Week 3: Elbow/Forearm Complex

Question 1

Which muscles perform elbow flexion?

Answer 1

biceps brachii
brachialis
brachioradialis

Question 2

Which muscles perform elbow extension?

Answer 2

triceps brachii
anconeus

Question 3

Which muscles perform forearm supination?

Answer 3

biceps brachii
supinator

Question 4

Which muscles perform forearm pronation?

Answer 4

pronator teres
pronator quadratus

Question 5

Which muscle is the prime mover in elbow flexion with forearm supinated?

Answer 5

biceps brachii

Question 6

Which muscle is the prime mover in elbow flexion with the forearm neutral?

Answer 6

brachioradialis

(think thumb side up –> radius is thumb side)

Question 7

Which muscle is the prime mover in elbow flexion with the forearm pronated?

Answer 7

brachialis

Question 8

What are the all the motions of the biceps brachii?

Answer 8

shoulder extension
elbow flexion
foream supination

Question 9

What are the two joints of the elbow-forearm complex?

Answer 9

humero-ulnar joint (elbow)
radio-ulnar joint (forearm)

Question 10

What are the bony landmarks of the distal humerus?

Answer 10

medial epicondyle
lateral epicondyle
trochlea
capitulum
olecranon fossa

Question 11

The medial epicondyle is the attachment for which muscles?

Answer 11

wrist and long finger flexors

Question 12

Inflammation of the medial epicondyle, or medial epicondylitis, is also commonly called ______ .

Answer 12

golfer’s elbow

Question 13

The lateral epicondyle is the attachment for which muscles?

Answer 13

wrist and long finger extensors

Question 14

Inflammation of the lateral epicondyle, or lateral epicondylitis, is also commonly called ______ .

Answer 14

tennis elbow

Question 15

Identify the structure labeled (n) and describe its function

Answer 15

trochlea
articulates with the ulna medially

Question 16

Identify the structure labeled (m) and describe its functionIdentify the structure labeled (m) and describe its function

hint: this structure only functions in one position

Answer 16

capitulum
articulates with the head of the radius laterally

(only in full flexion)

Question 17

Identify the structure labeled (k) and describe its function

Answer 17

olecranon fossa
convex surface on the posterior side of the humerus where the olecranon fossa (located on the ulna) articulates with the distal humerus

Question 18

What is the “carrying angle” of the elbow?

Answer 18

normal valgus at the elbow due to the medial end of the humerus (trochlea) being more distal than the lateral structures

valgus - medial, oblique angle of a joint which causes the limb to be angled away from the midline

Question 19

Define:

valgus

Answer 19

oblique medial angle of a joint causing a limb to be angled away from the midline of the body

example: knock knees, carrying angle of elbow

Question 20

Define:

varus

Answer 20

oblique lateral angle of a joint causing a limb to be angled toward the midline of the body

example: bow legs

Question 21

What kind of joint is the humero-ulnar joint?

Answer 21

uniaxial synovial joint:
hinge

Question 22

What kind of joint is the radio-ulnar joint?

two parts

Answer 22

proximal/superior radio-ulnar joint (elbow) - synovial
distal/inferior radio-ulnar joint (wrist) - fibrous (syndesmosis)

Question 23

What are the three ligaments of the elbow?

Answer 23

medial collateral ligament (MCL)
lateral collateral ligamnet (LCL)
annular ligament

Question 24

What is the location of the ligament and what does it do?

medial collateral ligament

Answer 24

location: medial/ulnar epicondyle to coronoid and olecranon process

function: limits abduction, limits valgus stress on the proximal forearm

(describe valgus stress)

Question 25

# What is the location of the ligament and what does it do? lateral collateral ligament

Answer 25

location: lateral/radial epicondyle to annular ligament and olecranon process function: limits adduction, limits varus stress to proximal forearm | (describe varus stress)

Question 26

# What is the location of the ligament and what does it do? annular ligament

Answer 26

location: holds radial head in place, lined with articular cartilage function: allows for rotation, limits dislocation of the radial head

Question 27

What is the ligament of the forearm? | (include location and purpose)

Answer 27

interosseous membrane location: between ulna/radius function: hold ulna and radius together

Question 28

What is the function of the olecranon bursa? ## Footnote What is a bursa?

Answer 28

between olecranon and skin on the posterior surface of the olecranon ## Footnote Fluid-filled sac that cushions and reduces friction within a joint

Question 29

Which three peripheral nerves innervate the elbow flexors/extensors and supinators/pronators?

Answer 29

musculocutaneous nerve radial nerve median nerve

Question 30

# Location and muscles it innervates: musculocutaneous nerve

Answer 30

anterior upper arm brachialis biceps brachii ## Footnote musculocutaneous nerve ONLY innervates two elbow flexors

Question 31

# Location and muscles it innervates: radial nerve

Answer 31

posteraior upper arm/lateral forearm brachioradialis triceps brachii anconeus supinator ## Footnote radial nerve innervates BOTH elbow extensors

Question 32

# Location and muscles it innervates: median nerve

Answer 32

anterior/medial forearm pronator teres pronator quadratus ## Footnote median nerve ONLY innervates pronators

Question 33

# Which nerve innervates this muscle: brachialis

Answer 33

musculocutaneous

Question 34

# Which nerve innervates this muscle: triceps brachii

Answer 34

radial

Question 35

# Which nerve innervates this muscle: brachioradialis

Answer 35

radial

Question 36

# Which nerve innervates this muscle: pronator teres

Answer 36

median

Question 37

# Which nerve innervates this muscle: anconeus

Answer 37

radial

Question 38

# Which nerve innervates this muscle: biceps brachii

Answer 38

musculocutaneous

Question 39

# Which nerve innervates this muscle: supinator

Answer 39

raidal