Answer VizD 1.5

Case 1.5

VizD Winners

Brian Kern                      Chris Guyer                Rob Klever

Scott Ottolini                  Devon Moore             David Mishkin

Kevin MacWilliams          Marjan Siadat             Allison Loynd

A 53-year-old woman presents to your ED after tripping down a flight of steps. On exam, you note marked swelling of her right orbit with proptosis of the right eye. You ask the patient to look to the side but she cannot move her eye.

1. What is the procedure being performed?
2. What is the most common reason to perform the procedure?
3. What complication are you trying to prevent in performing this procedure?


This week, Dr Susi Vassallo, author of the seminal work on emergency canthotomy, and previous EM resident at Detroit Receiving Hospital, will discuss the answer to this weeks VizD

Receiving: When indicated, why is it so important to perform a lateral canthotomy?
Dr Vassallo: Performance of lateral canthotomy is critical to decompression of the orbit and relief of pressure on the optic nerve. Otherwise, there is risk for ischemia to the optic nerve resulting in blindness.
Receiving: In your opinion, what is the most important technical aspect in performing this procedure?
Dr Vassallo: The most important technical aspect in performing the procedure is palpating the lateral canthal tendon and cutting it. It is more easily palpated than visualized.
Receiving: How often do you see this procedure performed? (no pun intended)
Dr Vassallo: This procedure is performed more often than one would think. When I first wrote this article, Dr. Peter Rosen, then editor of the Journal of Emergency Medicine did not think it was an emergency medicine procedure. We happened to be talking years later when Dr. Rosen was practicing in Jackson Hole Wyoming. He told me that one of his former residents had to perform the procedure without ophthalmology assistance; this is when he realized it was important for emergency physicians to understand the indications for the procedure and to know how to do it.
Receiving: How does it feel that Roberts and Hedges Procedure book uses your article and images for their chapter on lateral canthotomy?
Dr Vassallo: I am happy to see the pictures from our article in the book by Roberts and Hedges. Jim Roberts is one of my hero clinicians.
Receiving: Thank you for your time!
Dr Vassallo: Of course, you are very welcome!

Check out Dr Vassallo’s article

Here is video of the actual procedure

Thank you to everyone who submitted their answer.  Stay tuned for next week’s VizD

VizD is a weekly contest of an interesting or pathognomonic image from emergency medicine. Its goal is to integrate learning into a fun and relaxed environment. All images are original and are posted with the consent of the patient.

Answer radER Vol 1.4

radER Winners:

Devon Moore

Brian Kern

Brian McMichael

Answer to Case 1.4

A 56-year-old man was brought to your ED after bring involved in a MVC.  He was a restrained driver in a car that was traveling at 40 MPH and slammed into a tree.  The patient denies loss of consciousness.  A radiograph is seen below.


1.  What is the abnormality on the radiograph?

2.  Name the nerve(s) that are frequently injured in this type of injury?

3.  What are the motor and sensory physical exam findings corresponding to these nerve(s)?


1.  Left acetabular fracture.  A MVC is a very common mechanism that causes acetabular fractures when the knee hits the dashboard causing the flexed hip to move posteriorly into the acetabulum.

2.  The sciatic nerve is the most commonly inured nerve.  Exam findings should be clearly documented on the chart.   The femoral nerve can also be injured with a fracture of the acetabulum.

3. The motor component of the sciatic nerve is checked by testing the strength of the extensor hallucis longus.  This is performed by having the patient resist downward pressure on the great toe while held in extension.  The sensory component is examined by checking sensation over the dorsum of the foot and lateral calf.

The femoral nerve is less commonly injured than the sciatic nerve. The motor component is checked by extension of the knee as well as the patellar reflex.  The sensory component is examined by testing for sensation over the anterior thigh and inner calf.

It looks like an acetabular fracture since it involves the superior pubic ramus at its lateral extent, near the acetabulum.  A second fracture should be present and I believe is seen superior to the acetabulum – a slight break in the iliopubic line (arcuate line).  By the radiograph, the fracture would be classified as an anterior wall fracture.  A CT would show it well.  A superior pubic ramus fracture would generally be in the midportion of the pubic ramus and when it’s this displaced would be associated with an inferior pubic ramus fracture, and, likely as well, a second break in the pelvic ring, e.g., a sacral wing fracture.

The Teardrop Sign

The radigraphic teardrop sign is a landmark present in normal pelvic radiographs and is often disrupted with acetabular fractures.  However, if the patient is rotated, the teardrop sign may not be present.  In addition, the presence of the teardrop sign does not exclude a fracture.  Nonetheless, if the teardrop sign is absent in the right clinical setting, then you should be highly suspicious for an acetabular fracture.

Thank you for everyone who submitted an answer. Please stay tuned for next week’s radER.

radER is a weekly contest, hosted by Dr. Kerin Jones’ “Fracture”,  consisting of a radiograph selected from various areas of emergency medicine that are central to the education of medical students and residents in training.

Answer radER Vol 1.3

radER Winners:

Scott Ottolini           Julie Nguyen         Richard Gordon

Allison Loynd          Rob Klever            Marjan Siadat

Answer to Case 1.3

A 35-year-old man presents to your ED complaining of elbow pain after tripping on a patch of ice and landing on his outstretched hand.  You administer pain medication and obtain the following radiograph:

1. Name 2 abnormal findings on this radiograph?

2. What is the diagnosis?

3. What is the ED treatment and follow up for this patient?


1. An anterior and posterior fat pad sign

2. Occult radial head fracture

3. Sling, for comfort, pain medication, early range of motion exercises and orthopedic follow up

Physical Exam

The patient will fully flex their elbow but will not fully extended the elbow particularly the last 5-10º of extension.  This should also tip you off that there is a radial head fracture prior to taking x-rays.

A good lateral radiograph of the elbow is taken with the elbow held at 90° of flexion.  Normally you may see a lucency that represents fat present along the anterior surface of the distal humerus, and no lucency should be visualized along its posterior surface. A positive fat pad sign is when there is either an elevated anterior lucency, also known as a “sail” sign since it resembles a sail on a boat, or if a posterior fat pad is visible at all on a well taken lateral radiograph of the elbow.  Either a positive anterior or posterior fat pad is consistent with an occult fracture of the radial head.  Any elbow joint distention either hemorrhagic, inflammatory or traumatic gives rise to a positive fat pad sign.

Why do these occur?
Three small masses of fat rest in the radial, coronoid, and olecranon fossae and are enveloped by the fibers of the joint capsule separating the fat pads from the synovial lining.  This means that the fat pads are intracapsular and extrasynovial in location. The anterior fat pad consists of the radial and coronoid fat pads, which are normally pressed into the shallow radial and coronoid fossae by the brachialis muscle. On a lateral radiograph of the normal elbow the anterior fat pad is normally seen as a vertical faint line that is more radiolucent than adjacent muscle and is parallel to the anterior distal humerus. The posterior fat pad is normally pressed into the deep olecranon fossa by the triceps tendon and anconeus muscle and is invisible on a lateral radiograph of the normal elbow.
Thank you for everyone who submitted an answer. Please stay tuned for next week’s radER.

radER is a weekly contest, hosted by Dr. Kerin Jones’ “Fracture”,  consisting of a radiograph selected from various areas of emergency medicine that are central to the education of medical students and residents in training.