Variations of the lingual and inferior alveolar nerves and their anomalous relationship with the maxillary artery

The infratemporal fossa is a compact space with multiple contents. Explicit anatomical knowledge regarding the relationship between these neurovascular structures becomes imperative during any surgical intervention. Literature is abounding with variations in this region. It encompasses communication between branches of the mandibular nerve or entrapment of nerves by bony bridges, or even abnormal course and branching pattern of the arteries. However, there are many other variabilities in these structures that are less reported or unreported. The present study is an effort to report the characteristic variations of the lingual and inferior alveolar nerves and their anomalous relationship with the maxillary artery in the infratemporal fossa. The study was conducted bilaterally on 26 adult cadavers. The variations in the origin and course of the lingual & inferior alveolar nerves were noted. The course of the maxillary artery and its relation to the lingual and inferior alveolar nerves was also recorded. The variations were explained under the following types: a) communication between the lingual and inferior alveolar nerves, b) existence of a pterygospinous ligament/bar overlying/separating the lingual and inferior alveolar nerves, c) abnormal course/ absence of the chorda tympani nerve and an alternate taste pathway, d) multiple roots of the lingual and inferior alveolar nerves and e) the unusual course of the maxillary artery. Knowledge of these variations would aid the head & neck surgeons in minimizing the compression symptoms and also avoiding postoperative complications

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Measurement of Blood Flow in an Intracranial Artery Bypass From the Internal Maxillary Artery by Intraoperative Duplex Sonography.

This study explored the hemodynamic characteristics of a subcranial-intracranial bypass from the internal maxillary artery by measuring blood flow on intraoperative duplex sonography. The hemodynamic parameters of the internal maxillary artery (n = 20), radial artery (n = 20), internal maxillary artery-middle cerebral artery bypass (n = 42), and internal maxillary artery-posterior cerebral artery bypass (n = 9) were measured by intraoperative duplex sonography. There was no significant difference in the internal diameters of the internal maxillary and radial arteries (mean ± SD, 2.51 ± 0.34 versus 2.56 ± 0.22 mm; P = .648). The mean radial artery graft length for subcranial-intracranial bypasses was 88.5 ± 12.78 mm (95% confidence interval [CI], 80.8-90.2 mm). Internal maxillary artery-middle cerebral artery bypasses required a shorter radial artery graft than internal maxillary artery-posterior cerebral artery bypasses (77.8 ± 2.47 versus 104.8 ± 4.77 mm; P = .001). The mean flow volumes were 85.3 ± 18.5 mL/min (95% CI, 76.6-93.9 mL/min) for the internal maxillary artery, 72.6 ± 26.4 mL/min (95% CI, 64.3-80.9 mL/min) for internal maxillary artery-middle cerebral artery bypasses, and 45.4 ± 6.7 mL/min (95% CI, 40.7-50.0 mL/min) for internal maxillary artery-posterior cerebral artery bypasses. All grafts were opened after the success of the salvage procedures had been established, and the early patency rates (1 month after the operation) were 95% for internal maxillary artery-middle cerebral artery bypasses and 100% the internal maxillary artery-posterior cerebral artery bypasses. Measurement of blood flow by intraoperative sonography can be helpful in decision making and predicting graft patency and success after neurosurgical bypass procedures.

Maximal and submaximal mouth opening with mouth gags in cats: implications for maxillary artery blood flow.

The use of spring-loaded mouth gags in cats can be associated with the development of central neurological deficits, including blindness. In this species, the maxillary arteries are the main source of blood supply to the retinae and brain. Spring-loaded gags generate constant force after placement that could contribute to bulging of the soft tissues between the mandible and the tympanic bulla. Under these circumstances, the maxillary arteries can become compressed as they course between these osseous structures. Smaller gags that might apply less force to the mouth were investigated to determine if they preserved maxillary artery blood flow. Six healthy adult cats were anesthetized. Electroretinography (ERG) and magnetic resonance angiography (MRA) were performed without the use of a mouth gag and during submaximal (plastic mouth gags of 20, 30 and 42 mm in length between canine teeth) and maximal mouth opening. Maximal mouth opening produced alterations in ERG waveforms consistent with circulatory compromise in 1/6 cats and reductions in signal intensity during MRA in 4/6 cats. Placement of a 42 mm plastic gag produced a reduction in MRA signal in 1/6 cats. No changes were observed with smaller gags. The force applied against the mouth was significantly higher with the spring-loaded gag than with any other gags. The use of a smaller mouth gags was associated with fewer alterations of indicators of maxillary artery blood flow. Nevertheless, a 42 mm plastic gag, equivalent to the size of a needle cap, resulted in an abnormal MRA in one cat.

Functional anatomy of the temporo-mandibular joint (II).

Jaw movement is analyzed as an action between two rigid components jointed together in a particular way, the movable mandible against the stabilized cranium. Opening and closing movements are symmetrical; that is, both sides of the cranio-mandibular articulation are making the same movements. Protrusive and retrusive movements may also be symmetrical. The mandibular muscles determine all the complicated postures and-movements of the jaw. Their behavior can be greatly clarified by restating certain fundamentals crucial to purposive muscular activity. The joint derives its arterial supply from the superficial temporal artery and the maxillary artery. Branches of the auriculo-temporal and masseteric nerves and postganglionic sympathetic nerves supply the tissues associated with the capsular ligament and the looser posterior bilaminar extension of the disc.

A case of a divided maxillary artery in the infratemporal fossa.

A divided maxillary artery was found in the left infratemporal fossa of a 63-year-old male cadaver during a student dissection practice. The maxillary artery, which arose from the external carotid artery at the posterior border of the ramus of the mandible, was divided into two branches in the infratemporal fossa. The deep branch of the maxillary artery was deep to the lateral pterygoid muscle and the inferior alveolar, buccal and lingual nerves, giving off the anterior tympanic, middle meningeal, anterior deep temporal, buccal, and posterior superior alveolar arteries. The deep branch passed through the pterygomaxillary fissure. On the other hand, the superficial branch of the maxillary artery, which was superficial to the lateral pterygoid muscle, gave off the inferior alveolar artery and other branches. The maxillary artery on the right side displayed a normal branching pattern within the infratemporal fossa. These findings indicate that the deep and superficial branches of the maxillary artery remained without disappearing during the development of the maxillary artery originated from the stapedial artery.

[Modern morpho-functional concepts in cephalic arterial distribution]. / Conceptii morfo-functionale moderne in distributia arteriala cefalica.

The present paper provides a general morphofunctional study of the oro-maxillary-facial cephalic arterial area that shows some particular hemodynamic characteristics. The internal maxillary artery supplies a very large territory, with numerous and wide anastomoses. In order to understand the hemodynamic characteristics of this artery, we analyzed some older theories, such as: Ludwig von Bertalanffy's General Systems Theory, Walter Zimmermann's Telome Theory, and some general rheological principles also.

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.

Nitric oxide and parasympathetic vascular and secretory control of the dog nasal mucosa.

Nasal vascular and secretory responses to local intra-arterial injection of acetylcholine (ACh) and vasoactive intestinal polypeptide (VIP) and to electrical stimulation of the nasal parasympathetic nerve fibres were recorded in dogs anaesthetized with pentobarbital. The influence of pretreatment with atropine and propranolol and the nitric oxide synthetase (NOS) inhibitor Nomega-nitro-L-arginine (L-NNA) was analysed. As a marker for NOS, NADPH-diaphorase (NADPH-d) histochemistry was studied in the sphenopalatine ganglion, trigeminal nerve and nasal mucosa. Local intra-arterial infusion of ACh and VIP evoked dose-dependent vasodilatation and nasal secretion which were not modified in the presence of L-NNA. The NO donor nitroprusside induced dose-dependent vasodilatation but no secretion. Atropine did not reduce the vasodilatation evoked by the parasympathetic nerve stimulation, but did reduce the secretory response by 55% (p < 0.05). During L-NNA infusion, the atropine-resistant vasodilatation evoked by parasympathetic nerve stimulation was reduced by a further 80% (p < 0.01) and the non-cholinergic secretory response was reduced by a further 30% (p < 0.05). Simultaneous infusion of the NO donor nitroprusside reversed the secretory response but not the vasodilator response to parasympathetic nerve stimulation. Histochemical studies revealed that NADPH-d activity was co-localized with VIP in parasympathetic axons. These observations suggest that NO could act as a non-cholinergic parasympathetic neurotransmitter in the vascular and secretory control of the dog nasal mucosa.

Effects of calcium channel blockers on cold-induced vasodilatation and elevated sympathetic tone in the canine internal maxillary artery bed.

This study was concerned with the interactive effects of cold-induced vasodilatation, blockade of voltage-sensitive Ca2+ channels and sympathetic nerve stimulation in the nasal vascular bed of anesthetized dogs. To estimate the distribution of the internal maxillary artery blood flow to capillaries and to arteriovenous anastomoses (AVA), the microsphere technique in combination with electromagnetic flowmetry was used. Intraarterial infusion of verapamil resulted in a dose-dependent vasodilatation and a redistribution of the internal maxillary artery blood flow. Simultaneously applied electrical stimulation of the cervical sympathetic trunk resulted in a significant fall in blood flow, caused mainly by a decrease in capillary flow. Verapamil infusion combined with cold exposure led to a simultaneous elevation of the AVA and capillary flows. When electrical stimulation of the cervical sympathetic trunk was also applied, the AVA and capillary flows were affected in different manners, depending on the sequence of the stimulations. Analysis of capillary flow data in the various nasal and facial tissue compartments indicates that cold exposure, blockade of the voltage-dependent Ca2+ channels and an elevated sympathetic tone modify the local nutritive blood flow.

Modulation by neuropeptide Y of parasympathetic nerve-evoked nasal vasodilatation via Y2 prejunctional receptor.

1. In pentobarbitone anaesthetized dogs, preganglionic stimulation of the superior cervical sympathetic nerve (15V, 1 ms, 10 Hz) induced marked reduction of nasal arterial blood flow, whereas parasympathetic nerve stimulation (5 V, 1 ms, 10-30 Hz) evoked frequency-dependent vasodilatation. 2. Sympathetic nerve stimulation for 3 min at 10 Hz evoked significant (P < 0.05) and prolonged attenuation of the vasodilator response to subsequent parasympathetic stimulation. Pretreatment with phentolamine (0.5 mg kg-1 h-1), propranolol (1 mg kg-1) and atropine (0.5 mg kg-1) reduced the vasoconstrictor effect of sympathetic stimulation by 35 +/- 4% whereas the parasympathetic nerve-evoked vasodilatation was not significantly modified. Atropine-resistant parasympathetic vasodilatation remained significantly attenuated for more than 30 min after non-adrenergic sympathetic nerve-evoked vasoconstriction. 3. Vasodilator effects of exogenous vasoactive intestinal polypeptide and peptide histidine isoleucine and vasoconstrictor effects of exogenous neuropeptide Y (NPY) and the NPY analogue [Leu31, Pro34] NPY (Y1-receptor agonist, 8 nmol kg-1), were not altered by adrenoceptor antagonists and atropine f1p4eas the effects of exogenous noradrenaline and acetylcholine were virtually abolished. Attenuation of parasympathetic-evoked vasodilatation could be mimicked by exogenous NPY (8 nmol kg-1) and the NPY analogue, N-acetyl [Leu28, Leu31] NPY 24-36 (Y2-receptor agonist, 20 nmol kg-1) but not by exogenous Y1-receptor agonist. The Y2-receptor agonist did not show significant vasoconstrictor action. 4. It is concluded that sympathetic nerve stimulation attenuates parasympathetic vasodilatation via NPY release acting on prejunctional Y2 receptors.

Effect of multiple ligations of the external carotid artery and its branches on blood flow in the internal maxillary artery in dogs.

PURPOSE: The effect of occlusion of the external carotid system on blood flow of the internal maxillary artery was investigated in 16 dogs. METHODS: The external carotid system was occluded by ligation or clamping at different levels separately or simultaneously and the blood flow of the internal maxillary artery was measured with an electromagnetic flowmeter before and after each occlusion. RESULTS: The ligation of the external carotid artery below (low ligation) and above (high ligation) the origin of the occipital, lingual, and facial arteries reduced the blood flow by 61.1% and 71.5%, respectively. Low ligation together with ligation of the lingual artery reduced the blood flow by 73.5%. Multiple ligations (high and low ligations combined with ligations of the occipital, lingual, and facial arteries) reduced the blood flow by 81.8%. The internal maxillary artery was sectioned after the multiple ligations, and retrograde flow from the distal segment was studied. The flow was only a trace and could not be measured with the flowmeter. Total blood loss from both ends almost equaled the blood flow of the proximal segment, 18.2% of normal. CONCLUSIONS: Multiple occlusion appears to be the most effective treatment for hemorrhage from the initial part of the internal maxillary artery.

Nutrient and shunt flow responses to vidian nerve stimulation in nasal and facial tissues of the dog.

The potency of parasympathetic vasomotor efferent nerves in controlling blood flow of the face and nose was indicated by the following features attributed to the maxillary artery and their vascular compartments in dogs. Electrical stimulation of the vidian nerve induced a frequency-dependent increase in maxillary flow, which was due to a significant decrease in resistance to flow in nutrient and shunt vessels. Pronounced increases in perfusion rates mainly occurred in evaporative tissues of the nose, in particular the naso-maxilloturbinates and alar fold during vidian nerve stimulation, while those, for example, of the skin remained unchanged. Adrenergic and subsequent cholinergic blockade left the response pattern of maxillary flow to vidian nerve stimulation basically unaffected. Both nutrient and shunt flows contributed to the parasympathetically induced increases in maxillary flow while responses were compartmentalized similar to that found in untreated animals. Apart from sympathetic vasoconstrictor inputs, these results show that cholinergic and non-cholinergic parasympathetic vasodilator inputs contribute to the adjustment of vasomotor tone in the maxillary vascular bed.

Sympathetic control of blood flow to AVAs and capillaries in nasal and facial tissues supplied by the internal maxillary artery in dogs.

Total blood flow and perfusion pressure (PP) of the internal maxillary artery (IMA) were recorded bilaterally during electrical stimulation (8 V, 2ms) of the right cervical sympathetic nerve at frequencies (f) of 0.3, 0.5, 1.0 and 3.0 Hz in anesthetized, paralyzed and artificially ventilated dogs. Distribution of IMA-FLOW to precapillaries (CAP-FLOW) and arteriovenous anastomoses (AVA-FLOW) was determined by the tracer microspheres technique. During electrical stimulation (ES) IMA-FLOW was affected only unilaterally and decreased in a hyperbola-like fashion with the increase of f, while contralateral IMA-FLOW remained unchanged. Systemic blood pressure as well as PP of both IMA remained unchanged while heart rate was only increased during ES at maximal f. The reduction of IMA-FLOW was mainly due to marked vasoconstrictor responses of the AVAs, which were already attained at low f while significant vasoconstrictor responses of precapillaries occurred at higher f and were less pronounced. The early response of AVAs to increasing sympathetic activation enables IMA-FLOW to be adjusted in a physiological range of sympathetic activities, before CAP-FLOW is substantially reduced. The predominance of AVA-FLOW in blood flow control of the IMA was also supported by the conformity in their hyperbolic relationship with maxillary resistance at rest and during enhanced levels of sympathetic vasoconstrictor activity.

Blood flows in the maxillocarotid anastomoses and internal carotid artery of conscious dogs.

Although the external carotid artery is known to contribute to the cerebral blood flow in anesthetized dogs, quantitative information on the anastomoses and their role in conscious dogs is lacking. This study was carried out to determine blood flows in these anastomoses and the internal carotid artery, and also to examine the functional significance of the anastomoses in conscious dogs. Fifteen-micron radioactive microspheres were injected into common and external carotid arteries of four conscious dogs through chronically implanted catheters. Blood flows were determined by the reference sample method and by comparing microsphere distributions in the brain and the masseter muscle. Blood flows were estimated to be 140 +/- 32, 7.7 +/- 1.4, and 3.3 +/- 1.1 ml/minute (mean +/- SD) in the common carotid artery, internal carotid artery, and anastomoses on each side, respectively. Additional evidence indicated that the anastomotic flow so determined was primarily the flow in the anastomotic artery. Humoral responses to angiotensin II infusions were also studied in conscious dogs. External carotid angiotensin increased plasma 11-hydroxycorticosteroid concentration (used as an index of ACTH secretion) but did not increase plasma vasopressin concentration to the same extent as common carotid infusion. Therefore, the external carotid artery is functionally important in perfusing the brain in conscious dogs.

The effect of experimental ligation of the external carotid artery and its major branches on haemorrhage from the maxillary artery.

The effect of ligation of the external carotid artery and its major branches on blood flow from the maxillary artery was investigated in four Chacma baboons. The left common carotid artery and its branches were surgically exposed and the maxillary artery was isolated, sectioned and cannulated. Blood flow from the proximal segment of the maxillary artery was determined with and without occlusion of the common carotid artery, the external carotid artery above and below the origin of the linguo-facial trunk and the posterior auricular occipital trunk. Ligation of the external carotid artery below and above the origin of the lingual and facial arteries reduced maxillary artery blood flow by 40% and 73% respectively. Ligation of the external carotid artery above the origin of the lingual and facial vessels, together with ligation of the posterior auricular occipital trunk reduced maxillary artery blood flow by 99.2%. On the basis of these experimental findings, it is suggested that maxillary artery haemorrhage in man may be most effectively controlled by ligation of the external carotid artery in the retromandibular fossa, distal to the origin of the posterior auricular artery, combined with ligation of the superficial temporal artery at the root of the zygoma.

Vascular changes in the pterygopalatine fossa after craniofacial dysjunction surgery.

A study was undertaken to determine vascular changes and the timing of these changes after craniofacial dysjunction surgery. Ten adult male Macaca cynomulgus monkeys were studied with techniques using angiograms and vascular vinyl cast preparations before and after unilateral Le Fort III osteotomy. After surgical disruption of the maxillary artery, the flow of blood was initially maintained by anastomotic branches of the ipsilateral internal carotid artery. Stepwise reconstruction of the disrupted maxillary artery took place via numerous collateral vessels that bridged the site of disruption; continuity of the artery was nearly normal by five weeks.

[Physical symptoms in the orbit during ophthalmodynamography (author's transl)]. / Uber physikalische Erscheinungen in der Orbita während der Ophthalmodynamographie

Analysing physical process occurring in the orbit during ophthalmodynamography the author comes to the conclusion that the "systolic pressure" as recorded ophthalmodynamographically is not a real pressure present in the ophthalmic artery, but a sum of this pressure and of that which is necessary to overcome the resistence of the orbital tissues. A considerable influence of the blood flow in the system of the external carotid artery is explained by superficial localisation of arterial branches belonging to the system and consequently by direct transmission of volume and pressure changes in the blood flow to the registering device, practically without damping effect of the orbital tissues.