MR Imaging of Muscle Injuries

Donna G. Blankenbaker, MD; Arthur A. De Smet, MD

Disclosures

Appl Radiol. 2004;33(4) 

In This Article

Muscle Herniation

Muscle herniations are an uncommon complication of muscle injury. The lower extremity is most often involved in herniations and the tibialis anterior is the most frequently involved muscle.[3,4,6,27,28,29] The most common cause of herniation is blunt trauma that produces a rent within the fascia through which the adjacent muscle can protrude.[29] Another cause is muscle hypertrophy due to exercise, which can produce stretching of the vascular fenestrations of the fascia. The muscle can then herniate through these fenestrations.[6,29] Usually this diagnosis is made clinically, but occasionally the findings on physical examination are equivocal and the patient is referred for imaging. A patient may complain of a mass and exertional pain at the site of injury weeks following an injury.[3] If the herniation is small, pain may result only when the patient is actively exercising. MR imaging is superior to computed tomography for assessment of a muscle herniation because MR is able to distinguish the differing signal characteristics of the muscle and adjacent fascia. The fascial defect may not always be identified during MR imaging with the muscle relaxed. In this situation, dynamic imaging using short MR scans during muscle contraction may define the muscle herniation[3,4,6,27,28,29] (Figure 11).

Figure 5.

Hamstring avulsion following a water-skiing accident. (A) Sagittal T2-weighted fat-suppressed image through the proximal thigh reveals edema and hemorrhage along the hamstring muscles (long arrow). Peri-fascial fluid is noted to track along the hamstrings (large arrow). The proximal tendon is wavy in appearance (small arrow). (B) Sagittal T1-weighted image shows distortion and retraction of the hamstrings (large arrow). (C) Axial T2-weighted fat-suppressed image shows edema and hemorrhage (large arrow) at the origin of the hamstrings. The avulsion of the conjoined tendon (hamstring origin) is seen from the adjacent ischial tuberosity (small arrow). (D) Axial T1-weighted image reveals distortion of the conjoined tendon (arrow). (E) T2-weighted fat-suppressed image more distal shows edema and hemorrhage within the hamstrings, especially the semimembranosus (small arrow) and semitendinosus (large arrows). There is extensive surrounding perifascial fluid and blood. (F) T1-weighted image shows enlargement of the hamstring muscles with abnormal signal characteristics.

Figure 5.

Hamstring avulsion following a water-skiing accident. (A) Sagittal T2-weighted fat-suppressed image through the proximal thigh reveals edema and hemorrhage along the hamstring muscles (long arrow). Peri-fascial fluid is noted to track along the hamstrings (large arrow). The proximal tendon is wavy in appearance (small arrow). (B) Sagittal T1-weighted image shows distortion and retraction of the hamstrings (large arrow). (C) Axial T2-weighted fat-suppressed image shows edema and hemorrhage (large arrow) at the origin of the hamstrings. The avulsion of the conjoined tendon (hamstring origin) is seen from the adjacent ischial tuberosity (small arrow). (D) Axial T1-weighted image reveals distortion of the conjoined tendon (arrow). (E) T2-weighted fat-suppressed image more distal shows edema and hemorrhage within the hamstrings, especially the semimembranosus (small arrow) and semitendinosus (large arrows). There is extensive surrounding perifascial fluid and blood. (F) T1-weighted image shows enlargement of the hamstring muscles with abnormal signal characteristics.

Figure 5.

Hamstring avulsion following a water-skiing accident. (A) Sagittal T2-weighted fat-suppressed image through the proximal thigh reveals edema and hemorrhage along the hamstring muscles (long arrow). Peri-fascial fluid is noted to track along the hamstrings (large arrow). The proximal tendon is wavy in appearance (small arrow). (B) Sagittal T1-weighted image shows distortion and retraction of the hamstrings (large arrow). (C) Axial T2-weighted fat-suppressed image shows edema and hemorrhage (large arrow) at the origin of the hamstrings. The avulsion of the conjoined tendon (hamstring origin) is seen from the adjacent ischial tuberosity (small arrow). (D) Axial T1-weighted image reveals distortion of the conjoined tendon (arrow). (E) T2-weighted fat-suppressed image more distal shows edema and hemorrhage within the hamstrings, especially the semimembranosus (small arrow) and semitendinosus (large arrows). There is extensive surrounding perifascial fluid and blood. (F) T1-weighted image shows enlargement of the hamstring muscles with abnormal signal characteristics.

Figure 5.

Hamstring avulsion following a water-skiing accident. (A) Sagittal T2-weighted fat-suppressed image through the proximal thigh reveals edema and hemorrhage along the hamstring muscles (long arrow). Peri-fascial fluid is noted to track along the hamstrings (large arrow). The proximal tendon is wavy in appearance (small arrow). (B) Sagittal T1-weighted image shows distortion and retraction of the hamstrings (large arrow). (C) Axial T2-weighted fat-suppressed image shows edema and hemorrhage (large arrow) at the origin of the hamstrings. The avulsion of the conjoined tendon (hamstring origin) is seen from the adjacent ischial tuberosity (small arrow). (D) Axial T1-weighted image reveals distortion of the conjoined tendon (arrow). (E) T2-weighted fat-suppressed image more distal shows edema and hemorrhage within the hamstrings, especially the semimembranosus (small arrow) and semitendinosus (large arrows). There is extensive surrounding perifascial fluid and blood. (F) T1-weighted image shows enlargement of the hamstring muscles with abnormal signal characteristics.

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