Clinical anatomy of the orbitomeningeal foramina: variational anatomy of the canals connecting the orbit with the cranial cavity

PURPOSE

In addition to the optic canal and the superior orbital fissure, orbits are connected with the cranial cavity via inconstant canals including the orbitomeningeal foramen. This study has been carried out in order to define many anatomical and radiological details of the orbitomeningeal foramen that are relevant in the clinical practice.

METHODS

Almost 1000 skulls and 50 computerized tomographies were examined to determine incidence, number, length, and caliber of the orbitomeningeal foramen as well as the topography of their orbital and cranial openings. A retrospective study of angiographies carried out on more than 100 children was performed to look for arteries candidate to run through the orbitomeningeal foramen.

RESULTS

Orbitomeningeal foramina were detected in 59.46% of skulls and in 54% of individuals by computerized tomography. Orbits with two to five foramina were found. Canals were classified as M-subtype or A-subtype depending on their cranial opening. Large foramina, with the caliber ranging between 1 and 3 mm, were found in 12.17% of orbitomeningeal foramen-bearing orbits. By computed tomography the average caliber measured 1.2 ± 0.3 and 1.5 ± 0.5 mm (p < 0.005) at the orbital and cranial openings, respectively (p < 0.005). Angiographies showed meningo-lacrimal and meningo-ophthalmic arteries, meningeal branches of the lacrimal and supraorbital arteries, and some unidentified arteries that could pass through the orbitomeningeal foramina.

CONCLUSIONS

Orbitomeningeal foramina are a common occurrence. When large they may house important arteries that can be the source of severe bleedings during deep dissection of the lateral wall of the orbit. Orbital surgeons should be aware of their existence.

Morphological features of the porcine lacrimal gland and its compatibility for human lacrimal gland xenografting

In this study, we present first data concerning the anatomical structure, blood supply and location of the lacrimal gland of the pig. Our data indicate that the porcine lacrimal gland may serve as a potential xenograft candidate in humans or as an animal model for engineering of a bioartificial lacrimal gland tissue construct for clinical application. For this purpose, we used different macroscopic preparation techniques and digital reconstruction of the histological gland morphology to gain new insights and important information concerning the feasibility of a lacrimal gland transplantation from pig to humans in general. Our results show that the lacrimal gland of the pig reveals a lot of morphological similarities to the analogous human lacrimal gland and thus might be regarded as a xenograft in the future. This is true for a similar anatomical location within the orbit as well as for the feeding artery supply to the organ. Functional differences concerning the composition of the tear fluid, due to a different secretory unit distribution within the gland tissue will, however, be a challenge in future investigations.

[Lacrimal gland changes in sarcoidosis according to the results of spatial digital ultrasonography]

Clinical changes of lacrimal gland (LG) in sarcoidosis are studied. 33 patients (66 orbits) with verified systemic sarcoidosis were examined using digital ultrasound. Different varieties of LG structural changes in sarcoidosis are studied. Different types of LG structural changes were determined in patients with sarcoidosis defined as pseudoedematous and combined forms. Analysis of the results let us reveal characteristic local acoustic changes. Obtained results may be useful for diagnosis of LG changes in patients with sarcoidosis.

Identification of orexins and cognate receptors in the lacrimal gland of sheep

The aim of the present work was to study, by means of immunohistochemical and RT-PCR techniques, the presence and distribution of immunopositivity for orexin A and B (OXA and OXB) and orexin type 1 and 2 receptors (OX(1)R and OX(2)R) in the lacrimal gland of sheep as well as the gene expressions for prepro-orexin (PPOX) and cognate receptors. In serial sections, positive staining for OXA and OXB were localized in the same nervous fibers within the connective tissue septa. Positive staining for OX(1)R was evidenced in the wall of small arteries while that for OX(2)R was observed in the secretory portion of the acinar gland cells with a characteristic localization in the apical cytoplasm. RT-PCR analysis showed the presence of transcripts for PPOX, OX(1)R and OX(2)R in the sheep lacrimal gland; the gene expression of OX(1)R was two-fold greater (p<0.01) than that of OX(2)R. Taken together the present findings raise intriguing questions on the potential role of the orexinergic system in the regulation of lacrimal gland functions that require further investigations.

[Ultrasound spatial clinical analysis of the orbital part of the lacrimal gland in health]

The paper presents an algorithm of ultrasound spatial analysis of the unaltered lacrimal gland. The algorithm has been used to define its shape, size, density, structural features and the pattern of blood supply, as well as the anatomic and topographic position in the orbit. The study was conducted in the B- and 3D-modes of color and energy Doppler mapping on both sides. The procedure was based on the clinical examination of 40 healthy individuals aged 20 to 75 years who had no systemic vascular and lymphoid tissue lesions or functional impairments of the lacrimal gland itself. The study defined the mean values of the ultrasound section of the lacrimal gland: 1-1.8 and 0.5-0.8 cm for vertical and horizontal ones, respectively; the mean volume of the lacrimal gland of 0.66 to 1 cm(3) and the densitometric parameters (density and vasculogenicity index); three types of structural manifestations of the unaltered lacrimal gland were identified. The proposed algorithm of ultrasound study of the lacrimal gland may enhance the accuracy and validity of results in the differential diagnosis of various orbital diseases.

CT arteriography for orbital tumors: diagnostic and surgical value

The aim of this study is to investigate the efficacy of dynamic computed tomography (CT) during selective angiography (CT-arteriography) of orbital tumors in the evaluation of intratumoral vascular anatomy, feeding artery territory, and histological diagnosis. Among 35 consecutive cases with various orbital lesions, those cases showing tumor staining or pooling of the contrast medium on digital subtraction angiography (DSA) were evaluated by CT-arteriography (n = 14). The information obtained by CT-arteriography was compared with that provided by enhanced MRI (n = 31) and dynamic MRI (n = 21), in which the contrast medium was injected intravenously. In addition to the visualization of fine vascular anatomy, CT-arteriography emphasized areas of nodular enhancement and non-enhancing cystic/necrotic components as well as the intratumoral feeding arteries. Patterns of CT-arteriography were categorized into three subgroups: homogeneous enhancement (benign lymphoid lesion), partial enhancement (schwannomas and carcinomas), and patchy multinodular enhancement (specific for cavernous angiomas). In addition, CT-arteriography with selective arterial catheterization clearly delineated the feeding artery territories. CT-arteriography, with a minimal dose of contrast medium, can offer significant advantages over intravenously injected dynamic neuroimaging, and provides additional valuable preoperative information about the orbital tumor under investigation.

Importance of the anatomic features of the lacrimal artery for orbital approaches

Knowledge of variations in the possible patterns of origin, course, and distribution of the lacrimal artery are necessary for the diagnosis and important for the treatment of orbital disorders. The vascularization of 38 lacrimal glands was studied by orbital dissection subsequent to injection of the arterial bed with red-dyed latex. The origin, calibration, and branches of the lacrimal artery and its topographic relations were investigated. In all subjects, arteria lacrimalis originated from ophthalmic artery. On the right, the lacrimal artery sprang from the angle of the ophthalmic artery in 63.15% of the cases, from the curve of the ophthalmic artery in 26.31%, and from the first part the ophthalmic artery in 5.26%. The outer diameter of the lacrimal artery was measured as 1.02 +/- 0.17 mm on the right and 1.03 +/- 0.16 mm on the left. In 68.42 of the cases on the right and in 52.63 of the cases on the left, the lacrimal artery was present, and the lacrimal nerve was seen in a superolateral position with respect to the origin of the artery. Variability of the glandular branch in its course toward lacrimal gland was observed. Recurrent meningeal branch was seen in six cases on the right and in five on the left. On the right, of the six cases, two passed through meningoorbital foramen, and four passed through superior orbital fissure and entered middle cranial fossa. On the left, of the five cases, two passed through meningoorbital foramen, and three passed through superior orbital fissure and entered middle cranial fossa. In this case, the lacrimal gland is the site of an intraorbital anastomosis between internal and external carotid systems. This article confirms the well-known variability of the lacrimal arterial branches and their relation to the lacrimal gland. These variations have been discussed and described with respect to the embryonic development. A better understanding of the vascular anatomy of the lacrimal gland should allow modification of surgical techniques to reduce bleeding during biopsy or excision of the lacrimal gland.

Doppler sonography of the normal lacrimal gland

PURPOSE

We used Doppler sonography to determine the resistance index (RI) and pulsatility index (PI) of the normal lacrimal artery (LA) in both females and males. We also compared the values obtained at various periods of reproductive life.

METHODS

The study was performed in 25 prepubertal girls, 28 females of reproductive age, and 27 postmenopausal women, 23 pregnant women, and 104 healthy males. Doppler sonography was used to determine the RI and PI of the LA.

RESULTS

The mean PI for the entire patient population was 1.48 +/- 0.60 and the RI was 0.72 +/- 0.09. The RI and PI values of the LA did not differ between males and females. Similarly, the mean RI and PI values of the LA did not change significantly between the various reproductive phases.

CONCLUSION

The PI and RI of the lacrimal gland are similar in both sexes. Moreover, they are not altered by changes in levels of sex steroids.

Distribution of pterygopalatine ganglion efferents to the lacrimal gland in man

To trace the path taken by the putative postganglionic secretomotor fibres to the lacrimal gland the contents of the orbital and pterygopalatine fossa were removed whole, cut coronally into slabs and embedded in resin. Thin sections were cut at varying intervals to reconstruct the pathway taken. One group of rami orbitales issuing from the pterygopalatine ganglion passed dorsally adjacent to the lateral wall of the orbit, joined the retro-orbital plexus at the apex, and 5-10 rami lacrimales advanced from the plexus to enter the gland. An accessory ophthalmic artery, a branch of the middle meningeal artery, entered the orbit through the superior fissure orbital joining the ophthalmic or lacrimal artery. Perivascular nerves of the artery continued to the gland as supplementary rami lacrimales and in some orbits others served the vasculature of the eye and orbit. The nerves are presumably derived from the middle meningeal supply and may include otic parasympathetic fibres. The route taken by parasympathetic nerves serving the human lacrimal gland is demonstrated here for the first time and apart from the perivascular meningeal artery source, it is similar to that described in monkeys. The traditional assumption that secretomotor nerves pass to the gland via the zygomatic and lacrimal nerves is therefore unlikely and clinical measures to reduce lacrimation based on that assumption and involving severance of ophthalmic branches is not indicated.

The lacrimal fascia redefined

It has been commonly accepted that the lacrimal fascia is an intact septum, composed of connective tissue, that separates the orbital cavity into a large compartment, which contains the eyeball, and a small compartment, which contains the lacrimal sac and nasolacrimal duct. the septum, however, is not necessarily always intact. We found a circular or oval opening in the lacrimal fascia in 37 of 52 specimens (71.2%) examined. The opening, which we shall refer to as the lacrimal fascial foramen, was located at variable levels in the lacrimal fossa. The lacrimal fascial foramen was buried in fatty tissue through which passed a branch of either the inferior palpebral artery or the infraorbital artery and a vein of the nasolacrimal duct. The clinical implications of the lacrimal fascial foramen in obstruction of the nasolacrimal duct are discussed.

Anatomy and histology of the lacrimal fluid drainage system

Five human specimens of the lacrimal canaliculus and sac were examined by light and scanning electron microscopy. The superior and inferior lacrimal canaliculi are lined with stratified squamous epithelium that is non-keratinized and non-mucin-producing. The common canaliculus is also lined with stratified squamous epithelium, but its lumen is much narrower than the lumen of the superior and inferior canaliculi. The common canaliculus opens into an ample space called the vestibule, where the epithelium changes to high pseudostratified columnar and then low pseudostratified columnar. The vestibule continues to the infundibulum of the lacrimal sac. The infundibulum is formed by several epithelial folds that radiate from the vestibular opening to the lacrimal sac. The vestibule and infundibulum are consistent transitional structures from the common canaliculus to the lacrimal sac. The connective tissue of the lamina propria from the common canaliculus to the lacrimal sac has two histological characteristics: numerous free cell aggregates (= lymphoid structure) and numerous venules and capillaries (= cavernous structure).

Temporary uniocular blindness and ophthalmoplegia associated with a mandibular block injection. A case report

A mandibular block injection produced temporary uniocular blindness, total ophthalmoplegia, mydriasis, and ptosis of the eyelid, with diplopia developing as the sight returned. These effects lasted 25-30 minutes. The explanation offered as to the cause of the anaesthetic phenomenon is an intra-arterial injection into the maxillary artery with backflow of anaesthetic solution into the middle meningeal artery. The instantaneous blindness results from the anaesthetic agent being carried into the central artery of the retina through an anastomosis of the ophthalmic and middle meningeal arteries via the recurrent meningeal branch of the lacrimal artery. Although of short duration, the symptoms mimic a more serious carotid artery embolus occluding the ophthalmic artery. Complications of mandibular blocks have been reported in the literature, however total blindness and ophthalmoplegia are extremely rare. This case report highlights an event where individual anatomical variation of the maxillary and middle meningeal arteries has allowed anaesthetic solution to be delivered to an ectopic site.

The cavernous body of the human efferent tear ducts: function in tear outflow mechanism

PURPOSE

To determine the structure and function of a system of large blood vessels integrated in the bony canal between the orbit and the inferior nasal duct.

METHODS

Thirty-one dissected lacrimal systems of adults were analyzed by using gross anatomy, histology, and electron microscopy as well as corrosion vascular casts.

RESULTS

More than two thirds of the bony canal between orbit and inferior nasal duct is filled by a plexus of wide-lumened veins and arteries. The vascular system is embedded in the wall of the lacrimal sac and nasolacrimal duct and is connected to the cavernous tissue of the inferior turbinate. Three types of blood vessels can be distinguished inside the vascular tissue that surrounds the lumen of the lacrimal passage: barrier arteries, capacitance veins, and throttle veins.

CONCLUSIONS

The surrounding vascular plexus of the lacrimal sac and nasolacrimal duct is comparable to a cavernous body. While regulating the blood flow, the specialized blood vessels permit opening and closing of the lumen of the lacrimal passage, effected by the bulging and subsiding of the cavernous body, and at the same time regulate tear outflow. Other functions such as drainage of absorbed tear fluid components and a role in immunologic response are under discussion as well. Malfunctions in the cavernous body may lead to disturbances in the tear outflow cycle, ocular congestion, or total occlusion of the lacrimal passages. Variations in the conditions for swelling of the cavernous tissue may have led to the (mistaken) description of valves in the lacrimal passage.

Submandibular and lacrimal gland immunoglobulin in the C3H.MRL-Faslpr autoimmune mouse model of Sjögren's syndrome

OBJECTIVE

To distinguish potential autoimmune and nonautoimmune mechanisms underlying the salivary gland inflammation seen in Sjögren's syndrome and normal aging.

STUDY DESIGN

Immunohistochemical studies were conducted on the lacrimal and salivary glands of 2- and 5-month-old C3H.MRL-Faslpr autoimmune strain mice and age-matched C3H/HeJ nonautoimmune controls.

METHODS

Glandular inflammatory foci, interstitial areas, and vasculature were stained for immunoglobulin G (IgG), immunoglobulin A (IgA), and complement to determine differences in their local immune parameter. Differences between the two strains were compared for immune changes attributable to autoimmune disease and between the two normal groups for normal aging changes.

RESULTS

Greater staining of IgG, IgA, and complement occurred in the inflammatory foci and interstitial areas of 5-month-old C3H.MRL-Faslpr lacrimal and submandibular glands compared with 5-month-old controls. Normal mice showed some increased immunoglobulin staining with aging, but little or no complement in any glands.

CONCLUSIONS

These differential findings suggest that the systemic autoimmune disease plays a more direct role in focal glandular inflammation in Sjögren's syndrome, whereas less severe immune mechanisms are involved in the inflammation of normal glands.

Vascular anatomy of the lacrimal gland

This study was undertaken to establish the detailed vascular architecture of the lacrimal gland. The common carotid arteries of seven fresh human cadaver heads were injected with a compound consisting of a partially polymerized monomer, to which a catalyst and promoter were added to cause hardening. The soft tissue was then digested, using 40% potassium hydroxide, to obtain detailed casts of the lacrimal artery. The authors describe the anatomy of 14 cadaver lacrimal arteries from their entrance into the lacrimal gland to their terminal conjunctival branches. Consistent vascular patterns within the lacrimal gland were observed. A better understanding of the vascular anatomy of the lacrimal gland should allow modification of surgical techniques to reduce bleeding during biopsy or excision of the lacrimal gland.

Correlation between vasodilatation and secretion in the lacrimal gland elicited by stimulation of the cornea and facial nerve root of the cat

PURPOSE

To determine whether reflex vasodilatation can be elicited in the cat lacrimal gland by electrical stimulation of the cornea, whether the vasodilatation elicited by electrical stimulation of the facial nerve root found to be the efferent arm of the cornea-lacrimal gland reflex pathway correlates with the evoked secretion in the lacrimal gland, and what kind of receptors and which autonomic ganglia are involved in lacrimal vasodilator and secretory responses.

METHODS

Electrical stimulation of the cornea or facial nerve root was used to evoke a blood flow increase in the lacrimal gland and tear secretion of the urethane-chloralose-anesthetized, paralyzed, and cervically sympathectomized cat.

RESULTS

The lacrimal vasodilator response depended on stimulus intensity and frequency and correlated well with the tear secretion. Injection of 2% lidocaine solution into the retrobulbar area, where the pterygopalatine ganglion is located, abolished the vasodilator and the secretory responses. Pretreatment with hexamethonium (an autonomic ganglion blocker) greatly attenuated the secretory response, even at a low dose (1 mg/kg given intravenously), although at this dose, the vasodilator response was only slightly affected. Neither phentolamine (an alpha-adrenoceptor antagonist) nor propranolol (a beta-adrenoceptor antagonist), nor a vasoactive intestinal peptide antagonist had any effect on the vasodilator or secretory responses. Scopolamine (a muscarinic receptor antagonist), although having no effect on vasodilatation, had a profound inhibitory effect on the secretory response.

CONCLUSIONS

These results suggest that whereas the vasodilator and secretory responses in the lacrimal gland were well correlated, they were mediated by different mechanisms.

[Development variations of the R. anastomoticus cum a. lacrimali in Japanese]

This report describes the developmental variations of the R. anastomoticus cum a. lacrimali in 150 Japanese cadavers (300 orbits). The orbits were classified into seven types on the basis of the diameters, directions and anastomoses of the ophthalmic artery (OA), lacrimal artery (LA) and R. anastomoticus cum a. lacrimali (RAL). The definitions and frequencies of the seven types were as follows. 1) Normal type: The diameter of the RAL was smaller than that of the LA (240 orbits, 80.0%). 2) Thin type: The diameter of the RAL was comparable to or larger than that of the LA, but smaller than that of the OA (19 orbits, 6.3%). 3) Thick type: The diameter of the RAL was comparable to or larger than that of the OA (5 orbits, 1.7%). 4) OA type: The OA was absent or vestigial, and the blood of the orbital contents was supplied mainly by the RAL instead of the OA (1 orbit, 0.3%). 5) LA type: The LA arose from the RAL instead of the OA (23 orbits, 7.7%). 6) MMA type: The middle meningeal artery (MMA) was absent or vestigial, and the blood of the dura mater was supplied mainly by the RAL instead of the MMA (1 orbit, 0.3%). 7) Absent type: The RAL could not be found (12 orbits, 4.0%). The OA, MMA and LA types are established anomalies of the RAL that have been described anatomically and clinically. However, few studies have investigated the developmental variations of the RAL in detail. The results of this study suggest that the developmental variations of the RAL are more remarkable than reported previously.

Classification of the ophthalmic artery that arises from the middle meningeal artery in Japanese adults

In a study of Japanese adults, we found that the orbital branch (OB) passing through the superior orbital fissure frequently anastomosed with the lacrimal artery or the ophthalmic artery (12/20). However, the OB passing through the meningo-orbital foramen (mof) only associationaly anastomosed with branches of the ophthalmic artery (4/79). Furthermore, the OB in the orbit, excluding the lacrimal gland as previously reported. We examined 116 cases in which the OB passed through the mof in 129 adult Japanese cadavers (45.0% in 258 sides). The OB passing through the mof was always distributed to the periorbital region and the area that it supplied was limited to the periorbita in about half of those cases. In another half of the cases (58/116), the area supplied included the lacrimal gland.

Kinetic analysis of rat exocrine gland muscarinic receptors in vivo

Recently we employed two enantiomers of the muscarinic antagonist quinuclidinyl iodobenzilate (IQNB), and pharmacokinetic analyses, to define and quantitate nonspecific and specific binding to rat parotid gland muscarinic acetylcholine receptors (mAChRs) in vivo (Hiramatsu et al., 1993). The present studies were designed to utilize this same approach for evaluating mAChRs in three other morphologically different rat exocrine glands: the submandibular, sublingual and lacrimal glands. The metabolism and tissue distribution of the intravenously injected IQNB enantiomers were determined, and the resulting data were assessed in terms of their goodness of fit to several multicompartmental models. All three exocrine glands showed substantial nonspecific ligand distribution as measured with the receptor-inert enantiomer (SS)-IQNB. Nonspecific distribution represented 45, 21 and 36% of total ligand distribution in submandibular, sublingual and lacrimal glands, respectively, as measured with the receptor-active enantiomer (RR)-IQNB. The rank order of the binding potential, kinetically equivalent to Bmax/Kd, for (RR)-IQNB and these mAChRs was lacrimal > sublingual > submandibular glands (674 +/- 235 > 575 +/- 109 > 345 +/- 29). These results demonstrate that specific mAChRs in the exocrine glands can be measured in vivo with the (RR)-IQNB enantiomer and that despite some small quantitative differences, the distribution of (RR)- and (SS)-IQNB is similar in the three exocrine glands but is substantially different from that in brain and heart.

Regional differences within the external 'duct' of the rat exorbital lacrimal gland

The lacrimal cord is the fibrous structure that extends between the rat exorbital lacrimal gland and the eyelid. Disagreement exists about the number of ducts it contains and with which lid the orifice is associated. Therefore, 18 lacrimal cords from adult rats were studied by light microscopy. Additionally, in five specimens the continuations of the major ducts were observed immediately intraglandularly. Adjacent to the exorbital lacrimal gland, the lacrimal cord may contain six or more ducts. Farther toward the eye, it has five, four, and then three ducts; the latter typically at about its midpoint. Close to the infraorbital gland two or one are present. Approaching the temporal aspect of either lid, the ducts of both the infraorbital and exorbital lacrimal glands course within the lacrimal cord and usually merge. In some adult rats, when the eyelids are retracted laterally, it is evident that a crescentic fold of the palpebral conjunctiva contains a vertical pair of whitish, convex structures, the 'temporal canthal domes'. When present, one can serve as a marker for the duct orifice located close to the conjunctival fornix. Pseudostratified columnar epithelium lines the ducts from the orifice to the region of the infraorbital lacrimal gland. From the latter toward the exorbital lacrimal gland the epithelium may become pseudostratified cuboidal. That type exists close to and immediately within the exorbital gland. The variation in duct number within the lacrimal cord would have physiological consequences. By analogy with the circulatory system, it is expected that flow would occur more slowly within the multiple ducts in and near the exorbital lacrimal gland than in the one or two near the canthus. Where flow is slower, contact time of the secretion with the duct epithelium would be greater. Thus, modification of the lacrimal secretion is likely not to occur uniformly in the duct system but would take place primarily in and near the exorbital lacrimal gland rather than toward the duct orifice.

Homologies of the meningeal-orbital arteries of humans: a reappraisal

Two arteries connect the anterior branch of the middle meningeal artery to the lacrimal artery. One vessel, the sphenoidal artery, passes through the superior orbital fissure. The other vessel, the meningolacrimal artery, passes through the cranio-orbital foramen. An analysis of data derived from embryology, comparative anatomy, and patterns of adult variation indicates that the meningolacrimal artery is homologous with the ramus superior of the stapedial artery, an embryologically and phylogenetically primitive vessel. The sphenoidal artery probably forms late in human ontogeny and represents an evolutionary novelty. Its distribution is probably restricted to hominoids and may be exclusive to humans and orangutans (Pongo pygmaeus). The sphenoidal artery is associated with three other derived features: the sphenoparietal sinus and sulcus and a laterally expanded superior orbital fissure. The high frequency of the sphenoidal artery in Homo and Pongo probably represents a case of parallelism. The earliest paleontological evidence of an enlarged sphenoidal artery in the Hominidae occurs in Indonesian Homo erectus (Sangiran VI).

The ophthalmic artery and its branches, measurements and clinical importance

Seventy-one Caucasian orbits (36 right, 35 left) were studied by dissection. The diameter of the ophthalmic a. (2 mm from the origin) was 1.54 +/- 0.04 mm (male) and 1.31 +/- 0.05 mm (female). In individual cases, there were no significant differences in vessel diameter between the right and left sides but, differences in vessel diameter between males and females were more commonly observed in the arteries which leave the orbit (extraorbital group), the individual vessels having a larger diameter in males. The incidence of the ophthalmic a. passing in the orbit medially under the optic n. was 18.6%. The lacrimal a. was observed to arise from the ophthalmic a. in only 82.5% of the cases examined, 15.9% of the cases showed the origin to be at the anastomotic branch of the middle meningeal.

Ultrastructure of the blood vessels in the Harderian gland of the hamster (Mesocricetus auratus): existence of sinusoids

The Harderian gland blood supply of female and male hamsters was studied using light and electron microscopy. A profuse vascularization surrounding secretory acini was observed. Among the blood vessels, the existence of large and irregular sinusoidal capillaries was apparent. These sinusoids appeared in close association to the basal aspect of the secretory cells. Typical, small, fenestrated capillaries were also observed within the connective tissue. The existence of this particular vascularization together with other morphological features of the secretory cell basal pole suggest a possible endocrine function of these orbital glands.

Non-adrenergic sympathetic vasoconstriction in the eye and some other facial tissues in the rabbit

The effects of unilateral sympathetic nerve stimulation (SNS) on regional blood flow in the rabbit were studied with radioactive microspheres. SNS at 10 or 4 Hz caused an approximately 60% reduction in choroidal blood flow, which was partly resistant to alpha-adrenoceptor blockade with phenoxybenzamine. The vasoconstriction evoked by SNS at 2 Hz was completely abolished by alpha-adrenoceptor blockade. A similar response was seen in the iris, ciliary body, masseter muscle and lacrimal gland. In the harderian gland, however, SNS (2 Hz) after alpha-adrenoceptor blockade caused a significant reduction in blood flow. In the salivary glands, combined beta- and alpha-adrenoceptor blockade with propranolol and phenoxybenzamine revealed a slight non-adrenergic vasoconstriction during SNS at 10 Hz; however, the blood flow was significantly increased during SNS at 4 and 2 Hz following alpha-adrenoceptor blockade. These results indicate that there is a frequency-dependent, non-adrenergic component in the sympathetic vasoconstriction of the eye and several facial tissues. In the salivary glands, beta-adrenoceptor-mediated vasodilatation tends to mask a non-adrenergic vasoconstriction.

[Arterial vascularization and innervation of the lacrimal gland. Apropos of 100 dissections]

The authors report the different types of arterial vascularization and lacrimal gland innervation, noticed in 100 human orbits with arterial latex injected. The lacrimal artery may be unique, arising either from the ophtalmic artery, the most frequent case (vascularization of type I) or from the external carotid system (vascularization of type II): it is possible that 2 lacrimal arteries are simultaneously present, originating from the 2 carotid system (vascularization of type III). The lacrimal gland is innerved by the lacrimal nerve and by one or several nervous branches, originated from the maxillary nerve. 3 possibilities can be found: a zigomatic branch from the maxillary nerve makes a preglandular anastomosis with the lacrimal nerve; a real lacrimal loop, which may form either an intraglandular anastomosis or be completely independant of the lacrimal nerve. Sometimes, several zigomatic rami do exist. These different variations and their frequency are analyzed and referred to the literature.

[Structuro-functional units of the salivary and lacrimal glands]

By means of the multilayer graphic and plastic reconstruction methods using series of semithin sections, spatial tridimensional organization of the epithelial complexes and blood microcirculatory bed in the rat palatal salivary glands and the lacrimal gland of the human newborn have been studied. Since their ducts serve not only for discharging their secrete into the external medium, but also for accumulation (as collectors), the sublobular unit--adenomere should be referred to as a part of elementary level of organization of the epithelial complexes. The adenomere has in its composition a collecting centrally situating duct. However, while studying structure of the blood microcirculatory bed, it is found out that there is not any strict territorial correspondence between its functional units and structural units of the glandular epithelium. Nevertheless, giving a great importance to a tight syntopic connection of the collecting ducts of the adenomeres with the postcapillary venules (that belong to filtrating microvessels), these are sublobular units--adenomeres that are distinguished as structural-functional units in the glands.

Intravenous pyogenic granuloma of the ocular adnexa. Report of two cases and review of the literature

Intravenous pyogenic granuloma is a recently described form of pyogenic granuloma (PG) in which the angiomatous proliferation is confined entirely within the lumen of a vein. To our knowledge, only four cases involving the ocular adnexa, including two that we encountered, have been described. Histologically, this benign lesion is similar to PG of other locations and is characterized by lobular congeries of capillaries embedded in a fibromyxoid matrix containing scattered chronic inflammatory cells. The whole lesion appears as a single polypoid mass projecting into the lumen of a dilated vein. The histogenesis of this lesion remains obscure. Complete local excision is the treatment of choice. Intravenous PG can be differentiated from other intravascular fibroangiomatous proliferations, including intravascular papillary endothelial hyperplasia, intravenous atypical vascular proliferation, intravascular fasciitis, and organized thrombus.

The arteries of the lacrimal gland

The vascularization of 70 lacrimal glands was studied by orbital dissection subsequent to injection of the arterial bed with red-dyed latex. The origin, diameter and collateral branches of the lacrimal artery and its anatomical relations were investigated. Three types of lacrimal vascularization were seen. In the type I variety, the lacrimal artery originates from the ophthalmic artery and runs along the margin of the rectus lateralis muscle. In this case, the lacrimal artery is a major source of vascular supply to the muscle. In the type II variety, the lacrimal artery originates from the middle meningeal artery. In this case, the lacrimal artery is only a very modest source of vascular supply to the muscle. The type III variety features two lacrimal arteries vascularizing the lacrimal gland. One of the arteries originates from the ophthalmic, while the other arises from the middle meningeal. In this case, the lacrimal gland is the site of an intraorbital anastomosis between the internal and external carotid systems. The lacrimal gland is innervated by the lacrimal nerve and the lacrimal rami of the maxillary nerve. Preliminary results regarding certain morphological features of the lacrimal nerve are reported in this paper.

A literature review of the vascular system in the human orbit

Some clinical ophthalmological problems led us to a study of literature data about the blood vessels in the human orbit. This inquiry confronted us with a profound knowledge of individual vessels. Remarkably, the arterial system appears to be in general more variable than the venous system. Radiologists have also noticed the difference in variability between the two vascular systems. Mainly for this reason, they consider topographical information obtained from phlebograms more useful than that obtained from arteriograms. However, the spatial arrangement of the orbital vessels has been given little consideration in literature. The same can be said of the relationship of the vessels with their immediate surroundings, connective tissue. Of the arterial system, only the ophthalmic artery and the posterior ciliary arteries have been described in this way, and only in relation to the optic sheath. Of the venous system, few authors mention the relation of parts of it with elastic tissue and the tight connective tissue of the superior orbital fissure. Only one author observed a complete septal structure in which the superior ophthalmic vein is suspended. The reports on the connective tissue relationships thus appear to be fairly fragmentary. Finally, the architecture of orbital microvascularization has also hardly been dealt with. A field for further anatomical study thus seemed to invite exploration.

The development of the anterior falcate and lacrimal arteries in the human

Certain arteries of the head were studied in injected human fetuses from 143 to 290 mm C.-R., as well as in the orang-utan and gorilla, and in microscopical sections from 29 to 162 mm C.-R., as well as in an adult. It was found that, during human ontogenesis, an anterior falcate artery supplies the dura mater of the medial part of the frontal bone. It appears at 40 mm and reaches its full development by 115 mm. Normally it becomes reduced and is transformed into the anterior meningeal artery postnatally. It communicates with the meningeal branches of the lacrimal artery. Under pathological conditions that affect the dura mater, the falcate artery may appear postnatally in angiograms.

Aspects of treatment. Surgery of the lacrimal sac

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An anomalous origin of the middle meningeal artery

A human skull is described in which the middle meningeal artery probably arose bilaterally from the lacrimal artery. The branches of the middle meningeal vessels, however, were normal both in their position and distribution. This anomaly is a rare occurrence and is of neurosurgical importance.

Adrenergic and cholinergic innervation of the hamster Harderian gland

Examination of Harderian glands of adult male and female golden hamsters by appropriate histochemical techniques reveals that adrenergic nerves are associated only with the blood vessels. Acetylcholinesterase-positive fibers are present in the connective tissue surrounding the gland, along the ducts, and among the acini.

The Harderian gland of the domestic fowl. I. Histology, with reference to the genesis of plasma cells and Russell bodies

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