thymus lobule morphology trait thymus corticomedullary boundary morphology trait Any measurable or observable characteristic related to the shape, structure, color, or pattern of the dense region demarcating the thymus medulla from the surrounding cortex that is characterized by numerous blood vessels (predominantly arterioles) with some perivascular connective tissue, mature and immature T lymphocytes, dendritic cells, variable numbers of perivascular B-lymphocytes and plasma cells; site of entry of bone marrow stem cells and exit of mature, functional T cells. Trait.ontology VT:0009543 thymic corticomedullary boundary morphology trait thymus CMZ morphology trait thymus cortico-medullary boundary morphology trait thymus cortico-medullary junction morphology trait thymus cortico-medullary zone morphology trait thymus corticomedullary zone morphology trait