[Anatomical structure and morphometric parameters of the distal segment of the lacrimal drainage system]. / Anatomicheskoe stroenie i morfometricheskie pokazateli vertikal'nogo otdela slezootvodyashchikh putei.

The article analyzes the literature data concerning the anatomical structure of the tear ducts with a focus on morphometric studies of individual structures. It is noted that, despite the high information content of cadaveric studies, most of the information to date has been obtained with the use of intravital radiation visualization methods. It is shown that the lacrimal drainage system has age, gender, and racial characteristics. Most studies focus on features of the bone nasolacrimal canal, while there is a relative shortage of research devoted to soft-tissue nasolacrimal duct. The analysis showed that most of the studies are devoted to particular morphometric indicators, which makes it difficult to obtain a complete objective picture of the size of the tear duct. Information about its volume can be found only in a couple of studies. The numerical values of the obtained data vary, which can be explained by a different approach to the selection of research subjects, sample sizes, anatomical criteria and the calculation method of morphometric parameters. There are only a few studies on morphometric parameters of the nasolacrimal duct in healthy humans, which is extremely important for determining the pathogenesis of disorders of the patency of the lacrimal drainage system.

Imaging and anatomical parameters of the lacrimal punctum and vertical canaliculus using optical coherence tomography.

Purpose: The anatomical parameters of normal lacrimal puncta and vertical canaliculus using optical coherence tomography (OCT) and the OCT imaging features of punctal lesions were analyzed to provide a basis for clinical diagnosis and treatment. Methods: From June to September 2019, 40 volunteers (80 eyes) from Tongji Hospital were enrolled. The external punctal diameter (ELP) was measured using slit-lamp microscopy and OCT. The internal lacrimal punctal diameter (ILP) at 100 µm, vertical canalicular length (VCL), and tear meniscus depth were measured by OCT with open eyes. Twenty-eight volunteers (56 eyes) underwent the same examinations with their eyes closed. The OCT imaging features of 26 patients (27 eyes) with lacrimal lesions were examined. Results: The ELP of the right and left healthy eyes under slit-lamp microscopy were 564.40 and 555.40 µm respectively. Under OCT, the ELP, ILP, and VCL of the right and left eyes were 628.20 um and 616.85 µm, 343.40 µm and 346.95 µm, 731.95 um and 709.20 µm respectively. The ELP was larger when measured by OCT than slit-lamp microscopy (p<0.05). Twenty-eight volunteers (56 eyes) had measurements taken under different conditions. The ELP, ILP, and VCL of the open and closed right eyes were 667.54 and 567.21 µm, 369.18 and 303.18 µm, 715.00 and 417.14 µm, respectively. The ELP, ILP, and VCL of the open and closed left eyes were 655.86 um and 551.68 µm, 369.25 um and 313.54 µm, 719.96 um and 433.89 µm respectively. The anatomical parameters of the open eyes were greater than those of the closed eyes (p<0.05). Thus, we identified the imaging features of lacrimal stenosis, punctal obstruction, punctal tear, lacrimal atresia, and lacrimal mass using OCT. Conclusions: OCT can be used to measure the anatomical parameters of lacrimal puncta and vertical canaliculus in vivo. In addition, OCT can detect punctal lesions in vivo and provide an objective basis for the clinical diagnosis and treatment of punctal lesions.

Anatomic Danger Zones of the Head and Neck.

BACKGROUND: Dermatologic procedures require a detailed understanding of surface anatomy to avoid complications. The head and neck region has prominent danger zones including nerves and vasculature that may be at risk during cutaneous surgery. A thorough understanding of these danger zones can help avoid complications that may lead to functional or cosmetic impairment. METHODS: The anatomic literature regarding the course of high-risk structures of the head and neck was reviewed. Structures deemed at risk during dermatologic procedures were included in the analysis. The final analysis focused on branches of the facial nerve, parotid duct, spinal accessory nerve, trigeminal nerve, and the lacrimal system. Anatomical information was compiled regarding each high-risk structure to develop a "danger zone" at which each respective structure is at risk. RESULTS: The danger zone for each structure was compiled based on the review of the literature and depicted in the figures. CONCLUSION: With careful attention to anatomy and the meticulous surgical technique, there is great potential for reduction in surgical injury to danger zones of the head and neck.

Mohs Surgery for Periocular Tumors.

BACKGROUND: Skin cancers of the periorbital area present unique challenges to Mohs surgeons. OBJECTIVE: The need for precise and high-quality Mohs micrographic surgery (MMS) is paramount because of the complex anatomy, vital structures, and potential threat to vision. METHODS: A thorough comprehension of anatomy is essential to help predict tumor behavior and ensure successful outcomes for patients. RESULTS: Tumors occurring at the medial and lateral canthi are of greatest concern for deeper orbital penetration. CONCLUSION: In this study, we present our experience with MMS of periorbital tumors, including clinical pearls and techniques to aid the Mohs surgeon.

Anterior maxillary wall and lacrimal duct relationship in Orientals: CT analysis for prelacrimal access to the maxillary sinus.

BACKGROUND: The pre-lacrimal window approach (PLWA) is a promising technique in approaching lesions of the anterior wall and floor of the maxillary sinus. Simmen et al. previously reported that this approach is feasible in only 2/3 of their patients. This percentage appears to be lower than that of our local (mainly Chinese) population based on our clinical experience. Our study aims to measure the distance between the anterior maxillary wall and lacrimal duct in ethnic Chinese. A higher incidence of sphenoid-ethmoidal cells has been reported in Orientals. We postulate that there is also a higher incidence of wider pre-lacrimal recesses in Orientals thus making the PLWA more feasible to perform in Orientals. METHODS: 100 consecutive sinus CT scans of adult patients with various rhinologic diseases that did not distort the bony anatomy of the maxilla were reviewed (2 sides each). The distance between the anterior maxillary wall and the anterior border of the lacrimal duct was measured in 200 sides. We have adopted the methodology of measurements previously published by Simmen et al.  This is so that we could compare between Oriental and Occidental paranasal sinuses. RESULTS: A distance of more than 7 mm was found in 39.5% of our subjects and a distance of > 3-7 mm was seen in 53.5%. In 6.5% of our subjects we found a prelacrimal recess < 3 mm. CONCLUSION: The PLWA could have been performed without removal of the bony lacrimal canal in 39.5% of our subjects ( > 7 mm). Good access to the anterior maxilla wall could also have been possible for 53.5% with sub-periosteal removal of the bony lacrimal canal and medial maxillary wall. Thus, the PLWA would have been feasible for 93% of our subjects. These percentages are significantly higher than Simmen's study of 68.5% in an Occidental population.

Consistency of the lateral canthus as an anatomic landmark and its clinical implications.

Successful oculofacial procedures require the availability of a reliable surgical and anatomic landmark. This study aimed to determine the usefulness of the lateral canthus as a surface landmark. Seventy-seven from 42 Korean cadavers were dissected. The horizontal distance from the lateral canthus to the lateral orbital margin and the vertical distances from the zygomaticofrontal suture and the inferior orbital margin to the lateral canthus were measured. The mean horizontal distance from the lateral canthus to the lateral orbital margin was 7.8 mm. Although the horizontal position of the lateral canthus appears to alter with age, the variation was only 2-3 mm. The mean vertical distances from the zygomaticofrontal suture and inferior orbital margin to the lateral canthus were 8.1 and 17.2 mm. The vertical position of the lateral canthus did not vary with age, being located inferiorly within a fingernail width from the zygomaticofrontal suture. The lateral canthus, which is easily accessible and supported by muscular and fibrous lateral orbital attachments, exhibits small anatomic variations. Thus, the lateral canthus could act as a reliable surface landmark for identifying the location of underlying structures and describing a lesion on the face. Clin. Anat. 32:630-634, 2019. © 2019 Wiley Periodicals, Inc.

Eyebrow Position and Shape Favored by Korean Women.

PURPOSE: The shape and position of the eyebrows are among the most important facial features from an esthetic point of view. However, significant cultural differences exist with respect to the eyebrow shape and position that are considered ideal. The purpose of this study was to identify the position and shape of eyebrows preferred by Korean women and to apply these, including forehead lifts, to the clinics. METHODS: The authors took full facial photographs in the Frankfort plane of Korean women aging from young childhood to their 50s. On the basis of these, 2 parameters were calculated: first, the height-to-width ratio (HWR), the ratio between the vertical distance from the brow apex to the palpebral fissure and the horizontal distance from the medial canthus to the lateral canthus; and second, the takeoff angle (TOA), the angle between the straight line connecting the 2 lateral canthi and the line from the brow apex through the center of the medial brow segment. The authors then had drawings of "Anastasia arch" eyebrows made; as high eyebrows are considered beautiful in Korea, and the eyebrows of women in their 20s were the highest, the drawings depicted the mean HWR and TOA values for this age group and their various degrees of deviation. These drawings were shown to 300 women aged 21 to 40 years from May 1 to June 30, 2014; they were instructed to choose the drawing they preferred among the 5 drawings differing in HWR and again among the 5 differing in TOA. RESULTS: Among the 99 Korean women in their 20s, the mean HWR and TOA was 1:1.01 ±â€Š0.23 and 12°â€Š±â€Š5.2°, respectively. Regarding the survey, the most preferred HWR was 1:1.0, which was selected by 204 respondents (68%); the most preferred TOA was 10°, which was chosen by 122 respondents (40.7%). CONCLUSION: This study shows that HWR gradually decreases and TOA increases with age. Furthermore, Korean women's preferred eyebrows have an HWR of ∼1:1 and a TOA of ∼10°. These results could guide plastic surgeons performing periorbital rejuvenation surgeries, including brow lifts, not only for Koreans but also for North-East Asians.

Morphology and morphometry of lacrimal drainage system in relation to bony landmarks in Caucasian adults: a cadaveric study.

PURPOSE: The objective of this study is to examine the morphometry of the lacrimal drainage system with reference to bony landmarks in the vicinity. METHODS: Twenty midsaggitalized heads obtained from sixteen preserved cadavers were studied. Measurements involved detailed morphometry of anterior and posterior lacrimal crests, bony lacrimal sac fossa, entrance and length of the bony nasolacrimal duct (NLD), attachment of Horner's muscle, and characteristics of the inferior meatal opening of the NLD. RESULTS: The mean lengths of anterior and posterior lacrimal crests were 16.3 and 12.5 mm, respectively. At the midpoint of the posterior lacrimal crest, Horner's muscle was found to be attached at a mean of 1.3 mm posterior to the crest. The mean dimensions of the bony lacrimal sac fossa at superior, mid and inferior levels were 6.5, 8.7, and 5.9 mm, respectively. The mean contribution of the lacrimal bone to the lacrimal sac fossa was 56.2%. The mean anteroposterior and transverse diameters of the entrance of the bony NLD were 5.7 and 4.7 mm, respectively. The most common type of NLD opening in the inferior meatus was that of "vertical sulcus" (70%, 14/20). The mean distance of the NLD opening from the anterior nasal spine and Limen nasi were 22.2 and 18.9 mm, respectively. CONCLUSION: This study provides useful anatomical and positional relationship of bony lacrimal landmarks and nasolacrimal duct in Caucasian adults.

Three-Dimensional Topography of the Supratrochlear Nerve With Reference to the Lacrimal Caruncle, and Its Danger Zone in Asians.

BACKGROUND: The supratrochlear nerve (STN) is relatively superficial and therefore vulnerable to iatrogenic injury. OBJECTIVE: To elucidate the course of STN with reference to the lacrimal caruncle, with the aim of preventing nerve injury during surgery in the forehead region. MATERIALS AND METHODS: Thirty-four hemifaces from 18 Korean cadavers were dissected. The vertical line through the apex of lacrimal caruncle and the horizontal line through the supraorbital margin were used as horizontal and vertical reference lines, respectively. The course of STN in the frontal view and the point at which it pierced the overlaying musculature were examined. RESULTS: After exiting the corrugator muscle cushion, the STN enters the subcutaneous plane by piercing the frontalis muscle. These piercing points occurred at mean horizontal and vertical distances relative to the medial branch of the STN of 9.2 and 9.6 mm, respectively; the corresponding distances for the lateral branch of the STN were 1.1 and 15.3 mm, respectively. CONCLUSION: When performing surgery in the medial forehead region, the surgeon must ensure that the dissection plane of forehead tissue is more superficial: superiorly within 1.5 cm from the supraorbital margin and medially within 1.0 cm from the vertical line through the apex of lacrimal caruncle.

Anatomy of the Corrugator Muscle.

The aim of this article is to systematically review the anatomy and action of the corrugator muscle. PubMed and Scopus were searched using the terms "corrugator" AND "anatomy." Among the 60 full texts from the 145 relevant abstracts, 34 articles without sufficient content were excluded and 4 articles drawn from the reference lists were added. Among the 30 articles analyzed (721 hemifaces), 28% classified by oblique head and transverse head, and 72% did not. Corrugator originated mostly from the medial supraorbital rim (45%), followed by the medial frontal bone (31%), the medial infraorbital rim (17%), and the upper nasal process (7%). Corrugator extended through the frontalis and orbicularis oculi (41%), only the frontalis (41%), or only the orbicularis oculi (18%). Corrugator ran superolaterally (59%), or laterally (41%). Corrugators inserted mostly to the middle of the eyebrow (57%), or the medial half of the eyebrow (36%), but also to the glabella region (7%). The length of the corrugator ranged 38 to 53 mm. The transverse head (23.38 mm) was longer than the oblique head (19.75 mm). Corrugator was thicker at the medial canthus than at the midpupillary line. Corrugator was innervated by the temporal branch of the facial nerve (66%), the zygomatic branch (17%), or the angular nerve (zygomatic branch and buccal branch, 17%). Supraorbital nerve (60%) or supratrochlear nerve (40%) penetrated the corrugator. The action was depressing, pulling the eyebrow medially (91%), or with medial eyebrow elevation and lateral eyebrow depression (9%). Surgeons must keep this anatomy in mind during surgical procedures.

Quantitative MR imaging of intra-orbital structures: Tissue-specific measurements and age dependency compared to extra-orbital structures using multispectral quantitative MR imaging.

The orbit can be affected by unique pathologic conditions and often requires MRI evaluation. The purpose of this study was to investigate the age-related changes in multiple intra-orbital structures using quantitative MRI (qMRI). Thirty-eight subjects (20 males, 18 females; ages 0.5-87 years) underwent MRI with a mixed turbo spin echo sequence. T1 and T2 measurements were obtained within ROI in 6 intra-orbital structures (medial and lateral rectus muscles, medial and lateral retrobulbar fat, lacrimal gland, and optic nerve), and compared with those of corresponding extra-orbital structures (masseter muscle, subcutaneous cheek fat, buccal fat, parotid gland, and frontal white matter). Statistical analyses were performed using Pearson's correlation coefficients. T1 and T2 values of the extra-ocular muscles increased with age, with higher T1 and T2 values compared to the masseter muscles. Retrobulbar fat showed significant age-associated increases in T1 values in the lateral side and in T2 values in both sides. T1 and T2 values in the lacrimal gland increased with age, while the parotid gland showed an age-associated increase in T2 values and decrease in T1 values. Optic nerves demonstrated age-related changes, similar to that of frontal white matter; rapid decreases with age in T1 and T2 times in early stages of life, and slight increases in T1 and T2 times later in life. Intra-orbital structures demonstrated specific qMRI measurements and aging patterns, which were different from extra-orbital structures. Location-specific age-related changes of intra-orbital structures should be considered in the qMRI assessment of the orbital pathology.

Emerging Points of the Supraorbital and Supratrochlear Nerves in the Supraorbital Margin With Reference to the Lacrimal Caruncle: Implications for Regional Nerve Block in Upper Eyelid and Dermatologic Surgery.

BACKGROUND: Blocking the supraorbital nerve (SON) and supratrochlear nerve (STN) by injecting anesthetic distal to the surgical site has the advantage in upper eyelid surgery that avoids obscuring the surgical landmarks and compromising the levator function. OBJECTIVE: To identify the emerging points of the SON and STN in the supraorbital margin with reference to the lacrimal caruncle. METHODS: Forty-nine orbits from 27 embalmed Korean cadavers were dissected. The lacrimal caruncle and facial midline were used as landmarks. The emerging points of the SON and STN in the supraorbital margin were determined. RESULTS: The emerging points of the SON and STN were, respectively, located at 3.0 mm lateral and 3.3 mm medial to the vertical line through the apex of the lacrimal caruncle along the supraorbital margin. The horizontal distances from the facial midline to the emerging points of the SON and STN were 22.8 and 15.2 mm, respectively. CONCLUSION: The optimum sites for achieving SON and STN block are, respectively, located approximately 3 mm lateral and 3 mm medial to the vertical line through the apex of lacrimal caruncle along the supraorbital margin. This knowledge will help the surgeon achieve an easy and accurate approach for regional nerve block.

Gross anatomy and morphometric evaluation of the canine lacrimal and third eyelid glands.

OBJECTIVE: The lacrimal gland (LG) and the third eyelid gland (TELG) are two intraorbital glands that, in dogs, secrete the aqueous component of the tear film. Despite the central importance of these structures for maintaining ocular surface health, the gross anatomy of the glands remains understudied. We investigated the macroscopic morphometric characteristics of the LG and TELG in three different dog breeds. PROCEDURES: Twenty-six dog heads were dissected to expose the LG and TELG; the length, width, thickness, and weight of each were measured. During the dissections, the relationships between the glands and adjacent ocular structures and the blood and nerve supplies to the LG were photo-documented. RESULTS: The LG had a flat and irregular shape with morphological variations among dogs. The LG was located on the dorsolateral aspect of the globe underneath the orbital ligament. The average length, width, and thickness (SEM) of the LG (mm) were 16.5 ± 0.7, 12.5 ± 0.4, and 2.7 ± 0.1 and of the TELG 10.5 ± 0.6, 11.0 ± 0.3, and 3.3 ± 0.1, respectively. The mean weights (SD) of the LG and TELG (mg) were 315.7 ± 21.1 and 263.3 ± 13.2, respectively. Beagles were observed to have significantly smaller LGs compared to pit bull terriers and pointer mixed-breed dogs. CONCLUSIONS: The present study provides detailed normative anatomical and morphometric data for the LG and TELG. These data will aid researchers investigating alterations induced by disease states and should inform strategies for the local delivery of pharmacologic and cellular therapeutics.

Brows Asymmetry Correction With the Direct Approach: Myth or Reality?

OBJECTIVES: The current article is aimed to test the effectiveness of direct and indirect brow lifting to correct brows asymmetry. METHODS: Fifty patients treated with direct brow lift between January of 2011 and January of 2013 were investigated. All patients were men and treated under local anesthesia. In all patients, the brow lifting was associated with an upper blepharoplasty. The amount of brow elevation produced was assessed by comparison of the preoperative and at 1-year postoperative vertical distances between the superior eyebrow hairline and the interpupillary line at midpupil and at lateral and medial canthus. Paired sample t-test was used to investigate brow lifting amelioration after 1 year. The differences in measurements between the 2 sides were plotted to evaluate the degree of symmetry between 2 sides. In addition, a comparison was performed; a series of 45 patients treated with temporal (ie, indirect) approach. RESULTS AND CONCLUSIONS: The paired sample test demonstrated that direct brow lifting is a proper surgical technique to correct brow asymmetry. Also temporal (ie, indirect) approach is able to ameliorate brow asymmetry but direct technique provide better results. The direct brow lifting is a reliable, reproducible and safe surgical procedure, provides excellent and long-lasting results, and is very efficacious in brows asymmetry correction.

Functional Morphology of the Upper and Lower Eyelids, Third Eyelid, Lacrimal Gland and Superficial Gland of the Third Eyelid in the Red Kangaroo (Macropus rufus).

A study concerning the upper (UE) and lower (LE) eyelids, lacrimal gland (LG), superficial gland of the third eyelid (SGTE) and third eyelid (TE) was conducted on 4 sexually mature red kangaroos (2 males and 2 females). Gross anatomical, histological, histometrical, histochemical and ultrastructural (TEM) components were compared. Tissue sections were stained with haematoxylin and eosin, azan-trichrome, van Gieson, Masson-Goldner trichrome, methyl green-pyronin Y, periodic acid-Schiff, alcian blue pH 2.5, aldehyde fuchsin and Hale's dialysed iron. The location of the LG, SGTE, TE, UE and LE was similar to that of other mammals. Organized lymphoid follicles were also found in the LE. The TE resembled the letter T and was composed of cartilage (hyaline tissue). The LG was relatively larger than the SGTE. The LG and SGTE were multilobar tubuloacinar glands. The LG had more plasma cells than the SGTE. The SGTE and LG secretions were mucoserous in composition. The TEM study showed that the secretory cells of the LG and SGTE have a similar ultrastructural appearance. Two types of secretory vesicles were detected in the cytoplasm in acini and one type of secretory vesicle was found in the tubules of these glands.

Anatomical landmarks of the lateral nasal wall: implications for endonasal lacrimal surgery.

PURPOSE OF REVIEW: An accurate understanding of the anatomy of the lateral nasal wall is key to achieving complete exposure of the lacrimal sac during endonasal dacryocystorhinostomy (EnDCR) and the avoidance of complications such as basal skull fracture and orbital fat prolapse. This review provides a comprehensive summary of the clinical and cadaveric anatomical studies of the lateral nasal wall to date and their application to endonasal lacrimal surgery. RECENT FINDINGS: The maxillary line and the axilla of the middle turbinate are the major landmarks commonly utilized by lacrimal surgeons to localize the lacrimal sac. Numerous clinical, cadaveric and radiologic studies have attempted to define the relationship of these and other important anatomical landmarks, closely related to the lacrimal sac and routinely encountered during endonasal surgery, such as the frontal process of the maxilla, the agger nasi air cell and the uncinate process. A greater understanding of the relevant endonasal anatomy over time has led to safer and more effective surgical techniques. SUMMARY: Greater insights into the precise anatomical relationship of the lacrimal sac to other structures on the lateral nasal wall has enabled lacrimal surgeons to perform EnDCR surgery in a more accurate, efficient and well tolerated manner, matching its success to that of the external approach.

Medial canthal support structures: the medial retinaculum: a review.

The medial canthus is supported by several structures with a complicated 3-dimensional arrangement in a narrow space. Although the medial canthal tendon occupies a major portion of the area, the medial canthal support structures include the following entities: Horner's muscle, the medial rectus capsulopalpebral fascia including the medial check ligament, the medial horn of the levator aponeurosis, the medial horn supporting ligament, the medial horn of the lower eyelid retractors, the preseptal part of the orbicularis oculi muscle, and 3 variations of the Lockwood's ligament. We named the composite of these structures the "medial retinaculum," which is similar to the "lateral retinaculum" of the lateral canthus. Profound comprehension and consideration of the medial retinaculum warrants safe and effective surgery in the medial canthal region.

Gross, histologic, and micro-computed tomographic anatomy of the lacrimal system of snakes.

OBJECTIVE: To describe the lacrimal system of snakes using contrast micro-computed tomography (micro-CT) with 3-dimensional reconstruction, fluorescein passage ('Jones') testing, histology, and gross dissection. ANIMALS STUDIED: One royal python and 19 snake cadavers representing 10 species. PROCEDURES: Direct observation following injection of fluorescein into the subspectacular space, micro-CT following injection of three contrast agents into the subspectacular space, gross dissection following injection of latex into the subspectacular space, and histopathology. RESULTS: Injection of fluorescein confirmed patency, but not course of the lacrimal duct. Barium enabled clear visualization of the lacrimal duct, whereas two iodinated contrast agents proved inadequate. Collectively, micro-CT, anatomic dissections, and histology suggest tears are produced by a single, large, serous, retrobulbar gland, released into the subspectacular space via several ductules, and drained through a single punctum originating in the ventronasal subspectacular space, and the lacrimal duct, which takes one of three routes of variable tortuosity before opening into the oral cavity in close association with the opening of the duct of the vomeronasal organ. CONCLUSIONS: The ophidian lacrimal duct has a generally tortuous course, and the details of its anatomy are species-variable. The tortuous course of the duct likely predisposes snakes to duct occlusion and must be considered when planning medical and surgical interventions in snakes with pseudobuphthalmos and subspectacular abscessation.

Origin of the Lower Orbicularis Oculi Muscle in Relation to the Nasojugal Groove.

The aim of this study was to clarify the location of the origin of the lower orbicularis oculi muscle (OOM) in relation to the nasojugal groove.In 45 lower eyelids of 44 patients, the origin of the lower OOM was identified. In 4 lower eyelids of 2 fresh cadavers, the breaking strength was measured. In 4 lower eyelids of 4 fixed cadavers, 3 parasagittal sections and 2 horizontal sections were made. In computed tomographic scans of 182 orbits of 99 patients, the maxillary attachment of the OOM was measured.The lower OOM originated along the orbital margin, and the mean (SD) width of the attachment was 10.5 (1.4) mm. The lower OOM ran obliquely laterally and downward. The force needed to tear the 3-mm-wide OOM was 8.40 (0.21) N. Histologically, the OOM was attached to the periosteum on the medial limbus line; however, it was not attached at the midpupillary line or the lateral limbus line. The most medial part of the lower OOM was attached to the periosteum. In the middle and lateral part of the lower eyelid, however, a fibrofatty tissue was found between the OOM and the periosteum. In computed tomographic scans, the OOM was almost always attached to the maxilla at the medial epicanthus (100%) and at the medial limbus line (92.3%). At the midpupillary line, fewer than half (45.6%) were attached. At the lateral limbus line (14.3%) and the lateral canthus (4.4%), they were rarely attached.In a relaxed state, the nasojugal groove is not evident because the attached portion does not pull at the wings. While squinting, the OOM contracts and the vertical width shortens, and thereafter, a surface puckering of the delicate periorbital skin appears.

Two Types of the Sinus of Maier: An Anatomic Study.

PURPOSE: To show the morphological characteristics of two different types of the sinus of Maier, one with a lacrimal sac diverticulum supplied by separate canalicular openings, and the other with a terminal dilatation of the common lacrimal canaliculus. METHODS: Twelve coronal specimens (6 right and 6 left) from 6 Japanese cadavers (age range, 70-90 years at death) and 15 axial specimens of 11 Japanese cadavers (8 right, 7 left; age range, 45-89 years at death), fixed in 10% buffered formalin, were used. All specimens were stained with Masson's trichrome. RESULTS: The sinus of Maier, with a lacrimal sac diverticulum supplied by separate canalicular openings, was shown in one coronally sectioned group, with a diameter of 1.29 mm. The mucosa between both openings (0.282 mm length) comprised stratified squamous epithelia, which was characteristic of the lacrimal canaliculi. The diverticular mucosa was lined by a stratified columnar epithelium, which corresponded to the lacrimal sac. The sinus of Maier, with a terminal dilatation of the common lacrimal canaliculus and with a diameter of 0.51 mm, was demonstrated in one axially sectioned group. CONCLUSIONS: The morphological characteristics of two types of the sinus of Maier were described in this study. One type was the lacrimal sac diverticulum supplied by separate canalicular openings, and the other was the terminal dilatation of the common lacrimal canaliculus.