The impact was perfect. Bone on concrete. After some ginger prodding and pulling, the doctor announced that the base of my thumb’s metacarpal bone had shattered against the carpus, the eight pebbles that give wrists their flexibility. My mind flashed to a gandy dancer raising a spike maul skyward, the sun framing his figure in a golden aura, then bringing that steel mallet down on a piece of wooden kindling.
“Impressive work,” the doc said, glancing up from the X-ray, as if I had done my best and succeeded in destroying the use of my right hand. 
It’s hard to be a writer when your dominant hand is maimed. Forget grasping tree branches or guiding a bean burrito toward your mouth. For six weeks, I signed credit card receipts with a shaky X.
Complete strangers see the cast and want to know. A few people have shaken their heads, declaring, “I’m not even going to ask.” Then, they pause, inhale. And they ask.
Let’s get this out of the way: I was skateboarding with my eight-year-old son. There are two reactions when I reveal this bit of information. A look that reads as “Well, what did you expect?” accompanied by (a) slow headshake, (b) sigh, (c) whistle, (d) all of the above. The second reaction is a look of modest admiration, along with the observation “Well, at least that’s a better story than…” I wish a good story provided a silver lining for a useless hand. I’d rather have the hand.
Prying open a bottle of salad dressing wedged into the crook of my right elbow, it becomes very clear to me that we live in a world designed for the kind of pinching, gripping, and squeezing that an opposable thumb provides. Button-down shirts are now the bane of my existence. My typing skills have been reduced to tap-tap-bam!—my hard cast leaving divots on the computer keyboard. Don’t even get me started on my pants. We may all put on pants one leg at a time, according to timeless wisdom, but my contortions involved in one-handed pantsing would make a yogi applaud.
All this to say, during the time I’ve been deprived of its use, my gratitude for my thumb has grown exponentially. I’ve come to better appreciate how this humble digit both separates us from and connects us to our nonhuman kin.
Before I looked further into the matter, I would have guessed that raccoons were the animals with whom we shared our thumbs, as well as our garbage. Those scamps put me in awe of the precision and grace of a hand. On a camping trip, I observed a raccoon clank through trash cans and cross-examine picnic tables for an hour, carefully choosing the most delectable morsels, shuffling through chip bag empties, and grooming his furry cheeks between snacks. He eventually swaggered my way, coming within a few inches of my boot. I’d wager he could have tied my laces for me, had he had the slightest interest in doing so.
But raccoons’ hands, dexterous and sensitive as they are, don’t possess an opposable thumb. I was pleased to discover that the opossum, the only North American marsupial, owns this agile digit. It’s unfortunate that opossums get a bad rap. I’m afraid that to most people’s eyes, opossums are … how should I put this … aesthetically challenged. But if one can get beyond the pointy teeth and hairless tail, opossums have many fine and unusual qualities.
For one, opossums have survived for millennia in places their marsupial cousins never ventured, which to me is an affirmation that life will find a way and a niche, no matter how a baby is carried to term. They also have prehensile tails, as well as a protein in their blood that can neutralize snake venom. Cool, right? But the common ancestral need that holds humans and opossums together is a morphological solution to tree security: the opposable thumb. Opossums’ flexible thumbs happen to be located on their hind feet. (Let’s pause for a moment and consider how great it would be to have an opposable toe, one that could support your body weight as you clung above the ground.)
The next time I see an opossum, she’s getting a thumbs up from me. I’m hoping it won’t cause her to faint.
Reflecting on my opossum kin got me thinking about anatomical histories embedded within the human body, which led me to a YouTube video about the evolutionary origins of the opposable thumb. The video offers a short but fascinating look into deep time bodily structures. I couldn’t help but snort-laugh when my eyes drifted to see how many people “liked” the video. Nine thumbs up; no thumbs down. Our approving thumbs have even invaded our computer icons and emojis.
Beyond its approving symbolic function, the real human thumb is a powerful instrument, a wonder and a danger. The thumb is a tool made out of bone that never leaves us. It enables us to firmly clasp an object of our choosing, to shape that object to better suit our purposes, and to transform that object into an extension of our desires. A stone, as our forbearers no doubt quickly discovered, can be used to crack nuts or crack skulls.
We held a rock. Then we held a hammer. A solderer. A diamond saw. A computer fabricator. The power of the human mind, channeled into the humble thumb, has constructed cities that tower above the fruited plains from whence we came. Who could have predicted that a mobile thumb, coupled with an active imagination, could cause so much trouble?
Anyone can hold up a hand and, with only a thumb and index finger, indicate the distance that separates us from other creatures. That much. Yet our thumb’s shaping powers often lead us to believe and act as if we are worlds apart.
My cast was removed a few weeks ago. My thumb has regained about 95% of its functionality. I hope to use it wisely. Maybe even make a few opossums proud of what we share.
