http://www.newyorkinjurycases.com/personal-injury-article.asp?id=19415

Figure 1 - the short and longpieces of the failed nail.

Case Study: 316 SS Nail Failureby High-Cycle Fatigue

Figure 2 - marks on external surface presumably due to surgical pliers used during removalof the fractured nail.

Scanning electron micrograph of outer surface away from fracture showing longitudinal striations due to surface buffing.

(A) (B)

(A) low-magnification and (B) higher-magnificationlight-optical micrographs of the long-piece fracture surfaceshowing the confluence of the cloverleaf slot, spiral machining marks, and circumferential machining marks.

Figure 4 - Scanning electron micrograph of surface away from fracture showing circumferential and spiral machining marks.

circumferential marks

spiral marks

Series of scanning electron micrographs at increasing magnification showing fracture along circumferential markwith secondary cracks emanating along spiral machining marks.

Scanning electron micrograph of inner surface of the nailnear the fracture surface in the short piece showing secondarycracks which follow the circumferential machining marks.