What is the palmaris longus muscle?
The palmaris longus is a muscle located in the forearm that connects the wrist to the elbow. It is a thin, elongated muscle that runs along the inner aspect of the forearm. Its main function is to flex the wrist, which means it helps to bring the hand towards the forearm. Along with the pronator teres, flexor carpi ulnaris, flexor carpi radialis and flexor digitorum superficial muscles, it helps to stabilize the wrist during certain movements.
The muscle is called “palmaris” because it is located on the palm side of the forearm, and “longus” because it is one of the longer muscles in the forearm. It’s an easy muscle to identify as it runs along the inner side of the forearm and you can see it contracting when you make a fist. It is not a vital muscle, it means that you can live without it. Some people are born without this muscle and they are not affected in their daily lives. (1)
Origin, insertion and function
Origin:
The palmaris longus muscle originates from the medial epicondyle of the humerus (upper arm bone) and the adjacent proximal (closer to the center of the body) portion of the medial supracondylar ridge of the humerus.
Insertion:
The palmaris longus muscle inserts (attaches) to the palmar (palm-facing) aspect of the flexor retinaculum (a fibrous band) and the tendon of the flexor carpi radialis muscle.
Function:
The palmaris longus muscle is a flexor muscle of the wrist and hand. It acts to flex (bend) the wrist joint and assist in the flexion of the hand. Additionally, it helps to provide stability to the wrist joint during movement. It also helps to protect the tendons that pass through the carpal tunnel in the wrist.
Common signs of weak palmaris longus muscles
Here are a few signs that could indicate that your palmaris muscle could be weak:
- Difficulty in flexing the wrist
- Weak grip
- Difficulty in performing hand and wrist movements
- Instability of the wrist joint
- Tendons pain or inflammation in the wrist area
- Weakness in grasping objects
- Weakness in performing fine motor tasks
- Pain or discomfort when performing activities that involve the wrist and hand.
Exercises to strengthen the palmaris longus
Here are some exercises that can help strengthen the pronator teres muscle:
Wrist curls:
Sit at a table with your forearm resting on the table and your hand hanging over the edge. Hold a weight in your hand and slowly lift your hand up, flexing your wrist, then lower it back down. Repeat for several repetitions.
Reverse wrist curls:
Sit at a table with your forearm resting on the table and your hand hanging over the edge, but this time with your palm facing down. Hold a weight in your hand and slowly lift your hand up, extending your wrist, then lower it back down. Repeat for several repetitions.
Forearm pronation and supination:
Hold a weight in one hand and sit with your forearm resting on a table. Slowly rotate your hand and wrist so that your palm faces downward (pronation), then rotate it back so that your palm faces upward (supination). Repeat for several repetitions on both arms.
Dumbbell hammer curls:
Hold a pair of dumbbells at your sides with your palms facing your body. Keep your elbows close to your sides and slowly lift the dumbbells up to your shoulders, flexing your elbow. Lower the dumbbells back to the starting position. Repeat for several repetitions.
Cable pronation/supination:
Attach a handle to a low-pulley cable and stand facing the machine. Hold the handle with your palm facing up and your arm extended. Slowly rotate your hand and wrist so that your palm faces downward (pronation), then rotate it back so that your palm faces upward (supination). Repeat for several repetitions on both arms.
It’s important to consult with a doctor or physical therapist before starting any new exercise program. Also, it’s important to use a weight that is light enough to allow you to complete the recommended number of repetitions with good form, but heavy enough to make the exercise challenging.