Strange bones #14: Two weird bone pathologies

'Pathology' is the study of what is left behind after death, but scientists also use 'pathology' to describe anything unusual on bones. After writing about my buzzard skeleton last week I went back to look at Storm which is a bird skeleton I collected in 2011 in Suicides Graves Wood. 

When I collected Storm there were black feathers about, so because of that and because of the bone size I guessed it was probably a corvid (crow) but I didn't know what type because the skull was missing.While looking at Storm's skeleton I spotted something unusual which I am going to write about this week, together with another metatarsal which dad picked up on a walk and brought back to show me.

This is Storm's skeleton laid out. It is not as complete as the buzzard, as the skull, radiuses, one of the ulnas, one of the femurs and one of the tarsusmetatarsuses is missing and the other one is broken.

But the unusual bit was in the sternum, which is this bone:

It was split in two, in a line which went down the right side of the keel (the ridge in the middle), and then across the bottom of the ridge here:

It's normally hard to say whether the break happened before or after death, or even when being stored. But what I thought was interesting was the bubbly bone growth on the sternum. That can be a sign of bone regrowing, or sometimes bone disease like cancers.

This is a close-up of some of the strange bone growth on a solid bit of the sternum:

This is on the bottom end of the smaller of the broken parts:

This is the extra bone growth underneath the sternum:

The extra bone growth seemed to be just on the sternum, not anywhere else. What could have caused this ?

What I think might have happened: The crow had a injury which fractured its sternum, so the break occurred some time before death and enough time for the bone to regrow. If the sternum was fractured it wouldn't be able to fly, so it would be on the ground, then a predator like a fox killed it by biting off its head. The fox probably didn't eat the body because the injury was infected, or it smelt bad.

The unusual metatarsal

Dad brought back this bone from Quoiggs Wood. It's the dirty looking one at the top, next to a 'normal' metatarsal. It's from roe deer (you can tell because of the shape and size) and it is an adult (because the bottom ends are fused onto the bone)

The unusual bit was at the toe end (the bottom end), just above where the toes join on. The bone is worn away and not rehealed in a circle around the whole bone:

This is next to the normal metatarsal before, and it shows a good bit of the bone was missing and no sign of rehealing or bone regrowth:

 

What I think could have happened #1: It could be a gnawing mark. Deer and rodents chew bones for calcium. There are gnaw marks further up on the bone where you can see the lines from the teeth:

But there are no such 'lines', but maybe the gnawing just went too deep in into the bone to show.

Theory #2: The deer was caught in a wire fence. I have seen tons of deer which die after getting a foot caught in the top two wires at the top, like this roe deer which dad tried to save:

or this dead roe deer which I wrote about finding here where the wire has gone down to the bone:

If the deer struggles, it could have caused these injuries. The problem is the fence nearby doesn't have the two top wires that catch deer like this.

So those are my theories, what are yours ? Leave a comment below !

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