Orbital lymphatic vessels: immunohistochemical detection in the lacrimal gland, optic nerve, fat tissue, and extrinsic oculomotor muscles / Vasos linfáticos orbitários: identificação imunohistoquímica na glândula lacrimal, no nervo óptico, no tecido adiposo e nos músculos extrínsecos oculomotores

ABSTRACT Purpose: To identify the lymphatic vessels in orbital specimens from human cadavers using light microscopy and immunohistochemical analysis. Methods: A postmortem study included 10 orbital specimens from 10 human cadavers. The orbital specimens were obtained no later than 12 hours after death. The orbital specimens were dissected into lacrimal gland, optic nerve, fat tissue, and oculomotor muscles. The histologic criteria to qualify as a lymphatic vessel were thin-walled channels of endothelium without a well-developed basal membrane and with an erythrocyte-free, irregular lumen. The immunohistochemical criteria were irregularly shaped, thin-walled vessels with an erythrocyte-free, irregular lumen and immunopositivity for podoplanin D2-40. Results: The lacrimal gland, optic nerve, fat tissue, and extraocular muscle sections were positively stained with podoplanin D2-40. Conclusions: This study demonstrated lymphatic vessels in the human orbit, more precisely, in the lacrimal gland, dura mater of the optic nerve, adipose tissue, and extrinsic oculomotor muscles via light microscopy and immunohistochemistry.(AU)

RESUMO Objetivos: Identificar vasos linfáticos em espécimes orbitários de cadáveres humanos através de microscopia óptica e análise imunohistoquímica. Métodos: Um estudo postmortem incluiu dez espécimes orbitários provenientes de dez cadáveres humanos. Todos os espécimes orbitários foram obtidos até 12 horas após a morte com uma técnica cirúrgica de exenteração orbitária e dissecados em glândula lacrimal, nervo óptico, gordura órbitária e músculos extraoculares. Para classificar como um vaso linfático, os critérios histológicos incluíram vasos endoteliais de parede única sem membrana basal bem desenvolvida, irregulares e lúmen sem hemácias, e os critérios imunohistoquímicos incluíram vasos endoteliais de parede única, com formato irregular e lúmen sem hemácias e reagentes a podoplanina D2-40. Resultados: As lâminas histológicas de glândula lacrimal, nervo óptico, tecido adiposo e músculos extraoculares reagiram positivamente a podoplanina D2-40. Conclusão: Este estudo demonstrou vasos linfáticos na órbita humana, mais exatamente, na glândula lacrimal, no nervo óptico, na gordura orbitária e nos músculos extrínsecos extraoculares via microscopia óptica e imunohistoquímica.(AU)

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.

Adding myofibroblasts to the lacrimal pump.

The lacrimal sac (LS) empties in the nasolacrimal duct to drain the tears in the inferior nasal meatus. Different studies indicated the role of the lacrimal pump in the lacrimal drainage. Although controversial, the lacrimal pump mechanism is an extrinsic one, either active, or passive. An intrinsic contractile potential of the LS was not documented previously. We thus aimed a retrospective immunohistochemical study to test the alpha-smooth muscle actin (α-SMA) and h-caldesmon expression in the LS wall. We used archived paraffin-embedded samples of LS from ten adult patients. The α-SMA + phenotype was detected in basal epithelial cells, in subepithelial ribbons of stromal cells, in vascular smooth muscle cells, as well as in pericytes. H-caldesmon was exclusively expressed in pericytes, vascular smooth muscle cells and myoepithelial cells of the subepithelial glands. The most striking feature we found in all samples was a consistent stromal network of α-SMA+/h-caldesmon- myofibroblasts. This finding supports an intrinsic scaffold useful for the lacrimal pump.

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.

Anatomical considerations in endoscopic lacrimal surgery.

PURPOSE: To provide a review of the anatomy of the lacrimal drainage system and lateral wall of the nose pertaining to endoscopic dacryocystorhinostomy. METHODS: The authors performed a PubMed search of articles published pertaining to the anatomy of the lateral wall of the nose and the anatomy of endonasal and external dacryocystorhinostomy surgery. RESULTS: The article covers the regional surface and surgical anatomy for endoscopic dacryocystorhinostomy (DCR), including the maxillary line, middle turbinate, agger nasi air cell, lacrimal sac and fossa and the upper portion of the nasolacrimal drainage system. It also explores the dimensions and location of bony ostium formation to ensure full exposure and marsupialisation of the lacrimal sac. Finally, it covers the anatomy of potential complications of endoscopic DCR surgery including penetration of the skull base and orbit, inadvertent entry to the maxillary sinus and breach of the skin. CONCLUSION: A good understanding of the anatomy of the lacrimal drainage system and the lateral wall of the nose will increase the likelihood of successful surgery and minimize the risk of complications and damage to neighbouring structures such as the orbit and skull base.

Evaluation of lacrimal gland dimensions with MR imaging in a Turkish population sample / Evaluación de las dimensiones de la glándula lagrimal con imágenes de RM en una muestra de población turca

SUMMARY: We aimed to evaluate the morphology of normal lacrimal gland in three different axes in a Turkish population sample by using magnetic resonance (MR) images in relation to sex, age, and side. Cranial MR images obtained by 3 Tesla MR unit of 85 individuals (40 female, 45 male; mean age 42.20±23.30 years; age range 2-83 years) performed in Göztepe Medical Park Hospital between December 2015 and July 2017 for non-orbital diseases were evaluated retrospectively. Anteroposterior, craniocaudal, and transverse dimensions of the lacrimal gland were measured on axial, coronal, and sagittal planes of MR images, and were evaluated in relation to side, age, and sex. Axial transverse and sagittal craniocaudal dimensions of lacrimal gland were significantly greater in the right side, as the coronal craniocaudal and sagittal anteroposterior dimensions were greater in the left side. Female and male individuals showed differences in terms of right-left sides in most of the parameters. In Spearman's correlation analysis, age of individuals was negatively correlated with left axial anteroposterior (r=-0.347, p=0.020), left axial transverse (r=-0.439, p=0.003), left coronal transverse (r=-0.429, p=0.003), and right coronal transverse (r=-0.436, p=0.003) dimensions of lacrimal gland. This is the first study determining certain morphometric parameters of the lacrimal gland in Turkish population sample. The side of lacrimal gland, and sex and age of individuals affect its dimensions. On the basis of reference measurements in the present study, orbital MR imaging can be used for the evaluation of lacrimal gland and its pathologies.

RESUMEN: El objetivo de este estudio fue evaluar la morfología de la glándula lagrimal normal en tres ejes diferentes en una muestra de población turca, mediante el uso de imágenes de resonancia magnética (RM) en relación con el sexo, la edad y lados izquierdos- derechos. Las imágenes RM obtenidas por RM 3 Tesla, en 85 individuos (40 mujeres y 45 hombres, edad media 42.20 ± 23.30 años, rango de edad entre 2 y 83 años) se realizaron en Göztepe Medical Park Hospital, entre diciembre de 2015 y julio de 2017. Considerando las enfermedades no orbitales, estas fueron evaluadas retrospectivamente. Se midieron las dimensiones anteroposterior, craneocaudal y transversal de la glándula lagrimal en los planos axial, coronal y sagital de las imágenes, y se evaluaron en relación con el lado, la edad y el sexo. Las dimensiones craneocaudal axiales transversales y sagitales de la glándula lagrimal fueron significativamente mayores en el lado derecho, y las dimensiones craneocaudal y anteroposterior sagital coronal fueron mayores en el lado izquierdo. Individuos femeninos y masculinos mostraron diferencias en términos de lados derecho-izquierdo en la mayoría de los parámetros. En el análisis de correlación de Spearman, la edad de los individuos se correlacionó negativamente con el anteroposterior axial izquierdo (r = -0.347, p = 0.020), transversal axial izquierdo (r = -0.439, p = 0.003), transversal coronal izquierdo (r = -0.429, p = 0.003), y las dimensiones transversales coronales derechas (r = -0.436, p = 0.003) de la glándula lagrimal. Este es el primer estudio que determina ciertos parámetros morfométricos de la glándula lagrimal en la muestra de la población turca. El lado de la glándula lagrimal, y el sexo y la edad de los individuos afectan sus dimensiones. En el presente estudio basado en las mediciones de referencia, la RM orbital se puede utilizar para la evaluación de la glándula lagrimal y sus patologías.

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.

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.

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.

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.

Location of the inferior oblique muscle origin with reference to the lacrimal caruncle and its significance in oculofacial surgery.

PURPOSE: To identify the location of the inferior oblique muscle (IOM) origin with reference to the lacrimal caruncle in order to facilitate safer oculofacial surgery by preventing morbidity associated with IOM injury. METHODS: Thirty-seven intact orbits of 20 embalmed Asian cadavers were dissected. The location of the medial border of the IOM origin was determined with respect to the apex of the lacrimal caruncle. In addition, the size of the IOM origin and the anteroposterior distance from the inferior orbital rim to the anterior border of the IOM origin were measured. RESULTS: The IOM origin was located at a mean distance of 1.2 mm lateral and 11.2 mm inferior to the apex of the lacrimal caruncle. In half of the orbits, the IOM origin was situated just on the vertical line through the apex of the lacrimal caruncle. The mean length and width of the IOM origin were 4.3 and 2.7 mm, respectively. The mean anteroposterior distance from the inferior orbital rim to the IOM origin was 1.9 mm. CONCLUSIONS: The lacrimal caruncle is easily identifiable and a reliable external landmark for prediction of the IOM origin. The IOM origin is located approximately where the vertical line through the apex of the lacrimal caruncle intersects the inferior orbital rim. The findings of this anatomical study of the exact location of the IOM origin can help to improve the safety of oculofacial surgery.

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.

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.

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.

Identification of the trochlea with reference to the lacrimal caruncle, and its significance as a landmark in orbitofacial surgery.

PURPOSE: The purpose of this study was to identify the location of the trochlea in order to prevent injury during orbitofacial surgery and to determine the reliability of the lacrimal caruncle as a visible external landmark for the trochlea at the superomedial orbital rim. METHODS: Fifty-one orbits from 27 embalmed cadavers were dissected. The lacrimal caruncle and supraorbital notch/foramen were used as external and bony landmarks, respectively. The location of the trochlea was determined with respect to these structures, and the size of trochlea was measured. RESULTS: The trochlea was 3.6 mm wide and 5.6 mm long, with a flange breadth of 5.4 mm. The vertical distance from the apex of the lacrimal caruncle to the superolateral tip of the trochlea was 15.8 mm, and that from the top of the supraorbital notch/foramen to the bottom of the trochlea was 11.4 mm. As the coefficient of variation and standard deviation were smaller for DCT (11.5 and 1.8, respectively) than for DST (17.0 and 1.9, respectively), it appears that the lacrimal caruncle is a reliable landmark. CONCLUSIONS: In contrast to the supraorbital notch, the lacrimal caruncle allows easy identification and serves as a reliable and visible external landmark for the prediction of the location of trochlea. The trochlea was located directly at 15.8 mm (i.e., approximately 1.5 cm) superior to the lacrimal caruncle. This anatomical study has yielded accurate measurements of the location of the trochlea, which may facilitate a safer orbitofacial surgery by preventing morbidity associated with trochlea injury.