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

47 Ankle and Foot 2215 47
A
B
C
Figure 47-11. MRI of normal ankle tendons in the oblique
coronal plane. FDL, flexor digitorum longus tendon; FHL,
flexor hallucis longus tendon; PB, peroneus brevis tendon;
PL, peroneus longus tendon; PT, posterior tibial tendon.
A, Through the posterior facet of the subtalar joint.
B, Through the middle facet of the subtalar joint. ST,
sustentaculum tali. A&N (artery and nerve) points to
the dotted circle surrounding the neurovascular bundle that
includes the posterior tibial artery and nerve. C, Through the
talonavicular joint. At this level, the PT tendon has divided
into separate slips. The white line with the round end points
to the portion of the PT that inserts onto the medial pole of
the navicular (N). The white line with the square end points
to the portion of the PT that passes under the navicular. This
patient has an os peroneum, which is why the PL tendon
appears enlarged and gray at this level (dark gray arrow).
The lack of edematous signal along the course of the extensor
hallucis longus on T2-weighted images should reassure
the radiologist there is no pathologic process.
Injury
Tears of the anterior ankle tendons are rare, and if the
patient indicates that the point of maximal tenderness is
directly over the anterior tendons, it is prudent to search
for other causes for pain, such as an unsuspected stress
fracture (Fig. 47-12).
Ganglion cysts can arise from any synovium-lined
structure, including the anterior ankle tendons. Figure
47-13 shows a synovial cyst arising from and partially
enveloping the anterior tibial tendon.
• Posterior Tendons
Normal Anatomy
For anatomic purposes, the Achilles and plantaris tendons
together make up the posterior group. The Achilles tendon
is the largest tendon in the body, originating in the midcalf
at the junction of the two heads of the gastrocnemius
muscle and the soleus muscle, and inserts onto the back
of the calcaneal tuberosity. Unlike the anterior, medial,
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