Quizzes

• What is the tidemark of cartilage?

  The line at the border of the calcified zone, inhibits passage of nutrients and gases from bone to the cartilage
• What is lacking in articular hyaline cartilage that makes it less able to self-repair?

  perichondrium
• What layer of articular cartilage is most likely to be damaged by shear forces?

  deep zone near the tidemark
• If both the liquid and solid phases are incompressible separately, what makes them act compressible to disperse compression forces?

  water leaving the cartilage
• Articular cartilage is made up of what type of collagen?


  type II
• How does articular cartilage get its nutrition?

  by imbibing synovial fluid when unloaded
• GAGs provide structure and rigidity to cartilage by what two mechanisms?

  Anionic repulsion and attraction of water
• Which phase of cartilage resists compressive forces first?

  fluid phase
• What happens to the permeability of articular cartilage when water content increases (total and %)?

  increases
• How can exercise help reduce the effects of osteoarthritis on articular cartilage (AC)?

  Increases GAG content
• Tendons and ligaments are made of what type of collagen?

  type I
• How does the crimp, seen in tendon and ligament collagen, show up on the stress strain curve?

  As the toe region (significant strain with minimal stress)
• Ligament failure is more due to skeletal maturity as opposed to viscoelasticity.
• How does increased temperature affect the creep of tendon or ligament?

  Increases with increased temperature (37-40 degrees C)
• At what timeframes across the lifespan are we most likely to experience an avulsion fracture rather than a midsubstance tendon rupture?

  When very young and when very old
• When a muscle starts to fatigue, as the person tries to maintain the same muscle force, what is seen on an EMG of that muscle?

  Increased signal, meaning more motor units are being recruited
• seen with the aging muscle

  decreased muscle mass

  senile sarcopenia

  apoptosis
• According to the Henneman size principle, smaller motor units are recruited before larger ones.
• What is muscle resting length?

  When the optimal overlap of actin and myosin allows the most crossbridges to form
• What functional purpose does pennation architecture serve within a muscle compared to parallel architecture in muscle?

  To provide more muscle force per unit volume compared to parallel muscle
• Which of the following defines the physiologic cross-sectional area of a muscle?

  The area of multiple cross-section made perpendicular to each of the muscle fibers
• The perimycium surrounds what portion of the muscle?

  muscle fascicle
• What makes up a motor unit?

  A motor neuron, all the motor end plates at each myofiber, and all the myofibers innervated by the motor nerve
• Which motion is most restricted in the capsular pattern of the hip?

  internal rotation
• Besides facing laterally, what other directions does the acetabulum face?

  anterior and inferior
• A person with femoral retroversion will likely present with what compensatory posture in the lower extremity?

  toe out
• Which of the following is a function of the hip labrum?

  increase stability of the joint
• Which of the following BEST defines Coxa Valga

  Increased angle of inclination
• What hip joint position results in the greatest tension in the three major hip ligaments?

  Extension
• Your patient's increased acetabular anteversion angle puts them at risk for what potential problem?

  anterior dislocation
• What muscle group can function as flexors, extensors, and adductors at the hip?

  Adductors
• What does a Compensated Trendelenberg Gait (AKA Compensated Gluteus Medius Gait) look like?

  Shift their COM over the ipsilateral side (the weaker hip abductor)
• Which of the following best describes the arthrokinematics of the hip when performing external rotation at 90o of hip flexion.  In other words, the hip is held stationary in the sagittal plane at 90o of hip flexion (as in sitting), while moving into external rotation.

  inferior roll/ superior glide
• What hip ligament(s) become(s) taut with hyperextension?

  Iliofemoral, Ischiofemoral, and Pubofemoral
• How is "Coxa Valga" defined?

  increased angle of inclination
• Which hip abductor is the strongest and why?

  Glut. Med: longest MA and largest Physiological Cross Sectional Area (pCSA)
• You have a patient do a double SLR (straight leg raise) and you notice a significantly increased lumbar lordosis and inability to lift the straight legs. What is the most likely cause of his increased lordosis?

  weak abdominals
• While lying prone and actively pulling the foot up behind you (as in the image below), AROM is much less than PROM. This is an example of what length-tension relationship?

  Active insufficiency of the hamstrings
• How would you describe the arthrokinematics of hip abduction from anatomic position?

  Superior roll, inferior glide