cubital joint

Question 1

classification

Answer 1

synovial hinge

Question 1

axes of movement

Answer 1

1 - transverse

Question 2

articular surfaces

Answer 2

humero-ulna
trochlea of humerus with trochlea notch of ulna
humeroradial
capitulum of humerus with head of radius

Question 3

two features of trochlea of humerus

Answer 3

concave in frontal plane
convex in sagittal plane

Question 4

feature of trochlear notch of ulna

Answer 4

congruent fit to groove of trochlea

Question 5

two features of capitulum of humerus

Answer 5

incomplete hemispherical shape
covered in hyaline cartilage, thickest centrally

Question 6

two features of head of radius

Answer 6

superior concave surface
raised edge for capitulo-trochlear groove

Question 7

what is the carrying angle

Answer 7

trochlea is tilted inferiorly on medial side causing lateral deviation of ulna and radius from humerus

Question 8

features of capsule

Answer 8

strong fibrous capsule
lined with synovial membrane
shared with superior radioulnar joint
blends with collateral ligaments (increases strength)
weaker anteriorly and posteriorly

Question 9

ligaments

Answer 9

ulnar collateral (anterior, posterior, transverse, intermediate)
radial collateral

Question 10

origin and insertion anterior band ulnar collateral ligament

Answer 10

medial epicondyle (anteriorly) -> coronoid process

Question 11

origin and insertion of posteiror band ulnar collateral ligament

Answer 11

medial epicondyle (posteriorly) -> olecranon

Question 12

origin and insertion of transverse band ulnar collateral ligament

Answer 12

coranoid process -> olecranon

Question 13

origin and insertion of intermediate band ulnar collateral ligament

Answer 13

medial epicondyle -> transverse band

Question 14

function of ulnar collateral ligament

Answer 14

limits abduction, anterior band helps limit extension

Question 15

origin and insertion of radial collateral ligament

Answer 15

lateral epicondyle -> blends with annular ligament of radius and margins of radial notch of ulna

Question 16

function of radial collateral ligament

Answer 16

limits adduction

Question 17

flexion degrees and limitations

Answer 17

145 (active) 160 passive
extensors, posterior joint capsule, soft tissue apposition

Question 18

extension degrees and limitations

Answer 18

0
flexors, anterior joint capsule, possibly bony apposition

Question 19

why is medial joint more stable than lateral?

Answer 19

articular surfaces - greater area and reciprocity
capsule - no bony attachment laterally
radial collateral ligament not as strong

Question 20

why is flexion more stable than extension?

Answer 20

greater contact between articular surfaces
head of radius moves closer to capitulum

Question 21

what position is most stable

Answer 21

90 degrees