolaryngologist are helpful to perform this task. Page 23 of 24

24 References Spiral and Multislice Computed Tomography of the Body, Mathias Prokop, Michael Galanski and cols., Thieme 2003 Diagnostic and Surgical Imaging Anatomy, Harnsberger, Osborn, Macdonald, Ross et cols,, Amirsys, first edition, January 2011 Page 24 of 24