โœ… Dr. Slothic Notes

๐Ÿ“Œ Scapholunate Ligament: Gross Anatomy and Key MRI Distinctions

MSK MRI 2025. 12. 10. 23:04

https://youtube.com/shorts/QjadaRb1aXM

 

1. Gross Anatomy Overview

The scapholunate ligament (SLL) consists of dorsal, volar, and intermediate (interosseous) components, supported by surrounding secondary stabilizers.


2. Dorsal Component

  • Short, transverse collagen fibers

  • Approximately 3 mm thick

  • Blends with the joint capsule, scaphotriquetral, and intercarpal ligaments

  • Strongest part of the SLL complex

  • Primary controller of flexion/extension

  • Complete tears are usually symptomatic


3. Volar Component

  • Oblique collagen fibers

  • Approximately 1 mm thick

  • Blends with the extrinsic volar radioscapholunate ligament

  • Controls rotational motion

  • Plays a major proprioceptive role


4. Intermediate (Interosseous) Component

  • Proximal and central; also called central or proximal component

  • Fibrocartilaginous

  • Sparse neurovascular supply

  • Weakest part of the SLL complex

  • Extends a few millimeters into the joint, resembling a meniscus-like structure

  • Often asymptomatic when torn in isolation

  • Classically tears at the scaphoid attachment


5. MRI Appearance: Key Points

5.1 Normal Appearance

  • Dorsal and volar components of both SLL and LTL appear bandlike on axial MRI

  • Typically show predominantly low signal intensity across all pulse sequences

5.2 Volar SLL Signal Characteristics

  • The volar SLL often demonstrates striated, heterogeneous, increased signal, especially on GRE sequences

  • This likely reflects associated loose vascular connective tissue

5.3 Critical Pitfall: RLT vs Volar SLL

  • The radiolunotriquetral ligament (RLT) lies intimately over the volar SLL

  • On axial images, this close relationship can mimic thickening or abnormal signal of the volar SLL

  • Radiologists must avoid misinterpreting the RLT as the volar SLL



#SLL, #scapholunate, #wristMRI, #carpalinstability, #dorsalSLL, #volarSLL, #interosseousSLL, #RLTligament, #MSKradiology, #wristanatomy, #Vibecase


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