Thumb pain: described as any pain from the base of your thumb (knuckle) to the tip of your thumb. To establish where exactly your thumb pain is coming from it can be very helpful identifying what structure is causing your pain. Thumb pain is our field of speciality, we are the experts.
Any pain or problem in your thumb will have a ripple effect on the rest of your hand, wrist and elbow. So if you are uncertain what the cause may be, rather let us have a look at it before you create even more problems. Thumb pain can be caused by any of the muscles, joints, tendons or nerves in your thumb. Let’s look at each of these structures:
On the palm side of the hand there are three muscles that move the thumb, situated at the base of the thumb. These muscles are the Adductor pollicis, Abductor pollicis brevis and the Opponens pollicis. The adductor pollicis pulls the thumb inwards, the abductor pollicis brevis moves the thumb away from the hand and the opponens pollicis brings the thumb around towards the palm of the hand to touch the opposite fingers hens the name ‘opponens’.
On the back of the hand there is one muscle called the first dorsal interosseous muscle that assists the adductor pollicis to close the thumb towards the side of the hand. The bulky muscle that you can palpate in the first web space.
On the palm side of the thumb there is a group of rope-like tendons that run from the forearm to the tip of your thumb. The Flexor Pollicis Longus and Flexor Pollicis Brevis that gives you the ability to bend the two joints of your thumb down.
On the back of the thumb there are two tendons called the Extensor Pollicis Brevis and Extensor Pollicis Longus that allows you to straighten your thumb. If you injure these tendons you will be unable to straighten your thumb to make the OK/sharp sign.
The Flexor group on the palm side of the thumb is more prone to injury. You can cut these tendons by either glass or a knife. Defending yourself against an incoming knife by shielding yourself with an open hand may lead to a severed flexor tendon group. Another scenario may be washing dishes and the glass breaks in your hand, or even trying to catch a falling sharp object.
Trigger finger (also known as trigger thumb) is a common phenomenon that involves the flexor tendon running in the thumb. A trigger thumb leaves the thumb stuck in a bent position.
Two branches of nerves give feeling and movement to the thumb. The median nerve supplies the palm side of the thumb. Similarly the radial nerve gives feeling to the top side of the thumb.
In most cases nerve compression, irritation or injury is closer to the wrist, but you will feel the dominant pain, burning, shocks, cramps, tingling, pins & needles or any other nerve pain in your fingertips and tip of the thumb.
There is a web of nerves that spreads out over your thumb to give your skin feeling. These digital nerves are almost always involved when severing a tendon, which cuts off the sensation to the skin after the laceration.
The thumb has three joints. First (at the base of the thumb) is the Carpometacarpal joint (CMCJ), then it is the Metacarpal phalangeal joint (MCPJ). The tip of the thumb bends at the Interphalangeal joint (IPJ).
The first joints affected by Osteoarthritis is the base of the thumb. Associated pain on movement of the thumb as well as pain when lifting or carrying objects is common. We regularly see that patients feel constant pain especially in the CMCJ when osteoarthritis has set in
Volar Plate is a ligament that prevents your thumb from hyperextending. Trying to catch a ball but the ball overextends your fingers, may rupture these sensitive yet vital ligaments.
Ulnar Collateral ligaments are ligaments on the insides of your thumb that prevents your thumb dislocating towards the outside. Radial Collateral ligaments are on the outside of your thumb that prevent the thumb deviating towards inside. These ligaments are at the MCP and IP joints.
The thumb joints are more vulnerable to dislocate. Any overload and force to the thumb may dislocate the other joints in any direction. During a dislocation it is important to note that torn ligaments are very likely. These ligaments are responsible to keep the MPJ and IPJ stable. If an injury occurs to these ligaments, the risk of you dislocating your thumb again is very high.
Game keepers thumb is a condition when the first knuckle of the thumb hyperextends to push the joint forward leaving the thumb in a over extended position.
Ligaments are mainly responsible to keep the joint stable. In conditions like arthritis the joint surfaces are destroyed to the point where the joints normal alignment may deviate to any side, causing excessive stress on the surrounding ligaments.
Ever hit your thumb with a hammer, or closed a cupboard on it, well this is how many of our patients fracture the tip of their thumb.
The bones in your fingers have the name “phalanges”. Each thumb has two phalanges. The bones in your thumb starting from the tip is the Distal Phalanx and next is your Proximal phalanx. The proximal phalanx connects your thumb to your hand.
Thumb fractures involve the crack or splinter of any of these two bones. You may not always be sure if you have broken your thumb or not. If a fracture occured and you try to bend the thumb it will be painful but you’ll still be able to move it. Don’t fool yourself. There might still be movement in your thumb, this does not mean that you have not broken your thumb. Swelling and bruising (bleeding) may be a better guide to the severity.
When an egg is in an upright position it is able to hold a much greater weight than when you turn it onto its side. In the same way, when you apply a force to your thumb at the wrong angle, it can be very fragile to break.
It doesn’t take much to fracture your thumb. Many patients come in with thumb pain that has been troubling them for more than a few weeks. When we take X-rays we usually find an old fracture still trying to heal. Then it’s too late to make changes if the bones has dislocated or started healing in the wrong position. Taking too long to seek medical help or delayed treatment can significantly change the time it takes to heal your thumb pain.
What needs to be tested to determine the source of your thumb pain
Range of Movement
Nerve tension test
Tendon gliding test