Forearm and Elbow

The capitulum is on the medial or lateral side of the distal humerus?

• Medial

• Lateral

Answer explanation

The capitulum is on the lateral side of the distal humerus and articulates with the head of the radius. Think of putting a "cap" on the head of the radius.

In anatomical position which forearm bone is lateral?

• Radius

• Ulna

• Humerus

Which bone of the forearm contains the olecranon process?

• Radius

• Ulna

Answer explanation

The ulna has two beak like process on the proximal aspect called the olecranon process and coronoid process. In between the two processes is the trochlear notch which articulates with the trochlea of the distal humerus.

The radial head is located on the distal part of the forearm?

• True

• False

Answer explanation

The radial head is located proximally and the ulnar head is located distally.

What type of movement does the elbow joint (humeroulnar & humeroradial) permit?

• Pivot/trochoidal

• Saddle/sellar

• Ellipsoidal

• Hinge/Ginglymus

Answer explanation

The elbow joints are hinge/ginglymus.

The proximal and distal radioulnar joint permits pivot/trochoidal and allows the forearm to pronate.

What are the 3 depressions (fossas) on the distal aspect of the humerus?

• Radial, ulnar, & olecranon

• Coronoid, olecranon, & ulnar

• Coronoid, olecranon, & radial

• capitellum, coronoid, & olecranon

Answer explanation

The Coronoid and Radial fossa are located on the anterior aspect of the distal humerus. The coronoid fossa is on the medial side and the radial fossa is on the lateral side (think of where the radius is located). The Olecranon fossa is located posteriorly and the olecranon process fits into this depression when the arm is fully extended.

What anatomy of the elbow is demonstrated by the Coyle method?

• olecranon

• radial head

• ulnar head

• capitulum

Answer explanation

The coyle method helps to see the radial head without superimposition from the ulna.

On a regular lateral, 1/2 the radial head will be superimposed by the ulna. By angling 45 degrees cephalic we can help to move the radial head away from the ulna.

What is the hand position for a Coyle Method of the Elbow?

• Palm down

• Thumb up

• Palm up

• Thumb upside down

Answer explanation

For a Coyle Method the palm should be down (pronated) this is different from a regular lateral view of the elbow. A regular lateral elbow the thumb would be pointing up.

What motion will cause the bones of the forearm to cross one another?

• Pronation

• Supination

• Flexion

• Extension

Answer explanation

When we pronate our forearm the radius will overlap the ulna and obscure anatomy. When performing an AP forearm, we want the forearm to be in a supinated position to give unobstructed view of both the radius and ulna.

Which of the following is NOT an anatomical part that makes up the 3 concentric arcs on a properly positioned true lateral elbow projection?

• Trochlear Sulcus

• The 2 Outer Ridges of Capitulum and Trochlea

• Trochlear notch of ulna

• All of these 3 structures ARE concentric arcs that are visualized on a lateral elbow

Answer explanation

In a TRUE lateral elbow (elbow is flexed 90 degrees) we should see:

Yellow: Trochlear sulcus (groove)

Green: Outer ridges of the capitulum and trochlea. Capitulum is lateral and will appear under the trochlear sulcus and then the trochlea

Pink: Trochlear notch of the ulna, also known as semilunar notch, and articulates with the trochlea of the humerus

If the elbow is rotated even slightly from true lateral, the arcs do not appear symmetrically & the elbow joint is not open.