“How do you explain it?” I asked, almost sweetly.

“Clearly that’s a gunshot wound.”

“I see no evidence of that.”

“Meaning?”

“No bullet fragments or metallic trace on the X-ray. No jagged edges. No shattered bits of bone. No radiating fractures or blowout fragments.”

“You’re saying the hole is antemortem trauma?”

“No. I am not.” I knew it was childish to bait Schechter but couldn’t help myself. The guy was so unpleasant I was looking forward to booting him under the bus.

“Explain.”

“The hole did not result from trauma of any kind.”

“Not trauma.” For the first time Schechter’s voice held a note of uncertainty.

“No.”

“Elaborate.”

“My explanation requires an understanding of sternal development.”

Schechter did the hand thing. With a bit less flair than before.

I gathered my thoughts, then began.

“The sternum begins life as two vertical cartilaginous bars lying one beside the other. Eventually, the bars fuse along the midline. The cartilaginous sternum then ossifies, meaning it turns to bone. This ossification progresses from six centers, four of which form the body, or long thin part, of the sternum. If there’s no objection I’ll confine my comments to the sternal body, since that’s where the hole is situated.”

“Please.” It was Schechter’s first use of the word all morning.

I moved the laser sideways across Rose’s sternum.

“Note the transverse ridges. Each marks the site of fusion of separate juvenile elements called sternebrae. Ossification begins in the first sternebra during the fifth to sixth fetal month, in the second and third during the seventh to eighth fetal month, and in the fourth during the first year after birth.

“That is, if things progress normally. But sometimes they don’t. Occasionally a sternebra ossifies from more than one point of origin. In the lower sternebrae this variation usually involves two centers placed one beside the other.”