Damage to any individual joint makes you acutely aware of just how much we come to rely on our bodies to do what we ask of them. Any individual joint that gets impacted often makes you realise how much we use our bodies in many wonderful ways. It’s good to understand the anatomy of things sometimes so that you can best pinpoint what an issue may be and also how to approach getting some relief in it. Also - what actions to avoid.
The wrist is a very important joint that we may not realise we rely on until we damage it. It’s also a highly complex one as it involves multiple bones and extensions and is also complicated by the fact that many of the muscles that act on the wrist originate much further up the arm at the elbow or along the forearm itself. The other important aspect of wrists strains is that as we age, the wrist is one of the top 3 fracture sites in the ageing person. Often we don’t do enough on our wrists as we age and this makes us susceptible to injury in this area.
The big thing with wrists is - we forget to use them. One of the first movement we do as a baby is crawling. On all fours, weight being distributed through our shoulders and wrists as we negotiate learning new movement patterns. Its also a primal movement pattern that helps us to develop cognitive ability and develop neural co-ordination and brain pathways. It also helps us to align our spine which we will explore in another article. The point is that crawling distributes a lot of that weight bearing motion into our wrists and helps us to develop strength here. Transferring power from the lower chain leg and hips into the shoulders.
The wrist is a highly moveable joint space. Its made up of a series of bones and muscles but perhaps the most important ones to talk about are the CARPAL BONES. A collection of 8 bones that all interrelate and rotate and move and enable remarkably dextrous motions that the wrist can perform. Think about how you can rotate your wrist in all different directions and patterns and how flexible it is. This is due largely to the carpal bones all allowing rotation and motion as they co-ordinate with the distal arm bones (ulna and radius) to create movement at the wrist. they lie in 2 rows at the base of the forearm.
Perhaps the most important bone to talk about in terms of injury is the SCAPHOID bone. This is the most common site of fracture in the wrist and strain as the Scaphoid, situated on the thumb side of the forearm forms the direct articulation with the radius and connects the wrist to the thumb. It also serves as a connection between the two rows of the carpal bones linking both the proximal and the distal rows together. Its a big bone that rules the wrist. Injury here is rife with issues if the articulation of the scaphoid is compromised. Not only does it render difficulty in hand and motor skills of the forearm, it also creates issues of compromised blood supply not only to the carpal bones themselves but to the hand and palm. Osteoarthritis and arthritis is also another issue with injury particular when issues are not diagnosed early and a ‘non union’ of the scaphoid bone occurs. Degenerative change here is often difficult to repair and regenerate.
Strains in the wrist can also come about from issues with the forearm flexors. These long tendons and muscles are a group of predominantly 5 flexors: For the purposes of this article we will look at the 4 tendons that are involved in wrist flexion.
Flexor Carpi Ulnaris
Flexor Carpi Radialis
Palmaris Longus
Flexor Digitorum Superficialis
All these muscles act on wrist flexion and are often a site of issue with strains and overuse of the wrist and forearm. Conditions such as Golfers Elbow involves these muscles and the strain they have at the origin of the medial elbow. When we are involved in excessive use of the forearm or wrist this can often lead to irritation of the forearm flexors often results in pain around the wrist and that makes other movements such as opening a door handle or gripping, painful and illicits mild to sharp pain along the wrist and forearm. Stretching the forearm muscles beyond the amount of tension they can withstand is perhaps the best description of these types of injuries and this often happens in a fall where a person may put out their hand to brace themselves or cushion the impact of a fall. The strain of the Flexors comes from the bending backwards of the wrist which asks the flexors to extend and then in that extension, absorb the strain of impact of bodyweight falling onto the outstretched palm. Often this is too much load and strains occur.
looking at the various muscles of the forearm can be quite confusing and difficult to differentiate. Palmaris Longus, Flexor Carpi Ulnaris (FCU) and Flexor Carpi Radialis. (FCR) Sound like a lot of Latin? Yep it can get confusing. But here is a good way to think of it. The Carpi Ulnaris runs along the ulna bone on the medial edge of your forearm. FCU is a two headed muscle that is very thin which connects along the hamate bone (carpal bone) heading towards the 5th digit. Its the little finger muscle. And its a long little thin muscle. So that may help to make you aware. The Flexor Carpi Radialis is likewise a smaller muscle that runs from the medial epicondyle of the elbow and then passes across the forearm towards the thumb where it inserts on the 2nd metacarpal (finger). Palmaris Longus is interesting in that it does not exist in 14% of the population!!!! Does this have an effect on grip strength - NO. But its use and development in humans has been downgraded with our ability to flex our thumb and use the Pollicis muscles that are used for active adduction of the thumb and fingers. The Palmaris Longus muscle is often used for tendon grafts and surgeries requiring reconnection.
The Flexor Diogitorum Superficialis is the largest muscle of the forearm and the big daddy of the anterior forearm. It is a two headed muscle much like biceps brachii and lies in between what is known as the superficial and deep layers of the forearm. The FDS has 4 tendons that spread out to each digit in the palm and individually flexes these muscles. This bulky beast of the forearm is often indicated in issues of strain at the wrist joint and is often indicated in climbing injuries and those with gripping motions. The ability of the FDS to individually flex each digit means it is used widely under load of gripping with flexion of the elbow and wrist.
Understanding these flexors can seem confusing but knowing the dexterity of this area and understanding the roles that each of these muscles play in the movement of not only the wrist but in the forearm and elbow flexion can help to alleviate small issues with grip, movement and pressure that we often think of as not being as vital as other big muscles - until we injure them. Getting stress and health through your wrists is vital to continue our quality of life particularly into our senior years. An element we will explore further in another article on the benefits of crawling.
