Muscle Breakdown: Palmaris Longus
Table Of Content
What Is the Palmaris Longus
The Palmaris Longus is a muscle located in the anterior forearm-for some people. Let us explain, the Palmaris Longus is missing in about 14% of the population! The Palmaris Longus is considered to be functionally insignificant for the upper limb, but does help in wrist flexion for those of us who have this muscle.
Palmaris Longus Muscle
The Palmaris Longus muscle itself is long and skinny. It is located between the Flexor Carpi Ulnaris and the Flexor Carpi Radialis muscles. It is considered to be a vestigial muscle and can be in both forearms, one forearm, or neither forearm. The muscle features a long tendon that inserts into the wrist and a short muscle belly.
Palmaris Longus Tendon
The Palmaris Longus Tendon runs from the belly of the muscle and into the insertion point in the wrist. We are able to perform various clinical tests to determine the presence of the Palmaris Longus in each forearm, and to palpate the Palmaris Longus tendon.
Two common tests that you can perform to visually identify the presence of the Palmaris Longus in each forearm are Schaeffer’s Test and Thompson’s Test.
Palmaris Longus Test
There are different tests that you can perform to determine the presence of the Palmaris Longus in the body. Two common examples are Schaeffer’s Test and Thompson’s Test.
Schaeffer’s Test involves resting the forearm on a table with your palm facing the ceiling. Move the thumb towards the pinky finger so that they are touching. Next, partially flex the wrist. If you can see a tendon bulging at the wrist joint, you can visually confirm the presence of the Palmaris Longus.
Thompson’s Test begins in the same fashion as Schaeffer’s Test by resting the forearm on a table. Next, make a fist with your hand and ensure that the thumb is on top of your fingers. Partially flex the wrist. If you can see a tendon bulging at the wrist joint, you can visually confirm the presence of the Palmaris Longus.
Palmaris Longus Tendonitis
Tendonitis occurs when a tendon becomes inflamed or irritated. This is most often the result of overuse of the tendon by repeating a movement multiple times. Palmaris Longus tendonitis can happen to anyone who has the muscle, especially those who frequently flex the wrist such as tennis players, construction workers or other craftsmen. Tendonitis can be diagnosed by your doctor and is usually treated conservatively.
This conservative treatment includes rest, ice, heat and the use of anti-inflammatory medication. Your treatment plan most likely will also include stretching and strengthening movements to promote the recovery and health of the tendon. If you are unsure if you have Palmaris Longus Tendonitis, or are exhibiting symptoms such as burning, pain and tenderness at the wrist, talk to your doctor.
Palmaris Longus Missing
You can visually determine if you have the Palmaris Longus muscle by performing any of the tests that we mentioned above. If you cannot visually see the Palmaris Longus, do not worry. Remember that about 14% of the population is missing the Palmaris Longus.
Palmaris Longus Function
The primary function of the Palmaris Longus is to aid in flexion of the wrist. The Palmaris Longus also helps to tense the Palmar Aponeurosis.
Palmaris Longus Evolution
The reason that some of us do not have a Palmaris Longus is that humans have evolved! The Palmaris Longus was used by our ancestors, (apes, monkeys and lemurs) to swing from trees. We humans do not need to swing from trees, and use our legs to get around. As a result we have evolved and the Palmaris Longus has become a vestigial muscle that no longer has a significant function.
Palmaris Longus Innervation
The Palmaris Longus is innervated by the Median Nerve.
Palmaris Longus Pain
Pain in the Palmaris Longus can manifest itself as pain in the hand and the wrist. When this occurs, it can be the result of a trigger point that needs to be released. A Registered Massage Therapist can help locate the trigger point and use circular techniques to press on this location and release the Palmaris Longus. Releasing the trigger point can help to reduce symptoms of pain and tension in the muscle.
Palmaris Longus Origin
The Palmaris Longus originates from the Medial Epicondyle of the Humerus.
Palmaris Longus Insertion
The Palmaris Longus inserts into the Palmar Aponeurosis and the Flexor Retinaculum. These are both located at the wrist joint.
Palmaris Longus Absence
Just as we mentioned above, not everyone will have the Palmaris Longus. This is okay! Research has shown that the absence of the Palmaris Longus does not affect one’s grip strength.
Palmaris Longus Action
Wrist flexion is the primary function of the Palmaris Longus. This means that actions such as brushing our hair, writing, playing racquet sports and painting all will engage the Palmaris Longus.
Palmaris Longus Muscle Test
Remember there are quick as easy muscle tests that you can perform at home to see if you have the Palmaris Longus muscle. Press your thumb and the pinky finger together and flex the wrist. You will be able to see the Palmaris Longus tendon in the middle of the anterior wrist if you have one.
Another Palmaris Longus muscle test involves forming a fist with your hand. Make sure that your thumb is on top of the fingers and flex the wrist. If you can see the Palmaris Longus tendon in the middle of the anterior wrist, you have tested positive for the muscle.
Palmaris Longus Exercises
We can stretch the Palmaris Longus, especially when the forearm and our wrist flexors feel tight. To exercise the Palmaris Longus, extend the arm straight out in front of the body. This means that your wrist is in line with the shoulder, the palm is facing outwards and your fingers are pointed upwards. Use your remaining hand to pull your fingers back towards the body. Hold this position for 30 seconds and then switch arms
