3 View Wrist Radiology Tutorial

Summary

This tutorial delves into the standard radiographic projections of the left wrist, highlighting the use of Mitchell markers to determine if the film was taken weight-bearing. It covers the anatomy of the wrist, including the radius, carpal bones, and metacarpal bones, and explains the importance of wrist projections for evaluating the carpal bones. The video also discusses variances like negative and positive ulnar variance and their implications. Additionally, it guides viewers through identifying various bones and joints in different radiographic projections, emphasizing the challenges in identifying the carpal bones and the significance of the triangular fibrocartilage of the wrist.

Takeaways

• 📌 The video discusses standard projections of the left wrist using a Mitchell marker, which helps differentiate between upright and tabletop film positions.
• 🔍 Mitchell markers contain BBS suspended in oil to indicate if the film was taken weightbearing or on a flat surface.
• 👀 The anatomy of the wrist includes the radius, ulna, carpal bones, and metacarpal bones, which are essential for understanding wrist projections.
• 🤚 The fingers are typically curled under in wrist projections to approximate the carpal bones to the cassette, unlike hand projections where the hand is extended.
• 📐 The wrist projection focuses on evaluating the carpal bones, unlike hand projections which focus on the full orientation of the fingers.
• ⚖️ The term 'variance' in wrist anatomy refers to the relative length of the radial and ulnar articular surfaces, with negative ulnar variance increasing stress on the lunate.
• 💡 The mnemonic 'SOME LOVERS TRY POSITIONS THAT THEY CAN'T HANDLE' is introduced to remember the order of the carpal bones in the proximal and distal rows.
• 🔑 The carpal bones are arranged with the scaphoid first on the thumb side in the proximal row, followed by the lunate, triquetrum, and pisiform in the distal row.
• 🤕 The joint spaces between the carpal bones are called intercarpal joint spaces, while the space between the carpal and the radius is the radiocarpal joint space.
• 👁‍🗨 The lateral projection of the wrist is challenging due to the superimposition of carpal bones, with the lunate being identifiable by its crescent shape.
• 📚 The tutorial concludes with an emphasis on the importance of identifying key carpal bones and joints in wrist radiographic projections for medical diagnosis.

Q & A

What is the purpose of the Mitchell marker in radiographic projections of the wrist?

The Mitchell marker is used to differentiate whether the film was taken upright or on a table. It contains BBs suspended in oil within the marker, which sink to the bottom when the person is standing (indicating weight-bearing) or to the center when on a flat surface (indicating tabletop films).

How does the position of the fingers affect the wrist projection?

In wrist projections, the fingers are typically curled under to approximate the carpals to the cassette. This is different from hand projections where the hand is extended out to get the full orientation of the fingers.

What is the difference between wrist and hand projections in terms of focus?

Wrist projections focus on evaluating the carpal bones, while hand projections are more concerned with the full orientation of the fingers and do not necessarily focus on the carpal bones.

What are the two main types of variances in the wrist related to the radius and ulna articular surfaces?

The two main types of variances are negative ulnar variance, where the ulnar articular surface is shorter or more proximal than the radial articular surface, and positive ulnar variance, where the ulnar surface is longer or more distal than the radial surface.

What is the significance of negative ulnar variance in the wrist?

Negative ulnar variance increases the stress upon the lunate and can predispose a patient to lunate avascular necrosis.

What is the mnemonic used by students to remember the order of the carpal bones in the proximal and distal rows?

The mnemonic is 'Some Lovers Try Positions That They Can't Handle,' which helps remember the order of the carpal bones starting with the scaphoid in the proximal row and the trapezium in the distal row.

What are the joint spaces between the carpal bones called?

The joint spaces between the carpal bones are collectively called the intercarpal joint spaces.

How is the orientation of the carpal bones different in the medial oblique projection compared to the PA projection?

In the medial oblique projection, the carpal bones are viewed from a slightly different angle, which can make identification more challenging, especially since the bones are superimposed.

What is the key to identifying the carpal bones in the lateral projection of the wrist?

In the lateral projection, the key is to identify the lunate, which is crescent-shaped, and then use it as a reference to identify the capitate and other bones, keeping in mind the superimposition of the carpal bones.

What are the two types of joints in the thumb, and how do they differ from the joints in the other digits?

The thumb has a proximal interphalangeal joint and a distal interphalangeal joint, differing from the other digits which have a proximal, middle, and distal phalanges, resulting in a proximal interphalangeal joint and a distal interphalangeal joint.

Why is the identification of the capitate bone important in the lateral projection of the wrist?

The capitate bone is important because it sits directly on top of the lunate, making it a reference point for identifying other carpal bones in the lateral projection.