Elbow

Question 1

What group of muscles have their origin at the Medial Epicondyle of the Humerus?

Answer 1

The flexor pronator group of the forearm.

Question 2

What group of muscles have their origin at the Lateral Epicondyle of the Humerus?

Answer 2

The extensor supinator group of the forearm.

Question 3

Why is the end-feel for elbow extension hard?

Answer 3

Because it is limited by the olecranon process coming into contact with the olecranon fossa.

Question 4

Describe what the carrying angle (valgus angle) at the elbow is

Answer 4

The normal slight valgus angle (136) at the elbow that causes the elbow to be closer to the midline of the body than the wrist.
This angle is created due to the distal humerus being slightly at a diagonal, in that the medial epicondyle is more distal than the lateral epicondyle.

Question 5

What is a cubitus valgus deformity?

Answer 5

A greater than normal amount of valgus angle at the elbow. Typically determined by comparing both arms.

Question 6

What is a cubitus varus deformity?

Answer 6

A less than normal amount of valgus angle at the elbow.

Question 7

How would these deformities occur?

Answer 7

Usually due to a distal humerus fracture that heals with an abnormal alignment of the medial or lateral epicondyle.

Question 8

Which ligament at the elbow controls a valgus force?

Answer 8

The medial collateral (UCL) ligament.

Question 9

Which ligament at the elbow controls a varus force?

Answer 9

The lateral collateral (RCL) ligament.

Question 10

Which ligament at the elbow stabilizes the radial head against the ulna and is disrupted with Nursemaid’s Elbow?

Answer 10

The annular ligament.

Question 11

How does a posterior elbow dislocation typically occur and why is this much more likely than an anterior dislocation at this joint?

Answer 11

Typically with the arm extended and the forearm supinated, and a fall onto the palm of the hand. The trochlear notch of the ulna prevents it from dislocating anteriorly because this has such a secure hold on the distal humerus. There is some disagreement between the two textbooks we use for this course, but what is generally accepted is that it is more common for the LCL to rupture first, and then if there is enough force, you have a posterolateral rotational motion that dislocates the radial head and proximal ulna posteriorly and finally the last stage would be rupture of the MCL.

Question 12

In what order are ligaments typically sprained with a posterior dislocation of the elbow in the above scenario?

Answer 12

LCL, capsule, MCL

Question 13

What injury is an indication for a “Tommy John” surgery?

Answer 13

An overuse tear or rupture of the UCL/MCL at the elbow.

Question 14

What is the Terrible Triad at the elbow?

Answer 14

LCL tear, radial head fracture and coronoid process fracture. Due to the valgus force at the elbow, with a strong compression force from a fall onto an outstretched arm, the radial head can be broken and along with that the posterolateral force ruptures the LCL and drives the ulna posteriorly fracturing the coronoid process.

Question 15

What is the “functional arc” at the elbow?

Answer 15

30 - 130 degrees of elbow flexion are considered necessary to accomplish most ADLs.

Question 16

Which nerve resides in the cubital tunnel and which in the cubital fossa?

Answer 16

The ulnar nerve is in the cubital tunnel at the medial elbow, “funny bone”, and the median nerve runs near the midline of the cubital fossa. The radial nerve also crosses anteriorly at the elbow briefly but on the lateral side.

Question 17

What are the functions of the interosseous membrane?

Answer 17

This is an attachment site for many muscles, prevents distraction of the ulna and radius from each other, and transfers some force or weight bearing from the radius to the ulna

Question 18

With pronation, which bone crosses over the other, or which remains stationary?

Answer 18

The ulna remains stationary and the radius crosses over it.

Question 19

How could a client compensate for lack of supination/pronation ROM?

Answer 19

With shoulder external/internal rotation.

Question 20

When does the humeroradial joint move in conjunction with the superior radioulnar joint?

Answer 20

During pronation and supination the radial head is spinning on the capitulum and also within the radial notch of the ulna.

Question 21

Can the superior radioulnar joint move independently from the distal radioulnar joint?

Answer 21

No

Question 22

When does pronation/supination rely on the humerus moving over the forearm?

Answer 22

If the hand is planted or stabilized against a surface.

Question 23

What is the most common complication after an elbow fracture?

Answer 23

Stiffness and loss of range of motion. Elbow flexion contracture if untreated.

Question 24

What is the most common bony area fractured at the elbow and why?

Answer 24

The radial head, because this is the most likely area of pressure with a fall onto an outstretched arm and a valgus force, and this is a narrow portion of bone.

Question 25

Which muscle is mostly likely to adhere to the anterior joint capsule at the elbow?

Answer 25

The brachialis lies just over the anterior joint capsule at the elbow and is hypothesized to be one of the causes of elbow stiffness after a period of immobilization.

Question 26

Is the head of the radius at the elbow or the wrist?

Answer 26

The Elbow

Question 27

n pronation which of the following is happening?

Answer 27

The radius is crossing over on top of the ulna

Question 28

Which of the following describes a normal amount of valgus at the elbow? *

Answer 28

A carrying angle of about 13 degrees, generally more in women than in men, with the elbow held closer to the body than the wrist if the client is in anatomical position

Question 29

Which of the following ligaments limits a varus force?

Answer 29

The lateral collateral ligament

Question 30

Which side of the elbow does the ulnar ligament travel along?

Answer 30

Medial

Question 31

An ulnar collateral ligament tear or “Tommy John” injury is the result of one traumatic event or an overuse syndrome?

Answer 31

Overuse syndrome

Question 32

Nursemaid’s elbow or radial head dislocation occurs due to failure of which ligament?

Answer 32

The annular ligament

Question 33

The muscle most often associated with lateral epicondylitis is the:

Answer 33

Extensor carpi radialis brevis

Question 34

Medial epicondylitis results from overuse of:

Answer 34

Wrist flexor muscles

Question 35

So far we have learned that the ulnar nerve can become entrapped in the following locations:

Answer 35

The Cubital Tunnel.

Guyon’s Canal.