A Bilateral Symmetrical Variant Formation of the Sural Nerve.

Typically, the sural nerve is formatted by the connection of the lateral sural cutaneous nerve (branch of the common fibular nerve) and the medial sural cutaneous nerve (branch of the tibial nerve). The current cadaveric report aims to describe a quite unusual symmetrical variant of the sural nerve. Classical dissection was performed on an 84-year-old donated male cadaver. On both sides, the sural nerve was formatted directly by the sciatic nerve. After its emanation, it continued its typical course between the gastrocnemius muscle heads. Sural nerve formation has been extensively studied due to its great clinical significance. The identified variant corresponds to one of the rarest types of sural nerve formation. Knowledge of sural nerve variants may play a crucial role in lower limb surgery and nerve harvest for reconstruction.

Systematic Review and Meta-analysis of Suprascapular Notch Morphological Variability: Do We Know Everything?

The suprascapular notch represents a depression on the lateral part of the superior border of the scapula, medially to the coracoid process. The current paper presents a systematic review with a meta-analysis of the suprascapular notch morphological variability. Related clinical implications were further discussed as well to emphasize the value of the topic. A total of 31 articles were included in the meta-analysis, which depicted great heterogeneity. Thus, due to the different classification systems, difficulties were faced in creating a complete and united classification. All the problems and pitfalls that arise from each classification system were discussed, and we concluded with the most complete one. The knowledge of the suprascapular notch morphological anatomy is of great importance, especially for orthopedic surgeons, due to its relationship with the suprascapular nerve. Thus, further research in this area is adequate.

Maxillary Artery Traversing Through the Temporal Muscle.

Few previous dissection reports demonstrated the possible course of the maxillary artery (MA) through the temporalis muscle (TM). A dissection study performed a long time ago established a 2% prevalence of this variant. As the variant was not studied on angiograms, we decided to do so. One hundred seventy archived computed tomography angiograms were used on 95 male and 75 female patients. The MA course through the TM was found in 11/170 cases (6.47%) but in 16/340 sides (5.58%). This is because, in 5/11 cases, the variant was bilateral. Therefore, preoperative computed tomography angiography could be helpful when surgical procedures using either the TM or the MA are designed. The course of the MA is variable, either deep or through the TM.

Fenestrated Maxillary Artery.

The external carotid artery divides terminally into the superficial temporal and maxillary arteries (MA), deep to the base of the neck of the mandible. Arterial fenestrations are commonly found in the vertebrobasilar and internal carotid systems but are rarely encountered, or reported, in the external carotid artery system. The archived computed tomography angiograms of a 70-year-old male patient were observed anatomically. Inferior to the posterior end of the lateral pterygoid muscle was found a fenestrated segment of the MA, oriented mediolaterally. The middle meningeal artery left the superior arm of that fenestration. The inferior arm of the fenestration gave off a temporoalveolar trunk, further divided into posterior deep temporal and inferior alveolar arteries. The MA fenestration and the temporoalveolar trunk are rare variations of the MA at the entrance in the infratemporal fossa. These make the MA prone to iatrogenic lesions during different surgical procedures addressed to this region.

Lymphatic lacunae of the human eye conjunctiva embedded within a stroma containing CD34+ telocytes.

An accurate identification of telocytes (TCs) was limited because of the heterogeneity of cell types expressing the markers attributed to TCs. Some endothelial lineage cells also could fit within the pattern of TCs. Such endothelial cells could line conjunctival lacunae previously assessed by laser confocal microscopy. We have been suggested that an accurate distinction of TCs from endothelial cells in the human eye conjunctiva could be achieved by use of CD31, CD34 and D2-40 (podoplanin); and that the conjunctival lacunae are in fact lymphatic. We aimed as testing the hypothesis by an immunohistochemical study on human eye conjunctiva biopsy samples. Samples of human eye conjunctiva from 30 patients were evaluated immunohistochemically by use of the primary antibodies: CD34, D2-40 and CD31. D2-40 was equally expressed within epithelia and laminae propria. Basal epithelial cells were D2-40 positive. Within the stromal compartment, the lymphatic marker D2-40 labelled several lymphatic vessels. CD31 labelled both vascular and lymphatic endothelial cells within the lamina propria. When capillary lymphatics were tangentially cut, they gave the false appearance of telocytes. Blood endothelial cells expressed CD34, whereas lymphatic endothelial cells did not. Stromal CD34-expressing cells/telocytes were found building a consistent pan-stromal network which was equally CD31-negative and D2-40-negative. The conjunctival lymphatic lacunae seem to represent a peculiar anatomic feature of eye conjunctiva. They are embedded within a CD34-expressing stromal network of TCs. The negative expression of CD31 and D2-40 should be tested when discriminating CD34-expressing TCs.

Critical Review: What Cell Types Are the Lung Telocytes?

Telocytes (TCs) are stromal cells defined by peculiar long, thin, moniliform prolongations known as telopodes. When isolated, their morphology often lacks the specificity for the proper definition of a particular cell type. Recent studies have linked TCs with different functions and different cell lineages. Although some authors have studied pulmonary TCs, their research has important limitations that we will attempt to summarize in this article. We will focus our analysis on the following: the culture methods used to study them, the lack of proper discrimination of TCs from lymphatic endothelial cells (LECs), whose ultrastructures are very similar, and the immune phenotype of TCs, which may appear in other cell types such as those related to the endothelial lineage or stem/progenitor cells. In conclusion, the cellular diagnosis of lung TCs should be considered with caution until properly designed studies can positively identify these cells and differentiate them from other cell types such as LECs and stem/progenitor cells. Anat Rec, 303:1280-1292, 2020. © 2019 American Association for Anatomy.

An Immunohistochemical Study of Gastric Mucosa and Critical Review Indicate that the Subepithelial Telocytes are Prelymphatic Endothelial Cells.

There are only a few studies regarding gut subepithelial telocytes (TCs). The telopodes, namely peculiar TCs' prolongations described on two-dimensional cuts, are not enough to differentiate this specific cell type. Subepithelial TCs were associated with the intestinal stem niche but a proper differential diagnosis with lymphatic endothelial cells (LECs) was not performed. In this study, we will critically review studies suggesting that distinctive TCs could be positioned within the lamina propria. Additionally, we performed an immunohistochemical study of human gastric mucosa to test the expression of D2-40, the lymphatic marker, as well as that of CD31, CD34, CD44, CD117/c-kit, α-smooth muscle actin (α-SMA) and vimentin in the gastric subepithelial niche. The results support the poorly investigated anatomy of intramural gastric lymphatics, with circumferential collectors located on both sides of the muscularis mucosae (mucosal and then submucosal) and myenteric collectors in the muscularis propria. We also found superficial epithelial prelymphatic channels bordered by D2-40+ but CD31-TC-like cells. Deep epithelial lymphatic collectors drain in collectors within the lamina propria. Blood endothelial cells expressed CD31, CD34, CD44, and vimentin. Therefore, the positive diagnosis of TC for subepithelial CD34+ cells should be regarded with caution, as they could also be artefacts, resulting from the two-dimensional examination of three dimensional structures, or as LECs. Lymphatic markers should be routinely used to discriminate TCs from LECs.

Agger Nasi Cells Versus Lacrimal Cells and Uncinate Bullae in Cone-Beam Computed Tomography.

The maxillary bone's frontal process, lacrimal bone, and ethmoidal labyrinth's uncinate process can each harbor pneumatizations, referred to as agger nasi cells (ANCs), lacrimal cells (LCs), and uncinate bullae (UBs), respectively. Different studies have failed to differentiate ANCs from LCs. We aimed at studying these 3 anatomic sites to establish the anatomical patterns that could be encountered. We performed a retrospective study on cone-beam computed tomography scans of 36 patients (72 sides); the anatomic identification was supported by bidimensional multiplanar reconstructions (MPRs) in all 3 planes and 3-dimensional volume renderings. We established 6 patterns of pneumatization as follows: (1) type I: single LCs (47%), (2) type II: distinctive adjacent LCs and ANCs (8%), (3) type III: LCs expanded as UBs (6%), (4) type IV: ANCs adjacent to LCs expanded with UBs (1%), (5) type V: ANCs expanded as LCs (27%), and (6) type VI: ANCs expanded as LCs and further expanded as UBs (11%). In a type I pattern case, we found a cell-in-cell aspect on sagittal MPRs, which was further demonstrated as being an anterolateral recess of the middle nasal meatus projected in front of an LC. Such an "agger nasi recess" of the middle meatus was not previously described. For an accurate anatomical diagnosis, computed tomography studies should use complementary MPRs in all anatomical planes, as well as 3-dimensional models, to avoid confusing ANCs with LCs and better document the drainage pathways.

Myocardial Telocyte-Like Cells: A Review Including New Evidence.

Telocytes (TCs) are a controversial cell type characterized by the presence of a particular kind of prolongations, known as telopodes, which are long, thin, and moniliform. A number of attempts has been made to establish the molecular phenotype of cardiac TCs (i.e., expression of c-kit, CD34, vimentin, PDGRFα, PDGRFß, etc.). We designed an immunohistochemical study involving cardiac tissue samples obtained from 10 cadavers with the aim of determining whether there are TC-like interstitial cells that populate the interstitial space other than the mural microvascular cells. We applied the markers for CD31, CD34, PDGRFα, CD117/c-kit, and α-smooth muscle actin (α-SMA). We found that, in relation to two-dimensional cuts, the endothelial tubes could be misidentified as TC-like cells, the difference being the positive identification of endothelial lumina. Moreover, we found that cardiac pericytes express PDGRFα, CD117/c-kit, and α-SMA, and that they could also be misidentified as TCs when using light microscopy. We reviewed the respective values of the previously identified markers for achieving a clear-cut identification of cardiac TCs, highlighting the critical lack of specificity.

Myocardial Bridging: A Meta-Analysis of Prevalence.

The main objective of this article was to analyze prevalence data about myocardial bridging (MB) in published studies. To this purpose, we performed a meta-analysis of studies published in English literature that contained data about the prevalence of MB and its anatomical characteristics. The overall prevalence was 19% (CI: 17-21%); autopsy studies revealed an overall prevalence of 42% (CI: 30-55%), CT studies 22% (CI: 18-25%), and coronary angiography 6% (CI: 5-8%). Most bridges were located on the left anterior descending artery (82% overall, 63% on autopsy studies), had a mean thickness of 2.47 mm and a mean length of 19.3 mm. In conclusion, autopsy studies should be the gold standard in evaluating the actual prevalence of myocardial bridges, while in vivo high-resolution CT scanning should be preferred to coronary angiography studies.

Endocardial tip cells in the human embryo - facts and hypotheses.

Experimental studies regarding coronary embryogenesis suggest that the endocardium is a source of endothelial cells for the myocardial networks. As this was not previously documented in human embryos, we aimed to study whether or not endothelial tip cells could be correlated with endocardial-dependent mechanisms of sprouting angiogenesis. Six human embryos (43-56 days) were obtained and processed in accordance with ethical regulations; immunohistochemistry was performed for CD105 (endoglin), CD31, CD34, α-smooth muscle actin, desmin and vimentin antibodies. Primitive main vessels were found deriving from both the sinus venosus and aorta, and were sought to be the primordia of the venous and arterial ends of cardiac microcirculation. Subepicardial vessels were found branching into the outer ventricular myocardium, with a pattern of recruiting α-SMA+/desmin+ vascular smooth muscle cells and pericytes. Endothelial sprouts were guided by CD31+/CD34+/CD105+/vimentin+ endothelial tip cells. Within the inner myocardium, we found endothelial networks rooted from endocardium, guided by filopodia-projecting CD31+/CD34+/CD105+/ vimentin+ endocardial tip cells. The myocardial microcirculatory bed in the atria was mostly originated from endocardium, as well. Nevertheless, endocardial tip cells were also found in cardiac cushions, but they were not related to cushion endothelial networks. A general anatomical pattern of cardiac microvascular embryogenesis was thus hypothesized; the arterial and venous ends being linked, respectively, to the aorta and sinus venosus. Further elongation of the vessels may be related to the epicardium and subepicardial stroma and the intramyocardial network, depending on either endothelial and endocardial filopodia-guided tip cells in ventricles, or mostly on endocardium, in atria.

Telocytes in parotid glands.

The parotid histological structure includes acinar, ductal, and myoepithelial cells, surrounded by a connective stromal component. The parotid stroma is mostly regarded as an inert shell, consisting of septa, which divide the parenchyma. Telocytes were recently identified as a new stromal cell type in various organs, including exocrine pancreas. We aimed to evaluate telocytes presence in parotid stroma and whether their topographical features might support an involvement in parotid function modulation. Serial ultrathin sections of human and rat parotid glands were studied and compared by transmission electron microscopy. Two-dimensional concatenation of sequenced micrographs allowed the ultrastructural identification of parotid telocytes, with their specific long, thin, and moniliform prolongations (telopodes). Telocyte location appeared frequently as a strategic one, in close contact or vicinity of both secretory (acini and ducts) and regulatory (nerves and blood vessels) apparatuses. They were also found in the interacinar and the subductal stroma. Two previously reported telocyte markers (c-kit/CD117 and vimentin) were assayed by immunohistochemistry. Actin expression was also evaluated. Telocytes are making a network, especially by branching of their long telopodes. Elements of this telocyte network are interacting with each other (homocellular connections) as well as with other cell types (heterocellular connections). These interactions are achieved either by direct contact (stromal synapse), or mediated via shed microvesicles/exosomes. Since telocyte connections include both neurovascular and exocrine elements (e.g., acini and ducts), it is attractive to think that telocytes might mediate and integrate neural and/or vascular input with parotid function.