Recently, Sherrat [J. Appl. Math. 47, 147 (1991)] introduced a model f
or the behaviour of an epithelial sheet after a section of the sheet h
ad been removed. Consideration of radially symmetric equilibria reduce
s the original PDE to an ODE boundary value problem. Sherratt employed
formal perturbation analyses to produce an expansion for the solution
by exploiting a small parameter epsilon. In this article the author g
ives a rigorous proof that, for each epsilon > 0, a solution exists an
d that it is unique. This is achieved using a topological shooting arg
ument. Also given are results concerning the physically relevant 'shar
p edge' of the solution near the boundary.