Introduction[edit | edit source]
Myotendinous junction (MTJ) is a part of the myotendinous unit. The myotendinous unit consists usually of bone, enthesis, tendon, myotendinous junction and muscle, and is responsible for producing skeletal movement.
The MTJ has a distinctive form with the muscle membrane having many infolds which the collagen fibrils from the tendon join with (see image 1) . This unique structure creates an increased area for force transmission between muscle and tendon resulting in better force dispersal and less focal stress.
The MTJ transmits large forces from muscle to tendon in strenuous exercise, and hence is a common location for muscle strains. Most of these can be prevented by heavy eccentric exercise.
Physiotherapy Implications[edit | edit source]
The myotendinous unit weakest region is the MTJ, and as such it is its most commonly injured part.
- Large pennate muscle that are multi arthrodial and produce large tensile stresses are the most likely to suffer from MTJ injuries e.g. biceps femoris, quadratus femoris, biceps brachii.
- The interdigitations of the MTJ become shorter with aging, lessening the contact area for force transmission, and increase risk of injury.
US and MRI[edit | edit source]
- Mild strain: feathery interstitial edema and fluid/hemorrhage around the MTJ
- Moderate strain: intramuscular hematoma and perifascial fluid/hemorrhage
- Severe strain: MTJ tear with laxity/discontinuity of the tendon and muscle ends, sometimes with retraction
References[edit | edit source]
- Radiopedia Myotendinous unit Available: https://radiopaedia.org/articles/myotendinous-unit?lang=us(accessed 12.6.2022)
- Radiopedia Myotendinous junction Available:https://radiopaedia.org/articles/myotendinous-junction?lang=us (accessed 12.6.2022)
- Jakobsen JR, Krogsgaard MR. The Myotendinous Junction—A Vulnerable Companion in Sports. A Narrative Review. Frontiers in physiology. 2021;12. Available;https://www.frontiersin.org/articles/10.3389/fphys.2021.635561/full (accessed 12.6.2022)
- Wikimsk MTJ Available:https://wikimsk.org/wiki/Myotendinous_Junction (accessed 12.6.2022)