7 Common Causes of Finger Numbness and What They Mean
Finger numbness can be your body’s way of telling you that something is not quite well in certain structures or body systems. From pinched nerves to nutritional deficiencies, a myriad of disorders or diseases can cause numbness as one of the key symptoms. Knowing how numbness relates to these factors can be crucial, particularly when it comes to early detection and timely intervention. Now let’s go ahead and take a look at 7 key causes of finger numbness.
1. Nerve impingement/entrapment Syndromes
Your nerves are these tiny sensitive structures, which transmit signals between different body parts and the central nervous system. The nerves in your hands and fingers help with feeling/sensing the world around you, and transmitting the information to the spinal cord and Brain through nerve signals. When these nerves are damaged or compressed anywhere along their length, their ability to transmit these signals is compromised. This causes partial or complete loss of sensation in the hands and fingers; something we call numbness. Common nerve entrapment syndromes include:
Carpal tunnel syndrome
This involves compression of the median nerve in the wrist area. This nerve is responsible for activating a number of muscles in the hand and providing sensation in several areas i.e thumb, index, middle fingers.
It can be irritated or compressed by swelling or mechanical stress in the wrist area, and the result is weakness and numbness in the thumb, index, and middle fingers.
Guyon’s Canal Syndrome
This involves compression of the Ulnar Nerve and artery, which pass the wrist through a little tunnel on the pinky side. It’s one of the leading causes of little finger numbness as the nerve supplies sensation to the pinky and ring fingers. Repetitive stress or compression in this area can cause pain and numbness in these fingers. The condition is common in cyclists, construction workers and other professions which involve repetitive loading and bending of the hand and wrist.
Cubital Tunnel Syndrome
This involves compression of the Ulnar Nerve on the inner side of the Elbow joint. The symptoms are similar to Guyon’s Syndrome.
However, the numbness and pain typically radiates from the elbow area moving along the forearm and into the hand. Sounds familiar? check out our dedicated article on Ulnar Nerve entrapment syndrome here.
Entrapment syndromes in the chest, shoulder and neck region
As mentioned earlier, nerves supplying the hand and fingers come from the neck/cervical spine. They pass through the shoulder areas as a network of nerves known as the Brachial Plexus, before descending into the arm and hand.
Structural problems in the shoulder and neck areas may end up compressing these nerves, causing numbness and other symptoms. Good examples include Disc herniations, where intervertebral discs in the neck region bulge and compress the roots of these nerves, causing numbness and pain along their course.
2. Circulatory problems
Poor blood supply to all or some of the fingers causes reduced Oxygen supply. This causes some structures, including sensory nerves to malfunction, which leads to numbness.
Something called Raynold’s phenomenon, which is one of the key causes of finger tip numbness, provides a good example. Lower temperatures and stress may cause narrowing of blood vessels in the fingers and toes, eventually reducing their blood and Oxygen supply. Deprived sensory nerves start to malfunction, causing numbness.
3. Diabetes
This is a condition where your blood sugar concentrations are consistently higher than the normal limit. More specifically, 126 milligrams per decilitre of blood or higher. There are two types:
Type 1: Marked by the body’s inability to produce Insulin; a hormone that helps with absorbing blood sugar(Glucose) into body cells where it’s either stored or used for energy.
Type 2: The most common form, marked by something called “Insulin resistance”, where the body struggles to use Insulin efficiently, causing high blood sugar.
High Blood Sugar causes damage to small blood vessels, depriving Oxygen supply to nerves. This eventually causes nerve damage, which translates to numbness and loss of sensation.
4. Nutritional Deficiencies
Just like any other body component, nerve cells need a variety of nutrients to survive and stay healthy. Key nutrients for nerve health include:
Vitamin B12: Plays a key role in maintaining a crucial component of nerve cells known as Myelin Sheath, which is responsible for efficient propagation of nerve signals.
Vitamin B6: Vital for production of special chemicals known as neurotransmitters, which help with propagating nerve signals between cells.
Vitamin B1: Plays a crucial role in the production of energy within nerve cells, and protection against harmful substances.
Copper: Helps with production of neurotransmitters and protection of nerve cells.
Any significant deficiencies in these nutrients reduces their ability to transmit nerve signals, causing numbness and other related symptoms.
5. Neurological Disorders
A good number of neurological disorders often start with numbness and weakness in lower(distal) parts of limbs, especially fingers and toes. Good examples include:
Demyelinating Disorders: Disorders which involve destruction of the Myelin Sheath i.e Multiple Sclerosis, Guillain Barre Syndrome.
Ischemic Disorders: Involves death of nerve cells due to compromised blood supply in the central nervous system i.e Stroke, Spinal Cord Infarction.
Alcoholic Neuropathy: Too much alcohol consumption may trigger a series of processes which cause structural damage to nerve cells.
6. Poor Posture and repetitive stress
Maintaining postures which subject nerves or blood vessels to sustained compression or tension can cause transient or long term numbness.
For instance, leaning on your elbow for too long causes sustained pressure in a little groove where your Ulnar nerve passes at the back of your elbow, causing numbness along your forearm and hand. Sports or activities which involve repetitive wrist movements can cause tension in your median nerve, leading to irritation and numbness along the areas it supplies in the hand.
7. Direct Trauma
Probably the most obvious cause. Any significant direct trauma to key nerves or blood vessels supplying the wrist and hand can cause numbness.
Symptoms can set in immediately or minutes/hours after the impact depending on the severity of the injury. Good examples include falling on an outstretched arm, or a direct hit to a nerve and surrounding structures with a blunt object.
When to See a Physiotherapist
Some forms of numbness can easily be dealt with at home i.e abandoning postures which put undue pressure on the implicated nerves. However, some forms need professional intervention. Here are some key signs to look out for:
Persistent numbness: This can be constant or intermittent episodes which hang on for days without a clear cause.
Additional sensory symptoms: Pain, burning sensations, significant or complete loss of sensation.
Weakness: Weak hand grip.
Additional body symptoms: Fever, fatigue, headaches.
Numbness is a product of compromised sensation due to structural or functional compromise to sensory nerves. Just like most body parts, finger numbness can be a sign of a wide range of issues, from direct trauma to systemic medical conditions like Diabetes. Early identification of the primary cause goes a long way when it comes to timely intervention.
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