From the Department of Radiology, Philippine Orthopedic Center, Maria Clara Street, Santa Mesa Heights, Quezon City, Metro Manila, Philippines 1100 (D.V.F.); Department of Radiology, Hospital Pablo Tobón Uribe, Medellín, Colombia (C.M.G., M.E.C.); and Department of Radiology, UCSD Medical Center, San Diego, Calif (E.S., M.N.P.).
Radiographics. 2018 Jan-Feb;38(1):124-148. doi: 10.1148/rg.2018170072. Epub 2017 Dec 8.
Muscle is an important component of the muscle-tendon-bone unit, driving skeletal motion through contractions that alter the length of the muscle. The muscle and myotendinous junction (MTJ) are most commonly injured in the young adult, as a result of indirect mechanisms such as overuse or stretching, direct impact (penetrating or nonpenetrating), or dysfunction of the supporting connective tissues. Magnetic resonance (MR) imaging is widely used for assessment of muscle injuries. This review illustrates the MR imaging appearance of a broad spectrum of acute, subacute, and chronic traumatic lesions of muscle, highlighting the pathophysiology, biomechanics, and anatomic considerations underlying these lesions. Concentric (shortening) contractions are more powerful, but it is eccentric (lengthening) contractions that produce the greatest muscle tension, leading to indirect injuries such as delayed-onset muscle soreness (DOMS) and muscle strain. Strain is the most commonly encountered muscle injury and is characteristically located at the MTJ, where maximal stress accumulates during eccentric exercise. The risk of strain varies among muscles based on their fiber composition, size, length, and architecture, with pennate muscles being at highest risk. Direct impact to muscle results in laceration or contusion, often accompanied by intramuscular interstitial hemorrhage and hematoma. Disorders related to the muscle's collagen framework include compartment syndrome, which is related to acute or episodic increases in pressure, and muscle herniation through anatomic defects in the overlying fascia. The healing response after muscle trauma can result in regeneration, degeneration with fibrosis and fatty replacement, or disordered tissue proliferation as seen in myositis ossificans. In athletes, accurate grading of the severity and precise location of injury is necessary to guide rehabilitation planning to prevent reinjury and ensure adequate healing. In elite athletes, MR imaging grading of muscle trauma plays an increasingly important role in recently developed comprehensive grading systems that are replacing the imprecise three-grade injury classification system currently used. RSNA, 2017.
肌肉是肌肉-肌腱-骨骼单元的重要组成部分，通过改变肌肉长度的收缩来驱动骨骼运动。肌肉和肌-腱连接（MTJ）在年轻成年人中最常受伤，这是由于过度使用或拉伸等间接机制、直接撞击（穿透或非穿透）或支持性结缔组织功能障碍所致。磁共振（MR）成像广泛用于评估肌肉损伤。本综述说明了一系列广泛的急性、亚急性和慢性创伤性肌肉损伤的 MR 成像表现，强调了这些损伤的病理生理学、生物力学和解剖学考虑因素。向心（缩短）收缩更有力，但正是离心（延长）收缩产生最大的肌肉张力，导致间接损伤，如迟发性肌肉酸痛（DOMS）和肌肉拉伤。拉伤是最常见的肌肉损伤，通常位于 MTJ 处，在离心运动时最大应力积聚于此。根据肌肉的纤维成分、大小、长度和结构，不同肌肉的拉伤风险也不同，其中羽状肌的风险最高。直接撞击肌肉会导致撕裂或挫伤，通常伴有肌内间质出血和血肿。与肌肉胶原框架相关的疾病包括间隔综合征，其与压力的急性或间歇性增加有关，以及肌肉通过筋膜上的解剖缺陷疝出。肌肉创伤后的愈合反应可导致再生、纤维化和脂肪替代的退行性变，或在骨化性肌炎中可见的组织异常增殖。在运动员中，需要准确分级损伤的严重程度和精确位置，以指导康复计划，防止再次受伤并确保充分愈合。在精英运动员中，MR 成像对肌肉创伤的分级在最近开发的综合分级系统中起着越来越重要的作用，这些系统正在取代目前使用的不精确的三级损伤分类系统。RSNA，2017 年。
