Anterior interosseous syndrome
Encyclopedia
Anterior interosseous syndrome or Kiloh-Nevin syndrome I is a medical condition in which damage to the anterior interosseous nerve
, a motor branch of the median nerve
, causes pain in the forearm and a characteristic weakness of the pincer movement of the thumb and index finger.
Most cases of Kiloh-Nevin syndrome are due to compression of the nerve as a result of trauma at the elbow, often associated with haemorrhage into the deep musculature.
Surgical decompression is effective at relieving symptoms and preventing ongoing nerve damage.
is a motor branch of the median nerve, which arises just below the elbow. It passes distally in the anterior interosseous membrane and innervates the long flexor muscles of the thumb, index and middle finger.
and elbow pain has been reported as being a primary complaint.
The characteristic impairment of the pincer movement of the thumb and index finger is most striking.
muscle.
If asked to make the “OK” sign, patients will make a triangle sign instead.
This 'Pinch-Test' exposes the weakness of the Flexor pollicis longus muscle and the flexor digitorum profundus I leading to weakness of the flexion of the distal phalanges of the thumb and index finger. This results in impairment of the pincer movement and the patient will have difficulty picking up a small item, such as a coin, from a flat surface.
There is little sensory deficit since the anterior interosseous nerve has no cutaneous branch.
supracondylar fractures, often associated with haemorrhage into the deep musculature;
injury secondary to open reduction of a forearm fracture; or dislocation of the elbow.
Direct trauma from a penetrating injury such as a stab wound is a common cause in less civilised countries.
Fibrous bands or arcuate
ligaments may entrap the median as well as the anterior interosseous nerves, in which case a patient may experience numbness as well as pain.
Rheumatoid disease and gouty arthritis may be a predisposing factor in anterior interosseous nerve entrapment.
Very similar syndromes can be caused by more proximal lesions, such as brachial plexus
neuritis.
Anterior interosseous nerve entrapment or compression injury remains a difficult clinical diagnosis because it is mainly a motor nerve and the syndrome is often mistaken for finger ligamentous injury.
Electromyography
(EMG) is generally most useful and will reveal abnormalities in the flexor pollicis longus, flexor digitorum profundus I and II and pronator quadratus muscles.
The role or MRI and ultrasound imaging in the diagnosis of Kiloh-Nevin syndrome is unclear.
In brachial plexus neuritis, conservative management may be more appropriate.
Spontaneous recovery has been reported, but is said to be delayed and incomplete.
There is a role for physiotherapy and this should be directed specifically towards the pattern of pain and symptoms. Soft tissue massage, stretches and exercises to directly mobilise the nerve tissue may be used.
Anterior interosseous nerve
The anterior interosseous nerve is a branch of the median nerve that supplies the deep muscles on the front of the forearm, except the ulnar half of the flexor digitorum profundus....
, a motor branch of the median nerve
Median nerve
The median nerve is a nerve in humans and other animals. It is in the upper limb. It is one of the five main nerves originating from the brachial plexus....
, causes pain in the forearm and a characteristic weakness of the pincer movement of the thumb and index finger.
Most cases of Kiloh-Nevin syndrome are due to compression of the nerve as a result of trauma at the elbow, often associated with haemorrhage into the deep musculature.
Surgical decompression is effective at relieving symptoms and preventing ongoing nerve damage.
History
The syndrome was first described by Parsonage and Turner in 1948 and further defined as isolated lesion of the anterior interosseous nerve by Leslie Gordon Kiloh and Samuel Nevin in 1952.Anatomy
The anterior interosseous nerveAnterior interosseous nerve
The anterior interosseous nerve is a branch of the median nerve that supplies the deep muscles on the front of the forearm, except the ulnar half of the flexor digitorum profundus....
is a motor branch of the median nerve, which arises just below the elbow. It passes distally in the anterior interosseous membrane and innervates the long flexor muscles of the thumb, index and middle finger.
Symptoms
Most patients experience poorly localised pain in the forearm. The pain is sometimes referred into the cubital fossaCubital fossa
The cubital fossa is the triangular area on the anterior view of the elbow of a human or other hominid animal. It is colloquially known as the "elbow pit".-Boundaries:...
and elbow pain has been reported as being a primary complaint.
The characteristic impairment of the pincer movement of the thumb and index finger is most striking.
Clinical signs
In a pure lesion of the anterior interosseous nerve there may be weakness of the long flexor muscle of the thumb (Flexor pollicis longus), the deep flexor muscles of the index and middle fingers (Flexor digitorum profundus I & II), and the pronator quadratusPronator quadratus
Pronator quadratus is a square shaped muscle on the distal forearm that acts to pronate the hand.As it is on the anterior side of the arm, it is innervated by a branch of the median nerve, the anterior interosseous nerve...
muscle.
If asked to make the “OK” sign, patients will make a triangle sign instead.
This 'Pinch-Test' exposes the weakness of the Flexor pollicis longus muscle and the flexor digitorum profundus I leading to weakness of the flexion of the distal phalanges of the thumb and index finger. This results in impairment of the pincer movement and the patient will have difficulty picking up a small item, such as a coin, from a flat surface.
There is little sensory deficit since the anterior interosseous nerve has no cutaneous branch.
Causes
Injuries of the forearm with compression of the nerve is the most common cause: examples includesupracondylar fractures, often associated with haemorrhage into the deep musculature;
injury secondary to open reduction of a forearm fracture; or dislocation of the elbow.
Direct trauma from a penetrating injury such as a stab wound is a common cause in less civilised countries.
Fibrous bands or arcuate
Arcuate
Arcuate can refer to:* Arcuate delta, a type of river delta* Arcuate fasciculus* Arcuate line * Arcuate artery* Arcuate nucleus* Arcuate nucleus * Internal arcuate fibers of the brain...
ligaments may entrap the median as well as the anterior interosseous nerves, in which case a patient may experience numbness as well as pain.
Rheumatoid disease and gouty arthritis may be a predisposing factor in anterior interosseous nerve entrapment.
Very similar syndromes can be caused by more proximal lesions, such as brachial plexus
Brachial plexus
The 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...
neuritis.
Anterior interosseous nerve entrapment or compression injury remains a difficult clinical diagnosis because it is mainly a motor nerve and the syndrome is often mistaken for finger ligamentous injury.
Diagnosis
Electrophysiologic testing is an essential part of the evaluation of Anterior interosseous nerve syndromes. Nerve conduction studies may be normal or show pronator quadratus latency.Electromyography
Electromyography
Electromyography is a technique for evaluating and recording the electrical activity produced by skeletal muscles. EMG is performed using an instrument called an electromyograph, to produce a record called an electromyogram. An electromyograph detects the electrical potential generated by muscle...
(EMG) is generally most useful and will reveal abnormalities in the flexor pollicis longus, flexor digitorum profundus I and II and pronator quadratus muscles.
The role or MRI and ultrasound imaging in the diagnosis of Kiloh-Nevin syndrome is unclear.
Treatment
Surgical decompression can give excellent results if the clinical picture and the EMG suggest a compression neuropathy.In brachial plexus neuritis, conservative management may be more appropriate.
Spontaneous recovery has been reported, but is said to be delayed and incomplete.
There is a role for physiotherapy and this should be directed specifically towards the pattern of pain and symptoms. Soft tissue massage, stretches and exercises to directly mobilise the nerve tissue may be used.