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✅ Knee MRI Mastery/Chap 3.Collateral Ligaments

(Fig 3-B.24) Distal Biceps Femoris Myotendinous Junction Tear

by MSK MRI 2024. 5. 22.

https://youtu.be/VauF4m8PmIk

https://youtu.be/6WOItzqJj1g

 

📌 MRI Grading Systems 

  • Initial MRI grading systems relied on the pattern of muscle signal intensity alterations to classify muscle injuries into grades:
  • Grade 0: Symptomatic injury without MRI findings
  • Grade 1: Edema only, without architectural distortion
  • Grade 2: Architectural distortion with intramuscular hemorrhage and tissue gaps
  • Grade 3: Complete disruption of the musculotendinous junction

 

✅ Biceps Femoris Injuries 

Biceps femoris injuries are most commonly described as:

  • Avulsion or partial avulsion injuries
  • Tears of the distal myotendinous junction

An association between partial tendinous avulsion of the biceps femoris and Segond fractures has been described.



✅ Case Summary In the case discussed, the patient presented with:

  • ACL high-grade partial tear at the femoral attachment
  • Small non-displaced Segond fracture
  • No defect at the myotendinous junction of the biceps femoris muscle
  • Feathery pattern muscle edema noted only in the biceps femoris short head muscle

Follow-up:

  • Follow-up MRI two months later showed complete resolution
  • Consistent with a Grade 1 muscle strain (edema only)

 

✅ Anatomical Review of distal musculotendinous junction of the biceps femoris

  • Midportion: T-shaped low signal structure represents the distal musculotendinous junction of the biceps femoris

→ Formed by epimysial condensations of the long and short heads

  • Distally, the posterolateral epimysial condensation of the short head forms the distal musculotendinous junction, appearing as a shallow convex structure.

 

RadioGraphics 2018; 38:124–148

AJR Am J Roentgenol. 2003 Mar;180(3):647-53

Orthop J Sports Med. 2017 Jul 20;5(7):2325967117714998

 

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#AcuteMuscleTear, #BicepsFemorisInjury, #MuscleTearGrading, #SegondFracture, #ACLTear, #MyotendinousJunctionTear, #MuscleBelly, #SportsInjury,