Home / Conditions Treated / Elbow and Forearm / Pronator Syndrome
ELBOW

Anatomy

The elbow and forearm form a functional unit whose primary role is to accurately position the hand in space. view 

Elbow Contusion

An elbow contusion results from blunt direct trauma and produces muscle strains and ligament sprains. view 

Ligament Tears and Elbow Fractures

Fractures about the elbow are the result of high energy injuries. view 

Forearm Compartment Syndrome

Compartment syndrome in all extremities is an orthopedic emergency. view

Elbow/Forearm Wounds/Amputations

Wounds occurring in the forearm and elbow must be treated as an emergency because the risk of infection if left open increases about 7 hours after an injury has occurred. view

Elbow Arthritis

Arthritis in the elbow can occur after an injury (post-traumatic arthritis), congenital lack of blood supply to the bone causing flaking off of the cartilage called Osteochondritis Dessicans. view

Cubital Tunnel Syndrome

Cubital tunnel syndrome is the compression of the ulnar nerve at the level of the elbow. view

Pronator Syndrome

Pronator syndrome is the compression of the median nerve around the elbow and palmar side of the forearm. Because it is the same nerve that causes carpal tunnel syndrome, there is overlap in the symptoms making the diagnosis difficult, at times. view

RTS & PIN Palsy

Radial tunnel syndrome and posterior Interosseous Nerve palsy are both a result of compression of the Posterior interosseous nerve with a more severe compression occurring in posterior interosseous nerve palsy. view

Lateral Epicondylitis, Medial epicondylitis, Distal Biceps Tendon Rupture

Lateral epicondyltis also called tennis elbow and medial epicondylitis called golfers elbow is a condition affecting the forearm muscles’ on the humeral bone at the elbow called the lateral and medial epicondylitis respectively. view

Elbow Stiffness

The cause of a stiff elbow is either at the bony level or the collagen capsule/ligament level or both. view

Elbow and Forearm Infections

The elbow, like the shoulder is well perfused with ample blood supply allowing for circulating white blood cells to offer excellent protection against infection and, consequently an elbow infection is uncommon. view

Elbow Tumors

Tumors are divided into benign and malignant types. A benign tumor is an abnormal growth of a particular cell type presenting as a mass. view

PRONATOR SYNDROME

Pathology

Pronator syndrome is the compression of the median nerve around the elbow and palmar side of the forearm.

The median nerve is one of the five nerves arising from the brachial plexus and traveling down the arm to innervate the forearm and hand muscles.

Responsibilities of the Median Nerve

  • Most of the flexor mass muscles
  • The muscles on the palmar side of the thumb
  • Sensations of the thumb, index, long and thumb side of the ring finger

When the median nerve is compressed, the sensation of these 3 ½ fingers is progressively lost and the muscle girth of the forearm muscles decrease due to muscle atrophy.

Depending on where the compression occurs will depend upon whether the sensation and muscle strength is affected.

Four Sites of Median Nerve Compression

  1. A bony or cartilaginous spur called a supracondylar process. The spur creates a tunnel above and inside the elbow with a restricted diameter. This causes both sensory and motor deficits in the forearm and hand.
  2. The pronator muscle, for which this syndrome is named. The median nerve travels under this muscle as it leaves the elbow. Fascial bands in the pronator muscle can constrict the median nerve. This constriction will produce similar symptoms as in the compression produced by the supracondylar process.
  3. The bicipitalaponneurosis, a normal fascial band on the volar side of the elbow. The biceps tendon contributes some fibers to thisanother structure the median nerve travels under and on rare occasions can compress the median nerve producing similar sensory and motor symptoms.
  4. As the median nerve travels down the arm, it will divide into the anterior interosseous nerve (AIN) and the remainder of the median nerve travels down the arm to innervate the hand. As the AIN splits from the median nerve proper, it travels under a fibrous arch of the muscles called the flexor digitorum superficialis (FDS) arch which is the fourth area of median compression in pronator syndrome. Since the AIN is mostly a motor nerve to the forearm muscles, the forearm muscles atrophy and develop weakness resulting in difficulty bending the last joint of the thumb and index finger without affecting sensation to the hand.

The physical exam and EMG/NCS nerve study are the only two studies necessary to make a diagnosis. Many patients with pronator syndrome have a false negative nerve conduction study and the experience of the surgeon will dictate if surgery will be required.

The median nerve also causes carpal tunnel syndrome, resulting in an overlap of symptoms. This can make diagnosing Pronator syndrome difficult.

Pronator syndrome can also present as a dynamic condition that only occurs with repetitive forearm activities involving wrist flexion, extension and forearm rotation.

 

Treatment

Pronator syndrome is initially treated conservatively.

Initial Treatment

  • Elimination of the offending repetitive activity
  • Therapy
  • Anti-inflammatory medication
  • A resting wrist splint

If these measures fail, or if the forearm and the arm atrophy (loss of muscle girth in the forearm and thumb) is severe or progressive, surgery is the best option.

Surgery for pronator syndrome, like carpal tunnel surgery, is done to release the offending structures.

The presence of a supracondylar process (bony spur on the inside of the arm bone) is rare. When a supracondylar process is present, the incision must be above the elbow.

However, the majority of cases of pronator syndrome are the result of pronator muscle compression, FDS sheath edge effect or the bicipital aponeurosis. These anatomically tight areas are all released though a small single forearm incision.

After surgery, a soft dressing is applied and motion exercises are begun immediately. Full recovery is expected within one month after surgery if severe muscle atrophy is not present.