This appeal involves the validity of patent No. 2,494,229 issued to John G. Col-lison for a surgical bone screw for use in applying an internal fixation plate to a fractured bone. The District Court, in a full and carefully reasoned opinion, reached the conclusion that this patent was invalid for lack of invention over the prior art. 230 F.Supp. 572 (D.Md. 1964).

We have carefully examined the record in light of the appellant’s contentions and find ourselves in complete accord with the District Court’s disposition of the case. Concluding that the patent is invalid, we have no occasion to consider alternative defenses raised below and in this court.

Affirmed.