Sciatica is one of the most common nerve problems I see, and also one of the most misunderstood. Most people know it as pain travelling down the back of the leg – but a surprising number of people experience pain down the front of the thigh or leg and are unsure whether it can really be sciatica at all. In this article I will explain why sciatica happens, and why it does not always follow the path people expect.
Sciatica is a nerve type pain caused by irritation or compression of one of the spinal nerves in the lower back. It is often described as sharp, burning or shooting, and may come with pins and needles, numbness or weakness in the leg or foot. The pain follows the path of the affected nerve, which is why it can travel from the lower back all the way down towards the foot.
The most common causes are a protruding or herniated disc pressing on a nerve, general wear and tear changes that narrow the space around the nerve, or narrowing of the spinal canal known as spinal stenosis.
The sciatic nerve, and the nerve roots that feed into it, supply much of the back of the leg. When one of these nerves is irritated, the pain is felt along the area that nerve serves – which, for the most commonly affected nerves, is the back of the thigh and calf. This is the classic pattern most people recognise as sciatica.
Here is the part that surprises people. Different nerves leaving the spine supply different areas of the leg. While the most commonly affected nerves serve the back of the leg, others supply the front of the thigh and the shin. If one of these nerves is the one being irritated, the pain is felt at the front rather than the back.
So pain down the front of the leg can absolutely still be coming from an irritated nerve in the spine. It does not fit the picture most people have of sciatica, which is why it often causes worry – but the underlying mechanism is the same. The location of the pain is simply a clue to which particular nerve is involved, and this is one of the reasons a careful examination is so valuable.
The reassuring news is that, wherever it is felt, sciatica is self-limiting in the majority of cases – it tends to settle on its own over a period of weeks to a few months. Initial treatment is usually conservative: staying as active as comfort allows, appropriate pain relief, and physiotherapy. Where pain is severe or slow to settle, a targeted nerve root injection can help, and surgery to relieve the pressure on the nerve is considered only where symptoms are severe, where there is significant weakness, or where the pain has not responded over a reasonable period.
If your leg pain is severe, is not improving after several weeks, or comes with weakness in the leg or foot, it is worth seeking a specialist opinion – and you should seek urgent attention if you develop any difficulty controlling your bladder or bowels. As a Consultant Neurosurgeon in Cambridge, I can assess the cause of your leg pain, wherever it is felt, and explain the most appropriate treatment for you.
