GENERAL INFORMATION
The Flexor Pollicis Longus is a deep muscle located in the anterior compartment of the forearm. It is primarily responsible for flexing the thumb and plays an important role in thumb movements and grip strength.
ORIGIN
This muscle originates from two points:
- The anterior surface of the radius (one of the two forearm bones) near the interosseous border.
- The interosseous membrane is a fibrous membrane between the radius and ulna.
INSERTION POINT
It inserts onto the base of the distal phalanx of the thumb.
MAJOR ARTERIES
The Flexor Pollicis Longus muscle receives its blood supply from branches of the ulnar artery and radial artery.
NEURAL INNERVATION
This muscle is innervated by the anterior interosseous branch of the median nerve, which originates from the brachial plexus.
TRIGGER POINT
Trigger points in the Flexor Pollicis Longus muscle may cause pain or discomfort in the forearm and thumb.
CONCENTRIC FUNCTION
The concentric function of this muscle involves the contraction of its muscle fibres, resulting in flexion of the thumb. This action allows for gripping, grasping, and thumb opposition movements.
ECCENTRIC FUNCTION
The eccentric function of the Flexor Pollicis Longus muscle occurs when the muscle fibres lengthen under tension. This process aids in controlling the extension of the thumb during thumb extension movements.
ISOMETRIC FUNCTION
The isometric function of this muscle involves contracting and generating tension without changing its length. This function helps stabilise the thumb during activities that require a static hold or resistance.
RELATED MUSCLE SCIENTIFIC NAMES
There are no directly related muscle scientific names to list under this category for the Flexor Pollicis Longus.
ANTAGONIST MUSCLES
- Extensor Pollicis Longus: Extends the thumb and assists in thumb abduction, countering the flexion provided by the Flexor Pollicis Longus.
- Extensor Pollicis Brevis: Extends the thumb and assists in wrist abduction, opposing the Flexor Pollicis Longus.
COMMON INJURIES
- Flexor Tendon Strain: Overuse or excessive loading of this muscle, leading to strain or tendon damage, causing pain and limited thumb movement.
- Tendonitis: Inflammation or irritation of the Flexor Pollicis Longus tendon, commonly occurring at its insertion point or along the course of the tendon, resulting in pain and swelling.
EXERCISES
- Thumb curls with resistance bands or weights: Hold a resistance band or weight and curl the thumb towards the palm, targeting the Flexor Pollicis Longus. Enhances thumb flexion strength.
- Grip strengthening exercises with thumb emphasis: Squeeze a grip strengthener, focusing on the thumb to improve overall grip strength and thumb flexor muscles.
- Thumb opposition exercises: Touch the thumb to each fingertip, resisting a small object, strengthening the thumb’s flexors and improving agility.
- Wrist flexion exercises with added thumb flexion: Perform wrist curls while flexing the thumb simultaneously, engaging both the wrist and thumb flexor muscles.
- Thumb adduction and abduction exercises: Use resistance bands to move the thumb towards and away from the hand, enhancing thumb coordination and strength.
STRETCHES
- Thumb and hand stretches: Spread the fingers and thumb wide, then bring them together, repeating to increase flexibility and reduce tension in the thumb and hand.
- Wrist flexor stretch: Extend the arm forward, palm up, and gently pull the thumb back with the other hand to stretch the wrist flexors.
- Forearm stretch: Extend the arm with the palm facing down and gently pull back on the hand to stretch the forearm muscles and thumb.
- Thumb extension stretch: Extend the thumb and hold it straight, then gently pull back with the other hand to stretch the thumb flexors.
- Wrist extension stretch: Extend the arm forward, palm down, and gently pull the thumb and fingers back with the other hand to stretch the wrist extensors.
