LOWER LEG

GENERAL INFORMATION

The muscles of the lower leg are primarily responsible for foot and ankle movement, playing vital roles in various activities. Additionally, Lower leg muscles control plantarflexion, dorsiflexion, inversion, and eversion of the foot, thereby providing stability and strength. Furthermore, the lower leg consists of two compartments: anterior for dorsiflexion and posterior for plantarflexion, each supporting movement.

ORIGIN OF LOWER LEG

• Gastrocnemius: Lateral and medial condyles of the femur.
• Soleus: Posterior surface of the head of the fibula, medial border of the tibia.
• Tibialis Anterior: Lateral condyle and upper two-thirds of the lateral surface of the tibia.
• Fibularis Longus: Head and upper two-thirds of the lateral surface of the fibula.
• Fibularis Brevis: Lower two-thirds of the lateral surface of the fibula.

INSERTION POINT

• Gastrocnemius and Soleus (combined as Achilles tendon): Posterior surface of the calcaneus (heel bone).
• Tibialis Anterior: Medial cuneiform and base of the first metatarsal.
• Fibularis Longus: Medial cuneiform and base of the first metatarsal.
• Fibularis Brevis: Tuberosity of the fifth metatarsal.

MAJOR ARTERIES

• Posterior Tibial Artery: Supplies the posterior compartment, including the gastrocnemius and soleus.
• Anterior Tibial Artery: Supplies the anterior compartment, including the tibialis anterior.
• Fibular Artery: Supplies the lateral compartment, including the fibularis longus and brevis.

NEURAL INNERVATION

• Gastrocnemius and Soleus: Tibial nerve (S1, S2).
• Tibialis Anterior: Deep fibular (peroneal) nerve (L4, L5).
• Fibularis Longus and Brevis: Superficial fibular (peroneal) nerve (L5, S1).

TRIGGER POINT

Trigger points in the lower leg, particularly in the gastrocnemius and tibialis anterior. They often cause referred pain in the foot or Achilles tendon. Overuse, poor footwear, or improper running technique can activate trigger points, leading to tightness and discomfort, especially during walking or running.

CONCENTRIC FUNCTION

• Gastrocnemius and Soleus: Plantarflex the foot at the ankle joint, essential for movements like running, jumping, and walking on tiptoes.
• Tibialis Anterior: Dorsiflexes the foot, lifting the foot towards the shin during walking and running.
• Fibularis Longus and Brevis: Evert the foot and assist in plantarflexion, helping stabilise the foot during walking and running on uneven surfaces.

ECCENTRIC FUNCTION

• Gastrocnemius and Soleus: Control dorsiflexion of the foot, especially during the lowering phase of walking or running, ensuring smooth foot placement.
• Tibialis Anterior: Controls plantarflexion after heel strike, preventing the foot from slapping down on the ground.
• Fibularis Longus and Brevis: Control foot inversion during the stance phase, providing stability and preventing excessive inward rolling of the foot.

ISOMETRIC FUNCTION

Lower leg muscles help stabilise the foot and ankle during static positions, such as when standing on one leg or maintaining balance on uneven terrain. The gastrocnemius and soleus maintain tension in the Achilles tendon during sustained plantarflexion, such as when holding a position on tiptoes.

RELATED MUSCLE – SCIENTIFIC NAMES

• Flexor Hallucis Longus: Assists in plantarflexion and flexion of the big toe.
• Tibialis Posterior: Aids in foot inversion and plantarflexion.
• Extensor Digitorum Longus: Works with the tibialis anterior to dorsiflex the foot and extend the toes.
• Flexor Digitorum Longus: Assists in toe flexion and plantarflexion.
• Extensor Hallucis Longus: Dorsiflexes the foot and extends the big toe.

ANTAGONIST

• Tibialis Anterior: In contrast, it opposes the gastrocnemius and soleus by actively dorsiflexing the foot.
• Extensor Digitorum Longus: Similarly, it opposes the flexor muscles by extending the toes.
• Extensor Hallucis Longus: On the other hand, it opposes the fibularis muscles by inverting the foot.
• Tibialis Posterior: Opposes the fibularis muscles by inverting the foot.
• Quadriceps Femoris (Rectus Femoris): Assists in knee extension, working against the gastrocnemius, which helps flex the knee.

COMMON INJURIES

• Achilles Tendonitis: Inflammation of the Achilles tendon, often caused by overuse or repetitive strain, resulting in pain and stiffness at the back of the heel.
• Shin Splints: Pain along the tibia due to inflammation of the tibialis anterior or posterior, commonly caused by overtraining or improper footwear.
• Calf Strain: A tear in the gastrocnemius or soleus muscles, often from sudden acceleration or overstretching, leading to pain and swelling.
• Peroneal Tendonitis: Inflammation of the tendons of the fibularis muscles, causing pain and instability on the outer ankle and foot.
• Plantar Fasciitis: Inflammation of the plantar fascia, leading to pain in the heel and arch, often associated with tight calf muscles or excessive pronation.

EXERCISES FOR LOWER LEG

• Calf Raises: Stand with feet shoulder-width apart and then lift your heels off the ground in order to strengthen the gastrocnemius as well as soleus, thereby improving calf strength and endurance.
• Tibialis Anterior Raises: Stand with heels on the ground and lift your toes towards your shin, engaging the tibialis anterior to improve dorsiflexion strength.
• Eversion with Resistance Band: For this exercise, wrap a resistance band around the foot and then push outward, effectively targeting the fibularis muscles and improving ankle stability.
• Toe Walking: Walk on your toes for a set distance, engaging the calf muscles while also enhancing balance and lower leg strength.
• Heel Walking: Walk on your heels, keeping the toes lifted to strengthen the tibialis anterior and improve ankle as well as foot control.

STRETCHES FOR LOWER LEG

• Standing Calf Stretch: Stand facing a wall, then step one foot back and press the heel into the floor to stretch the gastrocnemius as well as the soleus.
• Seated Shin Stretch: Sit with knees bent and press the tops of the feet into the floor in order to stretch the tibialis anterior.
• Heel Drop Stretch: Stand on the edge of a step, and then lower the heels below the step, holding to stretch the Achilles tendon and calf muscles.
• Peroneal Stretch: Sit with legs extended, grab the toes, and pull them towards the body while keeping the legs straight to stretch the fibularis muscles.
• Ankle Circles: Sit or stand, rotate the ankle in slow circles to stretch and mobilise the muscles of the lower leg, improving flexibility and range of motion.