Abstract: Objective To observe the histological and morphological changes of mouse’s cross-territory ear flap model of vascular. Methods The right-ear of mice as experimental group, the caudal of the mouse ears were cut for 2/3 with eye scissors from caudal to cephalic direction, ear’s flap based on a vascular pedicle but crossed three vascular territories was created.The left-ear as the control group, just clearing the hair. The ear of mice were surgically cut in 0 d, 1 d, 3 d, 5 d, 7 d respectively post-operation, and fixed in 10% formaldehyde for histological observation of the changes of choke I area and choke II area in the ear’s flap. Results At different time points, the average value of choke I area of blood vessels in the experimental group was larger than that of the other groups (P<0.01). The amount of venous blood vessels in choke I and choke II area respectively reached peak value at 3 d and 5 d, and then decreased gradually, and this trend may be related to the establishment of the venous reflux in the basal part of the ear flap.In choke I and choke II area, the mean values of arterial and venous blood vessel filling degree were 38.85%, 40.64% and 57.02%, 61.48%, respectively. Conclusions ①After establishment of extended flap, the dilation of veins seemed to passive , whereas the dilation of arteries seemed to active; ② The number of the choke vessels between the dynamic and potential territories that are involved in dilation and extent of the dilation are much smaller than that of the choke vessels between the anatomic and dynamic territories; ③ The change of vascular diameter has positive effect on the survival of skin flap.

Key words: Mouse, Ear flap, Histopathological observation, Choke vessels