google ads
Search

Everything you need to know about Computed Tomography (CT) & CT Scanning


Foot Anatomy Quiz

1. Which of the following is true with respect to the fracture depicted here:

A. Intraarticular fractures are more common
B. This fracture is extraarticular
C. Extraarticular fractures have a better prognosis
D. Associated fractures in other locations are rare
E. A and C

Correct! Incorrect. The correct answer is E.
Intraarticular calcaneal fractures are more common than extraarticular and have a worse prognosis. Concomitant ipsilateral lower extremity fractures are present in 20-46% of cases, and spinal fractures in 10-30%.

2. Which of the following is true with respect to tarsal and metatarsal fractures following hyperflexion injury?

A. More tarsal fractures are detected with CT compared to radiographs
B. More metatarsal fratcures are detected with CT compared to radiographs
C. Joint malalignment may be detected on CT but not evident on a radiograph
D. CT can reveal more fractures than MR in this setting
E. All of the above

Correct! Incorrect. The correct answer is E.
A study comparing radiographs, CT and MR in the setting of hyperflexion injury revealed that CT was most accurate in detecting tarsal and metatarsal fractures, and more accurate than radiographs for detecting joint malaignment. The most common fractures were 2nd metatarsal (of the metatarsal bones) and cuboid (of the tarsal bones).

3. What is the most common site of tarsal fracture?

A. Calcaneus
B. Talus
C. First Cuboid
D. Cuneiform
E. Navicular

Correct! Incorrect. The correct answer is A.
The calcaneus is most common, and the talus is the second in frequency.

4. Which of the following is true with respect to the entity displayed here:

A. The first metatarsophalangeal (MTP) joint is most classically involved
B. No other MTP joints are ever involved
C. Erosions typically occur on the medial and dorsal surface of the head of the first metatarsal
D. All of the above
E. A and C

Correct! Incorrect. The correct answer is E.
While the 1st MTP joint is classically involved in gout, any MTP joint can be affected. The erosions of the 1st metatarsal head are typically medial and dorsal.

5. The most common site of the entity displayed here is:

A. Talocalcaneal
B. Talonavicular
C. Calcaneonavicular
D. Calcaneocuboid
E. A and C

Correct! Incorrect. The correct answer is E.
The vast majority of tarsal coalitions involve talocalcaneal and calcaneonavicular joints. Whether one of these two types or the other is actually more common controversial.

6. Which of the following is true?

A. And oblique radiograph can diagnose calcaneonavicular coalition
B. Plain film radiograph diagnosis of talocalcaneal caoalition is more challenging than calcaneonavicular coalitions
C. CT or MR can determine id the coalition is fibrous, cartilaginous or bony
D. Patients often present with pain in the 2nd decade
E. All of the above

Correct! Incorrect. The correct answer is E.
While an oblique radiograph can detect calcaneonavicular coalition, detection of talocalcaneal coalitions can be more challenging with radiographs. CT and MR may be necessary. CT and MR are useful to determine if the coalition is osseous or fibrous and to detect secondary degenerative changes. Cross sectional imaging is also essential to elucidate the extent of the coalition prior to surgery.

7. With respect to the enitity displayed in this image, which of the following is true:

A. In the presence of an ankle joint effusion with no fracture apparent on conventional radiograph, CT should be performed if there is a high clinical suspicion for this type of lesion.
B. The most common cause is trauma.
C. These lesions can occur medially or laterally on the talar dome.
D. The medical lesions occur in the posterosuperior half of the dome of the talus; however, the lateral lesions are situated anterosuperiorly.
E. All of the above.

Correct! Incorrect. The correct answer is E.
In the presence of an ankle joint effusion with no fracture apparent on the conventional radiograph, CT should be performed if there is a high clinical suspicion for an osteochondral defect of the talus. The most common cause is trauma. Other hypothesized etiologies include ischemic necrosis, spontaneous necrosis, abnormal vascular anatomy and congenital abnormalities. Osteochondral defects can occur medially or laterally in the talar dome. The medial lesions occur in the posterosuperior half of the dome of the talus; however, the lateral lesions are situated anterosuperiorly.

8. Which of the following is a false with respect to the fracture depicted on this case:

A. Staging reflects the presence of displacement and dislocation
B. Higher staged fractures have increased risk of ischemia due to blood supply disruption
C. Mechanism of fracture is abrupt force from below with dorsiflexion of the foot
D. CT is useful for follow up to determine joint alignment, to exclude any residual intrarticular bone fragments and to detect complicaitons of nonunion and osteoarthritis
E. All of the above

Correct! Incorrect. The correct answer is E.
Talar neck fractures are classified by the presence of displacement and the degree of associated subluxation or dislocation. Stage I includes nondisplaced vertical neck fractures. A displaced fracture with subtalar dislocation or subluxation equates is classified as stage II, which usually disrupts 2-3 sources of blood supply to the bone. Stages III includes those displaced fractures with subtalar and tibiotalar subluxation or dislocation, and stage IV fractures are vertically displaced with subtalar or tibiotala subluxation or dislocaiton, as well as talonavicaular subluxation or disclocation. These latter types of injury generally disrupt all 3 sources of blood supply to the talus.

9. Which of the following is true with respect to the pathology depicted here:

A. In diabetics, foot ulcers are usually to source of an infection
B. Common locations include skin below the metatarsal heads, distal toes, under calcaneus and over malleoli
C. Although pedal infection typically arises from the region of an ulcer in diabetics, ischemic ulcers do not always develop infections
D. Nearly 90% of the bone infection arises adjacent to infected foot ulcers
E. All of the above

Correct! Incorrect. The correct answer is E.

10. Which findings distinguish this from the talar beak of a tarsal coalition?

A. Location posterior to the talonavicular joint
B. Location anterior to the talonavicular joint
C. Associated findings of OA
D. A and C

Correct! Incorrect. The correct answer is D.
Osteoarthritis can result is a talar break. This is distinct from the beak of tarsal coalition in its loation (posterior to the talonavicular joint) and in its association with other findings of osteoarthritis.
© 1999-2020 Elliot K. Fishman, MD, FACR. All rights reserved.