Muscle Breakdown: Flexor Digitorum Longus
Table of Contents
What Is The Flexor Digitorum Longus Muscle
The Flexor Digitorum Longus is a skeletal muscle that is located medially in the lower leg. The Flexor Digitorum Longus is a bilateral muscle, meaning that each leg has its own Flexor Digitorum Longus. This skinny muscle helps us to run, walk and jump. Essentially, it is involved in most actions that require flexion of the foot and toes.
Flexor Digitorum Longus Muscle & Cadaver
Flexor Digitorum Longus Function
The primary function of the Flexor Digitorum Longus is to produce flexion at the foot. Specifically, flexion of the second to fifth digits and plantar flexion of the foot. With so many muscles in the lower limb, it can be challenging to recall each function. Luckily, the function of the Flexor Digitorum Longus is right in its name.
Flexor Digitorum Longus Origin
The origin of the Flexor Digitorum Longus is the Tibia, specifically on the medial and posterior surface.
Flexor Digitorum Longus Insertion
The insertion of the Flexor Digitorum Longus is the distal phalanges of the second-fifth digits of the foot.
Flexor Digitorum Longus Innervation
The Flexor Digitorum Longus is innervated by the Tibial Nerve.
Flexor Digitorum Longus Cat
Our furry friends can have the same or similar muscles in their bodies. For example, a Cat also has a Flexor Digitorum Longus. The use of a cadaver can be helpful if you are studying the muscle in this species.
Flexor Digitorum Longus Tendon
The Flexor Digitorum Longus travels down the medial side of the lower leg, where the muscle turns into a tendon just above the medial malleoli and continues into the plantar compartment of the foot. The Flexor Digitorum Longus Tendon ends with its division into four smaller tendons that insert into the distal phalanges of digits 2-5.
Flexor Digitorum Longus Tendonitis
While you can develop tendonitis of the Flexor Digitorum Longus, you are more likely to experience this irritation in the Flexor Hallicus Longus. Tendonitis can arise in any tendon from overuse or an acute injury. Luckily, tendonitis can generally be treated conservatively by following the R.I.C.E. protocol. This consists of rest, ice, compression and elevation. If you believe you are experiencing symptoms of tendonitis such as pain, burning, and stiffness at the muscle, be sure to rest and contact your doctor so they can rule out other injuries.
Flexor Digitorum Longus Pain
You can experience pain in the Flexor Digitorum Longus from running or training on uneven surfaces such as sand or gravel. The increased need for flexion of the toes on these surfaces can create increased tension in the muscle and increase the risk of injury at the ankle. The risk of injury is even further increased if you are running or training barefoot on these uneven surfaces, as the ankle is not supported by a shoe.
Flexor Digitorum Longus Action
As the primary function of the Flexor Digitorum Longus is to flex the toes and assist in flexion at the ankle, any movement that requires plantar flexion of the foot will engage the Flexor Digitorum Longus. This includes actions such as running, walking, swimming, jumping and playing most sports.
Flexor Digitorum Longus Hand
Often the Flexor Digitorum Longus is mixed up with the Flexor Digitorum Profundus, which is located in the hand. Even though both muscles are in very different locations of the body, they have almost an identical function of flexing the toes (Flexor Digitorum Longus) and the fingers (Flexor Digitorum Profundus).
Flexor Digitorum Longus Foot
The Flexor Digitorum Longus can be difficult to understand at a first glance. The origin of the muscle can is easy to identify, initiating at the posterior aspect of the Tibia. However, when we follow the muscle down towards the ankle, it can be easy to lose sight of when the tendon goes. The tendon of the Flexor Digitorum Longus travels underneath the sole of the foot and then splits into four smaller tendons to insert into the distal phalanges of the second to fifth toes. Remember that these tendons insert into the plantar surface of each digit. This what allows us to flex the toes and grip the ground beneath our feet.
Flexor Digitorum Longus Injury
Sometimes, a fracture in the lower leg can cause the Flexor Digitorum to become entrapped. This may require the lower leg to be put into a splint, followed by partial weight-bearing activities. The Flexor Digitorum Longus can also be torn, however, you are more likely to injure the Flexor Hallicus Longus.
Flexor Digitorum Longus Strain
It is unlikely that you will strain the Flexor Digitorum Longus. As we previously mentioned, you are more likely to injure the Flexor Hallicus Longus due to the location of its muscle tendon.
Flexor Digitorum Longus Trigger Point
The Flexor Digitorum Longus has a trigger point close to its origin in the muscle belly. A massage therapist will often manipulate the trigger point of a muscle to release tension and promote the health of the muscle. The trigger point of a muscle is important to relieve pain that can be referred down the muscle to another area of the body. For instance, plantar midfoot pain can be relieved by manipulating the Flexor Digitorum Longus trigger point.
Flexor Digitorum Longus Antagonist
The antagonist to the Flexor Digitorum Longus is the Extensor Digitorum Longus. This muscle functions to dorsiflex the foot and extend the second – fifth digits of the foot.
Flexor Digitorum Longus Stretch
The best way to stretch the Flexor Digitorum Longus is to move the toes into an extended position. You can accomplish this in both a standing and seated position. While standing point the toes of one foot into the air so that only the heel of the foot is in contact with the floor. Use your hands to reach towards the toes while keeping your leg straight (a slight bend at the knee is fine). Hold this position for at least 30 seconds. You will feel a stretch throughout the back of the lower leg.
To perform the Flexor Digitorum Longus stretch in a seated position, have a seat in a chair with one leg extended in front of the body. Use your hands to reach for your toes. Similar to the standing variation, only the heel of the foot should be in contact with the floor. If you cannot reach your toes, try wrapping a towel around the foot and pulling the ends towards the body until you can feel a stretch in the back of the lower leg. Hold this position for at least 30 seconds.
Flexor Digitorum Longus Exercises
There are a few different exercises that you can perform to strengthen the Flexor Digitorum Longus. Check them out below!
Seated or Standing Toe Raise
Have a seat on a chair with your feet flat on the floor. When you are ready, plantar flex the foot by coming up onto the toes. Repeat this movement for 3 sets of 10-15 reps. You can progress this exercise by performing toe raises in a standing position, and then adding a load!
Marble Pick Up
If you have some marbles handy, this can be a fun exercise to try! Have a seat in a chair with some marbles spread out on the ground in front of the inactive foot. Use your toes to pick up one marble at a time and move them off towards the opposite side.
Walking/Running Barefoot
Walking or running barefoot can also help to strengthen the Flexor Digitorum Longus. This will help you to improve your balance as you no longer have the stability of your shoes. If you don’t want to train without shoes, try switching up the surface that you are training on. For instance, instead of running on the sidewalk or pavement, try running on the grass or sand every so often.
This will challenge your brain and strengthen the muscles of the lower leg. If you choose to train on these uneven surfaces, please exercise caution as they can contribute to an increased risk of injury at the ankle. Listening to your body and how the impact feels at the ankle can be a useful guide as to what your body can tolerate.
