Doppler imaging of the ophthalmic vasculature of the normal dog: blood velocity measurements and reproducibility

The purpose of this study was to assess the feasibility and reproducibility of color Doppler imaging (CDI) of the vasculature of the normal canine orbit and eye. Eight normal Beagles were evaluated by Doppler imaging. The goals of the study were to determine the location, spectral waveform morphology, specific blood velocity parameters, and reproducibility for the ophthalmic and orbital vessels most frequently identified in the normal dog. Vessels identified a majority of the time (> 50%) included: external ophthalmic artery, dorsal external ophthalmic vein, ventral external ophthalmic vein, internal ophthalmic artery, anterior ciliary artery and vein, short and long posterior ciliary arteries, primary retinal arteries, and vortex veins. Other vessels imaged less frequently included: external ethmoidal artery (50%), and primary retinal veins (25%). For each blood vessel the time averaged velocity, peak systolic velocity, minimum diastolic velocity, pulsatility index, and resistive index were determined. The ophthalmic and orbital vessels have unique spectral waveforms and velocities which serve as a basis for identification. Reproducibility of the most commonly imaged vessels of the canine eye and orbit with Doppler imaging was high (< 10% variation). Doppler imaging has the potential for determining noninvasively and consecutively the blood velocity parameters found in orbital and ocular diseases, including orbital inflammations and neoplasms; intraocular inflammations and neoplasms; vascular diseases including systemic vascular disease (hypertension), vasculopathies, and anemia; the glaucomas; and documentable follow-up after medical and/or surgical treatment of these diseases.     

Progressive changes in ophthalmic blood velocities in Beagles with primary open angle glaucoma

Objective To measure changes in the ocular and orbital blood flow velocities by color Doppler imaging (CDI) in beagles with primary open angle glaucoma as the disease progressed from early to advanced stages. Methods CDI measurements were performed periodically on 13 glaucomatous Beagles during the nontreated mild, moderate and advanced stages of POAG over the course of 4 years. CDI was performed with the dogs lightly anesthetized (butorphanol 0.1 mg/kg IV, acepromazine maleate 0.02 mg/kg IV, and atropine sulfate 0.05 mg/kg) while the CD transducer was placed directly on the cornea anesthetized with 0.5% tetracaine hydrochloride. Intraocular pressure (IOP) by pneumatonography or TonoPen XL, heart rate and mean arterial blood pressure were measured at the beginning, middle and end of each study. The ophthalmic vessels examined included: external ophthalmic arteries and veins, long and short posterior ciliary arteries, anterior ciliary arteries and veins, primary retinal arteries, and vortex veins. Recordings of each vessel included peak systolic velocity (PSV), end diastolic velocity (EDV) and time averaged velocity (TAV), and when possible the resistive index (RI) and pulsatility index (PI) were computed. Results CDI abnormalities were present before intraocular pressure exceeded the normal range. As the animals aged, and the glaucoma progressed with higher levels of IOP, significant changes occurred in nearly all vessels, and generally included a major increase in RI (P < 0.001) and an increase in the PI (P < 0.001). Mean arterial blood pressure (105 ± 18 mmHg) and heart rate (118 ± 33/min) remained reasonably constant. The IOP gradually increased as the disease progressed (early and normotensive: 19.4 ± 3.9 mmHg; moderate: 29.7 ± 2 mmHg; and advanced: 44.5 ± 6 mmHg). The ocular veins seemed most influenced early on in the disease. Late in the disease, ocular venous blood flow could not be consistently demonstrated. An increase in the PI of ocular veins occurred in the moderately and severely affected glaucomatous Beagles. As the IOP increased, there were trends of increasing resistive index and pulsatility index in most arteries, and periods of marked decreased velocities of the vortex and external ophthalmic veins in severe cases. Conclusion CDI measurements in Beagles with primary open angle glaucoma during the course of 4 years indicate easily measurable and repeatable progressive blood flow abnormalities before the elevation of IOP and, thereafter, with gradually increased levels of IOP.     

Scanning electron microscopy of corrosion casts of the optic nerve microcirculation in dogs

Scanning electron microscopy of vascular corrosion casts of the optic nerve region in normal and glaucomatous Beagles demonstrated that the blood supply to the laminar optic nerve is derived from short posterior ciliary arteries, cilioretinal arteries, and longitudinal pial vessels. The short posterior ciliary arteries formed a ring of striated pillars around the scleral canal. The central retinal artery was not present in the dog. Differences between the casts in normal and glaucomatous dogs were not detected.     

The effect of an L-type calcium channel blocker on the hemodynamics of orbital arteries in dogs

Purpose (1) To determine the effect of the l ‐type calcium channel blocker amlodipine on color Doppler ultrasound‐determined vascular resistance and blood flow velocities in the distal retrobulbar arteries of dogs; (2) to determine any effect of blood pressure and PCO₂ rate on such color Doppler‐determined circulatory measurements. Methods Color Doppler imaging measurements of the short posterior ciliary artery, long posterior ciliary artery, and ophthalmic artery of normal eyes of 10 dogs were obtained under isofluorane anesthesia before and 1 week after oral amlodipine administration. Mean systemic arterial blood pressure and PCO₂ were monitored. Results The mean resistive index decreased significantly in the short posterior ciliary artery (P = 0.0347), in the long posterior ciliary artery (P = 0.0092), and ophthalmic artery (P = 0.0004) following systemic amlodipine administration. The end diastolic velocity increased significantly in the long posterior ciliary artery (P = 0.0368) and ophthalmic artery (P < 0.0001). The peak systolic velocity increased significantly in the ophthalmic artery (P = 0.0256). Mean systemic arterial blood pressure was significantly negatively associated with resistive index (P < 0.0001) and significantly associated with the log of the end diastolic velocity (P < 0.0001). Conclusions Systemically administered amlodipine increases color Doppler imaging‐determined blood flow velocity and decreases vascular resistive index in the ophthalmic artery, short posterior ciliary artery and long posterior ciliary artery of normal dogs. Changes in systemic arterial blood pressure can significantly affect the measurement of color Doppler imaging parameters.     

Vasculature of the orbital rete in the Japanese deer (Cervus nippon)

The vasculature of the orbital rete (rete mirabile ophthalmicum) in Japanese deer ( Cervus nippon ) was studied using corrosion casting, scanning electron microscopy, and histology. The orbital rete is a flat, triangular- or leaf-shaped arterial network, which consists of a complex of small arterioles, that intermixes with a similar complex of the supraorbital vein at the base of the orbital cavity. Blood to the retina passes through the orbital rete. The orbital retial arterioles leave the parent external ophthalmic artery at right angles forming T-shaped bifurcations, and follow a tortuous, undulating course. Each retial arteriole is connected by side branches and forms a rope-ladder-like network. Some of the side branches are surrounded by a groove representing the intra-arterial cushion that regulates blood flow at branching sites. The central retinal artery supplying the retina originates from the orbital rete. The ciliary arteries supplying the choroid arise from the external ophthalmic artery proximal to the orbital rete. The anatomical specializations of the orbital rete may involve buffering the blood pressure and flow to the retina and regulating ocular tissue temperature as in the carotid rete. In addition, the orbital rete may help dampen the tension that the vessel exerts on the retina, by stretching in response to eyeball movement.     

Functional anatomy of the ocular circulatory system: vascular corrosion casts of the cetacean eye

OBJECTIVE: To examine the functional anatomy of the ocular circulation in four bottlenose dolphins (Tursiops truncatus) and five melon-headed whales (Peponocephala electra). PROCEDURE: Eyes were obtained postmortem from whales that died while in captivity and/or were found beached. Specimens from whales were investigated using scanning electron microscopy (SEM) of vascular corrosion casts and histology. The thermal characteristics of live dolphin eyes were measured using an infrared imaging system. RESULTS: The whale eye receives its primary blood supply from the ophthalmic rete, which extends just behind the eyeball. The ophthalmic rete diverges from the basilar rete and the cervical rete via the posterior thoracic artery. The iris and ciliary processes are supplied by iridic arteries via the major arterial circle that is located around the iris edge. The retinal vessels show the holangiotic type. Choroidal arteries run in parallel arrays so as to interdigitate the densely packed choroidal veins. The venules in the conjunctival fold and palpebral conjunctiva form a well-developed venous plexus. Thermographic examination revealed that the eye shows a substantially higher degree of thermal emission than adjacent skin areas. CONCLUSIONS: The cetacean eye is characterized by a unique vascular pattern and multivessel plexuses, which are quite different from those of terrestrial mammals. This suggests that the ocular vasculature might function as a thermoregulatory system so that the appropriate operating temperature for the photoreceptors can be maintained in a deep and cold aquatic environment. The distinctive plexuses in the orbit might also be for pooling blood in the eye to conserve oxygen during dives. The ophthalmic rete might play a role in a pressure-damping effect on cetacean ocular circulation as well.     

Consecutive water provocative tests in normal and glaucomatous Beagles.

Water provocative tests were evaluated in normal and glaucomatous Beagles. Schiotz tonometry was performed before water was administered (50 ml/kg) by stomach tube and for the next 90 minutes. The mean increase in Schiotz tonometric values in normal dogs ranged from 3.1 to 8.6 mm of Hg and in glaucomatous dogs, 7.3 to 19.9 mm of Hg. Beagles with glaucoma had progressive, gradually increased responses to water provocative tests.     

EFFECTS OF SEDATION WITH MIDAZOLAM AND BUTORPHANOL ON RESISTIVE AND PULSATILITY INDICES IN HEALTHY DOGS

Resistive index (RI) and pulsatility index (PI) are indirect measurements of blood flow resistance that may be measured by pulsed wave Doppler ultrasonography. Chemical restrain may potentially alter the indices although it is required to perform ultrasonography in some patients. The purpose of this study was to describe values for both intrarenal and ocular RI and PI within the same subject in clinically normal dogs sedated with a midazolam and butorphanol combination and evaluate if there are any significant changes between sedated and nonsedated dogs. Fifteen healthy Beagle dogs were studied by Duplex Doppler interrogation in interlobar or arcuate arteries of the kidney and long posterior ciliary artery. Pulse rate and systolic blood pressure were also determined. All measurements were recorded before and after the administration of a sedative combination of midazolam (0.2 mg/kg) and butorphanol (0.2 mg/kg). Mean comparison tests (paired t-tests or Wilcoxon's rank-sum test) were used to determine if any significant differences existed between right and left renal values or right and left ocular values. A correlation study (Pearson or Spearman) was applied between RI, PI, and systolic pressure, and pulse rate. RI and PI were significantly higher in sedated Beagles than in unsedated Beagles. There was neither correlation between index and systolic blood pressure nor pulse rate. In conclusion, provided that normal RI and PI increase in sedated animals, then reference ranges should be higher when sedated--healthy or ill--animals are evaluated.     

Influence of normovolemic anemia on Doppler characteristics of the abdominal aorta and splanchnic vessels in Beagles

OBJECTIVE: To ultrasonographically evaluate hemodynamics in the abdominal aorta (AAo) and splanchnic vessels in dogs with experimentally induced normovolemic anemia. ANIMALS: 11 healthy Beagles. PROCEDURE: The AAo, cranial mesenteric artery (CMA), celiac artery (CA), hilar splenic artery (HSA), and main portal vein (MPV) were evaluated in conscious dogs immediately before and after experimental induction of severe normovolemic anemia (Hct, 16%) and during recovery from moderate and mild anemia (Hct, 26% and 34%, respectively). Peak systolic velocity (PSV) or peak velocity (PV), time-averaged mean velocity (TAVmean), pulsatility index (PI), resistive index (RI), blood flow, congestion index (CI), and heart rate (HR) were recorded. Results were compared for anemic and control states. RESULTS: Severe anemia caused significant increases in HR (25% to 70%), PSV (AAo, 45.8%; CMA, 56.1%; and CA, 41.9%), PV (MPV, 84.2%), and TAVmean, (AAo, 69.4%, CMA, 64.3%; CA, 29.7%; and MPV, 76.9%) and significant decreases in PI (AAo, 26.1%; HSA, 19.3%) and Cl (MPV, 45.2%).There was no significant change in PI of the CMA or CA, portal blood flow, or RI of any artery. Significantly higherTAVmean persisted in all vessels during moderate anemia, but higher PSV persisted only in the CMA; PI (CMA and CA) and RI (CA) decreased significantly, but portal blood flow increased significantly. Significant increase in TAVmean (AAo and CMA) persisted during mild anemia, and PI (AAo, CMA, and HSA) and RI (CMA) were significantly lower. CONCLUSIONS AND CLINICAL RELEVANCE: Doppler ultrasonography revealed hyperdynamic circulation in the AAo and splanchnic vessels in dogs with experimentally induced normovolemic anemia.     

Effects of anti-glaucoma drugs on resistive index of the medial long posterior ciliary artery using color Doppler imaging in Beagle dogs

Color Doppler imaging (CDI) was carried out to evaluate the effects of anti-glaucoma drugs on ophthalmic circulation using CDI-derived resistive index (RI) values. CDI was performed on nine Beagle dogs, and RI values were calculated for the medial long posterior ciliary artery before and after the administration of anti-glaucoma drugs. A significant increase in RI values was found after topical administration of levobunolol (p < 0.05) or dipivefrin (p < 0.05). Pilocarpine showed no effects on RI values after topical administration. The results suggest that some anti-glaucoma drugs could affect ophthalmic blood flow.     

Anatomic, radiographic and physiologic comparisons of the internal carotid and maxillary artery in the horse

The anatomy of the internal carotid and maxillary arteries was examined using angiography, subtraction angiography and arterial cast preparations in three horses. Subtraction angiography was superior to angiography in demonstrating the anatomy of the occipital, external ophthalmic, ethmoidal and palatine arteries. In three horses manipulation of the internal carotid and occipital arteries during angiography resulted in vasospasm which prevented filling of these vessels with contrast. Direct arterial blood pressure measurements of the maxillary artery impinging on the guttural pouches was measured in four anaesthetized and standing horses. Arterial pressure recordings from the maxillary artery indicate there is retrograde blood flow from contralateral vessels into the occluded arterial segment. Vasospasm prevented measurement of arterial pressure in the internal carotid artery.     

Ultrastructural changes in laminar optic nerve capillaries of beagles with primary open-angle glaucoma

Ultrastructural examination of optic nerve capillaries in the canine lamina cribrosa revealed many spherical, membrane-bound, electron-dense inclusions that closely resembled Weibel-Palade bodies, in pericytes and endothelial cells of preglaucomatous, early, moderately, and advanced affected Beagles with hereditary primary open-angle glaucoma. This ultrastructural difference between the laminar capillary endothelial cells of normal and glaucomatous Beagles could represent a functional vascular disorder, because Weibel-Palade bodies are associated with microcirculatory abnormalities.     

Quantitation of uveoscleral outflow in normotensive and glaucomatous Beagles by 3H-labeled dextran

In uveoscleral outflow, aqueous humor leaves the anterior chamber and passes caudally through the trabecular meshwork and the sclerociliary cleft to enter the supraciliary and suprachoroidal spaces. The fluid is then absorbed by choroidal and scleral circulations. Using 3H-labeled dextran, uveoscleral outflow was quantitated in normotensive and glaucomatous Beagles under general anesthesia. The intrascleral plexus was isolated and 3H-labeled dextran was injected into the anterior chamber. Intrascleral plexus contents were sampled every 5 minutes over a 30- to 60-minute period. The eyes were enucleated, sectioned, and prepared for scintillation counting. Uveoscleral outflow accounted for 15% and 3% of the total aqueous humor outflow in the normotensive dogs and in the advanced glaucomatous dogs, respectively. In the advanced glaucomatous Beagle, conventional and uveoscleral outflow pathways were reduced and contributed to the etiopathogenesis of glaucoma.     

Ocular complications of persistent hyperplastic primary vitreous in three dogs

Persistent hyperplastic primary vitreous (PHPV) syndrome associated with either severe ocular complications or multiple ocular lesions was diagnosed in three young dogs, a Samoyed, a Spanish Pachon, and a mixed breed dog. Due to opacification of the anterior ocular structures, B-mode and color-flow Doppler ultrasonography were performed to aid diagnosis. The Samoyed presented with unilateral hyphema; the Spanish Pachon presented with unilateral secondary glaucoma associated with uveitis and hyphema OD and leucocoria OU; and the mixed breed presented with bilateral leucocoria. B-mode ultrasonography of the Samoyed revealed a subcapsular cataract and a hyperechoic tubular structure attached from the optic disk to the posterior lens capsule. In the Spanish Pachon B-mode ultrasonography of the right eye indicated microphakia, cataract formation, and a retrolental mass with a thin hyperechoic strand stretching from the optic disk to the posterior lens; and for the right eye cataract formation, PHPV, retinal detachment, and vitreous hemorrhage. In the mixed breed dog, B-mode ultrasonography of both eyes indicated microphthalmia, retrolental mass, and hyperechoic lenses. By color-flow Doppler imaging, blood flow was present in the retrolental mass of the right eye suggesting a persistent hyaloid artery.     

Use of color doppler imaging for determining the resistive index of the medial long posterior ciliary artery in clinically normal conscious dogs

OBJECTIVE: To evaluate the use of color Doppler imaging (CDI) for determining the resistive index (RI) of the medial long posterior ciliary artery (mLPCA) in clinically normal conscious dogs. ANIMALS: 18 (10 sexually intact males, 8 sexually intact females) dogs between 1 and 5 years old. PROCEDURE: Color Doppler ultrasonography was performed on both eyes with dogs in a sitting position. Each eye was imaged from the region dorsal to the zygomatic arch with the transducer positioned in a horizontal plane. The mLPCA was localized, and RI was calculated from velocities obtained for 3 similar Doppler waveforms. To determine the reproducibility of CDI-derived RI, measurements were repeated twice at a 10-day interval. RESULTS: Mean (+/- SD) RI of the mLPCA was 0.68 +/- 0.07 (95% confidence interval, 0.65 to 0.70; n = 36 eyes). Resistive index did not significantly differ between right and left eyes or male and female dogs. In addition, body weight was not correlated with RI. Repeated measurements of RI did not yield significantly different results (interclass correlation coefficient, 0.8297). CONCLUSION AND CLINICAL RELEVANCE: Color Doppler imaging appears to be a valid technique for determination of RI of the mLPCA in conscious dogs. This technique may be useful for investigating the pathophysiologic processes of many ocular and orbital vascular disorders in dogs.     

Incidence of canine glaucoma with goniodysplasia in Japan : a retrospective study

The incidence of primary and secondary glaucoma in dogs was investigated. A total of 1244 dogs received ophthalmologic examinations, including tonometry and gonioscopy. Goniophotographs were taken using a goniolens to evaluate the iridocorneal angle (ICA) as well as pectinate ligament (PL). The anterior width of the ciliary cleft and the total distance from the origin of the PL to the anterior corneal surface were measured from the goniophotographs. Glaucoma was diagnosed based on the cupping of the optic nerve head, clinical signs, ocular changes, and high IOP, and it was synchronized with gonioscopic grades to differentiate between primary and secondary glaucoma. We investigated 1244 dogs of 29 breeds, including the mixed breed; among these, glaucoma was diagnosed in 127 dogs (162 eyes). Of 162 eyes, primary glaucoma was diagnosed in 129 eyes and secondary glaucoma in 33 eyes. Shiba Inu dogs (42 dogs, 33%) showed the highest incidence of glaucoma, followed by Shih-Tzu (21 dogs, 16.5%). Furthermore, all the glaucomatous Shiba Inu dogs had primary glaucoma with abnormal ICA grades and dysplastic PLs. The findings of our study reveal that the Shiba Inu breed in Japan may have a hereditary predisposition to glaucoma.     

Localization of smooth muscle actin in the iridocorneal angle of normal and spontaneous glaucomatous beagle dogs

Purpose To date, our knowledge of the canine trabecular meshwork (TM) with regard to contractility is incomplete. It is important to understand the potential contractile capability within the TM and possible changes associated with spontaneous hypertensive glaucoma. To that end we have examined the presence of actin, including smooth muscle (SM) actin, in the normal and glaucomatous canine iridocorneal angle (ICA) morphologically and immunohistochemically. Methods Sections from the ICAs of 12 Beagles with inherited glaucoma (3 months to 6 years old) and age‐matched normal Beagles were treated with target retrieval, protein and power blocked and sequentially incubated with the primary antibody (rat anticanine SM actin) and the secondary antibody (rabbit antirat immunoglobulin), followed by peroxidase labeled streptavidin and incubation with substrate‐chromogen solution (AEC). Smooth muscle fibers that lined an artery within canine heart tissue were used as positive controls. Separate specimens were prepared for ultrastructual observation. Results Ultrastructurally, cells within the inner, posterior region of the corneoscleral TM and outer, posterior region of the uveal TM contained many microfilaments, 6 nm in diameter (i.e. actin). Immunohistochemistry demonstrated that cells within these regions possessed SM actin, having been greatest posteriorly, but extended anteriorly to a lesser extent. In the preglaucomatous affected dog the localization pattern for SM actin was identical to that seen in the normal dogs. With the progression of the disease the pattern disappeared. Conclusions The interior presence of myofibroblastic cells within the canine ICA suggests that these cells and the smooth muscle cells of the ciliary body along the same plane of orientation function to facilitate the removal of aqueous humor and are likely to be influenced by vascular mediators. The contractile apparatus for the ICA in the dog with inherited glaucoma appeared identical to that of the normal dog prior to expression of the disease, but weakened as the disease progressed.     

Microvasculature of the hamster eye: scanning electron microscopy of vascular corrosion casts

The architecture of the retina, choroid and anterior eye segment was investigated in 12 Syrian hamsters using scanning electron micrographs of methylmethacrylate corrosion casts. The hamster eye receives its primary blood supply from the long posterior ciliary artery, which directly enters the optic nerve head, and divides into three branches: the central retinal artery and medial and lateral long posterior ciliary arteries. In the retina the central retinal artery divides into six radiating branches. Retinal arterioles form a slender and long course to capillaries. Retinal capillaries are extremely thin in diameter and form a sparse capillary network. The choroid is supplied by the long posterior ciliary arteries. Choroidal arterioles exhibit a thick and short course to the choriocapillaris. The choriocapillaris is thick and sinusoid-like, forming a dense network in the choroid. The ciliary body, iris and bulbar conjunctiva are supplied by the anterior ciliary arteries, which are branches of the long posterior ciliary arteries. Capillaries supplying the anterior margin of the ciliary process are large in diameter with an irregular bore, forming a thoroughfare channel draining blood in the ciliary arterioles into the pars plana vessels. Blood from the retina is drained by the central retinal veins. Venules from the anterior eye segment empty into the vortex veins via the pars plana vessels. Venous blood from the choroid is drained only by vortex veins via the choroidal veins. The functional significance of the vascular architecture and species differences are discussed.     

Histomorphologic and morphometric evaluation of the uterine horns in nulliparous and multiparous Beagles

OBJECTIVE: To macroscopically, histomorphologically, and morphometrically compare uterine tissues obtained from nulliparous and multiparous dogs. ANIMALS: 12 dogs constituting 2 homogenous groups (7 nulliparous Beagles and 5 multiparous Beagles, each of which had at least 7 pregnancies). PROCEDURE: Serum concentrations of progesterone and estradiol-17beta were determined. Samples of uterine tissues were fixed, embedded in paraffin, and cut into serial cross sections. Morphometric analysis was performed on systematically selected trichrome-stained sections. RESULTS: Mean absolute volume of the uterine wall did not differ between groups. Volume of blood vessels was significantly higher and relative mean value for myometrial connective tissue was significantly lower in the multiparous dogs. Arteries in the myometrium of multiparous dogs had pronounced thickening of the intima (ie, pregnancy sclerosis) and a concomitant thinning of the smooth muscle layer (tunica media). Furthermore, the elastica interna of these arteries appeared to be disintegrating and was highly and irregularly folded. Adventitia of the myometrial veins in multiparous dogs contained numerous layers of elastic fibers; however, only a few layers were observed in the adventitia of corresponding veins in nulliparous dogs. CONCLUSIONS AND CLINICAL RELEVANCE: In this study, we documented that in contrast to other species, the uterus of nonpregnant dogs does not increase in size and volume even after at least 7 pregnancies. Furthermore, sclerotic alterations of uterine arteries are proof of at least 1 pregnancy. Results of this study may be useful in the evaluation of uterine diseases.     

The arterial supply of the eye of the yak (Bos Grunniens)

The heads and necks of 10 yaks were dissected to study the arterial supply to the eye of the yak in the Qinghai-Tibetan Plateau. The supply came from the internal ophthalmic, external eight ophthalmic, superficial temporal and malar arteries. The internal ophthalmic was one of sources of the posterior long ciliary artery. The external ophthalmic artery gave rise to branches to supply the dorsal oblique muscle and otherwise, and to take part in the formation of the ophthalmic rete mirabile. The ophthalmic rete mirabile gave off many branches to supply the rectus muscles of the eye and otherwise. The malar artery was one of the branches derived from the infraorbital artery, and its branches supplied the inferior, superior and third eyelids and otherwise. The superficial temporal artery detached off some branches to supply the lateral angle of the eye and otherwise, and anastomosed with the lacrimal artery of the ophthalmic rete mirabile.