Ulnar nerve entrapment
Encyclopedia
Ulnar nerve entrapment is a condition where the ulnar nerve
becomes trapped or pinched due to some physiological abnormalities.
, sometimes called Guyon's tunnel syndrome, is a common nerve compression affecting the ulnar nerve as it passes through a tunnel in the wrist called Guyon's canal
. This problem is similar to carpal tunnel syndrome but involves a completely different nerve. Symptoms include a feeling of pins and needles in the ring and little fingers, and may progress to a burning pain in the wrist and hand followed by decreased sensation in the ring and little fingers. One common cause of this syndrome is from pressure of bicycle handlebars seen with avid cyclists. Another is from hard, repetitive compression against a desk surface while using a computer mouse.
, the outer edge of the elbow. This compression of the nerve often leads to a tingling or 'pins and needles' sensation in the little and ring fingers. Most cases will be minor and tend to come and go with time. Common causes are sleeping with the arm folded up, so the hand is at the person's neck and the elbow is sharply bent. These people frequently wake up with tingling in the fingers, because the nerve has been pinched or squeezed while asleep. Treatment of these types of causes are easy to remedy and can involve simply altering sleeping positions to avoid aggravating the elbow area. In more extreme cases however where tingling is persistent, surgery is an option to move the nerve away from the area.
Although the nerve can be entrapped in several places near the elbow, the cubital tunnel is the most common.
Compression at the elbow, known as cubital tunnel syndrome, causes numbness in the small finger (also known as the "pinky"), along the half (lengthwise) of the ring finger closest to the small finger, and the back half of the hand over the small finger. Initially, the numbness is transient and usually occurs in the middle of the night or in the morning. The sensation is similar to hitting one's "funny bone," but lasts a bit longer. Over time, the numbness is there all of the time, and weakness of the hand sets in. The "ulnar claw
," or a position where the small and ring fingers curl up, occurs late in the disease and is a sign the nerve is severely affected.
The claw hand is worse for Guyon canal stenosis, or nerve compression at the wrist. This is an example of the ulnar paradox
. Also, if the nerve is compressed at the wrist, the back of the hand will have normal sensation.
innervates the fourth and fifth fingers, and symptoms such as numbness, weakness, and tingling appear there. The ulnar nerve also innervates the intrinsic muscles of the hand, which on paralysis lead to a characteristic clumsiness in ulnar nerve palsy. Clinical tests, like card test, Froment sign, can be easily performed for assessment of ulnar nerve. However, a complete diagnosis should identify the source of the impingement, and further testing may be necessary to determine which of many possible underlying causes is relevant.
, which is characterized by numbness in the thumb, index, middle, and half of the ring finger. Compression of the radial nerve
causes numbness of the back of the hand and thumb, and is much more rare.
The difference between the ulnar lesion and a median lesion is that in the median nerve lesion the index and middle finger cannot be flexed when the patient is told to make a fist. However, in the ulnar nerve lesion the pinky and ring finger cannot be unflexed if the patient is told to extend fingers.
Some people are affected by multiple nerve compressions, which can complicate diagnosis.
Initial conservative therapy includes identifying positions and activities that aggravate symptoms and stopping them. For example, if the person experiences symptoms when holding a telephone up to the head, then the use of a telephone headset will provide immediate symptomatic relief and reduce the likelihood of further damage and inflammation to the nerve.
Physical therapy
, occupational therapy
and osteopathy
often provide relief. Surgery may be required for some causes, such as thoracic outlet syndrome
.
are at higher risk for any kind of peripheral neuropathy
, including ulnar nerve entrapments.
Cubital tunnel syndrome is more common in people who spend long periods of time with their elbows bent, such as when holding a telephone to the head. Flexing the elbow while the arm is pressed against a hard surface, such as leaning against the edge of a table, is a significant risk factor. The use of vibrating tools at work or other causes of repetitive activities increase the risk, including throwing a baseball.
Damage to or deformity of the elbow joint increases the risk of cubital tunnel syndrome. Additionally, people who have other nerve entrapments elsewhere in the arm and shoulder are at higher risk for ulnar nerve entrapment.
Ulnar nerve
In human anatomy, the ulnar nerve is a nerve which runs near the ulna bone. The ulnar collateral ligament of elbow joint is in relation with the ulnar nerve. The nerve is the largest unprotected nerve in the human body , so injury is common...
becomes trapped or pinched due to some physiological abnormalities.
Classification
The ulnar nerve passes through many tunnels and outlets which could cause the nerve to be compressed or "pinched". Entrapments are classified according to the location of the compressed. Some causes or origins noted could be:- Problems originating at the neck (thoracic outlet syndromeThoracic outlet syndromeThoracic outlet syndrome is a syndrome involving compression at the superior thoracic outlet involving compression of a neurovascular bundle passing between the anterior scalene and middle scalene...
, disease of the cervical spine) - Brachial plexusBrachial plexusThe brachial plexus is a network of nerve fibers, running from the spine, formed by the ventral rami of the lower four cervical and first thoracic nerve roots...
abnormalities - ElbowElbowThe human elbow is the region surrounding the elbow-joint—the ginglymus or hinge joint in the middle of the arm. Three bones form the elbow joint: the humerus of the upper arm, and the paired radius and ulna of the forearm....
abnormalities (fractures, growth plate injuries, cubital tunnelCubital tunnelThe cubital tunnel is a channel which allows the Ulnar nerve to travel over the elbow.Chronic compression of this nerve is known as Cubital Tunnel Syndrome, a form of Repetitive Strain Injury akin to Carpal Tunnel Syndrome .-See also:* Ulnar nerve...
problems, improper use) - WristWristIn human anatomy, the wrist is variously defined as 1) the carpus or carpal bones, the complex of eight bones forming the proximal skeletal segment of the hand;...
abnormalities (fractures, Guyon canal problems) - Artery aneurysms or thrombosisThrombosisThrombosis is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel is injured, the body uses platelets and fibrin to form a blood clot to prevent blood loss...
- InfectionInfectionAn infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...
s, tumorTumorA tumor or tumour is commonly used as a synonym for a neoplasm that appears enlarged in size. Tumor is not synonymous with cancer...
s, diabetes, hypothyroidismHypothyroidismHypothyroidism is a condition in which the thyroid gland does not make enough thyroid hormone.Iodine deficiency is the most common cause of hypothyroidism worldwide but it can be caused by other causes such as several conditions of the thyroid gland or, less commonly, the pituitary gland or...
, rheumatismRheumatismRheumatism or rheumatic disorder is a non-specific term for medical problems affecting the joints and connective tissue. The study of, and therapeutic interventions in, such disorders is called rheumatology.-Terminology:...
, and alcoholismAlcoholismAlcoholism is a broad term for problems with alcohol, and is generally used to mean compulsive and uncontrolled consumption of alcoholic beverages, usually to the detriment of the drinker's health, personal relationships, and social standing...
Guyon's canal syndrome
Guyon's canal syndromeGuyon's canal syndrome
Guyon's canal syndrome, sometimes referred to as Handlebar palsy, is caused by entrapment of the ulnar nerve in the Guyon canal as it passes through the wrist....
, sometimes called Guyon's tunnel syndrome, is a common nerve compression affecting the ulnar nerve as it passes through a tunnel in the wrist called Guyon's canal
Ulnar canal
The ulnar canal or ulnar tunnel, also called Guyon's canal, is a space at the wrist between the pisiform bone and the hamate bone through which the ulnar artery and the ulnar nerve travel into the hand.-Eponym:...
. This problem is similar to carpal tunnel syndrome but involves a completely different nerve. Symptoms include a feeling of pins and needles in the ring and little fingers, and may progress to a burning pain in the wrist and hand followed by decreased sensation in the ring and little fingers. One common cause of this syndrome is from pressure of bicycle handlebars seen with avid cyclists. Another is from hard, repetitive compression against a desk surface while using a computer mouse.
Cubital tunnel syndrome
Cubital tunnel syndrome occurs when the ulnar nerve is obstructed during its path along the cubital tunnelCubital tunnel
The cubital tunnel is a channel which allows the Ulnar nerve to travel over the elbow.Chronic compression of this nerve is known as Cubital Tunnel Syndrome, a form of Repetitive Strain Injury akin to Carpal Tunnel Syndrome .-See also:* Ulnar nerve...
, the outer edge of the elbow. This compression of the nerve often leads to a tingling or 'pins and needles' sensation in the little and ring fingers. Most cases will be minor and tend to come and go with time. Common causes are sleeping with the arm folded up, so the hand is at the person's neck and the elbow is sharply bent. These people frequently wake up with tingling in the fingers, because the nerve has been pinched or squeezed while asleep. Treatment of these types of causes are easy to remedy and can involve simply altering sleeping positions to avoid aggravating the elbow area. In more extreme cases however where tingling is persistent, surgery is an option to move the nerve away from the area.
Although the nerve can be entrapped in several places near the elbow, the cubital tunnel is the most common.
Optional diagnoses
Entrapment of the ulnar nerve is most likely caused by extended pressure of the elbow on a hard surface repeatedly over a period of time. For example, the resting of the elbows on the arms of a chair while typing at a work station. This condition is also known as drivers elbow, often time caused by resting or bracing the elbow on the arm rest of vehicles over extended periods of time.Signs and symptoms
The symptoms of ulnar nerve entrapment depend on where the nerve is being compressed.Compression at the elbow, known as cubital tunnel syndrome, causes numbness in the small finger (also known as the "pinky"), along the half (lengthwise) of the ring finger closest to the small finger, and the back half of the hand over the small finger. Initially, the numbness is transient and usually occurs in the middle of the night or in the morning. The sensation is similar to hitting one's "funny bone," but lasts a bit longer. Over time, the numbness is there all of the time, and weakness of the hand sets in. The "ulnar claw
Ulnar claw
A hand imitating an ulnar claw created by distal ulnar lesion or papal hand of a proximal median nerve lesion. The metacarpophalangeal joints of the 4th and 5th fingers are extended and the Interphalangeal joints of the same fingers are flexed....
," or a position where the small and ring fingers curl up, occurs late in the disease and is a sign the nerve is severely affected.
The claw hand is worse for Guyon canal stenosis, or nerve compression at the wrist. This is an example of the ulnar paradox
Ulnar claw
A hand imitating an ulnar claw created by distal ulnar lesion or papal hand of a proximal median nerve lesion. The metacarpophalangeal joints of the 4th and 5th fingers are extended and the Interphalangeal joints of the same fingers are flexed....
. Also, if the nerve is compressed at the wrist, the back of the hand will have normal sensation.
Diagnosis
Identifying which of the three hand nerves is impinged is usually quite simple. The ulnar nerveUlnar nerve
In human anatomy, the ulnar nerve is a nerve which runs near the ulna bone. The ulnar collateral ligament of elbow joint is in relation with the ulnar nerve. The nerve is the largest unprotected nerve in the human body , so injury is common...
innervates the fourth and fifth fingers, and symptoms such as numbness, weakness, and tingling appear there. The ulnar nerve also innervates the intrinsic muscles of the hand, which on paralysis lead to a characteristic clumsiness in ulnar nerve palsy. Clinical tests, like card test, Froment sign, can be easily performed for assessment of ulnar nerve. However, a complete diagnosis should identify the source of the impingement, and further testing may be necessary to determine which of many possible underlying causes is relevant.
Differential diagnoses
Entrapment of the median nerve causes carpal tunnel syndromeCarpal tunnel syndrome
Carpal Tunnel Syndrome is an entrapment idiopathic median neuropathy, causing paresthesia, pain, and other symptoms in the distribution of the median nerve due to its compression at the wrist in the carpal tunnel. The pathophysiology is not completely understood but can be considered compression...
, which is characterized by numbness in the thumb, index, middle, and half of the ring finger. Compression of the radial nerve
Radial nerve
The radial nerve is a nerve in the human body that supplies the upper limb. It supplies the medial and lateral heads of the triceps brachii muscle of the arm, as well as all 12 muscles in the posterior osteofascial compartment of the forearm and the associated joints and overlying skin.It...
causes numbness of the back of the hand and thumb, and is much more rare.
The difference between the ulnar lesion and a median lesion is that in the median nerve lesion the index and middle finger cannot be flexed when the patient is told to make a fist. However, in the ulnar nerve lesion the pinky and ring finger cannot be unflexed if the patient is told to extend fingers.
Some people are affected by multiple nerve compressions, which can complicate diagnosis.
Prevention
Cubital tunnel syndrome may be prevented or reduced by maintaining good posture and proper use of the elbow and arms, such as sleeping with the arm straight at the elbow instead of keeping it tightly bent. A recent example of this is popularization of the concept of cell phone elbow.Treatment
Effective treatment generally requires resolving the underlying cause.Initial conservative therapy includes identifying positions and activities that aggravate symptoms and stopping them. For example, if the person experiences symptoms when holding a telephone up to the head, then the use of a telephone headset will provide immediate symptomatic relief and reduce the likelihood of further damage and inflammation to the nerve.
Physical therapy
Physical therapy
Physical therapy , often abbreviated PT, is a health care profession. Physical therapy is concerned with identifying and maximizing quality of life and movement potential within the spheres of promotion, prevention, diagnosis, treatment/intervention,and rehabilitation...
, occupational therapy
Occupational therapy
Occupational therapy is a discipline that aims to promote health by enabling people to perform meaningful and purposeful activities. Occupational therapists work with individuals who suffer from a mentally, physically, developmentally, and/or emotionally disabling condition by utilizing treatments...
and osteopathy
Osteopathy
Osteopathy and osteopathic medicine are often used interchangeably for the philosophy and system of alternative medical practice first proposed by A. T. Still MD, DO in 1874....
often provide relief. Surgery may be required for some causes, such as thoracic outlet syndrome
Thoracic outlet syndrome
Thoracic outlet syndrome is a syndrome involving compression at the superior thoracic outlet involving compression of a neurovascular bundle passing between the anterior scalene and middle scalene...
.
Epidemiology
People with diabetes mellitusDiabetes mellitus
Diabetes mellitus, often simply referred to as diabetes, is a group of metabolic diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced...
are at higher risk for any kind of peripheral neuropathy
Peripheral neuropathy
Peripheral neuropathy is the term for damage to nerves of the peripheral nervous system, which may be caused either by diseases of or trauma to the nerve or the side-effects of systemic illness....
, including ulnar nerve entrapments.
Cubital tunnel syndrome is more common in people who spend long periods of time with their elbows bent, such as when holding a telephone to the head. Flexing the elbow while the arm is pressed against a hard surface, such as leaning against the edge of a table, is a significant risk factor. The use of vibrating tools at work or other causes of repetitive activities increase the risk, including throwing a baseball.
Damage to or deformity of the elbow joint increases the risk of cubital tunnel syndrome. Additionally, people who have other nerve entrapments elsewhere in the arm and shoulder are at higher risk for ulnar nerve entrapment.