elbow joints

Question 1

how many joints are within the elbow complex

Answer 1

4 joints

provide increased mobility for the hand and wrist

also provide stability

Question 2

what does the elbow allow

Answer 2

the hand to approach or extend away from the body

Question 3

what does the forearm do

Answer 3

adjusts the hand’s approach to an object

Question 4

joints of the elbow

Answer 4

humeroulnar joint

humeroradial joint

Question 5

humeroulnar joint

Answer 5

articulation b/w the antero-medial aspect of the distal humerus and the proximal ulna

the trochlea of the humerus and the trochlear notch of the ulna

Question 6

what is the trochlea and what is the trochlear notch within the humerolulnar joint

Answer 6

trochlear is concave transversely and convex anteroposteriorly

trochlear notch is semicircular shaped concave surface

Question 7

humeroradial joint

Answer 7

articulation b/w the capitulum and the head of the radius

capitulum –> convex

head of the radius –> concave

Question 8

humeroradial and humeroulnar joints are…

Answer 8

one compound joint that functions as a hinge joint

uniaxial, diarthrodial joint with 1 degree of freedom

allows for flexion and extension(sagittal plane around a frontal axis)

Question 9

normal ROM of the humeroulnar and humeroradial joints

Answer 9

0-145 degrees (actively)

0-160 degrees (passively)

anything beyond 0 degrees is hyperextension

Question 10

what is the axis of motion for the elbow joint

Answer 10

oblique

passes through the center of the capitulum and the trochlea

runs from lateral to medial, superior to inferior

Question 11

arthrokinematics of the elbow joint in flexion

Answer 11

concave on convex

bone motion, roll and glide are anterior

Question 12

arthrokinematics of the elbow joint in extension

Answer 12

concave on convex

bone motion, roll and glide are posterior

Question 13

accessory motions for flexion

Answer 13

adduction

d/t the alignment of the joint axis and shape of the articular surfaces

supination (can be overcome, more of a tendency)

Question 14

accessory movements for extension

Answer 14

abduction

d/t the alignment of the joint axis and shape of the articular surface

pronation (can be overcome, more of a tendency)

Question 15

valgus position

Answer 15

when the distal segment of a joint is more lateral than the proximal segment

has to do with frontal plane alignment

Question 16

valgus stress

Answer 16

a stress that tends to make the distal segment more lateral

Question 17

varus position

Answer 17

when the distal segment is more medial

Question 18

varus stress

Answer 18

a stress that tends to make the distal segment more medial

Question 19

radioulnar joints

Answer 19

superior radioulnar joint

inferior radioulnar joint

intermediate radioulnar joint

Question 20

superior radioulnar joint

Answer 20

the articulation located on the lateral aspect of the proximal ulna

directly below the trochlear notch

occurs b/w the convex radial head and the concave radial notch of the ulna (1/5)

occurs b/w the radial head and a ring formed by the annular ligament (4/5)

Question 21

inferior radioulnar joint

Answer 21

the articulation b/w the head of the ulna, the ulnar notch of the radius and the intra-articular disk

Question 22

intra-articular disk

Answer 22

triangular shaped

articulates proximally with the ulnar head and distally with the carpal bones

concave on both sides

Question 23

intermediate radioulnar joint

Answer 23

occurs along the 2 shafts of the bones and is held together by the interosseous membrane

is a syndesmosis joint

Question 24

interosseous membrane primary role

Answer 24

membrane’s primary role is to keep the bones in proper alignment

Question 25

what type of joints are the superior and inferior radioulnar joints

Answer 25

pivot or trochoid joints

diarthrodial, uniaxial joints with 1 degree of freedom

Question 26

what motions do the superior and inferior radioulnar joints allow

Answer 26

pronation and supination

transverse plane around a vertical axis

Question 27

full supination to full pronation ROM

Answer 27

0-150/170

Question 28

the radioulnar joints are

Answer 28

mechanically linked

motion at one joint is accompanied by motion at another joint

Question 29

axis of motion for radioulnar joints

Answer 29

longitudinal

extending from the radial head to the ulnar head

moving bone = radius

Question 30

arthrokinematics in the supinated position

Answer 30

the radius and ulna are parallel

radius is lateral to the ulna

Question 31

arthrokinematics during pronation

Answer 31

the radius crosses over the ulna and moves medially

the radius is considered the moving bone

Question 32

arthrokinematics for pronation

Answer 32

bone motion is the radius moving anteriorly

Question 33

arthrokinematics for supination

Answer 33

bone motion is the radius moving posteriorly

Question 34

at the proximal radioulnar joint, during pronatio

Answer 34

the convex radial head moves on the concave radial notch of the ulna

ulna moves very little

Question 35

supination at the proximal radioulnar joint (arthrokinematics)

Answer 35

bone motion and roll –> posterior

glide –> anterior

Question 36

pronation at the proximal radioulnar joint (arthrokinematics)

Answer 36

bone motion and roll –> anteriorly

glide –> posteriorly

Question 37

at the distal radioulnar joint

Answer 37

the concave ulnar notch of the radius moves on the convex ulnar head

Question 38

distal radioulnar joint during supination

Answer 38

radius moves posteriorly

ulnar head moves medially and anteriorly

Question 39

distal radioulnar joint during pronation

Answer 39

radius moves anteriorly

ulnar head moves laterally and posteriorly