Lecture 2: Mechanics of Locomotion

Question 1

adduction

Answer 1

toward median plane

Question 2

abduction

Answer 2

away from median plane

Question 3

inward rotation

Answer 3

relative to long axis

Question 4

outward rotation

Answer 4

relative to long axis

Question 5

circumduction

Answer 5

conical movement
combo of all other movements (rotation, abduction, adduction)

Question 6

pronation

Answer 6

rotates forepaw caudally

Question 7

supination

Answer 7

rotates forepaw cranially

Question 8

pronation and supination: definition

Answer 8

partial rotation of the proximal extremity of the radius within annular ligament of the ulna while the distal extremity is carried in an arc around the ulna

Question 9

plantigrade

Answer 9

walking on soles of feet/hands

Question 10

digitigrade

Answer 10

walking on fingers/toes
not touching ground with heels

Question 11

unguligrade

Answer 11

walking on hooves (specialized fingertips)

Question 12

location of limb mass with extended distal limbs (and why/importance)

Answer 12

concentrated close to trunk
more muscle further from body requires more torque and energy to move

Question 13

how do elongated limbs provide energetic savings

Answer 13

larger animals have lower metabolic rate –> can have limbs further from body = cost of locomotion is less

Question 14

synovial sheaths function

Answer 14

pulley for long tendon
reduce friction

Question 15

retinacula: definition, function

Answer 15

contain flexors and extensors
pulley for long tendon
tendon groups that pass under a band of connective tissue

Question 16

advantage of elongated tendons for energy storage

Answer 16

short muscle belly + elongated tendon = stores elastic energy for movement
stretch and elastic recoil**

Question 17

is there an energetic cost associated with standing

Answer 17

yes

Question 18

what contracts to maintain a standing quadrupedal posture

Answer 18

limb and back extensors

Question 19

what can smaller animals do during locomotion that large animals can’t

Answer 19

increase stride length with vertebral column flexion/extension

Question 20

support phase of gait cycle begins with

Answer 20

heel strike

Question 21

swing phase of gait cycle begins with

Answer 21

toe off

Question 22

how do flexors and extensors relate during walking (hint: EMG)

Answer 22

fire at different times
counteract each other to work together