GENERAL INFORMATION
The flexor hallucis longus is a muscle located in the lower leg’s deep posterior (back) compartment. It plays a crucial role in flexing the big toe and supporting the foot’s arch during walking, running and jumping.
ORIGIN
The flexor hallucis longus muscle originates from the middle of the fibula, the smaller bone in the lower leg.
INSERTION POINT
The flexor hallucis longus muscle inserts into the base of the big toe’s distal phalanx (end bone).
MAJOR ARTERIES
It receives its blood supply from the following arteries:
- Posterior tibial artery
- Fibular artery
NEURAL INNERVATION
It is innervated by the tibial nerve, which arises from the sciatic nerve. The tibial nerve provides motor innervation to the flexor hallucis longus, allowing it to contract and produce movement.
TRIGGER POINT
Trigger points in the muscle can develop, although they are less common than other muscles. However, when they do occur, trigger points may cause pain and discomfort in the foot and lower leg.
CONCENTRIC FUNCTION
The concentric function of the muscle involves the shortening or contraction of the muscle. Consequently, this function is primarily responsible for flexing the big toe, allowing it to move downward.
ECCENTRIC FUNCTION
The eccentric function of the muscle refers to the controlled lengthening of the muscle while resisting an external force. Therefore, it is involved in movements such as controlling the upward movement of the big toe and decelerating the foot during landing.
ISOMETRIC FUNCTION
The isometric function of the muscle involves contracting the muscle without any change in length. For example, isometric contractions of the flexor hallucis longus occur during activities that require maintaining the position of the big toe, such as gripping or pushing off the ground.
RELATED MUSCLE SCIENTIFIC NAMES
- Musculus flexor hallucis longus
ANTAGONIST
The antagonist muscle to flexor hallucis longus is the extensor hallucis longus muscle. This muscle is responsible for extending (lifting) the big toe.
COMMON INJURIES
- Tendinitis: Inflammation of the tendon due to overuse or repetitive stress.
- Tendinopathy: Degenerative changes in the flexor hallucis longus tendon, often caused by chronic overuse or ageing.
- Sprains: Injury to the ligaments surrounding the muscle and tendon, often caused by sudden movements or trauma.
EXERCISES
- Toe curls: Place a small towel or cloth on the ground and use the toes to curl and grip the fabric.
- Resistance band exercises: Using a resistance band looped around the big toe, performing resisted flexion and extension exercises to strengthen the muscle.
- Standing calf raises: Performing calf raises while focusing on engaging the flexor hallucis longus muscle to enhance its strength and function.
STRETCHES
- Toe extension stretch: Pull the big toe upward, stretching the muscle.
- Plantar fascia stretch: Stretching the plantar fascia indirectly stretches the muscle.
- Calf stretches: Stretching the calf muscles can help alleviate tension in the muscle.