Orthotic Abilities Inc Overview

Terminology

  • SUPINATION: A triplanar motion of the foot that includes adduction, plantarflexion, and inversion. In the lower extremity, it often means the foot is rolled inward with the calcaneus inverted and the forefoot adducted, leading to a more rigid foot structure.

  • PRONATION: A triplanar motion of the foot involving abduction, dorsiflexion, and eversion. In the lower extremity, it means the foot is rolled outward with the calcaneus everted and the forefoot abducted, increasing foot flexibility for shock absorption.

  • INVERSION: The movement of the sole of the foot inward toward the midline of the body, primarily occurring at the subtalar joint.

  • EVERSION: The movement of the sole of the foot outward away from the midline of the body, primarily occurring at the subtalar joint.

  • VARUS: A deformity in which the distal segment of a bone or joint is angled inward, toward the midline (e.g., Genu Varum, where the knees bow outward).

  • VALGUS: A deformity in which the distal segment of a bone or joint is angled outward, away from the midline (e.g., Genu Valgum, where the knees bow inward).

Lower Extremity Anatomy

  • Hip Structure: The pelvic girdle, composed of the ilium, ischium, and pubis, forms a stable base that articulates with the vertebral column (sacroiliac joints) and the lower limbs (hip joints). The acetabulum is a deep socket that accepts the head of the femur to form a highly mobile ball-and-socket joint.

  • Important Landmarks:

    • ASIS (Anterior Superior Iliac Spine): A prominent bony projection on the anterior aspect of the ilium, used as a reference point for measurements and muscle attachments.

    • PSIS (Posterior Superior Iliac Spine): A bony landmark on the posterior aspect of the ilium, often palpable and used for pelvic alignment assessments.

    • Q Angle (Quadriceps Angle): The angle formed by a line from the ASIS to the center of the patella and a line from the center of the patella to the tibial tuberosity. A normal Q angle is approximately 10^\circ-15^\circ in males and 15^\circ-20^\circ in females. Deviations can indicate patellar tracking issues and increased risk of knee pain.

  • Knee Joint: The largest and most complex joint in the body, classified as a ginglymus (hinge) joint but also allows for some rotation. It consists of articulations between the femur, tibia, and patella. Key structures include:

    • Ligaments: ACL (Anterior Cruciate Ligament), PCL (Posterior Cruciate Ligament) for anterior/posterior stability, and MCL (Medial Collateral Ligament), LCL (Lateral Collateral Ligament) for medial/lateral stability.

    • Menisci: Medial and lateral menisci are C-shaped cartilaginous structures that act as shock absorbers and improve joint congruence.

  • Lower Leg:

    • Tibia: The primary weight-bearing bone of the lower leg, essential for knee and ankle joint articulation.

    • Fibula: A slender bone contributing to ankle stability and providing attachment sites for muscles, but not significant in weight-bearing.

  • Foot Structure: Composed of 28 bones (sesmoids not included below), divided into three regions:

    • Rearfoot: Talus (ankle bone) and Calcaneus (heel bone). Primary weight bearing, balancing, and propulsive organ

    • Midfoot: Navicular, Cuboid, and three Cuneiform bones. Forms the arches of the foot and provides stability.

    • Forefoot: Five Metatarsals and 14 Phalanges. Essential for push-off during gait and balance.

    • Arches: The foot features medial longitudinal, lateral longitudinal, and transverse arches, crucial for weight distribution, shock absorption, and propulsion.

Foot Mechanics

  • Pronation: During the initial contact and loading response phases of gait, the foot pronates, becoming a mobile adapter. This motion allows the foot to absorb ground reaction forces by increasing flexibility and distributing pressure.

  • Supination: During the midstance and terminal stance phases of gait, the foot supinates, transforming into a rigid lever for efficient propulsion off the ground. This rigid structure facilitates powerful push-off.

  • Normal Foot Motion: The foot dynamically alternates between controlled eversion for shock absorption and adaptation during early stance, and inversion for rigidity and lever arm formation during late stance and push-off. This intricate motion, primarily coordinated at the subtalar joint, is critical for efficient and injury-free locomotion.

Common Foot Conditions

  • Pes Planus (Flat Foot): Characterized by a collapsed or absent medial longitudinal arch. It can be flexible (arch disappears with weight-bearing). Symptoms often include arch pain, heel pain, fatigue in the feet and legs, and potential issues further up the kinetic chain (e.g., knee valgus). Causes can include ligamentous laxity, muscle weakness, or congenital factors.

  • Pes Cavus (High Arch): Characterized by an abnormally high medial longitudinal arch that remains elevated even with weight-bearing. This foot type is often rigid, limiting pronation and shock absorption. Symptoms may include pain, calluses over lateral foot borders, plantar fasciitis, and increased lateral ankle instability due to poor ground contact.

  • Turf Toe: A sprain of the plantar plate ligamentous complex of the first metatarsophalangeal (MTP) joint, caused by hyperextension of the big toe. It is common in athletes playing on artificial turf. Symptoms include pain, swelling, and limited motion, particularly extension. Treatment involves limiting MTP joint extension (e.g., taping, stiff-soled shoes) and managing inflammation.

  • Plantar Fasciitis: Inflammation and degeneration of the plantar fascia, a thick band of tissue running along the bottom of the foot from the heel to the toes, supporting the arch. It is a common cause of heel pain, often worse with the first steps in the morning or after periods of rest. Associated with overuse, tight calf muscles, improper footwear, and anatomical factors like pes planus or pes cavus. A heel spur may be present but is often a secondary finding, not the primary cause of pain.

  • Achilles Tendinopathy: Degeneration or inflammation of the Achilles tendon, which connects the calf muscles to the heel bone. It typically causes pain and stiffness along the back of the heel, especially during or after activity, and often worse in the morning. Causes include overuse, sudden increases in activity, tight calf muscles, and improper footwear.

  • Shin Splints (Medial Tibial Stress Syndrome): Pain along the inner edge of the tibia (shin bone) due to repetitive stress on the tibia and connective tissues that attach muscles to the bone. Common in runners and athletes involved in high-impact sports. Symptoms include pain during exercise, which may subside with rest but can return with continued activity. Contributing factors include sudden increases in training intensity, inadequate footwear, and biomechanical issues like excessive pronation.

  • Bunions (Hallux Valgus): A bony bump that forms on the joint at the base of your big toe. It occurs when the big toe pushes against the next toe, forcing the joint of the big toe to stick out. Symptoms include pain, swelling, redness, and difficulty wearing shoes. Causes include inherited foot type, improper footwear (narrow, pointed shoes), and certain arthritic conditions.

  • Morton's Neuroma: A painful condition that affects the ball of your foot, most commonly the area between your third and fourth toes. It involves a thickening of the tissue around one of the nerves leading to your toes. Symptoms include a sharp, burning pain in the ball of your foot, or a feeling of standing on a pebble in your shoe. It is often caused by irritation, injury, or compression of the nerve, frequently linked to high heels, tight shoes, or certain foot deformities.

  • achilles tendonitis: can result from inadequate strength or overuse of gastroc-soleus complex; degeneration of tendon 

  • posterior tibialis tendonitis: tenderness of navicular insertion or just behind medial malleolus 

  • plantar fasciitis: as increased loads are applied it becomes progressively stiffer to resist deformation. Tension promotes calcaneal inversion and subtalar joint supination, establishing a rigid lever for push off 

Biomechanics/ROM

  • Knee ROM:

    • Flexion: Up to 135^{\circ}

    • Extension: 0^{\circ}-10^{\circ} (hyperextension beyond 0^{\circ} can indicate ligamentous laxity or structural variations).

  • Ankle ROM (Talocrural and Subtalar Joints):

    • Dorsiflexion: Approximately 20^{\circ} (critical for normal gait and squatting mechanics).

    • Plantarflexion: Approximately 50^{\circ}

    • Inversion: Approximately 20^{\circ} (primarily subtalar joint).

    • Eversion: Approximately 10^{\circ} (primarily subtalar joint).

Assessment Techniques

  • Palpation: A hands-on technique used to identify bony landmarks (e.g., medial/lateral malleoli, calcaneus, metatarsal heads), assess joint positions, and detect areas of tenderness, swelling, muscle spasm, or altered tissue texture along structures like the Achilles tendon or plantar fascia.

  • Weight Bearing Assessment: Involves evaluating the alignment and mechanics of the foot and lower kinetic chain under load. This includes:

    • STJ (Subtalar Joint) Neutral Position: A key reference point for assessing foot alignment, where the talus is optimally positioned in the mortise. It's often assessed in non-weight-bearing but its influence on weight-bearing is observed.

    • Tibial Curvature and Alignment Measurements: Observing for conditions like Genu Varum, Genu Valgum, or tibial torsion.

    • Navicular Drop Test: Measures the change in the height of the navicular bone from non-weight-bearing to weight-bearing, indicating the degree of pronation or arch collapse.

    • Postural Analysis: Comprehensive observation of the lower limb alignment from the hips down to the feet, assessing for compensations and imbalances that affect gait and function.