11 - Radiographic Interpretation Flashcards
Normal radiograph
- Systematic approach
- First look at the soft tissue going around the foot
- If you can’t see soft tissue (only see bone), there is a good chance the settings in the tube head wasn’t good
- If the soft tissue looks similar to the bone, there was probably underpenetration
- You should be able to see soft tissues, cortices, joint spaces
- Determination of foot type
- Foot is a 3-D object
- So, take 3 views of the foot
3 common views of the foot
- AP
- Lateral
- Medial oblique
Foot types
- Normal foot type
- Supinated foot type
- Pronated foot type
Things you should NOT see on a normal foot
- Increased soft tissue attenuation & densities (swelling)
- Breaks in the Cortex (fracture, bone infection)
- Widening or decreasing of the joint space, and alignment (infection, arthritis)
- Mechanical Deformities (HAV, Hammertoes, Tailor’s Bunion)
- Accessory Bones
- Gas in the Soft Tissues
- White vessels (this means they have calcification of the vessels which is pathological)
- Black spots on bottom surface of foot can be ulceration or a breakdown of tissue
Determining the foot type
- X-ray taken in the weightbearing position
- Standard views include: AP (top), lateral (side), oblique (45 degree angle)
The radiograph should be labeled as weightbearing or non-weightbearing
If the radiograph is taken in the non-weightbearing position you CANNOT determine the foot type * Need a “loaded” foot to determine foot type*
Talus bone
- The position of the Talus is the key to the interpretation of the normal vs. abnormal foot type
- Talus is a PASSIVE BONE
- This means there are no tendons attached to the talus ***
- The talus will ONLY move in relation to the calcaneus ***
Talar position with lateral view
The body of the talus is normally parallel with the weight supporting plane
Talar position with AP film
- The head of the talus is closely bound to the calcaneus and is superimposed over the anterior portion of the calcaneus
- The outline of the sustentaculum tali may be visualized
Cavus foot type
- High arch
- Increased Calcaneal Inclination Angle
- Posterior Break in the Cyma Line
- Bullet Hole Sign (slide 17)
Pronated foot type
- Decreased angle of the Calcaneus
- Lowered Arch
- Anterior Break Cyma Line
Calcaneal position lateral view
- Angle of Inclination
- Density of the sustentaculum tali
- Lateral tuberosity
Cyma line
Representation of the midtarsal articulation
- Talonavicular Joint
- Calcaneocuboid Joint
Lateral view of Cyma line
- Should form a smooth S
- When discussing a deformity it is always in relation to the Talonavicular joint
- Because the Calcaneocuboid joint is SO stable that it does not move
AP view of Cyma line
- Smooth S curve
- Not as accurate as the lateral view
- Less implications
Lis Franc’s ligament
Plantar ligament from the Medial Cuneiform to the 2nd Metatarsal Base (strong)
This forms the Lis Franc’s joint or tarsometatarsal joint
Lis Franc’s disruption or injury
The bones of the midfoot have very tight articulations - you should NOT see a separation greater than 2 mm between these bones - If you do see a large separation, there is a good chance there has been an injury of the ligaments
Could also see a deviation of the first or other metatarsal
Centers of ossification
- Growth plates in locations depending on the particular bone
- Some bones ossify earlier than others
Navicular ossification
- Primary center of ossification will appear between 11 months and 3 years and 8 months
- The average is 3 years
- A secondary center of ossification may occur on the tuberosity of the navicular bone
** 3 YEARS **
Lateral cuneiform ossification
- Lateral cuneiform ossification will occur within the first year
** 1 YEAR **
Intermediate cuneiform ossification
- Intermediate cuneiform ossification will occur between 1 year and 2 years and 11 months
** 2 YEARS **
Medial cuneiform ossification
- Medial cuneiform ossification will occur between 11 months and 2 years and 11 months
** 2.5 YEARS **
Print the chart on slide 32
Said we will focus on this but only went over bones above (navicular, cuneiforms)
Went through x-rays on 33 and 34 to determine the age of the individual based on the ossification centers that were present on x-ray
Accessory ossicles
- Small bones usually from a secondary ossification center that fail to unite with the remaining portion of the bone
- Often times confused with fractures
- Certain locations on an X-ray that occur more frequently than others
- Always check with Bilateral Films
- Most often asymptomatic
Common accessory ossicle
- Accessory navicular (Os tibiale externum)
- Os peroneum
- Os trigonum
Os trigonum
- Failed fusion of the Posterior Process of the Talus
- Confused often with a fracture “Shepherd’s Fracture” where you fracture off this process
- Typically the fracture will have a little sharp point or a 90 degree angle whereas a process would be rounded
- Ossicles are typically bilateral, so this can help you differentiate as well
Bipartite sesamoid
- Often confused with a fracture of a sesamoid bone
- You can get a sharp edge, which would mean a fracture of this has occurred
- If you have a cartilagenous surface between the bones, you may be confused as to what you are looking at
- May need to use a bone scan to figure it out
Gas formation in the soft tissue
- Gas forming bacterial infection
- Looks like bubbles
- Look at other views to confirm
- Clinically, you may see some hemmorrhagic blistering associated with this (blood blister)
- If you rub you fingers over top of this tissue, it may sound like crinkling
Hallux abducto valgus deformity
- Many angles involved
- Angle between first metatarsal and second metatarsal will be increase (increased IMA)
- Because of the high IMA, it will cause the position of the hallux to change
- The hallux will go into an abducted position (pointing away from the midline of the body)
- You will see the valgus deformity
- Look for an irregular edge and bump on the medial side of the first metatarsal head
Fractures
- Breaks in the cortex of the bone
- Can be described in a variety of ways
Extra-articular fracture
Extra articular, non comminuted, nondisplaced fracture of the 5th metatarsal shaft
Slide 44
Intra-articular fracture
Intraarticular (within the joint)
Non comminuted
Slide 45
Hammertoe deformity
- Joint contractures are noted
- The superimposition of the other digits
- Might be able to see arthritic changes associated with the hammertoe deformity
- This will correlate with the reason that the deformity is rigid, semi-rigid or flexible
- Due to long-term adaptation, we see long term adaptation within the joint
- Patient may need soft tissue procedure, implant, fusion, etc. based on arthritic changes
Calcaneal fracture
- Non-weightbearing
- Slide 47 is a “text book” example of a calcaneal fracture
- There are other ways to determine if there is a subtle fracture that we cannot see radiographically
Calcified vessel
- Tunica media
- Does not narrow the lumen
- Example: Calcified dorsalis pedis
NOTE: went back to this at very end of lecture
- Can’t always see the lateral cuneiform
- You can see superimposition of the cuneiforms
- Take your time and try to trace the individual bones
- Especially if there has been trauma
- Make sure you actually do see a fracture and it isn’t just a joint space
