Type:
Educational Exhibit
Keywords:
Musculoskeletal joint, CT, MR, Ultrasound, Normal variants, Diagnostic procedure, Inflammation, Athletic injuries
Authors:
J. LEE, S. J. Lee, H. J. Choo, H. W. Jeong, Y.-M. Park, S. J. Choi; Busan/KR
DOI:
10.1594/ecr2013/C-1121
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 tear of the peroneal tendons
- Hypertrophy of the peroneal tubercle (Fig 7)
- Peroneus Quartus Muscle (Fig 8,
9,
10)
- m/c accessory muscle of the ankle
- Origin : muscular portion of peroneus brevis muscle in the distal 1/3
- Insertion : variable
- Descends posteromedial to the peroneal tendon
- Asymptomatic
- Low-lying Peroneus Brevis Muscle Belly (Fig 11)
- Common anatomical variation
- Anomalous extension of the peroneus brevis m.
into and distal to the fibular groove
Crowding of retromalleolar groove
Stretching of SPR
Longitudinal splitting of peroneus brevis tendon,
tenosynovitis,
and dislocation
- Os Peroneum (Fig 12)
- Round or oval-shaped sesamoid bone
- Substance of the distal peroneus longus tendon
- Calcaneocuboid joint level