Ankle and Foot 47 - Department of Radiology - University of ...

2294 VII Imaging of the Musculoskeletal System
A
B
C
Figure 47-97. Anterior process of the calcaneus (APC) fracture in a 51-year-old who was playing a jumping game. The patient, who was wearing
sandals, landed awkwardly and felt a large “pop” after forcefully inverting the foot. A, Lateral radiograph obtained when the patient came into the
emergency department the next day revealed the previously asymptomatic elongated APC (arrows). Careful scrutiny also reveals disruption of
the cortex (arrowhead), indicating a nondisplaced APC fracture. B and C, CT scans were obtained the same day. Sagittal (B) and axial (C) scans
revealed the APC fracture (black arrowheads) as well as the incidental finding of a calcaneonavicular nonosseous coalition (white arrowhead;
N, navicular). The patient was treated nonoperatively with a non–weight-bearing cast. When no healing was seen radiographically 9 weeks later,
an ultrasonic bone stimulator was used. Five weeks after that, healing was evident radiographically. Twenty-three weeks later, the injury was
essentially asymptomatic.
47-100), small nerve sheath tumors, focal synovitis, or
rarely even varicose veins, can potentially impinge on the
posterior tibial nerve. 22,30
• Stress Injuries
When the foot is subjected to new or excessive forces, such
as a change in physical activity or an increased level of
workout, certain bones may be subjected to a disproportionate
amount of the increased stress and exhibit a stress
response. The pattern of stress response depends on which
bone is involved and how long it has been untreated.
Figure 47-98. Bilateral nonosseous coalitions of the middle facet of
the subtalar joint in an 8-year-old. Coronal CT scan reveals an
abnormal vertical orientation of the right middle facet (white arrow).
On the left, the talar-side middle facet has an abnormal rounded
cortical surface (black arrow).
• Navicular Stress Fractures 34
Navicular stress fractures begin at the dorsal, central, proximal
navicular where it articulates with the head of the talus
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