Describe an arm without a forearm

Question

Usually an arm looks like this:

Shoulder -- upper arm -- elbow -- forearm -- wrist -- hand.

But suppose, because of either chemical poisoning or radiation in utero, Kevin was born without a left forearm. Then his elbow and wrist would be fused into some hybrid structure joint, and the left arm would look like this:

Shoulder -- upper arm -- elbow/wrist -- hand.

Suppose this had already been described in detail. Then Kevin leaves the narrative for a few hundred pages, and when he comes back I want to remind the readers which character he is. In particular I want to remind them of the layout of his left arm because it is to become plot relevant. So I want to insert a marker back to the original description without repeating it.

Since the hundred pages of text only spans a week or so in story (let's make it a working week with the narrator only seeing Kevin on weekends), the narrator certainly doesn't need to be reminded who Kevin is. So I decide to slip in something like. . .

"Kevin cycled at a restrained pace. He knew his _______ arm would prevent him from making quick turns in an emergency."

I think that's a fairly subtle way to remind the readers. But what should go in the blank space? Feel free to muck around with the format as you wish. What I really want is just a summary of the earlier description.

Answer 1

If I didn't mind bad puns, I'd call it 'foreshortened':

having the length reduced, curtailed or abridged.

(Definition from The Free Dictionary, American Heritage sense 2, paraphrased to suit the context.)

'Foreshortened' might be best if what is desired is a genteel tone, edging on discreet but with a possible slightly humorous doubletake on 'foreshortened by a forearm'. I mention the potential humor just so you're forewarned, because "forewarned is forearmed".

However, I'm stumped by the question:

reduced to a stump.

(Definition from The Free Dictionary, American Heritage, transitive verb sense 1, paraphrased to suit the context.)

Using 'stumped' might fit with a less genteel, more direct or colloquial tone. Nothing nuanced about stumped.

Answer 2

I'd call it his stunted arm...

stunt - prevent from growing or developing properly (oxforddictionaries)

---

Here's a typical example usage from The New Yorker (1980)...

My mother took hold of his ankle, whitening her knuckles against his stunted leg. His left leg was short. It made every step a lunge.

Answer 3

One could also call it a malformed or deformed arm. The former would emphasize that it had not developed properly, the latter that it had suffered some injury or environmental insult.