GENERAL INFORMATION
The leg posterior compartment of the lower limb refers to a group of muscles located at the back of the leg. These muscles play a crucial role in movements such as ankle plantar flexion, toe flexion as well as foot inversion.
ORIGIN
The specific origins of the muscles in the leg posterior compartment may vary. Still, generally, they originate from various locations on the posterior aspect of the femur, tibia as well as fibula.
INSERTION POINT
The muscles in the leg’s posterior compartment have different insertion points. These include various areas on the foot bones (metatarsals and phalanges) and tendons such as the Achilles tendon.
MAJOR ARTERIES
The leg posterior compartment muscles receive their blood supply from various arteries, including the posterior tibial artery as well as the fibular (peroneal) artery.
NEURAL INNERVATION
The muscles in the leg’s posterior compartment are innervated by the tibial nerve, also a branch of the sciatic nerve. The tibial nerve provides both motor innervation for muscle activation and sensory innervation for transmitting sensations from the lower limb.
TRIGGER POINT
Trigger points can develop in the muscles of the leg posterior compartment, leading to localised pain as well as discomfort. These trigger points can be associated with muscle overuse, strain, or imbalances. Therefore, addressing these trigger points is crucial for managing pain and ensuring proper muscle function.
CONCENTRIC FUNCTION
The muscles in the leg’s posterior compartment contract concentrically to generate force during specific movements. They play a primary role in ankle plantar flexion, which involves pointing the foot downward.
ECCENTRIC FUNCTION
During controlled movement and deceleration, the muscles in the leg’s posterior compartment function eccentrically to control the speed and force of movements, such as lowering the heel or decelerating the foot during walking or running. As a result, this eccentric function helps in maintaining balance and stability.
ISOMETRIC FUNCTION
The muscles in the leg posterior compartment can contract isometrically to provide stability and maintain posture during standing, as well as support the arches of the foot. Consequently, this isometric function is essential for postural control and balance.
RELATED MUSCLE – SCIENTIFIC NAMES
- Gastrocnemius (musculus gastrocnemius): The largest muscle in the calf, responsible for ankle plantar flexion and knee flexion.
- Soleus (musculus soleus): Located beneath the gastrocnemius, it plays a key role in standing and walking by maintaining posture.
- Plantaris (musculus plantaris): A small muscle with a long tendon assisting the gastrocnemius in plantar flexion.
- Popliteus (musculus popliteus): A small muscle located at the knee that helps to unlock the knee joint by rotating the femur.
- Flexor hallucis longus (musculus flexor hallucis longus): Runs along the lower leg to the big toe, facilitating toe flexion and contributing to the foot’s arch support.
- Flexor digitorum longus (musculus flexor digitorum longus): Flexes the other four toes and supports the foot’s arch.
- Tibialis posterior (musculus tibialis posterior): Located deep in the calf, it supports the arch of the foot and assists in foot inversion.
ANTAGONIST
- The antagonists to the gastrocnemius and soleus muscles are the muscles in the anterior compartment, such as the tibialis anterior and extensor digitorum longus. These muscles are responsible for dorsiflexion and toe extension, providing balanced muscle action for proper foot mechanics.
COMMON INJURIES
- Achilles tendonitis or rupture: Inflammation or tearing of the Achilles tendon, often due to overuse or sudden increases in activity.
- Muscle strains or tears: Overstretching or tearing of muscle fibres, commonly occurring during sudden, intense activities.
- Shin splints: Pain along the shin bone, typically caused by repetitive stress on the lower leg muscles and bone tissue.
- Plantar fasciitis: Inflammation of the tissue along the bottom of the foot, resulting in heel pain, especially in the morning.
- Compartment syndrome: Increased pressure within the muscle compartment, leading to pain and swelling, often requiring medical intervention.
EXERCISES
- Calf raises: Lifting the heels off the ground to strengthen the calf muscles, performed on flat ground or an elevated surface.
- Seated or standing heel raises: Raising the heels while sitting or standing to target the calf muscles, improving their strength and endurance.
- Toe curls: Curling the toes to strengthen the foot muscles, often done with resistance like a towel or exercise band.
- Resistance band exercises for ankle plantar flexion: Using a band to resist downward foot movements enhances the strength of the leg posterior compartment muscles.
- Ankle inversion exercises: Rotating the foot inward against resistance to strengthen the ankle and support the tibialis posterior.
STRETCHES
- Standing calf stretch: Stretching the calf muscles by leaning against a wall with one leg extended back, keeping the heel on the ground.
- Soleus stretch: Bending the knee slightly while stretching the lower calf, targeting the soleus muscle specifically.
- Seated toe flexor stretch: Bending the toes while seated to stretch the muscles of the foot is particularly beneficial for the flexor hallucis longus and flexor digitorum longus.
- Plantar fascia stretch: Stretching the arch of the foot by pulling back on the toes, relieving tension in the plantar fascia.
- Seated or standing Achilles tendon stretch: Stretching the Achilles tendon by leaning forward, maintaining flexibility and reducing the risk of injury.