iliocostalis syndrome?

[Ajgeb21]

My deadlift has always sucked, I’ve noticed I can barely fit the palm of my hand between my lowest rib and iliac crest. Also I have a difficult keeping lumbar extension with any kind of weight it just doesn’t look right at a warm up weight where I’m extending my low back as much as psychologically possible. I would describe it looking like how the average person looks right before pushing their belly between their thighs with there being the slightest bit of flexion, except with me extending as much as possible. It occurred to me this may not be anatomically normal and I’m wondering if this could be putting me in a mechanically disadvantaged position for a deadlift. Also my fingers only reach mid thigh. Would that qualify as short arms? On the positive I do quite well with overhead pressing and it has always seemed to be my best lift.

On linear progression

5’7” 200lbs
Current lifts

Squat 270 3x5
Dead 285 x5
Press 172.5 3x5
Bench 225 3x5

[Mark Rippetoe]

Obviously, I can't see from here. Post a video.