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Columbia University Irving Medical Center Programs in Physical Therapy

  • Course: PHYTM8125 Kinesiology & Biomechanics I

  • Instructor: Dr. Wing Fu, PT, PhD, MA

Key Anatomy

Bone Structures

  • Femur

  • Patellofemoral joint

  • Tibia (Proximal and Distal)

  • Fibula

Important Joints

  • Tibiofemoral joint

    • Comprises medial and lateral compartments

Biomechanical Functions

Functional Length Changes of the Lower Extremity (LE)

  • Swing Phase: Difficulty in knee flexion impacts mobility.

  • Stance Phase: Inability to fully extend the knee affects stability.

Force Transmission and Shock Absorption

  • Considerations during activities such as jumping from heights.

The Impulse-Momentum Theorem

  • Refer to video link for an overview of fundamental concepts (YouTube: fdeH6Ksedwk).

Arthrology: Knee Alignment

Frontal Plane Considerations

  • Tibiofemoral angle

    • Normal genu valgum: 170 to 175 degrees on the lateral side

Mechanical Effects (Knee Angles)

  • Angles < 170 degrees

    • Increased compression on the lateral side

    • Tension on medial structures (e.g., MCL)

  • Angles > 180 degrees

    • Increased compression on the medial side

    • Tension on lateral structures

Tibiofemoral Joint (TF Joint)

  • Articulations include ffemoral condyles (large and convex) and tibial condyles (smaller and nearly flat).

  • Joint stability is ensured not just by bony fit but also through

    • Muscles

    • Ligaments

    • Joint capsules

    • Menisci and body weight

Menisci of TF Joint

Functions

  1. Reduce compressive stress by increasing contact area.

  2. Stabilize the joint by increasing congruity.

  • Post-menisectomy conditions: Potential increased stress and instability.

Ligaments of the Tibiofemoral Joint

Collateral Ligaments

  • Functions:

    • Limit frontal plane motions

    • Stabilize the knee in sagittal plane

    • Tension increases at full extension

    • Limit extremes of internal/external rotation

Cruciate Ligaments

  • ACL and PCL Functions:

    • Resist infringe of knee motions including anterior-posterior shear forces

    • Guide arthrokinematics and improve proprioception

    • Injury may lead to knee instability.

Anterior Cruciate Ligament (ACL)

  • Functions:

    • Resists extension, primarily preventing anterior tibial displacement on femur

    • Reacts throughout flexion/extension

  • Test methods for injuries include Lachman's and anterior drawer tests.

Posterior Cruciate Ligament (PCL)

  • Functions:

    • Resists posterior tibial translation on femur

    • Becomes tighter with greater flexion, maximizing tension at 90-120 degrees.

Osteokinematics at TF Joint

  • Two degrees of freedom:

    • Flexion and extension in the sagittal plane

    • Internal and external rotation in the horizontal plane

  • Range of Motion (ROM)

    • 5 to 10 degrees extension beyond the neutral 0-degree position

    • 130 to 140 degrees flexion.

Arthrokinematics at the TF Joint

Tibial-on-Femoral Extension

  • ROLL - SLIDE mechanics and influence of screw-home rotation.

Femoral-on-Tibial Mechanics

  • Examination focuses on flexion and rotation dynamics.

Muscle Functions

Knee Extensors (Quadriceps)

  • Components: Rectus Femoris, Vastus Lateralis, Medialis, and Intermedius

  • Torque production mainly around 20 to 60 degrees of flexion.

Flexor-Rotator Functions

  • Hamstrings, Sartorius, and Popliteus play significant roles in knee personalization; controlling movements during gait phases.

Functional Role of the Patella

  • Acts as a pulley mechanism for quadriceps function, enhancing extension movement dynamics.

Patellar Tracking

  • Q-angle metric to assess lateral pull, notable in females due to anatomical differences.

Ankle and Foot Overview

Functions

  • Stability and mobility are crucial for gait and weight-bearing activities

  • Ankle joints: Talocrural (ankle), and Proximal/Distal Tibiofibular joints

Osteology and Movements

  • Key structures include tibia, fibula, tarsals, and metatarsals.

  • Fundamental movements: Inversion, Eversion, Dorsiflexion, and Plantarflexion, along with their axes and planes.

Subtalar Joint Mechanics

  • Primary roles in inversion/eversion, adapting foot movements for gait stability.

  • Couple actions across three cardinal planes for effective locomotion.

Summary of Joint Actions

  • Comprehensive assessments of osteokinematics guide therapies for rehabilitation and enhancement of mobility.