Distal Humerus Anatomy

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Questions and Answers

What is typically not visible on an X-ray unless there is trauma or incorrect flexion of the elbow?

Supinator fat stripe

Proximal radioulnar joint

Posterior fat pad (correct)

Anterior fat pad

In which projection are the proximal radius and ulna completely superimposed?

Lateral view

Medial oblique (correct)

AP view

Lateral oblique

Which condition is characterized by abnormally dense bone commonly referred to as 'marble bone'?

Osteoporosis

Osteomyelitis

Osteopetrosis (correct)

Bursitis

What describes the inflammation of fluid-filled sacs enclosing joints?

Bursitis Signup and view all the answers

Which fat pad may indicate a diagnosis of radial head or neck fractures that are not easily seen?

Supinator fat stripe Signup and view all the answers

Which structures are best visualized in a Medial Oblique Projection of the elbow?

Coronoid process of the ulna and trochlea Signup and view all the answers

What is the recommended arm position for obtaining a Medial Oblique Projection?

Arm fully extended with palm down Signup and view all the answers

What pathology may be indicated when elevated fat pads are visualized in the lateral projection of the elbow?

Fractures or dislocations Signup and view all the answers

During the Lateral Projection of the elbow, how should the patient's shoulder be positioned?

On the same plane as the forearm Signup and view all the answers

What angle should be used to rotate the arm when preparing for a Medial Oblique Projection?

45° Signup and view all the answers

Which part of the humerus articulates with the ulna?

Trochlea Signup and view all the answers

What structure is found on the lateral aspect of the distal humerus?

Lateral epicondyle Signup and view all the answers

What is the purpose of the olecranon fossa?

To receive the olecranon process when the arm is extended Signup and view all the answers

Which of the following structures is NOT found on the distal humerus?

Humeral head Signup and view all the answers

In a true lateral elbow view, which of the following arcs represents the trochlear sulcus?

The smallest arc Signup and view all the answers

Which fossa is located on the anterior aspect and receives the radial head?

Radial fossa Signup and view all the answers

How is the trochlea described in terms of shape?

Pulley or spool-like Signup and view all the answers

What should the elbow be flexed to for a true lateral view?

90 degrees Signup and view all the answers

Which depression is more medial and receives the coronoid process?

Coronoid fossa Signup and view all the answers

What is a key characteristic of the lateral epicondyle compared to the medial epicondyle?

It is a smaller projection Signup and view all the answers

What is the purpose of the Axial Lateromedial Projection for the elbow?

To assess the joint space between the radial head and capitulum Signup and view all the answers

Which condition is indicated for the Axial Mediolateral Projection?

Fractures or dislocations of the coronoid process Signup and view all the answers

What angle should the central ray (CR) be directed for the Axial Lateromedial Projection?

45 degrees towards the shoulder Signup and view all the answers

At what degree should the elbow be flexed for the Axial Lateromedial Projection?

Flexed at 90 degrees Signup and view all the answers

What should be visualized in the different positions during the Radial Head Laterals?

The radial tuberosity Signup and view all the answers

Which fossa on the humerus receives the radial head?

Radial fossa Signup and view all the answers

Which view is primarily used to visualize occult fractures of the radial head or neck?

Radial Head Laterals Signup and view all the answers

What should the evaluation criteria indicate for the Axial Mediolateral Projection?

The joint space between the coronoid process and trochlea must be open. Signup and view all the answers

Which elbow projection is best for demonstrating the radial head and neck as well as the capitulum of the humerus?

External (lateral) oblique elbow projection Signup and view all the answers

What is the correct hand positioning for a medial (internal) AP oblique elbow projection?

Supinated Signup and view all the answers

How much should the elbow be bent for a lateral elbow projection?

90 degrees Signup and view all the answers

Which Coyle method requires you to angle the CR 45 degrees toward the shoulder?

Axial lateromedial projection Signup and view all the answers

Where is the central ray (CR) located for an AP elbow projection?

At the mid-elbow joint Signup and view all the answers

Study Notes

Distal Humerus

The distal humerus is the expanded distal end of the humerus, divided into medial and lateral parts.
The trochlea is the medial condyle, shaped like a pulley or spool, articulating with the ulna.
It features two outer margins and a smooth depressed center (trochlear sulcus)
The capitulum is the lateral condyle, articulating with the radial head.
It means "little head", and you can remember it by associating it with "cap" being on top of "head" .
The lateral epicondyle is a small projection on the lateral aspect of the distal humerus above the capitulum.
The medial epicondyle is larger and located on the medial edge of the distal humerus.
The coronoid fossa is an anterior depression that receives the coronoid process.
The radial fossa is another anterior depression, more lateral than the coronoid fossa, that receives the radial head.
The olecranon fossa is a posterior depression that receives the olecranon process when the arm is fully extended.

Joints

The elbow joint is the articulation between the distal humerus, proximal radius, and proximal ulna.
The proximal radioulnar joint is the articulation between the proximal radius and ulna, allowing for rotation of the forearm.

Fat Pads

Anterior fat pad - Visible on lateral elbow projection, located anterior to the elbow joint.
Posterior fat pad - Usually not visible unless trauma present or the elbow isn't flexed correctly.
Supinator fat stripe - May indicate a radial head or neck fracture.

True Lateral Elbow

The elbow should be flexed 90 degrees.
There are three concentric arcs:
- 1st and smallest - Trochlear sulcus
- 2nd - Capitulum (smallest) and Trochlea (largest)
- 3rd - Trochlear notch of the ulna

Medial Oblique (Internal) AP Projection - Elbow

Best visualizes the coronoid process of the ulna and the trochlea.
40 SID
Arm fully extended
Pronate hand into a natural palm-down position then rotate the arm internally till the distal humerus/anterior elbow is rotated 45 degrees.
CR perpendicular to IR, directed to the mid-elbow joint.
Radial head and neck should be superimposed and centered over the proximal ulna.

Lateral (Lateromedial) Projection - Elbow

40 SID
Seat patient at end of table, with elbow flexed 90 degrees.
Drop shoulder so it is on the same plane as forearm.
Rotate hand & wrist into true lateral position (thumb up).
CR perpendicular to IR, directed to mid-elbow joint.
Three concentric arcs are visible.

Special Projections - Elbow

Trauma Axial Laterals (Coyle Method) - Elbow

40 SID, two projections:
- Axial Lateromedial Projection - Visualizes radial head best.
- Axial Mediolateral Projection: Coronoid process best visualized.

Axial Lateromedial Projection – Elbow (Radial Head)

Clinical indications: fractures and dislocations of the radial head.
Elbow flexed 90 degrees if possible, hand pronated.
CR angled 45 degrees towards shoulder, centered to the radial head, mid-elbow joint.
Joint space between the radial head and capitulum is open, radial head, neck, and tuberosity are free of superposition.

Axial Mediolateral Projection - Elbow (Coronoid Process)

Clinical indications: fractures and dislocations of the coronoid process.
Elbow flexed only 80 degrees, hand pronated.
CR angled 45 degrees from shoulder, centered to the mid-elbow joint.
Anterior portion of the coronoid appears elongated, but in profile, joint space between coronoid process and trochlea should be open, and the radial head and neck should be superimposed by ulna.

Radial Head Laterals - Elbow

Clinical indications: occult (hidden) fractures of the radial head or neck.
40 SID
Arm flexed 90 degrees.
Upper extremity & shoulder all on the same plane.
Four projections:
- Supinate hand and externally rotate as far as patient can tolerate.
- Place hand in true lateral.
- Pronate hand.
- Internally rotate hand as far as patient can tolerate.
CR perpendicular to IR and directed at radial head.
Radial tuberosity should be visualized in different positions.

Common Pathologies

Osteomyelitis is an infection of the bone or bone marrow, which can be caused by bacteria introduced through trauma or surgery.
Bursitis is the inflammation of bursae, fluid-filled sacs surrounding joints, leading to pain and limited movement.
Osteopetrosis is a rare genetic condition characterized by abnormally dense bone (marble bone).

Positioning

AP Elbow

CR perpendicular to IR and directed to the mid-elbow joint.
Hand is positioned in a natural palm-down position.
Mid-elbow joint is found near the center of the humeral epicondyles.

Partial Flexion Elbow Projection

-Performed when the patient cannot fully extend their elbow.
Center the CR to the mid-elbow joint.
Flex patient's arm 80-90 degrees.
Two images are recommended: - One image with the CR perpendicular, and - One image with the CR angled 10-15 degrees cephalically.

Medial/Internal Oblique Elbow

Best demonstrates the coronoid process.
The hand is pronated and rotated internally 45 degrees.

Lateral Elbow

Elbow is flexed 90 degrees.
The shoulder and elbow are on the same plane.
CR perpendicular to IR, directed to the mid-elbow joint.
Mid-elbow joint is found near the center of the humeral epicondyles.
Three concentric arcs should be visualized.

Coyle Method

Axial Lateromedial Projection: Visualizes radial head, CR is angled 45 degrees towards shoulder.
Axial Mediolateral Projection: Visualizes coronoid process; CR is angled 45 degrees towards shoulder.
The hand is pronated for both.

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Description

Test your knowledge on the anatomy of the distal humerus with this quiz. It covers key features like the trochlea, capitulum, and various fossa. Perfect for students studying human anatomy or preparing for exams.