Learning objectives
- Normal anatomy of the lateral ankle
- Variable pathologic conditions that can cause lateral ankle pain or instability
- Diagnostic US and MR imaging findings of these lesions
Background
Normal Anatomy
- Tendon (Fig 1,
2)
- Ligament (Fig 3,
4,
5)
Anatomic Pitfalls
- Magic angle phenomenon (Fig 6)
- Increased SI within normal tendons
- fibers form an angle of about 55° with the main magnetic vector
- SE with short TEs or GE with short TEs and high FA
- Mild plantar flexion
Anatomic Variants
- Morphologic Variations in the Retromalleolar Fibular Groove
- Smooth & concave : 82%
- Flat : 11%
- Convex : 7%
- Lateral dislocation,
longitudinal...
Imaging findings OR Procedure details
Peroneal tendon
- Peroneal tendinosis (Fig 13)
- Non-inflammatory degenerative process within the peroneal tendons
- Athletes (m/c),
elderly individuals,
diabetics,
patients with inflammatory arthritis,
and individuals with displaced Fx of the lateral malleolus and calcaneus
- Peroneal Tenosynovitis
- Inflammation of the tendon or tendon sheath
- m/c tendon disorders of the lateral ankle
- Etiology
- Trauma,
repetitive local stress,
systemic joint disorders
- Peroneus Brevis Tears (Fig 14,
15,
16)
- Young athletes,
elderly
- Associated conditions
- ligamentous injuries
-insufficiency of...
Conclusion
This exhibit reviews the ultrasound and MRI features of the lateral ankle pathology and variations.
In particular,
ultrasound is emphasized for the dynamic evaluation of peroneal tendon subluxation and dislocation,
and occult tear of the lateral ligament.
After viewing this exhibit,
the reader will be familiar with the imaging anatomy of the lateral ankle and be able to recognize the full spectrum of pathologies that can cause lateral ankle pain or instability.
References
1.
Zehava S et al.
MR imaging of the Ankle and Foot.
RadioGraphics 2000; 20:S153–S179.
2.
Philip Robinson et al.
Soft-Tissue and Osseous Impingement Syndromes of the Ankle: Role of Imaging in Diagnosis and Management.
RadioGraphics 2002; 22:1457–1471.
3.
Lyndon K et al.
Magnetic resonance imaging findings in anterolateral impingement of the ankle.
Skeletal Radiol (2000) 29:34–39.
4.
Philip Robinson et al.
Anterolateral Ankle Impingement: MR Arthrographic Assessment of the Anterolateral Recess.
Radiology 2001; 221:186–190.
5.
J M Mellado et al.
Accessory ossicles and sesamoid...