(Fig 3-A.34) Anterior and Direct Semimembranosus Arms

https://youtu.be/X4EXbWCrTTM

https://youtu.be/GSIg93UH3Ochttps://youtu.be/GSIg93UH3Oc

 

1️⃣Direct Arm (Principal Attachment):

• Attaches directly to the posteromedial aspect of the tibia, just distal to the joint line, in a groove known as the tuberculum tendinis.
• Forms a C-shaped, 5-mm-thick band with the anterior arm along the posteromedial tibia, difficult to distinguish from each other.
• Exhibits hyperintensity at its insertion site on MRI, which may be due to fat accumulation or magic angle artifact, and is not abnormal.

2️⃣Anterior Arm (Tibial or Reflected Arm, Pars Reflexa):

• Inserts into the medial proximal tibia, superior to the superficial MCL, and under the POL.
• Seen on peripheral medial sagittal images curving anteriorly and on coronal images as a hypointense structure adjacent to the medial tibia.
• Magic angle artifact noted in its thicker posterior portion.

Radiographics. 2015 Jul-Aug;35(4):1123-37

Skeletal Radiol. 2014 Jun;43(6):781-91.

J Am Acad Orthop Surg. 2017 Nov;25(11):752-761

Am J Sports Med. 2019 Jul;47(8):1797-1803

 

"Visualizing MSK Radiology: A Practical Guide to Radiology Mastery"

© 2022 MSK MRI Jee Eun Lee All Rights Reserved.

No unauthorized reproduction, redistribution, or use for AI training.
#PMC, #POL, #semimembranosus, #kneeMRI, #OPL, #meniscotibialligament, #posteromedialcorner, #Kneeanatomy, #semimembranosustendon