Forearm/elbow

Question 1

the elbow is a ___________ joint

Answer 1

modified hinge

Question 2

“carrying angle”

Answer 2

cubitus valgus

Question 3

what makes up the carrying angle?

Answer 3

angle between long axis of humerus and long axis of forearm

Question 4

normal cubitus valgus angle

Answer 4

15º

Question 5

functional implication of cubitus valgus

Answer 5

ulnar nerve stretched more across medial elbow

Question 6

what reinforces MCL?

Answer 6

prox wrist flexors and pronators

Question 7

normal PROM of elbow

Answer 7

5-0-145

Question 8

is a loss of flexion or extension more meaningful at the elbow?

Answer 8

flexion

Question 9

elbow arthrokinematics

Answer 9

open chain:

concave on convex - roll and glide in same direction

Question 10

what makes up the humeroradial joint?

Answer 10

fovea of radial head

capitulum of humerus

Question 11

what makes up humeroulnar joint?

Answer 11

trochlear notch of ulna

trochlea of humerus

Question 12

what makes up the prox radioulnar joint?

Answer 12

ulnar radial notch
annular ligament
radial head

Question 13

what makes up the distal radioulnar joint?

Answer 13

ulnar notch of radius
head of ulna
articular disc

Question 14

TFCC

Answer 14

triangular fibrocartilage complex

Question 15

proximal part of TFCC articulates with _______ and distal part articulates with _________

Answer 15

ulnar head; carpals

Question 16

primary stabilizer of distal radioulnar joint

Answer 16

TFCC

Question 17

a pt comes in complaining of lateral wrist pain. what do you assume might be implicated?

Answer 17

TFCC

Question 18

direction of axis of radioulnar joints

Answer 18

vertical

Question 19

3 joints that can limit sup/pro

Answer 19

prox and distal radioulnar

humeroradial

Question 20

normal ROM of pronation

Answer 20

75º

Question 21

normal ROM of supination

Answer 21

85º

Question 22

neutral position between supination and pronation

Answer 22

thumbs up

Question 23

how many DOF of radioulnar joints?

Answer 23

1

Question 24

how do we compensate for supination/pronation ROM limitations?

Answer 24

ER/IR

Question 25

proximal radioulnar joint arthrokinematics

Answer 25

convex radial head rotates in fibro-osseous ring on concave radial notch - ring prohibits typical arthrokin

Question 26

distal radioulnar joint arthrokinematics

Answer 26

concave radius and convex ulna - roll and glide in direction of radial head motion

Question 27

pronation/supination occur closed chain as a function of...

Answer 27

glenohumeral ER/IR

Question 28

3 elbow flexors

Answer 28

1. biceps 2. brachialis 3. brachioradialis

Question 29

what elbow flexor generates the most force?

Answer 29

brachialis

Question 30

biceps is most effective with _______

Answer 30

supination

Question 31

when is brachioradialis most effective?

Answer 31

during elbow flexion with neutral forearm - esp during rapid movements

Question 32

in what orientation do triceps generate max force? why?

Answer 32

~90º bc length tension

Question 33

triceps frequently act as a _________

Answer 33

stabilizer

Question 34

elbow extension often performed with __________

Answer 34

shoulder flexion

Question 35

in a pushup, what keeps the triceps from extending the elbow AND shoulder?

Answer 35

anterior delt - opposes shoulder extension torque

Question 36

law of parsimony application to elbow extension

Answer 36

anconeus --> triceps

Question 37

law of parsimony application to supination

Answer 37

supinator --> biceps

Question 38

choose the stronger movement: supination or pronation

Answer 38

supination

Question 39

2 primary supinators

Answer 39

supinator | biceps

Question 40

4 secondary supinators

Answer 40

radial wrist extensors EPL ext indicis brachioradialis (if starting from pronated position)

Question 41

what angle is biceps best able to supinate at? why?

Answer 41

90º - LoF is perpendicular to and radius

Question 42

2 primary pronators

Answer 42

pronator quadratus | pronator teres

Question 43

law of parsimony application to pronation

Answer 43

quadratus --> teres

Question 44

3 secondary pronators

Answer 44

1. FCR 2. palmaris longus 3. brachioradialis (from supinated position)

Question 45

the law of parsimony states that the nervous system tends to activated _______________ for the control of a given joint action

Answer 45

the fewest muscles or muscle fibers possible

Question 46

why does the law of parsimony happen?

Answer 46

energy conservation - when bigger muscles are used, other muscles also turn on to stabilize/counteract

Question 47

tasks with low-level force demands are often accompished by...

Answer 47

uniarticular muscles

Question 48

fx of the cervical spine may result in..

Answer 48

C6 quadriplegia

Question 49

an essential component to maximizing movement efficiency in a person with paralysis

Answer 49

"muscle substitution"

Question 50

what is muscle substitution?

Answer 50

movement strategies that enable people with paraplegia to use an innervated muscle to substitute for part of the functional loss imposed by a paralyzed muscle

Question 51

people with C6 quad usually can't use their ________

Answer 51

elbow extensors

Question 52

what muscles can "substitute" for elbow extensors?

Answer 52

clavicular head of pec major and/or anterior delt

Question 53

explain how shoulder muscles can sub for elbow extensors

Answer 53

shoulder muscles adduct and/or horizontally flexes the GH joint, pulling humerus toward midline with hand firmly fixed distally