MS II Final Exam Review

Based on content covered in class

Describe anatomical pulleys (function/purpose, examples)

• function: increase moment arm of muscle to increase torque with less force

  • muscle doesn’t have to work as hard

  • Torque = moment arm x force, so if you increase the moment arm but don’t change the force, torque increases

  • examples: patella for rectus femoris, calcaneus, acromion for deltoid, greater trochanter for glute med

What is the consequence of anatomical pulleys?

• bursa inflammation

• tendonapathy

Describe active insufficiency and give an example

• limitation from agonist muscle

• think about length-strength curve

• if a muscle is maximally shortened, in this position it will produce minimal force

• example: if I flex my shoulder and then try and do a a bicep curl, my biceps brachii is not producing its maximal force because it’s already shortened

Describe passive insufficiency and give an example

• limitation from antagonist muscle

• antagonist muscle can’t maximally lengthen, so it doesn’t allow agonist muscle to generate max force

• example: if my hamstrings are tight, I won’t be able to get into full knee extension even if my quads are contracting a maximum force

What is the function of mechanoreceptors? What might happen if they are not functioning properly?

• communicate proprioception to the brain

• if not functioning, brain not aware of body in space, leads to instability or balance issues

What is the function of muscle spindles?

• sense a stretch of a tendon and cause a reflexive contraction

• ex: if falling backwards, muscle spindles in tibialis ant. detect stretch and reflexively contract the muscle to bring tibia back over ankle

What is the function of golgi tendon organ?

• sense increased tone/tension in a muscle and cause a reflexive relaxation

• ex: feeling of muscles “letting go” if trying to suddenly lift a heavy weight

What is reciprocal inhibition?

• When an agonist muscle contracts, the antagonist muscle has to relax

• ex: if biceps contract, triceps have to relax

What is the capsular pattern of the shoulder?

ER, AB, IR

What is the capsular pattern of the hip?

flexion, MR, AB, some extension

What is the capsular pattern of the knee?

flexion, extension

What does loose pack position mean?

position where a joint is most relaxed (ligaments are lax)

What does closed pack position mean?

position where joint is most tight, ligaments are tight