ABSTRACT Objective To correlate the significance of osseous, chondral, tendon, and ligamentous injuries with anatomical variations in low-grade versus high-grade acute ankle sprains. Methods We retrospectively identified the magnetic resonance imaging findings of acute ankle sprains (<15 days). Participants with a history of previous sprains, arthritis, tumors, infections, or inflammatory conditions were excluded. Images were independently evaluated by two musculoskeletal radiologists and assessed for osseous, chondral, tendon, and ligamentous injuries and anatomical variations. Participants were divided into low-grade versus high-grade sprain groups, according to the presence of a complete tear in at least one component of the lateral ligament complex. Results The final study group comprised 100 magnetic resonance images (mean age, 36 years), the majority of males (54%), the right ankle (52%), and a mean sprain duration of 5 days. Participants with high-grade sprains presented with increased rates of medial malleolus edema (p<0.001), moderate and large articular effusions (p=0.041), and shorter calcaneonavicular distance (p=0.008). Complete tears of the anterior talofibular ligament and calcaneofibular ligaments were observed in 100% and 51.2% of the participants in the High-Grade Group, respectively. The deltoid ligament complex was partially torn in this group (55.8% versus 8.8%, p<0.001). Extensor tendon retinaculum lesions occurred significantly more frequently in this group (41.9%) compared to the overall study population (23%) (p<0.001). Conclusion Participants with high-grade ankle sprains presented with shorter calcaneonavicular distances and increased rates of medial malleolus edema, deltoid complex partial tears, extensor retinaculum lesions, and articular effusion. osseous chondral lowgrade low grade highgrade high <15 15 (<1 days . days) arthritis tumors infections excluded groups 10 age 3 years, years , years) 54%, 54 54% (54%) 52%, 52 52% (52%) p<0.001, p0001 p p<0.001 0 001 (p<0.001) p=0.041, p0041 p=0.041 041 (p=0.041) p=0.008. p0008 p=0.008 008 (p=0.008) 512 51 2 51.2 HighGrade High Grade Group respectively 55.8% 558 55 8 (55.8 88 8.8% p<0.001. p<0.001) 41.9% 419 41 9 (41.9% 23% 23 (23% effusion <1 1 (< (54% (52% p000 p<0.00 00 (p<0.001 p004 p=0.04 04 (p=0.041 p=0.00 (p=0.008 51. 55.8 (55. 8.8 41.9 4 (41.9 (23 < ( (54 (52 p00 p<0.0 (p<0.00 p=0.0 (p=0.04 (p=0.00 55. (55 8. 41. (41. (2 (5 p0 p<0. (p<0.0 p=0. (p=0.0 (41 p<0 (p<0. p=0 (p=0. (4 p< (p<0 p= (p=0 (p< (p= (p