Welcome back to the series of articles about physiotherapy and tennis elbow (also known as lateral epicondylitis, lateral epicondylosis and lateral epicondylalgia). So far we have covered who is affected by tennis elbow, the anatomy of the elbow and which muscles or tendons are most likely to be injured. This article will try to give an overview of a huge subject: the physiology of tendons and why they get injured, now this is a massive topic in physiotherapy and has been the subject of huge amounts of research (and in fact our knowledge on this topic is still developing) so I will only be touching the surface.
Firstly we need to look at what tendons actually are and why they might get injured in tennis elbow. Simply put a tendon is a piece of connective tissue that joins muscle to bone and is comprised of well organised mostly one directional collagen fibres (Wang et al 2003). Unlike muscles tendons can not contract themselves and are relatively inelastic (with a much lower proportion of elastin – only about 1-2% Jozsa & Kannus 1997). So basically muscles do the contraction and force generation but tendons, because they connect to the bones and are relatively inelastic, transfer that force over to the bones and move our joints. A key fact about tendons is that they generally will have a much lower blood supply than muscles and in turn have a lower metabolic rate which affects their ability to heal and makes an injury to a tendon much slower to recover and heal properly (Abate et al 2009). Furthermore the point at which muscle turns into tendon (the musculo-tendinous junction) is the point which is most often injured and is subject to large mechanical forces (Abate et al 2009).
Okay – how does this affect tennis elbow? Well, as we found out in the last article, extensor carpi radialis brevis (ECRB) is the most commonly injured muscle in tennis elbow and this muscle is most commonly injured at either the musculo-tendinous junction or at the lateral epicondyle (bony bit of the elbow) where the common extensor tendon inserts into the bone. Therefore understanding tendons and how they react and function is key to understanding tennis elbow.
The common extensor tendon as shown above is the continuation of all the extensors of the wrist and fingers and therefore any time you extend your wrist or your fingers to pick anything up it is put under stress. So it isn’t really a surprise that if you do too much of anything like picking things up then this tendon may get irritated and sore and that your physiotherapist will be able to find fairly easily a very sore spot on the lateral epicondyle of your elbow.
Next blog post will look in more detail at the physiology of what happens when the tendon gets injured in tennis elbow and hopefully manage to summarise and simplify decades of research on tendinopathies.
Abate M., Gravare-Silbernagel K., Siljeholm C., Di Iorio A., De Amicis D., Salini V., Werner S., Paganelli R. (2009) Pathogenesis of tendinopathies: inflammation or degeneration? Arthritis Research and Therapy 11 (3): 235
Jozsa, L., and Kannus, P., Human Tendons: Anatomy, Physiology, and Pathology. Human Kinetics: Champaign, IL, 1997
Wang J., Jia F., Yang G., Yang S., Campbell B., Stone D., Woo S., (2003) Cyclic Mechanical Stretching of Human Tendon Fibroblasts Increases the Production of Prostaglandin E2 and Levels of Cyclooxygenase Expression: A Novel In Vitro Model Study Connective Tissue Research 44: 128 – 133
Welcome back to the new series of articles about physiotherapy and common injuries and pathologies seen by physiotherapists. Last time we took a brief look at one of the most common musculo-skeletal conditions that a physiotherapist will encounter – tennis elbow (also known as lateral epicondylitis, lateral epicondylosis and lateral epicondylalgia). This article will now look at the anatomy of the elbow and the muscles connected to it in detail so that we can have a good idea of what is hurting or being injured in tennis elbow and can maybe start to have an idea of what causes it.
The elbow is an amazing piece of biomechanical design and is comprised of 3 bones – the humerus which is the upper arm bone and two bones in the forearm called the radius and ulna. The radius runs from the elbow to the thumb and the ulna starts at the bony prominence on the back of your elbow (olecranon process) and runs down to the wrist. To make it easy to remember which bone is which, when I was a student I used to repeat “the ulna is underneath the radius”. Simple I know but effective nonetheless when you are a physio student desperately trying to cram in your anatomical knowledge.
Now as we are looking at tennis elbow we are not going to look or worry too much about the actual elbow joint itself except to say that it has two ways of movement – flexion and extension (basically straightening and bending) and pronation and supination (pronation is rotating the hand palm down and supination palm up). It may seem strange that in a condition called tennis elbow we will be ignoring the elbow joint itself but hopefully the reason why will become clear soon.
The key part of the elbow in tennis elbow that we really need to examine is the lateral epicondyle – this is the point where all of the wrist extensors and finger extensors start from and is the point at which pain is felt in tennis elbow, it is also called the common extensor origin (for reasons which will become apparent soon) and is the site of attachment for the common extensor tendon. Pain here is the cardinal sign for tennis elbow that all physiotherapists look for.
Running from the lateral epicondyle and the common extensor origin are all of the muscles that extend the wrist and the fingers – extensor carpi radialis brevis, extensor carpi ulnaris, extensor digitorum, extensor indicis and extensor digiti minimi. Two other muscles have attachments at the lateral epicondyle – supinator and anconeus. All of these muscles merge together here to form what is known as the common extensor tendon which then attaches to the lateral epicondyle. So it is fairly obvious that this common extensor origin is an important point in wrist and finger extension and may well be a likely site of injury that physiotherapists will need to examine.
Before moving on it is worth considering the actions of a couple of these muscles in more detail extensor carpi radialis brevis and extensor carpi ulnaris have an important synergistic role in stabilising the wrist – they both act at the same time in concert with their flexor brothers (flexor carpi ulnaris and flexor carpi radialis) to prevent side to side movement at the wrist (ulnar and radial deviation). The two extensors also act together at the same time you grip an object to hold the wrist in extension a bit and prevent the finger flexors from flexing the wrist. In fact studies have shown that extensor carpi radialis brevis is the tendon most commonly injured in tennis elbow and the most common point that it is injured at is the common extensor tendon.
So hopefully from the above brief anatomy lesson we can now see that any extension or even flexion of the wrist is going to put a large amount of stress through the common extensor tendon and in turn if this tendon receives any injury we are likely to feel pain at the lateral epicondyle – which is where patients with tennis elbow will normally describe to their physiotherapist that they feel pain when they pick things up.
The next article will look at the physiology and some of the reasons why tendons get injured and why tennis elbow can often become chronic and last for a long time.
This will be the first blog post in an upcoming series about physiotherapy and common pathologies or injuries seen by physiotherapists. We will be examining in detail the causes and nature of various pathologies, who they affect, treatment options, self-management and how physiotherapy can help. The first pathology that I would like to deal with is an extremely common but frustrating and painful condition called tennis elbow that as a physiotherapist I encounter regularly in practice.
Tennis elbow has several other more complicated sounding names such as lateral epicondylitis, lateral epicondylosis and lateral epicondylalgia. All of which basically try to describe the fact that the pain people feel is at the outside (lateral) bony bit of the elbow (epicondyle). The pain normally comes on when picking up heavy objects, twisting items such as screwdrivers and can be quite sharp and uncomfortable.
It is one of the most common musculo-skeletal conditions that a physiotherapist will see and affects approximately 3 – 11/1000 patients per annum (Dingenmanse et al 2012). It is thought to occur in 1.4% of the population (Shiri et al 2006), now these do not sound like huge numbers but when you consider the size of the UK population (roughly 60 million) then 1.4% of the whole population is a lot of people! It is 7 – 9 times more common than the next most common elbow injury: golfer’s elbow (medial epicondylitis) (Walz et al 2010) and causes prolonged time off work especially in chronic sufferers (Walker-Bone et al 2012). Numerous studies have shown that it is associated with handling tools and repetitive twisting and lifting actions of the forearm (Van Rijn et al 2009) basically meaning that if you are an electrician, carpenter, manual labourer or a housewife then you are at an increased risk of developing the condition.
So… what causes it? Well that is a common question for physiotherapists and seemingly a simple question. Unfortunately it is a complicated answer and will need us to look in some detail at both the anatomy of the elbow and physiology of tendons. Which will be covered in the next blog post.
Dingenmanse R., Randsdorp M., Koes B., Huisstede B. (2012) Evidence for the effectiveness of electrophysical modalities for treatment of medial and lateral epicondylitis: a systematic review British Journal of Sports Medicine Published Online
Shiri R., Viikari-Juntura E., Varonen H., Heliovaara M. (2006) Prevalence and determinants of lateral and medial epicondylitis: a population study. American Journal of Epidemiology 164 (11): 1065 – 1074
Van Rijn R., Huisstede B., Koes B., Burdorf A. (2009) Associations between work-related factors and specific disorders at the elbow: a systematic literature review Rheumatology 48: 528 – 536
Walker-Bone K., Palmer K., Reading I., Coggon D., Cooper C. (2012) Occupation and epicondylitis: a population-based study. Rheumatology (Oxford) 51 (2): 305 – 310
Walz D., Newman J., Konin G., Ross G. (2010) Epicondylitis: Pathogenesis,
Imaging, and Treatment Radiographics 30 (1): 167 – 185