Is the collateral circulation pattern in the hard palate affected by cleft deformity?

OBJECTIVES: To evaluate the influence of collateral vascularization on surgical cleft palate closure and deformities. MATERIALS AND METHODS: Corrosion casting was performed using red-colored acrylic resin in twelve fresh adult cadavers with a normal hard palate. Additionally, white-colored barium sulfate was injected into a fetus with a unilateral complete cleft palate, and layer-by-layer tissue dissection was performed. Both substances were injected into the external carotid arteries. Corrosion casting involved dissolving the soft and hard tissues of the orofacial area utilizing an enzymatic solution. RESULTS: In normal palates, bilateral intraosseous infraorbital arteries formed a network in the premaxilla with the intraosseous nasopalatine- and greater palatine arteries (GPAs). The perforating GPAs anastomosed with the sphenopalatine artery sub-branches. Bilateral extraosseous GPA anastomoses penetrated the median palatine suture. Complex vascularization in the retrotuberal area was detected. In the cleft zone, anastomoses were omitted, whereas in the non-cleft zone, enlarged GPAs were distributed along the cleft edges and followed the anatomical course anteriorly to initiate the network with facial artery sub-branches. CONCLUSIONS: The anatomical subunits of the palate exhibited distinct anastomosis patterns. Despite omitted anastomoses with collateral circulation in the cleft zone, arteries maintained their anatomical pattern as seen in the normal specimen in the non-cleft zone. CLINICAL RELEVANCE: Based on the findings in normal- and cleft palates, surgeons may expect developed anastomosis patterns in the non-cleft zone. Due to the lack of microcirculation in the cleft zone, the existent anastomoses should be maintained as much as possible by the surgical technique. This applies anteriorly in the incisive canal territory, alveolar ridges, and posteriorly in the retrotuberal area.

The human masseter muscle revisited: First description of its coronoid part.

INTRODUCTION: The masseter muscle is considered to be bilayered, consisting of a superficial and a deep part. However, a few historical texts mention the possible existence of a third layer as well, but they are extremely inconsistent as to its position. Here we performed an anatomical study to clarify the presence and morphological characteristics of a distinct third layer of the masseter muscle. MATERIALS AND METHODS: We dissected 12 formaldehyde-fixed human cadaver heads, analysed CTs of 16 fresh cadavers, evaluated MR data from one living subject and examined histological sections using methyl methacrylate embedding of one formaldehyde-preserved head. RESULTS: An anatomically distinct, deep third layer of the masseter muscle was consistently demonstrated, running from the medial surface of the zygomatic process of the temporal bone to the root and posterior margin of the coronoid process. Ours is the first detailed description of this part of the masseter muscle. CONCLUSIONS: To facilitate discussion of this newly described part of the masseter, we recommend the name M. masseter pars coronoidea (coronoid part of the masseter) as a further reference. The arrangement of its muscle fibers suggest it being involved in stabilising the mandible by elevating and retracting the coronoid process.