Arterial venous and lymphatic pathways intrinsic to the palate and fauces (implicated routes for metastatic lesions).
Since metastatic lesions of the palate are known to spread primarily via lymphatics and secondarily via veins it would seem likely that knowledge of their distribution would be essential to clinico-pathologic interpretation. Arteries, veins and lymphatics intrinsic to human fetal and neonatal dog palates were ascertained by perfusing each vessel type with a different coloured dye. Stereomicroscopic observations determined that the three vessel types are so intricately intermingled that companionship in distribution does not exist. It was determined that the greater palatine and nerve enter the palatal area via the greater palatine foramen and are constant companions to one another as they ramify in the palatal mucoperiosteum. The palatal venous plexus converges in the posterior palate forming a single vein that descends to the pharynx where it joins the pharyngeal venous plexus. Hard and soft portions of the palate do not drain separately to infratemporal and pharyngeal venous plexuses. Arterial and venous networks form three strata (mucosal, submucosal and periosteal) but the lymphatic network forms only two strata (mucosal and submucosal). Images of blood and lymph vessels were observed coursing into the bony palate via canals of Volkmann but no images of lymph vessels were observed coursing into bone. The bony palate appears to be alymphatic. Fibrous connective tissue investing the bony palate (periosteum) and that surrounding neurovascular bundles (connective tissue sheaths) appears to function as a barrier to lymphatic ingrowth since both structures did not contain imaged lymphatic vessels. However, the fibrous connective tissue band at the palatal midline (median palatal raphe) does not present a barrier to lymphatic continuity since imaged lymphatic vessels were observed extending across the midline. Lymphatic afferentia exit the palatal area in stromata investing the palatoglossus and palatopharyngeus muscles and subsequently join lymphatic networks intrinsic to the tongue and pharynx. Hence arteries enter while veins and lymphatics exit the palatal area at separate locations in the posterior palate. Distribution of lymphatic vessels were found to coincide with clinical observations as to direction of spread of malignant lesions from the posterior palate and upper faucial area to the tongue and pharynx. The study also provided a vasculo-anatomic basis for surgical consideration specific to cleft palate reconstruction and palato-pharyngeal hiatus closure.
D000818:Animals; D000831:Animals, Newborn; D001158:Arteries / Q000033:anatomy & histology; D004285:Dogs; D005314:Embryonic and Fetal Development; D006801:Humans; D008208:Lymphatic System / Q000033:anatomy & histology*; D009362:Neoplasm Metastasis; D010159:Palate / Q000033:anatomy & histology / Q000098:blood supply*; D010614:Pharynx / Q000033:anatomy & histology / Q000098:blood supply*; D010781:Photography; D014680:Veins / Q000033:anatomy & histology