LOCATION OF THE TUMOR.--For the purpose of considering the relation of these tumors to the different regions of the uterus we may call that part situated above the entrance of the Fallopian tubes the fundal zone, and that above the internal os uteri the corporal zone; all below this the cervical zone. Fibrous tumors may and do originate in all of these zones or regions, but they spring more frequently from the corporal {249} than either of the others, and less frequently from the fundal zone. The part of the corporal zone in which these tumors more frequently grow is the lower or cervical portion. There is another important view of the relation of the tumors to the uterus. The muscular fibres of that organ run in every direction with reference to the latitude and longitude of the uterine circumference--transversely, longitudinally, obliquely, spirally, etc. There is probably not much more definiteness in the layers constituting the walls of the uterus. If they cannot be completely separated into regular strata, there is sufficient distinctness in the layers to justify us in employing the term strata in connection with their arrangement, and this term will enable us to get a more exact understanding of the language used in the description of tumors. Authorities differ as to the exact number of strata to be found in the body of the uterus, but for clinical purposes it is convenient to describe them as follows: By drawing a line through the middle of the uterine wall longitudinally we will indicate a central stratum of fibres. A tumor originating in that line or stratum is what is usually called an intramural tumor. The number of tumors growing in this stratum is not very great as compared with those situated nearer the two surfaces. [Illustration: FIG. 25. Diagram showing Muscular Strata of Uterus, as divided for clinical purposes.]