AJR:213, December 2019 1331 eyelids act as wipers to spread the tear film across the globe [8]. This blinking action acts to push the tears toward the lacrimal lake at the medial canthus. Tears are principally re- moved by drainage through the puncta after each blink and by evaporation from the open eye. As the lids open, a drop in canalicular pressure occurs and fluid is sucked into the puncta from the lacrimal lake [8]. Tears then drain through the superior and inferior can- aliculi, common canaliculus, Rosenmüller valve, lacrimal sac, and nasolacrimal duct, finally emptying through the Hasner valve into the inferior meatus. The Hasner valve is a functional barrier to retrograde flow or re- flux of fluid [3–5, 9] (Fig. 1A). On cross-sectional imaging, the lacrimal sac lies in the bony lacrimal fossa formed by the anterior lacrimal crest of the frontal pro- cess of the maxillary bone and the posterior lacrimal crest of the lacrimal bone. It is nor - mal for the lacrimal sac and duct to be either fluid (tear) filled or air filled (Fig. 1B). The lacrimal sac is a preseptal structure because the anterior and posterior slips of orbicular - is oculi muscle invest the sac as it attaches to the lacrimal crests; thus, lacrimal sac in- fections preferentially spread in the preseptal space [3, 4] (Fig. 1B, inset). The nasolacrimal duct has intraosseous and membranous parts and generally slopes posteriorly as it ends be- low the inferior turbinate. The lacrimal sac and duct are surrounded by lacrimal fascia and rich venous plexuses, which directly A Comprehensive Review of Cross-Sectional Imaging of the Nasolacrimal Drainage Apparatus: What Radiologists Need to Know Osama A. Raslan 1 Arzu Ozturk 1 Nancy Pham 1 Jennifer Chang 1 Edward B. Strong 2 Matthew Bobinski 1 Raslan OA, Ozturk A, Pham N, Chang J, Strong EB, Bobinski M 1 Department of Radiology, Section of Neuroradiology, University of California Davis Medical Center, 4860 Y St, Ste 3100, Sacramento, CA 95817. Address correspondence to O. A. Raslan ([email protected]). 2 Department of Otolaryngology, University of California Davis Medical Center, Sacramento, CA. Neuroradiology/Head and Neck Imaging • Review This article is available for credit. AJR 2019; 213:1331–1340 0361–803X/19/2136–1331 © American Roentgen Ray Society N asolacrimal drainage apparatus abnormalities presenting with epiphora, punctual discharge, or medial canthal swelling are com- mon ophthalmic complaints accounting for approximately 3% of ophthalmologic clinic visits in some series [1, 2]. Although many na- solacrimal drainage apparatus diseases are diagnosed clinically, imaging can be helpful to assess for causative factors, document the anatomy, or visualize adjacent tissue [3]. Al- though there is a plethora of ear, nose, and throat and ophthalmologic literature about nasolacrimal drainage apparatus abnormali- ties, only scant radiology literature addresses the nasolacrimal drainage apparatus region [4–6]. The purpose of the present article is to provide radiologists with an up-to-date com- prehensive review of the cross-sectional im- aging of the anatomy of the nasolacrimal drainage apparatus as well as its abnormali- ties, surgical considerations, complications, and imaging pitfalls, thereby allowing more accurate and better communication between radiologists and clinicians. Radiologic Anatomy of the Nasolacrimal Drainage Apparatus Tears are secreted by the lacrimal glands at the superolateral aspects of the orbits [7] and then are mixed with mucous secretions of the conjunctival and eyelid glands, includ- ing the meibomian glands, making tears oily to resist evaporation. The upper and lower Keywords: dacryocystitis, dacryocystocele, nasolacri- mal canal, nasolacrimal drainage apparatus, nasolacri- mal duct, nasolacrimal stent, nasolacrimal surgery, nasolacrimal tumor doi.org/10.2214/AJR.19.21507 Received March 28, 2019; accepted after revision June 4, 2019. Based on a presentation at the Radiological Society of North America 2018 annual meeting, Chicago, IL. OBJECTIVE. The purpose of this study is to provide a comprehensive review of the ra- diographic anatomy and cross-sectional imaging findings of the full gamut of nasolacrimal drainage apparatus diseases, highlighting imaging findings from the different nasolacrimal drainage apparatus surgeries, posttreatment complications, and potential imaging pitfalls. CONCLUSION. Radiologists play a critical role in guiding the management of nasolac- rimal drainage apparatus diseases and should be familiar with the anatomy and characteris- tic imaging findings of commonly encountered nasolacrimal drainage apparatus abnormali- ties and surgeries. Raslan et al. Cross-Sectional Imaging of Nasolacrimal Drainage Apparatus Neuroradiology/Head and Neck Imaging Review Downloaded from www.ajronline.org by 171.243.67.90 on 05/26/23 from IP address 171.243.67.90. Copyright ARRS. For personal use only; all rights reserved
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