The AC Joint | Anatomy, Injury, & Diagnostic Test Cluster

The video tutorial provides an in-depth look at the anatomy of the acromioclavicular (AC) joint, detailing its components and their functions. It explains various types of AC joint injuries, their mechanisms, and symptoms. The tutorial also covers diagnostic tests used to identify AC joint injuries, emphasizing the importance of localized pain at the joint. The six types of AC joint injuries are discussed, highlighting the differences in ligament damage and clavicle displacement. The video concludes with a review of diagnostic test clusters that help confirm AC joint injuries.

Which structure is more anterior in the shoulder girdle, helping to identify the anterior view?

• Glenoid fossa

• Acromion

• Coracoid process

• Spine of the scapula

What is the role of the coracoacromial ligament in the AC joint?

• Stabilizes the AC joint

• Connects the clavicle to the scapula

• Supports the humerus

• Connects two parts of the scapula

What is a common mechanism of injury for the AC joint?

• Lifting heavy objects

• Direct blow to the sternum

• Repetitive overhead motion

• Fall on an outstretched elbow

In a Type 1 AC joint injury, which ligament is affected?

• AC ligament is intact

• Deltopectoral fascia is ruptured

• AC ligament is sprained

• Coracoclavicular ligament is ruptured

Which type of AC joint injury involves the clavicle displacing posteriorly?

• Type 4

• Type 5

• Type 2

• Type 3

What is the rarest type of AC joint injury?

• Type 5

• Type 4

• Type 6

• Type 1

Which diagnostic test involves crossing the arm over the body?

• Resistant extension test

• O'Brien's test

• Drop arm test

• Crossover test

What is a positive indicator for an AC joint injury during diagnostic tests?

• Pain in the neck

• Pain in the lower back

• Pain at the AC joint

• Pain in the lateral shoulder

Which test is NOT part of the diagnostic cluster for AC joint injuries?

• Neer test

• O'Brien's test

• Resistant extension test

• Crossover test

What is the likelihood ratio for a positive result in all three diagnostic tests for AC joint injury?

• 100

• 83

• 50

• 10