Elbow Anatomy

Question 1

What are the 3 bands of the medial (ulnar) collateral ligament?

Answer 1

3 bands: anterior oblique, posterior, and transverse

Question 2

What is the strongest component of the MCL? What type of stability does it provide?

Answer 2

Anterior band of the MCL is the strongest stabilizer to valgus stress in 90 degress of flexion.

Question 3

The MCL of the elbow originates on the ____ and inserts on the ____.

Answer 3

Origin: posterior medial epicondyle
Insertion: sublime tubercle of medial coronoid process.

Question 4

During a pitch, which phase of motion exerts peak valgus torque on the MCL of the elbow?

Answer 4

Late cocking and early acceleration

Question 5

Surgical release of the ____ bundle of the MCL addresses elbow stiffness since this portion is tight in flexion.

Answer 5

Posterior

Question 6

What are the (4) components of the lateral collateral ligament complex of the elbow?

Answer 6

1. Lateral ulnar collateral ligament
2. Lateral radial collateral ligament
3. Accesory lateral collateral ligament
4. Annular ligament

Question 7

The ____ prevents posterolateral instability of the elbow.

Answer 7

Lateral ulnar collateral ligament complex

Question 8

The LUCL of the elbow originates on the ____ and inserts on the ___.

Answer 8

Origin: lateral epicondyle of humerus
Insertion: Crista supinatoris of the proximal ulna

Question 9

What test is used to diagnose posterolateral elbow instability?

Answer 9

Lateral pivot shift test: axial compression, valgus and supination

Question 10

The ____ ligament stabilizes the radioulnar joint.

Answer 10

annular ligament

Question 11

What happens in a positive lateral pivot shift test of the elbow, denoting posterolateral instability?

Answer 11

Radial head is forced posterior to the capitellum as the elbow is brought into progressive extension, revealing a dimple on the lateral aspect of the elbow. This typically occurs at roughly 30⁰ of flexion. As the elbow is flexed, the radial head reduces.

Question 12

According to Driscoll classification, which injuries are associated with tip, anteromedial facet and basal coronoid fractures?

Answer 12

1. Coronoid tip - associated with valgus injury (terrible triad).
2. Anteromedial facet - associated with vaurs injury (isolated coronoid)
3. Basal coronoid - associated with monteggia fractures.

Question 13

Anteromedial coronoid facet deficiency is associated with ______ instability.

Answer 13

Posteromedial rotary instability

Question 14

The coronoid is a structural ______ stabilizer.

Answer 14

Varus

Question 15

What structure is at risk in reconstruction of the MCL (elbow), resulting in the most common complication associate with this surgery?

Answer 15

Ulnar Nerve

Notes: Initial MCL reconstruction technique involved routine transposition of the ulnar nerve and detachment of the flexor-pronator mass. Transient ulnar nerve neuropraxia remains the most common complication.