Do you ever experience radiating pain in your arm? It may be because of the entrapment of one of the three main nerves (radial nerve, median nerve, and ulnar nerve). Here, we are going to talk about pronator teres syndrome which is caused by entrapment of the median nerve.
In the median nerve, there are three possibilities for its entrapment.
- Entrapment of the median nerve at the wrist, causing carpal tunnel syndrome
- Entrapment of the median nerve at the forearm, causing anterior interosseous nerve syndrome
- And finally, entrapment at the elbow causes pronator teres syndrome
Pronator teres syndrome
It is also known as ape hand deformity or pronator syndrome.
It is a group of symptoms caused by the entrapment of the median nerve at the elbow.
Common entrapment sites include bicipital aponeurosis, ligament of Struthers, pronator teres (called pronator syndrome), fibrous arch of flexor digitorum superficialis (anterior interosseous syndrome).
Symptoms are seen in the distribution of the median nerve in the hand.
In the case of entrapment, the nerve is compressed which causes ischemic damage to the nerve.
It is four times more common in women.
Median nerve
The median nerve is one of the main nerves which plays a role in controlling the movements of the thumb which is crucial in the process of gripping by the hand.
It controls all the coarse movements of the hand as it supplies most of the main/long muscles of the front of the forearm, that’s why also known as the laborer’s nerve.
The median nerve lies medial to the brachial artery and then enters the cubital fossa. You can consider the median nerve the most medial content of the cubital fossa. After entering into the forearm, it likes between flexor digitorum superficialis and flexor digitorum profundus.
Then finally it reaches down to the region of the wrist where the median nerve lies deep and lateral to the palmaris longus tendon. Lastly, it passes deep into the flexor retinaculum through the carpal tunnel to enter the palm.
What causes pronator teres syndrome?
There are many causes for this entrapment of the nerve, most often idiopathic.
- There may be tumors
- The patient may have an accident that causes the elbow dislocation
- There may be structural abnormalities of the humerus
- One of the main causes is the occupation of the patient that requires repetitiv3e motion, repetitive stress, and sustained position of elbow and forearm.
- The patient may have direct trauma to the elbow.
- He may have impaired circulation in peripheral nerves, as seen in diabetes, etc.
- It is caused by the excessive development of the pronator teres muscle, which eventually causes the entrapment of the median nerve.
What are the signs and symptoms of pronator teres syndrome?
- Pain complaints include numbness (most common), tingling, and burning sensation.
- A patient can feel the pain in the area of the distribution of the median nerve in the hand, particularly the palm of the hand over the thenar eminence.
- The patient can feel the pain at the proximal volar forearm exacerbated by the repetitive forearm rotation or elbow motion.
- It is also known as ape hand deformity
- Tenderness to percussion or deep pressure over the pronator teres, proximal FDS.
- Sensory loss may follow early symptoms of pain.
Functional implications
- A patient can experience pain with wrist movements
- You may find difficulty with grasping and manipulation activities
- Dropping items from the hand
- There is impairment in the sensation
- Loss of strength in advance cases
Differential diagnosis
- Cervical radiculopathy
- Thoracic outlet syndrome
- Carpel tunnel syndrome
- Traumatic nerve lesion
- Anterior interosseous syndrome
- Rheumatoid or other arthritis
Findings and interpretation
Muscle weakness of
- Pronator teres
- Palmaris longus
- The Flexor digitorum superficialis
- Flexor pollicis longus
- The Flexor digitorum profundus
- Flexor carpi radiallis
You may find sensory changes in the median nerve distribution of the patient’s hand.
Tests for pronator teres syndrome
Cervical spine compression test
Resisted motion testing at the elbow (forearm pronation with elbow extension, elbow flexion, proximal interphalangeal flexion at the middle finger
Treatment of pronator teres syndrome
Medication
- NSAIDs
- Corticosteroid injection
Physical therapy intervention
Early conservative intervention
- Ergonomics plays a major role in sustaining our daily life. So, we need to do the proper analysis and activity modification to reduce repetitive motion, and positioning stress such as avoiding pronation.
Ergonomics in the workplace and at home
Second stage conservative intervention
- We need to do the immobilization of the elbow with a posterior gutter splint, holding the elbow at 90 degrees and forearm neutral
- Ultrasound therapy
- Median nerve gliding
- Manual therapy – myofascial release
Postsurgical intervention
- Activity modification and protected ROM
- Median nerve gliding
- Scar management and sensory desensitization
- Strengthening
Reference
The Color Atlas of Physical Therapy – Eric Shamus