The Thumb: the real hero of civilization

In paleo-anthropological circles it is well-known that the thumb was perfectly designed for picking up a club and hitting someone. It has even been proposed that this anatomical wonderment was the first sign of our potential civilisation; because of this itsy-bitsy protuberance we would get smarter.

You see, if we could do the club thing with aplomb, then we could do other stuff as well. And if we could get rid of irritating people along the way…well, how serviceable was that! So while we perfected clubbing and throwing over millions of years, we were also engaged in carving stones into tools and enjoying a general penchant for re-arranging our environment to suit ourselves. The thumb was it!

Thumbs up

Whichever way you want to look at it, the opposable thumb has made us what we are. Here are some facts about the thumb:

  • Right from the start, the thumb made itself felt, so to speak. It is fairly independent from the rest of our fingers, and possibly the least attractive. It is shorter but extremely flexible. Thumbs only have two bones, and owe their flexibility to their saddle-like joint to the rest of the hand and a little muscle known as the abductor pollicis brevis – which is a fancy way of saying you can pick things up.
  • The thumb may have helped us to develop language – after all, if you are busy doing something with your hands, then you are free to say something. And while we were working at all those weapons and useful cutting materials, we may have begun that very human habit of gossip. Chatting while we work with our hands is one of our unique human traits.
  • Thumbs have their own pulse. There’s a big artery in the thumb – the princeps pollicis And it’s the reason you can’t take someone’s pulse with your forefinger and thumb, you have to use your index finger and your middle finger to avoid your own thumb’s pulse getting in the way of the reading.
  • The thumb separates us from animals (well, we like to think so). A handful of other animals, mostly primates, have opposable thumbs, including: orangutans, chimpanzees, lemurs, giant pandas – and oddly enough a phylum of frogs known as phyllomedusa (a faintly disturbing thought) – although these species’ thumb-like apparatus is really just an extra sesamoid bone that acts like a thumb.
  • The thumb’s ability to make a wide variety of movement is amazing. The thumb can rotate, flex, swivel, pivot, pinch, grasp, manipulate objects. The strength and dexterity of the thumb allows us to do so many things, everything in our history in fact: write, craft, hold objects, construct, change the order of things. Everything we do is made entirely possible by the thumb.

Osteoarthritis: the bane of thumb bones

But the thumb can be fragile. The thumb may appear to only have two knuckles, but it actually has a third, right above the wrist, the first carpometacarpal joint. If that starts to hurt, or gets big enough to look like a bump or a mass, you may have carpometacarpal joint disorder (CMC), a common condition that is partly genetic and partly caused by repetitive use.

The thumb is one of the most debilitating areas to develop an arthritic problem. It’s very difficult to fix, and pain is often followed by an inability to use it at all. Surgery can help, but it will never restore full mobility.

Osteoarthritis occurs when the smooth cartilage that covers the ends of the bones begins to wear away. The joint at the base of the thumb, near the wrist and at the fleshy part of the thumb, enables the thumb to grip things in your hand. Arthritis of the base of the thumb is more common in women than in men, and usually occurs after 40 years of age. Prior fractures or other injuries to the joint may increase the likelihood of developing this condition.

Symptoms

  • Pain with activities that involve turning a key or opening a door
  • Swelling and tenderness at the base of the thumb
  • Aching discomfort after use
  • Loss of strength in grip
  • An enlarged, “out-of-joint” appearance
  • Limited motion
  • An X-ray may show deterioration of the joint, as well as any bone spurs or calcium deposits that have developed. Many people with arthritis at the base of the thumb also show symptoms of carpal tunnel syndrome.

Treatment

  • In early stages, you can use ice on the base of the thumb for 5 to 15 minutes several times a day.
  • Anti-inflammatories are recommended: aspirin or ibuprofen will reduce inflammation and swelling.
  • Wearing a supportive splint to limit the movement of your thumb has also proved useful. It allows the joint to rest and heal, protecting both the wrist and the thumb.
  • A steroid solution can be injected directly into the joint. This will usually provide relief for several months, but cannot be continued indefinitely.
  • Surgery can be performed, but there are several different methods: One option involves fusing the bones of the joint together. This, however, will limit movement. Another option is to remove part of the joint and reconstruct it using either a tendon graft or an artificial substance.
  • After surgery, you will have to wear a cast for 4 to 8 weeks, depending on which procedure is used. A rehabilitation programme, often involving a physical therapist, helps you regain movement and strength in the hand. You may feel some discomfort during the initial stages of the rehabilitation program, but this will diminish over time. Although full recovery from surgery takes several months, most patients are able to resume a degree of normal activities.

Value your thumbs! Every night remember all they have done for you in a day. Be grateful. And be careful. Love your bones!

NOFSA (National Osteoporosis Foundation South Africa)

NOFSA is the only non-profit, voluntary health organisation dedicated to promoting lifelong bone health. We focus on reducing the widespread prevalence of osteoporosis while working to find a cure for the disease, and by supporting research and developing programmes of education and advocacy.

Find out more about our work at: www.osteoporosis.org.za