Anatomy of the frontal branch of the facial nerve: the significance of the temporal fat pad

The anatomy of the temporal region, with reference to the frontal branch of the facial nerve, was examined in 12 fresh cadaver dissections. In all dissections, the frontal branch traveled in a constant plane along the undersurface of the temporoparietal fascia and was quite superficial as it crossed the zygomatic arch. The deep temporal fascia and superficial temporal fat pad are anatomically important structures which adjoin the periosteum of the zygomatic arch and lie deep to the frontal nerve. Based on these relationships, a safe method of dissection within the temporal region is formulated.     

Excision of the submandibular gland by an intraoral approach

To improve the outcome in patients with benign diseases of the submandibular gland, we have developed an entirely intraoral technique for excision of the submandibular gland. This procedure is anatomically safe and can be performed with minimal morbidity. We believe the essential surgical steps are as follows: (1) infiltration with Xylocaine plus epinephrine with an adequate waiting period for hemostasis; (2) careful identification of the submandibular duct/lingual nerve relationship; (3) anterior retraction of the mylohyoid muscle to expose the superficial lobe; (4) superiorly directed, extraoral, manipulation of the submandibular gland; and (5) close and blunt dissection to the gland laterally to avoid injury to the facial artery and vein.     

Depth of the facial nerve in face lift dissections

Facial nerve depth was measured in 12 cadaver face halves after bilateral face lift dissections. The main nerve trunk emerged anterior to the midearlobe and was 20.1 +/- 3.1 mm deep. Nerve exit from the parotid edge also was deep, averaging 9.1 +/- 2.8 mm for temporal, 9.2 +/- 2.2 mm for zygomatic, 9.6 +/- 2.0 mm for buccal, and 10.6 +/- 2.7 mm for mandibular branches. Distal to the parotid gland, danger areas where nerve branches became superficial were distal temporal, lower buccal, and upper mandibular branches over the masseter muscle and marginal mandibular as it crossed the facial artery. Some protection in these danger areas was provided by fascia, especially superficial temporal and masseteric, while platysma provided some protection for the mandibular branch. Fascial and muscle protection was less in thin cadavers. Face lift dissection can be rapid in areas where facial nerve branches are deep or absent, such as postauricular, inferior to the zygomatic prominence, and near the earlobe.     

Vagal communicating branches between the facial and glossopharyngeal nerves, with references to their occurrence from the embryological point of view.

A rare and hitherto not reported case in which a branch of the vagal nerve communicated simultaneously with the facial and the glossopharyngeal nerves was encountered in the body of a Japanese male cadaver in an anatomy class. This vagofacial-vagoglossopharyngeal (X.VII-X.IX) communicating branch was found to issue from the vagal nerve truck in close association with the pharyngeal branches (rami pharyngei nervi vagi), bifurcating soon into a vagofacial (X.VII) and a vagoglossopharyngeal division (X.IX). The X.VII division coursed forward and reached the posterior belly of the digastric muscle; after entering this muscle, this division broke up into filaments to communicate with the ramus digastricus of the facial nerve which was found to play an equivalent role in making the vagofacial ansa. The X.IX division, in contrast, took its course medially to reach the stylopharyngeal muscle. After entering this muscle, the X.IX division communicated with the stylopharyngeal branch of the glossopharyngeal nerve, which was found to be the equivalent to the X.IX division; these two form together the vagoglossopharyngeal ansa. Therefore, it could be concluded that the X.VII-X.IX communicating branch constitutes the vagal moieties of the vagofacial as well as the vagoglossopharyngeal ansae. The background of the appearance of the communicating branches observed in this report is discussed in the text from the developmental viewpoint on the basis of the findings obtained in chick embryos stained in whole mounts with anti-neurofilament protein antibody.     

The relationship of the superficial and deep facial fascias: relevance to rhytidectomy and aging.

Controversy persists regarding the relationship of the superficial facial fascia (SMAS) to the mimetic muscles, deep facial fascia, and underlying facial nerve branches. Using fresh cadaver dissection, and supplemented by several hundred intraoperative dissections, we studied facial soft-tissue anatomy. The facial soft-tissue architecture can be described as being arranged in a series of concentric layers: skin, subcutaneous fat, superficial fascia, mimetic muscle, deep facial fascia (parotidomasseteric fascia), and the plane containing the facial nerve, parotid duct, and buccal fat pad. The anatomic relationships existing within the facial soft-tissue layers are (1) the superficial facial fascia invests the superficially situated mimetic muscles (platysma, orbicularis oculi, and zygomaticus major and minor); (2) the deep facial fascia represents a continuation of the deep cervical fascia cephalad into the face, the importance of which lies in the fact that the facial nerve branches within the cheek lie deep to this deep fascial layer; and (3) two types of relationships exist between the superficial and deep facial fascias: In some regions of the face, these fascial planes are separated by an areolar plane, and in other regions of the face, the superficial and deep fascia are intimately adherent to one another through a series of dense fibrous attachments. The layers of the facial soft tissue are supported in normal anatomic position by a series of retaining ligaments that run from deep, fixed facial structures to the overlying dermis. Two types of retaining ligaments are noted as defined by their origin, either from bone or from other fixed structures within the face.(ABSTRACT TRUNCATED AT 250 WORDS)     

Tyrosine-hydroxylase-immunoreactive nerve fibers in the separated capsule of the rat adrenal gland

The present study applied the separated adrenal capsules of rats for wholemount immunocytochemistry and used tyrosine hydroxylase (TH) antibody as a marker for catecholamines. TH-immunoreactive nerve bundles without varicosities and fibers with varicosities were seen to run along or to encircle blood vessels entering the adrenal capsule from the outside, and then to run along a network of blood vessels in the intracapsular region. Also, the TH-immunoreactive nerve bundles and fibers were found to run along blood vessels in the subcapsular region. Some TH-immunoreactive nerve fibers and bundles with varicosities, unassociated with the blood vessels, were seen in the subcapsular region. In this region, TH-immunoreactive nerve fibers with varicosities were often seen to be closely associated with the cortical cells. Some TH-immunoreactive nerve fibers without varicosities were visible within the splanchnic nerve in the subcapsular region. The present study suggests that numerous catecholaminergic nerve fibers are associated with blood vessels forming a network in the superficial region of the rat adrenal gland.     

Cholinergic nerves in the thyroid gland

Summary The cholinergic innervation of the thyroid gland has been studied in the human. AChE positive nerve fibers are localized in the wall of the thyroid artery, arranged in two plexuses, a superficial (adventitial) and a deep one (medial). The glandular tissue is provided with cholinergic nerve fibers, localized between and around thyroid follicles. The present results suggest that the endocrine activity of the thyroid gland is also under the control of the autonomic nervous system.     

CGRP-immunoreactive sensory nerve fibers in the submandibular gland of the rat

Summary Indirect immunofluorescence technique was used to study the occurrence and distribution of CGRP immunoreactivity in the submandibular gland of normal rats and after unilateral sensory and sympathetic denervations. In normal rats, CGRP-immunoreactive nerve fibers and nerve trunks were seen around or in close contact with interlobular salivary ducts as well as around small blood vessels of the gland. Occasionally, CGRP-immunoreactive nerve fibers were also detected between or around the acini of the gland.The submandibular ganglia contained CGRP-immunoreactive nerve fibers, but the ganglion cells were not immunoreactive for CGRP. The trigeminal ganglion contained a population of CGRP-immunoreactive, mainly small sized ganglion cells and nerve fibers distributed throughout the ganglion. Unilateral electrocoagulation of the trigeminal nerve caused a significant reduction in the number of immunoreactive nerve fibers in the gland, although some fibers still were present in the ipsilateral glandular tissue. Unilateral superior cervical ganglionectomy caused no detectable effect on the number of CGRP-immunoreactive nerve fibers in the gland.The present results suggest that the rat submandibular gland contains CGRP-immunoreactive nerve fibers both around blood vessels and in glandular secretory elements. Denervation experiments support the view that the majority, but perhaps not all of them originate from the trigeminal ganglion.     

Surgical anatomy of the ligamentous attachments in the temple and periorbital regions

This study documents the anatomy of the deep attachments of the superficial fasciae within the temporal and periorbital regions. A highly organized and consistent three-dimensional connective tissue framework supports the overlying skin and soft tissues in these areas. The regional nerves and vessels display constant and predictable relationships with both the fascial planes and their ligamentous attachments. Knowledge of these relationships allows the surgeon to use the tissue planes and soft-tissue ligaments as intraoperative landmarks for the vital neurovascular structures. This results in improved efficiency and safety for aesthetic procedures in these regions.     

CGRP-immunoreactive sensory nerve fibers in the submandibular gland of the rat

Indirect immunofluorescence technique was used to study the occurrence and distribution of CGRP immunoreactivity in the submandibular gland of normal rats and after unilateral sensory and sympathetic denervations. In normal rats, CGRP-immunoreactive nerve fibers and nerve trunks were seen around or in close contact with interlobular salivary ducts as well as around small blood vessels of the gland. Occasionally, CGRP-immunoreactive nerve fibers were also detected between or around the acini of the gland. The submandibular ganglia contained CGRP-immunoreactive nerve fibers, but the ganglion cells were not immunoreactive for CGRP. The trigeminal ganglion contained a population of CGRP-immunoreactive, mainly small sized ganglion cells and nerve fibers distributed throughout the ganglion. Unilateral electrocoagulation of the trigeminal nerve caused a significant reduction in the number of immunoreactive nerve fibers in the gland, although some fibers still were present in the ipsilateral glandular tissue. Unilateral superior cervical ganglionectomy caused no detectable effect on the number of CGRP-immunoreactive nerve fibers in the gland. The present results suggest that the rat submandibular gland contains CGRP-immunoreactive nerve fibers both around blood vessels and in glandular secretory elements. Denervation experiments support the view that the majority, but perhaps not all of them originate from the trigeminal ganglion.     

Tyrosine hydroxylase- and neuropeptide Y-immunoreactive nerve fibers in the pineal complex of untreated rats and rats following removal of the superior cervical ganglia

Summary The distribution of tyrosine hydroxylase (TH)- and neuropeptide Y (NPY)-immunoreactive(IR) nerve fibers in the pineal complex was investigated in untreated rats and rats following bilateral removal of the superior cervical ganglia. In normal animals, a large number of TH- and NPY-IR nerve fibers were present in the pineal capsule, the perivascular spaces, and intraparenchymally between the pinealocytes throughout the superficial pineal and deep pineal gland. A small number of TH-IR and NPY-IR nerve fibers were found in the posterior and habenular commissures, a few fibers penetrating from the commissures into the deep pineal gland. To elucidate the origin of these fibers, the superior cervical ganglion was removed bilaterally in 10 animals, and the pineal complex was examined immunohistochemically. Two weeks after the ganglionectomy, the TH-IR and NPY-IR nerve fibers in the superficial pineal gland had almost completely disappeared. On the other hand, in the deep pineal and the pineal stalk, the TH-IR and NPY-IR fibers were still present after ganglionectomy. These data show that the deep pineal gland and the pineal stalk possess an extrasympathetic innervation by TH-IR and NPY-IR fibers. It is suggested that the extrasympathetic TH-IR and NPY-IR nerve fibers innervating the deep pineal and the pineal stalk originate from the brain.     

Histochemical demonstration of monoaminergic and cholinesterase-positive nerve fibres in regenerating rat submandibular gland autografts

Summary A cholinesterase localization method and a monoamine histofluorescence technique were used to locate nerve fibres in regenerating rat submandibular gland autografts. Experimental rats had a portion of one submandibular gland excised and cut into small fragments which were autografted immediately into the middle one-thrid of the tongue. Control rats had a portion of one submandibular gland removed and discarded, and their tongues were sham-operated. Seven to ten weeks later, the rats were killed and the tongues were removed, frozen and sectioned in a cryostat. A light microscopical study of the tongue sections subjected to the cholinesterase technique showed that the submandibular gland autografts contained many nerve fibres that exhibited cholinesterase activity. These cholinesterase-positive nerve fibres were distributed throughout the autografts. The fibres were associated with the numerous duct-like structures and the less numerous acini. In addition, ultraviolet illumination of tongue sections after treatment with a glyoxylic acid mixture revealed histofluorescent monoaminergic nerves within the autografts. These fibres were less prominent than the cholinesterase-positive fibres and appeared to run primarily along blood vessels within the autografts. The results suggest that autonomic nerves are present within regenerating submandibular gland autografts.     

The safe face lift with bony anatomic landmarks to elevate the SMAS

The risk for facial nerve injury has been reported to be increased with the inclusion of superficial musculoaponeurotic system (SMAS) elevation as compared with a skin-only face lift. The facial nerve courses through the parotid gland. The SMAS is elevated superficial to the parotid gland. However, in elevating the SMAS anterior to the parotid gland, the facial nerve is at risk of injury where its branches emerge from the anterior edge of the parotid gland. The purpose of this study was to identify bony anatomic landmarks to predict the location of the anterior edge of the parotid gland to avoid injury to the facial nerve branches as they exit the parotid gland. The authors dissected 20 cadaver face halves to determine bony landmarks-the masseteric tuberosity and the inferior lateral orbital rim-to predict the location of the anterior parotid edge. Then they measured the anterior edge of the parotid gland in relation to the vector formed between these two bony landmarks. They identified and measured the most anterior portion of the parotid gland in relation to this vector. Then the most posterior aspect of the parotid gland in relation to this vector was measured. In the 20 dissections, the authors found the most anterior portion of the parotid gland to be 2.7 +/- 1.0 mm anterior to the vector from the inferior lateral orbital rim to the masseteric tuberosity. The most posterior part of the anterior edge of the parotid gland in relation to this vector was found to be 1.0 +/- 1.5 mm posterior to this vector. The parotid gland measured an average of 38.8 +/- 3.5 mm in width from the tragus to the anterior parotid edge. In elevating the SMAS with a face lift, the facial nerve branches can be predicted to exit the anterior edge of the parotid gland, which can be located 38.8 mm anterior to the tragus and near the vector from the inferior lateral orbital wall to the masseteric tuberosity.     

Localisation of monoamines in nerves of the posterior salivary gland and salivary centre in the brain of Octopus

Summary Slices of the posterior salivary gland and of the superior buccal lobe of the brain of Octopus vulgaris take up ³H-5-hydroxytryptamine in vitro. By light and electron microscopical radioautography the uptake is localised in certain neuronal perikarya and axonal varicosities in the superior buccal lobe, and in nerves that end in the secretory tubules of the posterior salivary gland. These structures do not incorporate ³H-noradrenaline. After formaldehyde histochemistry, monoamine fluorescence is found in some neuronal perikarya of the superior buccal lobe, and in nerves entering the secretory tubules of the gland. The posterior salivary gland nerve, which originates in the superior buccal lobe and supplies the gland, shows a pronounced accumulation of fluorescence on the proximal side of a ligature applied in vivo. It is suggested that monoamines are transported from the brain to the gland by the posterior salivary gland nerves.J. B. would like to thank the Science Research Council, Great Britain, for financial support.     

Submandibular gland resection and bilateral parotid duct ligation as a management for chronic drooling in cerebral palsy

The control of chronic drooling in cerebral palsy has been difficult in the past. Previous methods to control drooling include the Wilkie procedure, which diverts the salivary flow from the parotid glands by means of surgically created tunnels to the tonsillar fossa, along with submandibular gland resection. An alternative is submandibular gland resection with bilateral parotid duct ligation. Previous published studies using this method have resulted in good to excellent results, but population sizes were felt to be too small to be conclusive. Since 1979, a total of 58 patients have been treated by parotid duct ligation with submandibular gland resection, and 86 percent have shown good to excellent results. These results compare favorably with those published by Wilkie. Also, parotid duct ligation is technically easier, associated with less postoperative morbidity, and has shown a decreased duration of hospitalization compared to parotid duct transposition.     

The intact parasympathetic nerve promotes submandibular gland regeneration through ductal cell proliferation

ObjectivesSalivary gland regeneration is closely related to the parasympathetic nerve; however, the mechanism behind this relationship is still unclear. The aim of this study was to evaluate the relationship between the parasympathetic nerve and morphological differences during salivary gland regeneration.Materials and MethodsWe used a duct ligation/deligation‐induced submandibular gland regeneration model of Sprague‐Dawley (SD) rats. The regenerated submandibular gland with or without chorda lingual (CL) innervation was detected by haematoxylin–eosin staining, real‐time PCR (RT‐PCR), immunohistochemistry and Western blotting. We counted the number of Ki67‐positive cells to reveal the proliferation process that occurs during gland regeneration. Finally, we examined the expression of the following markers: aquaporin 5, cytokeratin 7, neural cell adhesion molecule (NCAM) and polysialyltransferases.ResultsIntact parasympathetic innervation promoted submandibular gland regeneration. The process of gland regeneration was significantly repressed by cutting off the CL nerve. During gland regeneration, Ki67‐positive cells were mainly found in the ductal structures. Moreover, the expression of NCAM and polysialyltransferases‐1 (PST) expression in the innervation group was significantly increased during early regeneration and decreased in the late stages. In the denervated submandibular glands, the expression of NCAM decreased during regeneration.ConclusionsOur findings revealed that the regeneration of submandibular glands with intact parasympathetic innervation was associated with duct cell proliferation and the increased expression of PST and NCAM.     

Salivary gland development

Salivary glands provide an excellent model for the study of epithelial-mesenchymal interactions and branching morphogenesis. This review will discuss the anatomy of different types of glands, in a range of different organisms. Then, concentrating on the mouse submandibular gland, the stages of salivary gland development will be reviewed and the relative role of the mesenchyme and the epithelium will be discussed. Finally, the genes thought to play a role in development of the glands from initiation to differentiation will be reviewed.     

VIP and noncholinergic vasodilatation in rabbit submandibular gland

The effect of parasympathetic nerve activation on rabbit submandibular gland (SMG) blood flow and saliva secretion were studied before and after systemic administration of atropine or hexamethonium. The parasympathetic fibers were stimulated electrically (2 and 15 Hz, 10 V, 1 msec) at the plexus around the submandibular salivary duct or at the chorda lingual nerve. In untreated animals, stimulation of parasympathetic fibers caused a frequency-dependent increase of salivary secretion and blood flow in the SMG. Atropine treatment completely abolished saliva secretion at 2 Hz and 15 Hz and the increase in SMG blood flow during stimulation at 2 Hz. Although atropine significantly reduced the vasodilatory response at 15 Hz, the highest blood flow measured under such circumstances was still about 2.5 times the prestimulation value. After hexamethonium administration no blood flow increase or saliva secretion was seen upon chorda lingual stimulation. The concentration of vasoactive intestinal polypeptide (VIP)-like immunoreactivity in the venous effluent of the SMG increased during nerve stimulation. Atropine significantly reduced, and hexamethonium abolished this VIP-output elicited by parasympathetic nerve stimulation. Local infusion of VIP, peptide histidine isoleucine (PHI) and substance P all caused atropine-resistant vasodilation but no salivation. The present data suggest that VIP and possibly PHI play a role in the atropine-resistant vasodilatation in rabbit submandibular gland elicited by parasympathetic nerve stimulation. The contribution of sensory mediators such as substance P released by stimulation of afferent nerves in the chorda lingual nerve to the salivary and vasodilatory responses seems to be of minor importance in the rabbit submandibular gland.     

Innervation of the rat pineal gland by pituitary adenylate cyclase-activating polypeptide (PACAP)-immunoreactive nerve fibres

Pituitary adenylate cyclase-activating polypeptide (PACAP)-immunoreactive nerve fibres were demonstrated in the rat pineal gland. These fibres entered the pineal gland through the conarian nerve at the distal tip of the gland. A high density of the fibres was observed in the capsule of the gland, from where the immunoreactive elements penetrated into the pineal perivascular spaces and parenchyma. The majority of PACAP-immunoreactive nerve fibres also contained calcitonin gene-related peptide (CGRP). Some PACAP-immunoreactive nerve fibres contained neuropeptide Y (NPY), but only occasionally was PACAP colocalized with vasoactive intestinal peptide (VIP). After removal of both superior cervical ganglia, a high number of PACAP-containing nerve fibres were still present in the gland. In the nervous system PACAP is present in two isoforms, PACAP-38 and PACAP-27. The concentration of PACAP-38 in the superficial pineal gland was determined by radioimmunoassay to be 20.4 pmol/g tissue at midday and 18.9 pmol/g tissue at midnight. The concentration of PACAP-27 was only about 3% of the concentration of PACAP-38. In summary, this study is the first demonstration of a PACAP-containing innervation of the rat pineal gland. The PACAP concentration in the pineal gland does not exhibit a day-night difference. The colocalization of PACAP with calcitonin gene-related peptide in the pincalopetal nerve fibres indicates that the majority of PACAP-immunoreactive nerve fibres might originate from the trigeminal ganglion.     

Cysts, masses, and tumors of the accessory parotid gland.

An accessory parotid gland occurs in approximately 21 percent of human subjects. It is located anterior to the main parotid gland, usually just above Stensen's duct and connected by its own duct to the latter. Any lesions that can occur in the main parotid gland can also arise in an accessory parotid gland. For the excision of lesions of the accessory parotid gland, we prefer to turn the same cervicofacial flap used for a lateral or total parotidectomy. This permits one to fully visualize the superficial and deep main parotid segments, the trunk and the branches of the facial nerve, and the accessory parotid gland along with its duct system and Stensen's duct.