The anterior lobe of the parotid gland: a CT sialographic study.

OBJECTIVES: To investigate the imaging and anatomic features of the anterior lobe (AL) of the superficial parotid gland (SPG). METHODS: Computed tomographic sialography examinations were undertaken for 142 parotid glands in 77 patients. Whole computer tomography (CT) data were analyzed using multi-planar reformation and maximum intensity projection to generate sialographic CT images. The tributary ducts of the SPG were analyzed to classify the parotid morphology. Three-dimensional analyses were used to investigate the AL and its relationship with adjacent anatomic landmarks. RESULTS: Four major types (I-IV) and 2 minor types (V-VI) of the AL and the superficial parotid gland were observed. Type I AL (83/142) was contiguous and not separated from the retromandibular parotid gland. Type II AL (16/142) was detached from the retromandibular parotid gland with 1-4 tributary ducts. Type III AL (12/142) showed a small isolated lobe above the Stensen duct around the anterior edge of the masseter. Type IV (28/142) showed the absence of the AL. Type V (3/142) shows the absence of the retromandibular parotid gland. Type VI (3/142) showed the presence of ectopic salivary gland beneath the Stensen duct anterior to the retromandibular parotid gland. CONCLUSIONS: The AL gives rise to the morphological variations of the superficial parotid gland. AL also gives rise to the accessory parotid gland when it is detached from the retromandibular parotid gland.

Anatomic Danger Zones of the Head and Neck.

BACKGROUND: Dermatologic procedures require a detailed understanding of surface anatomy to avoid complications. The head and neck region has prominent danger zones including nerves and vasculature that may be at risk during cutaneous surgery. A thorough understanding of these danger zones can help avoid complications that may lead to functional or cosmetic impairment. METHODS: The anatomic literature regarding the course of high-risk structures of the head and neck was reviewed. Structures deemed at risk during dermatologic procedures were included in the analysis. The final analysis focused on branches of the facial nerve, parotid duct, spinal accessory nerve, trigeminal nerve, and the lacrimal system. Anatomical information was compiled regarding each high-risk structure to develop a "danger zone" at which each respective structure is at risk. RESULTS: The danger zone for each structure was compiled based on the review of the literature and depicted in the figures. CONCLUSION: With careful attention to anatomy and the meticulous surgical technique, there is great potential for reduction in surgical injury to danger zones of the head and neck.

Description and relationships of the parotid gland levels proposed by the European Salivary Gland Society staging system: an anatomical study.

OBJECTIVES: To perform an anatomical study to analyze the size, weight, and the relationships of the parotid levels proposed by the European Salivary Gland Society (ESGS). MATERIALS AND METHODS: Anatomical dissections of the parotid region in 19 human specimens were performed. All dissections were systematically carried out to study the dimensions and weight of each level. We also studied the facial nerve distribution between the different levels and the relative position of the facial nerve main trunk and parotid duct in regard to the Frankfort line plane. RESULTS: The facial nerve trunk and the parotid duct were identified in all the 19 specimens, which made it feasible to define the 4 principal levels of the parotid gland body (levels I-IV). Level V was identified in 9 out of 19 dissections (47.5%). For the whole gland, the mean for the height and width dimensions were 66.37 mm and 46.84 mm, respectively, and it weighted 18.13 g. In terms of relative weight regarding the whole gland, level II was always the heaviest, representing from 41 to 47% of the gland's weight, depending on the presence of level V. Levels I and III represent almost the same amount of relative weight as they range from 20 to 22% for each one. Level IV was the lightest body level representing 8-10% of the whole, and when present, level V represented less than 5% of the whole parotid weight. The temporal and zygomatic terminal branches were always found between the cranial levels, whereas the cervical and marginal nerves lie in all cases between the caudal levels. The buccal branches had multiple ramifications that lie between both cranial and caudal levels in 47% of the cases, being found exclusively between cranial levels in 21% and between the caudal levels in the remaining 32%. CONCLUSION: As traditionally reported, the caudal superficial portion of the gland represents the most voluminous portion of the gland, being labeled in our classification as level II. Levels I and III represent similar amounts of gland, though presenting a significantly different morphological disposition. Level IV is the smallest portion of the body gland and level V, when present represents a scarce 5% of the whole body gland weight. The ESGS levels have a clear anatomical basis and the basic references needed to define them are always present.

Anatomical Evaluation of Zygomaticus Major Muscle With Relation to Orbicularis Oculi Muscle and Parotid Duct.

OBJECTIVES: To evaluate morphological properties of the zygomaticus major (ZMj) and demonstrate its detailed anatomical relationships with the orbicularis oculi (OOc) and the parotid duct (PD). METHODS: Fifteen formalin fixed adult cadaver heads (7 males /8 females) aged between 45 and 92 years were dissected to reveal the ZMj, OOc, PD. Shape, lengths and thickness of the ZMj, positional relationships of the ZMj with respect to the OOc and PD (overlap, neighboring, being separate) were determined. Topographic localization of the ZMj according to lateral and medial canthi, tragus, mental tubercle and angle of mandible was evaluated. RESULTS: The shape of the ZMj was observed as band like in 15/29 (51%), fan like in 10/29 (34%) and bifid in 4/29 (13%) sides. Position of the ZMj with respect to the OOc and distal part of the PD was not constant. The ZMj was overlapped by the OOc in 15/29 (52%) sides while they were adjacent in 14/29 (48%) sides. The ZMj overlapped the distal part of PD in 16/29 (%55) sides. They were separate in 10/29 (35%) sides and adjacent in 3/29 (10%) sides. Topographic location of the ZMj with respect to lateral and medial canthii, tragus, angle of mandible and mental tubercle was demonstrated. No statistically significant relationships were found between the ZMj measurements with head circumference and face length. No statistically significant differences were found between sides and gender in terms of the ZMj morphology (P > 0.05). CONCLUSION: This study demonstrates the morphological features and topography of the ZMj along with its relationships with the OOc and PD that would be essential for clinical implications.

Study of morphological structure in human fetus Wharton's duct opening area.

OBJECTIVES: Not many morphological studies have been reported regarding the human salivary main duct, especially those based on observations of the fetal salivary main duct at various developmental stages. The relationships between fetal structural development and its function, functional disorders and diseases certainly have clinical significance. METHODS: In this study, we conducted a morphological observation of seven 5-9 month old human fetal sublingual caruncula, the common opening between the submandibular (Wharton's) duct and the sublingual (Bartholin's) duct. After seven specimens were removed and paraffin sections were prepared, HE and EVG staining were used for histological study of structural differences in the various developmental stages. Furthermore, anti-α-SMA staining was used to observe the distribution of the smooth muscle inside of the Wharton's duct wall. RESULTS: An abundance of elastic fibers were observed in the duct walls of both five and nine month old specimens with EVG staining. The smooth muscle fibers of five month old fetus were immature and were starting to distribute throughout the duct wall, whereas nine month old fetus' smooth muscle fibers were further developed and composed in layers. CONCLUSION: In this study, we confirmed that the Wharton's duct wall structure of nine month old fetuses was close to its adult structural formation, while the inner structure consisted of an ample distribution of elastic fibers and smooth muscle fibers. Based on the distribution pattern of the smooth muscle, we speculate that the Wharton's duct's opening area does not possess a sphincter-like function in the regulation of salivary flow.

Morphometrics of the Southern Green Stink Bug [Nezara viridula (L.) (Hemiptera: Pentatomidae)] Stylet Bundle.

The southern green stink bug, Nezara viridula (L.) (Hemiptera: Pentatomidae), is a cosmopolitan pest of high-value cash crops, including cotton (Gossypium hirsutum L.; Malvales: Malvaceae). The pest can ingest and transmit disease-causing bacterial and fungal pathogens of cotton. We hypothesized that the size of the food canal may contribute to selective transmission, as observed in previous reports. The objective of this study was to examine food canal size and other morphometric parameters of the southern green stink bug stylet bundle at two locations (labium and head) to improve our understanding of factors that may contribute to pathogen transmission. For the food canal, females possessed significantly larger canals than males, major axes were significantly longer than minor axes, and canal sizes were numerically higher at the labium compared with the head. For salivary canal, mean axes lengths were similar between sexes and the head and labium. For both food and salivary canals, axes lengths were longer and area was larger at the labium compared with the head. These findings indicate the presence of a "funnel effect" with canals becoming narrower proximally. Sex and location significantly affected the size of the intact stylet bundle. Results indicate the food canal size was not a factor affecting previously observed selective passive transmission. Major and minor axes measurements, coupled with morphological observations of canal shapes and observed "funnel effect" in the food and salivary canals, improve our understanding of the hemipteran stylet bundle and its relationship with the insect's internal morphology.

Role of Salivary Duct Morphology in the Etiology of Chronic Obstructive Parotitis: Statistical Analysis of Sialographic Features and Computational Fluid Dynamics Analysis of Salivary Flow.

PURPOSE: The causes of some cases of chronic obstructive parotitis (COP) without obstructive factors are still unclear. The authors hypothesized that some morphologic features of salivary ducts might contribute to the development of COP. This study investigated the role of salivary duct morphology in the etiology of COP. MATERIALS AND METHODS: The authors designed and implemented a case-and-control study. Cases were defined as patients with COP, diagnosed from September 2014 to May 2017 at the Affiliated Hospital of Stomatology of the Sun Yat-sen University (Guangzhou, China), and controls were healthy participants. The primary predictor variables were the occurrence of an accessory duct (AD), the number of branches uniting to form the Stensen duct (SD), the angle between the AD and the SD, and the angle between branches identified on sialographic computed tomograms. Data from the 2 groups were compared to investigate the association between these variables and COP. The χ2 test, Student t test, and logistic regression were computed, with significance set at a P value less than .05. Fluid dynamics analysis was used to analyze salivary flow field in models of salivary ducts with different morphologic features reconstructed from sialographic computed tomograms. RESULTS: The sample was composed of 39 patients with COP and 18 controls without COP. The 2 groups were not similar for incidences of an AD (71.8 vs 38.9%) and the angle between branches (96.5 ± 26.0° vs 71.5 ± 21.2°). There was no relevant difference between groups in the number of branches and the angle between the AD and the SD. The area of low velocity was larger in the model with the wider angle between branches. CONCLUSIONS: The results suggest that the presence of an AD and a wider angle between duct branches are associated with COP.

[Topographic features of lingual nerve and its relationship with other anatomical structures in maxillolingual groove].

By surgical interventions in maxillolingual groove area one should consider anatomical variations and topography of vessels, glands ducts and lingual nerve to prevent their injury. At the Department of Operative Surgery and Topographic Anatomy of the First Moscow State Medical University named after I.M. Sechenov we carried out anatomical study on cadavers (men and women, n=30).The study revealed topographical features of the lingual nerve and its relationship to other anatomical structures in the maxillolingual groove. It was found out that at the level of the second molar (96%) lingual nerve "crosses" duct of submandibular salivary gland, at the level of the third molar lingual nerve is located under the duct and lateral to it, closer to the inner surface of the body of the mandible. At the level of the first molar lingual nerve is located above and medial to Wharton duct and passes along sublingual-lingual muscles (m.hyoglossus).

Topographic relationships between the transverse facial artery, branches of the facial nerve, and the parotid duct in the lateral midface in a Korean population.

BACKGROUND: The aims of the present study were to clarify the topographic relationships between various structures in the lateral midface and to provide important anatomical information pertinent to face lifting or treatment of damage to the midface structure. METHODS: Thirty-two fixed cadavers were dissected (23 males and 9 females; mean age, 66.8 years) and 55 sides of midface were used. The transverse facial artery (TFA), zygomatic branch (Zb) and buccal branch (Bb) of the facial nerve, and the parotid duct (PD) were identified. The structures of the lateral midface were measured relative to the zygion and tragion. The vertical average distances from the zygion to each structure increased in the following order: ZB of the facial nerve, TFA, first Bb of the facial nerve, and PD. The horizontal average distance from the tragion to the point of emergence from anterior border of the parotid gland was also measured. RESULTS: The TFA was the closest and the third Bb of the facial nerve was the farthest away. The angles between the horizontal line and ZB of the facial nerve, TFA, PD, and first Bb of the facial nerve were +10.4, -2.3, -18.5, and -27.1 degrees, respectively. CONCLUSIONS: These results may be used to establish the precise locations and the courses of the important midface structures, and represent valuable data that may help to prevent complications during surgery for face lifting and reconstruction of the facial nerve and PD.

Niels Stensen and the discovery of the parotid duct / Niels Stensen y el descubrimiento del conducto parotídeo

Niels Stensen was a renowned Danish scientist, theologian and Catholic bishop. Stensen's early career was devoted to anatomy and it is in this discipline that he made many important contributions. His method in anatomy was rooted in systematic observations based on meticulously executed dissections of human and animal cadavers, as well as experiments on animals. His first important discovery in the field of anatomy, which is the main focus of this paper, was the discovery of the parotid duct. The discovery brought Stensen recognition and fame but only after a controversy in which he was accused of plagiarism by his mentor Gerard Blaes. Although still in an early stage of his career Stensen dealt with the accusation masterfully, producing further research which confirmed him as the discoverer of the parotid duct.

Niels Stensen fue un renombrado científico danés, obispo y teólogo católico. A principios de su carrera Stensen se dedicó a la anatomía, disciplina en la cual logró muchas contribuciones importantes. Su método de anatomía se fundamentaba en observaciones sistemáticas basadas en disecciones de cadáveres humanos y de animales ejecutadas meticulosamente, así como los experimentos con animales. Su primer descubrimiento importante en el campo de la anatomía, que constituye el tema principal de este trabajo, fue el descubrimiento del conducto parotídeo. El descubrimiento le trajo el reconocimiento y fama a Stensen, pero sólo después de una polémica en la que se le acusaba de plagio por su mentor Gerard Blaes. A pesar de haber estado en una etapa temprana de su carrera, Stensen se hizo cargo de la acusación con maestría, produciendo una mayor investigación que lo confirma como el descubridor del conducto parotídeo.

Study of human adult parotid duct in the area of penetration through buccinator muscle and their functional relationship as a sphincter.

The adult human parotid duct is roughly 6-8 cm long. From the parotid gland, parotid duct traverses through masseter muscle, penetrates through buccinator muscle, and opens into the oral cavity. This unique form of the parotid duct is likely correlated with the function of the duct, directly affected by the movement of the buccinator muscle during mastication and swallowing. Histological structure of the duct is known to be different in each region, and details of smooth muscle present in the parotid duct are mostly unclear. In this study, we conducted SEM and histological observations of the area where the parotid duct penetrates the buccinator muscle, and an observation of smooth muscle to investigate its existence using alpha-smooth muscle antibody. We confirmed the presence of an abundance of skeletal muscle bundles likely originating from the buccinator muscle under the epithelium of the parotid duct wall in the region where it penetrates the buccinator muscle. We also observed that some of the muscle fibers were completely attached to the epithelium. We observed a lack of smooth muscle in this region of the duct wall. From these results, we suggest that the area of the duct penetrating buccinator muscle plays a role in regulating the salivary passage through the contraction of the surrounding buccinator muscle fibers.

The salivary ducts of Wharton and Stenson: analysis of normal variant sialographic morphometry and a historical review.

Submandibular and parotid salivary glands acquire lengthy ducts as they migrate during development. No conclusive reports exist on clinically important anatomical normal variants and morphometry of the submandibular duct of Wharton and the parotid duct of Stenson. We retrospectively analyzed 67 normal digital subtraction sialograms on patients ranging from 16 to 85 years of age (M:F=15:52). In 43 sialograms, the mean parotid duct length was 50 mm. The mean width of the proximal, mid, and distal segments of the parotid duct were 1.8 mm, 1.1 mm, and 1.6 mm, respectively. An accessory parotid gland was present in 68% of patients, with a mean angle of confluence of its tributary duct with the parotid duct of 53°. In 24 sialograms the mean length of the submandibular duct was 58 mm. The mean width of the proximal, mid, and distal segments of the submandibular duct were 2.0 mm, 2.7 mm, and 2.1 mm, respectively. The submandibular duct genu had a mean angle of 115°. The effect of independent variables (age, gender, and side) was statistically tested on the dependent variables (length, mean calibre, and angle) using regression analysis. None of the independent variables affected variations in length, size and angulation. These reported comprehensive and detailed morphometrics are useful for therapeutic planning of luminal procedures on the salivary ducts, including sialography, sialoendoscopy, interventional therapies, and lithotripsy.

Microanatomic study of the vascular and duct system of the submandibular gland.

PURPOSE: Autologous microvascular submandibular gland (SMG) transfer is an effective treatment for severe keratoconjunctivitis sicca (KCS). However, epiphora (excessive tear secretion) may occur after the successful transfer of whole submandibular gland because tear secretion level is closely related to the size of the transferred gland. The aim of this study was to investigate the microanatomy of SMG to explore the possibility of partial SMG transfer to prevent postoperative epiphora. MATERIALS AND METHODS: Sixty intact and histologically normal human SMGs from patients with benign tumor of the mandible who underwent vascularized mandibular reconstruction and removal of the SMG for anastomosis of the blood vessels were included in the study. SMGs were perfused with methacrylate to form resin casts of blood vessels and ducts. The length and diameter of the blood vessels and ducts in the casts were measured using a sliding caliper. The numbers of lobules, distribution of arteries, veins, and ducts, as well as the relationship among them, were analyzed. RESULTS: The resin cast of the gland showed a treelike structure, with the vessels gradually dividing into multiple branches. The arteries, veins, and ducts run in parallel and were roughly divided into 3 levels: from the stem extending into the main branches (level I), into the narrower secondary branches (level II), and then the secondary branches subsequently divided into terminal branches (level III). The structures of the blood vessels and ducts were similar at each level in the lobules. In the vein casts, communicating vessels were found between the anterior facial vein and the concomitant vein of the facial artery. CONCLUSION: The characteristic treelike structure of the SMG vascular and ductal system may provide useful information for partial gland transfers.

Histological study of the parotid and mandibular glands of barking deer (Muntiacus muntjak) with special reference to the distribution of carbohydrate content.

We investigated the histology and carbohydrate content of the parotid and mandibular glands of the barking deer (Muntiacus muntjak). Three adult males were used. Paraffin wax sections of the glands were stained with haematoxylin and eosin (HE), alcian blue (AB), pH 2.5 and periodic acid Schiff (PAS). The acinar cells of the parotid gland were serous, whereas those of the mandibular gland were of the mixed type. The acini of the mandibular gland comprised serous and mucous cells with the mucous type predominating. AB and PAS staining showed high concentrations of acidic and neutral carbohydrates in the mucous cells, but not in the serous cells of the mandibular gland. These carbohydrates were also found in moderate-to-high concentrations in the secreted material in the mandibular duct lumen. However, these carbohydrates were not found in acinar cells of the parotid gland or in the serous cells of the mandibular gland. Thus, carbohydrates in the saliva of the barking deer appear to be produced mainly by the mucous cells of the mandibular glands.

Clinical and anatomic study on the ducts of the submandibular and sublingual glands.

PURPOSE: To investigate the relationship between the ducts of the submandibular gland (SMG) and sublingual gland (SLG) and discuss its clinical application relating to SMG radiologic examinations and transfer. MATERIALS AND METHODS: The microanatomy of the SMG and SLG was investigated by use of 30 adult cadavers through anatomic dissection by use of a microscope. The relationship between the SMG and SLG ducts was observed and recorded during operations of microvascular autologous SMG transfer in 63 cases of severe keratoconjunctivitis sicca. RESULTS: There were 3 patterns of SLG and SMG duct anatomic variation: 1) The SMG and SLG have their own respective ducts that secrete separately at the orifices of the ducts in the floor of the mouth. 2) The SLG has a major duct that joins the duct of the SMG. 3) The SLG only has many fine ducts (7-15) that secrete in the floor of the mouth. CONCLUSIONS: The anatomy of the ducts of the SMG and SLG is quite complicated. More attention should be paid to the anatomy of the ducts during surgery or imaging procedures related to the SMG.

In vivo imaging of human labial glands using advanced optical coherence tomography.

OBJECTIVE: Optical coherence tomography (OCT) has emerged as a high-resolution noninvasive clinical imaging application. The purpose of this study was to show OCT images of human labial glands obtained using a swept-source (SS) OCT system. STUDY DESIGN: Labial gland OCT imaging was carried out using our new SS-OCT system for 5 healthy volunteers using a hand-held in vivo OCT scanning probe. The labial tissue was scanned in a superior to inferior direction in 2 and 3 dimensions. RESULTS: The resulting 2- and 3-dimensional ultrahigh-resolution images of in vivo OCT human labial minor salivary glands revealed the epithelium, connective tissue, lobes, and duct. OCT was capable of providing simultaneous and noninvasive structural information with high resolution. CONCLUSION: This clinical imaging modality promises to have clinical impact in the diagnosis of such conditions as Sjögren syndrome and xerostomia.

Influence of the location of the parotid duct orifice on oral clearance.

OBJECTIVES: To determine the location of the parotid duct orifice in relation to the maxillary molars and its influence on oral clearance on the buccal surfaces of the maxillary molars. METHODS: A 2-mm hole was made at the centre of an adhesive therapeutic agent for aphthous stomatitis and the agent was placed on the mucosa so that the hole matched the parotid duct orifice. To locate the orifice, an impression of the buccal tooth surfaces and mucosa around the agent was taken with the teeth in centric occlusion. To evaluate the oral clearance rate, 12 subjects who displayed the parotid duct orifice within 1S.D. of the mean values obtained from the original 35 subjects were selected. 1% agar containing 1 mol/l potassium chloride was placed into three cylinders positioned horizontally, 6mm apart, in an acrylic holder centred over the mean duct location. The diffusion chambers were taken from the mouth at selected time intervals and the gel transferred quantitatively to flasks containing 300 ml of 100 ppm NaCl, which was assayed for potassium by atomic absorption spectrophotometry. Half-times for clearance were calculated. RESULTS: The mean location of the parotid duct orifice was -0.4 mm (range -7.5 to +6.1 mm) mesial to the contact surface between the maxillary first and second molars (where negative values indicate mesial and positive values distal) and 7.2 mm (range +3.8 to +10.4 mm) above a line touching the buccal cusps of the upper molars. The clearance half-time values were shortest for the central cylinder whether salivary flow was unstimulated or stimulated and when flow was unstimulated the clearance half-time was shorter for the mesial than the distal cylinder. CONCLUSION: The degree of individual variation in the location of the parotid duct orifice is great and its exact location will markedly affect oral clearance at different positions on the buccal surfaces of the upper molars.