Deck 8: The Elbow Complex

Question 1

Which of the following wrist muscles can play a significant role in resisting valgus stress to the elbow?

A) Brachioradialis
B) Flexor carpi ulnaris
C) Extensor carpi radialis
D) Flexor carpi radialis

Answer 1

B

Question 2

When the elbow is flexed using a lot of speed with the forearm in neutral (midposition),which elbow flexors are active?

Answer 2

Elbow joint muscles that cross only the humeroulnar joint cannot be affected by shoulder or radioulnar motion.These muscles are the medial and lateral heads of the triceps brachii,anconeus,and brachialis.

Question 3

What causes the carrying angle of the elbow joint? What functional purpose does the carrying angle serve?

Answer 3

The carrying angle is created by the obliquity of the humeral condyles and elbow joint axis.Although the elbow is a hinge joint,the axis is tilted slightly (down on the medial side).Thus,as the elbow flexes,the forearm moves medially on the humerus (like folding a piece of paper on a crooked fold).The effect is that elbow flexion brings the hand closer to the mouth (a very functional movement)without any glenohumeral rotation.

Question 4

When unresisted elbow extension against gravity is required,which of the elbow extensors is/are active?

Question 5

Which of the following structures is the primary stabilizer of elbow to valgus stress between 20° and 120° flexion?

A) Quadrate ligament
B) Oblique cord
C) Annular ligament
D) Medial collateral ligament

Question 6

The ________________radioulnar joint has a disc that is also known as ____________________.

A) superior,annular ligament
B) superior,triangular fibrocartilage complex (TFC)
C) inferior,annular ligament
D) inferior,triangular fibrocartilage complex (TFC)

Question 7

A football offensive lineman takes his three-point stance.The base of support (BOS)includes 1 upper extremity (hand placed on ground)and both lower extremities with his right elbow in 30° of flexion.Which of the following would best resist a valgus stress applied to the humeroulnar joint by an opposing player?

A) Lateral collateral ligament
B) Anterior medial collateral ligament
C) Lateral ulnar collateral ligament
D) Posterior medial collateral ligament

Question 8

During elbow extension from 90° flexion at the humeroradial joint,the radial head rolls in a(n)________________direction and glides in a(n)________________direction on the capitulum at the humeroradial joint.

A) anterior/cephalic,posterior/inferior
B) posterior/caudal,posterior/inferior
C) anterior/cephalic,anterior/inferior
D) posterior/caudal,anterior/inferior

Question 9

If there is no angulation between the long axis of the humerus and the long axis of the forearm,what condition exists?

Question 10

Which of the following muscles helps to support the medial collateral ligament when exposed to large valgus forces?

A) Brachioradialis
B) Flexor carpi ulnaris
C) Pronator quadrates
D) Anconeus

Question 11

In which position is the central band of the interosseous membrane the most taut?

A) Midway between supination and pronation
B) At full supination
C) At full pronation

Question 12

Which of the following would you consider to be a limiter of motion when a patient cannot achieve full elbow extension?

A) Passive tension of the flexor muscles
B) Tension in the posterior ligaments
C) Passive tension of the elbow extensor muscles
D) Posterior capsular tightness

Question 13

Which of the following groups of soft tissue structures could potentially limit full forearm supination?

A) Oblique cord,quadrate ligament,distal palmar radioulnar ligament
B) Lateral collateral ligament,oblique cord,distal anterior radioulnar ligament
C) Quadrate ligament,distal posterior radioulnar ligament,oblique cord
D) Distal posterior radioulnar ligament,interosseous membrane,oblique cord

Question 14

Which of the following muscles works to dynamically support the distal radioulnar joint?

A) Pronator quadratus
B) Pronator teres
C) Flexor carpi radialis longus
D) Palmaris longus

Question 15

Which of the following describes the arthrokinematic motion that occurs at the humeroulnar joint when the elbow is flexing to bring your hand to your mouth?

A) Caudal/anterior/cephalic glide of ulna on trochlea; medial glide of ulna on trochlea
B) Cephalic/posterior/caudal glide of ulna on trochlea; medial glide of ulna on trochlea
C) Caudal/anterior/cephalic glide of ulna on trochlea; lateral glide of ulna on trochlea
D) Cephalic/posterior/caudal glide of ulna on trochlea; lateral glide of ulna on trochlea

Question 16

Where would you position the elbow joint to optimize the biomechanical effects of both the brachialis and the biceps brachii?

Question 17

Which muscles are the first recruited in forearm supination and pronation?

Question 18

In full elbow extension,varus stability is provided by which of the following bony and/or noncontractile soft tissue structures?

A) Configuration of the joint surfaces,medial collateral ligament,anterior ligament
B) Posterior ligament,configuration of the joint surfaces,annular ligament
C) Oblique cord,quadrate ligament,configuration of the joint surfaces
D) Configuration of the joint surfaces,joint capsule,lateral collateral ligament

Question 19

Which of the following elbow flexors produces the greatest amount of compression in the elbow joint and therefore is a stabilizer of the elbow?

A) Biceps brachii
B) Pronator teres
C) Brachioradialis
D) Brachialis

Question 20

Which of the following structures will resist a valgus stress to the elbow at 30° of flexion?

A) Interosseous membrane
B) Annular ligament
C) Medial collateral ligament

Question 21

What is the causative mechanism and the structure(s)involved in "cubital tunnel syndrome"?

Question 22

What is the causative mechanism and the structure(s)involved in "Nursemaid's elbow"?

Question 23

What is the causative mechanism and the structure(s)involved in avascular necrosis of the radial head?

Question 24

What is the causative mechanism and the structure(s)involved in "tennis elbow"?