Leg, Ankle, and Foot Anatomy & Kinesiology

• The leg, ankle, and foot work together to provide support, mobility, and balance
• Understanding their anatomy and kinesiology is crucial in understanding various conditions affecting the lower limb

Leg Anatomy

• The leg extends from the knee to the ankle
• The primary bones of the leg are the tibia and fibula
• The tibia is the larger, weight-bearing bone located on the medial side of the leg
• The fibula is smaller and located on the lateral side of the leg which is primarily involved in ankle stability
• The interosseous membrane connects the tibia and fibula, providing stability, and serving as an attachment site for muscles

Leg Muscles

• The leg muscles are divided into anterior, posterior, and lateral compartments
• The anterior compartment muscles are primarily responsible for dorsiflexion of the foot and extension of the toes and include the tibialis anterior, extensor hallucis longus, extensor digitorum longus, and fibularis (peroneus) tertius
• The posterior compartment muscles are responsible for plantarflexion of the foot and flexion of the toes and include the gastrocnemius, soleus, plantaris, tibialis posterior, flexor hallucis longus, and flexor digitorum longus
• The lateral compartment muscles are primarily responsible for eversion of the foot and include the fibularis (peroneus) longus and fibularis (peroneus) brevis

Ankle Anatomy

• The ankle joint, also known as the talocrural joint, is formed by the distal ends of the tibia and fibula and the talus bone
• The medial malleolus of the tibia and the lateral malleolus of the fibula form the bony prominences on either side of the ankle
• The ankle joint allows for plantarflexion and dorsiflexion of the foot
• Several ligaments support the ankle joint, including the anterior talofibular ligament (ATFL), calcaneofibular ligament (CFL), and deltoid ligament
• The ATFL is the most commonly injured ligament in ankle sprains
• The CFL is located on the lateral side of the ankle and resists inversion
• The deltoid ligament is a strong ligament complex on the medial side of the ankle, resisting eversion

Foot Anatomy

• The foot is divided into three parts: the forefoot, midfoot, and hindfoot
• The hindfoot consists of the talus and calcaneus (heel bone)
• The midfoot consists of the navicular, cuboid, and three cuneiform bones
• The forefoot consists of the five metatarsals and the phalanges (toes)
• There are 14 phalanges in each foot: two for the big toe (hallux) and three for each of the other toes

Foot Arches

• The foot has three arches: the medial longitudinal arch, the lateral longitudinal arch, and the transverse arch
• These arches provide support, shock absorption, and flexibility during weight-bearing activities
• The medial longitudinal arch is the highest and most prominent arch, running along the medial side of the foot
• The lateral longitudinal arch is lower and less prominent, running along the lateral side of the foot
• The transverse arch runs across the midfoot, providing stability and weight distribution
• Plantar fascia is a thick band of tissue on the bottom of the foot that supports the arches and helps with push-off during walking

Foot Muscles

• The foot muscles are divided into intrinsic and extrinsic muscles
• Intrinsic muscles originate and insert within the foot and are responsible for fine motor control and support of the arches
• Extrinsic muscles originate in the leg and insert into the foot, providing larger movements such as plantarflexion, dorsiflexion, inversion, and eversion

Kinesiology of the Leg, Ankle, and Foot

• The movements of the leg, ankle, and foot are essential for gait (walking), running, jumping, and maintaining balance
• During gait, the ankle and foot undergo a complex sequence of movements, including heel strike, midstance, and toe-off
• Plantarflexion is essential for push-off during gait
• Dorsiflexion is important for clearing the foot during the swing phase of gait
• Inversion and eversion occur at the subtalar joint, allowing the foot to adapt to uneven surfaces

Common Conditions: Leg

• Shin splints, or medial tibial stress syndrome, involve pain along the tibia, often due to overuse or repetitive impact
• Compartment syndrome occurs when pressure builds up within a muscle compartment, leading to pain, swelling, and potentially reduced blood flow
• Stress fractures are small cracks in the bone, often caused by repetitive stress or overuse

Common Conditions: Ankle

• Ankle sprains are common injuries that occur when the ligaments supporting the ankle are stretched or torn, most often during inversion
• Achilles tendinitis is inflammation of the Achilles tendon, often due to overuse or improper footwear
• Ankle impingement occurs when soft tissues or bony structures in the ankle are compressed, causing pain and limited range of motion

Common Conditions: Foot

• Plantar fasciitis is inflammation of the plantar fascia, causing heel pain and arch pain
• Bunions are bony bumps that form at the base of the big toe, often due to pressure from shoes or abnormal foot mechanics
• Hammer toe, claw toe, and mallet toe are deformities of the toes that can cause pain and difficulty wearing shoes
• Metatarsalgia is pain in the ball of the foot, often due to overuse or improper footwear
• Morton's neuroma involves thickening of the tissue around a nerve in the foot, causing pain and numbness between the toes
• Flatfoot (pes planus) is a condition in which the arch of the foot collapses, leading to a flat appearance
• High arch (pes cavus) is a condition in which the arch of the foot is excessively high, which can lead to foot pain and instability

Examination and Assessment

• A thorough examination of the leg, ankle, and foot involves assessing range of motion, strength, sensation, and palpation
• Range of motion is assessed for dorsiflexion, plantarflexion, inversion, eversion, toe flexion, and toe extension
• Strength testing involves assessing the strength of the muscles responsible for these movements
• Palpation involves feeling for tenderness, swelling, or structural abnormalities
• Special tests, such as the anterior drawer test and talar tilt test, can be used to assess ligament stability in the ankle

Imaging Techniques

• X-rays are used to evaluate bony structures and identify fractures, dislocations, or arthritis
• MRI (magnetic resonance imaging) is used to evaluate soft tissues such as ligaments, tendons, and muscles, and to identify injuries such as sprains, strains, and tears
• Ultrasound is used to evaluate soft tissues and identify conditions such as plantar fasciitis, Achilles tendinitis, and Morton's neuroma

Treatment and Management

• Treatment for conditions affecting the leg, ankle, and foot depends on the specific condition and its severity
• Conservative treatments include rest, ice, compression, and elevation (RICE), as well as pain medication and physical therapy
• Physical therapy may involve exercises to improve range of motion, strength, and balance, as well as orthotics to support the foot and ankle
• In some cases, surgery may be necessary to repair torn ligaments, tendons, or fractures, or to correct deformities such as bunions or hammer toes