Version May 2024
INTRODUCTION — Muscle, tendon, and other soft tissue injuries involving the abdomen, flank, and lumbar region are relatively uncommon across sports but may affect throwing athletes and participants in contact sports and other sports or activities involving forceful twisting or rotation of the trunk.
The presentation, diagnosis, and nonoperative management of low-energy soft tissue injuries of the lower torso in adults and adolescents, including the abdomen, flank, and lumbar region, are reviewed here. Thoracolumbar spine injuries, major abdominal and pelvic trauma, and other soft tissue injuries are discussed separately:
●Major abdominal and pelvic trauma in adults (see "Initial evaluation and management of blunt abdominal trauma in adults" and "Blunt genitourinary trauma: Initial evaluation and management" and "Overview of the diagnosis and initial management of traumatic retroperitoneal injury" and "Pelvic trauma: Initial evaluation and management")
●Spine injury (see "Thoracic and lumbar spinal column injury in adults: Evaluation")
●Injuries in children (see "Pediatric blunt abdominal trauma: Initial evaluation and stabilization" and "Approach to the initially stable child with blunt or penetrating injury" and "Trauma management: Approach to the unstable child")
EPIDEMIOLOGY — Soft tissue musculoskeletal injuries around the abdominal wall and flank are relatively uncommon across all sports but relatively more common in specific sports, such as cricket and baseball [1-3]. Traumatic injuries generally arise from sports where collision and contact occur, but participants in ball sports and sports where players use sticks and other equipment, such as hockey and lacrosse, may sustain such injuries.
Abdominal wall muscles play a major role in trunk stabilization, and hence, athletes involved in running or jumping sports are at some risk. Sports that involve trunk hyperextension with or without rotation (as occurs in gymnastics) or sudden high-force rotation (as occurs with cricket fast bowling, baseball pitching, and racquet sports) can cause injury to the muscles of the abdominal wall and flank [1-6].
Little research has been performed about abdominal wall and flank injuries in sport, with the majority focusing on major sports such as baseball, cricket, and football (soccer) [1-5,7,8]. Most are case series, epidemiological reports, and radiological reviews. Injury statistics from the United States National Collegiate Athletic Association during the 2004 to 2005 season report a high of 0.71 abdominal muscle injuries, including strains and contusions, per 1000 player-hours during wrestling matches to a low of 0.01 injuries per 1000 player-hours during American football practices [9]. Studies of professional Australian rules football report a rate of 0.7 abdominal strain injuries per club per season, over a period of four years, with a recurrence rate of 14 percent, with over 70 percent occurring in matches [5]. An average of 1.5 games are missed from abdominal wall injury each season per club compared with 11.9 games for groin strains, suggesting that abdominal wall injuries are less common and possibly less severe.
CLINICAL ANATOMY — An in-depth discussion of the anatomy of the abdominal wall is provided separately. Key features for understanding the injuries discussed below are provided here. (See "Anatomy of the abdominal wall".)
The abdominal wall is composed of three muscle layers anterolaterally, laterally, and posterolaterally and a vertical paired strap-like muscle and associated fascia anteriorly.
Anteriorly, the primary muscles of the abdominal wall are the rectus abdominis (figure 1 and figure 2 and figure 3 and figure 4 and figure 5). The anterolateral, lateral, and posterolateral portions of the abdominal wall are comprised of three layered muscles: the superficial external oblique, the middle internal oblique, and the deep transversus abdominis.
●Rectus abdominis – The rectus abdominis muscles (figure 1) of the central abdomen are separated in the midline by the linea alba and encased in a thick fascial sheath that extends from the aponeuroses of the oblique and transversus muscles. The rectus originates from the costal cartilages of the fifth, sixth, and seventh ribs and the xiphoid process and inserts onto the pubic symphysis and pubic crest. The rectus muscles contribute to truncal stability and enable abdominal wall flexion.
●External oblique – The external oblique (figure 1 and figure 3) originates from the lower seven ribs and runs inferiorly and medially, inserting onto the iliac crests and pubic tubercle, and onto the linea alba via an aponeurosis that contributes to the rectus sheath. The lowermost portion of the external oblique forms the inguinal ligament. The external oblique assists with torso stability and contributes to lateral flexion, forward flexion, and rotation of the trunk.
●Internal oblique – The internal oblique (figure 1 and figure 3) extends from the thoracolumbar fascia posteriorly and from the iliac crest and lateral two-thirds of the inguinal ligament and runs upwards and medially to insert onto the inferior border of ribs 10, 11, and 12. Its aponeurosis contributes to the rectus sheath and inserts into the linea alba. The internal oblique contributes to lateral flexion and rotation of the trunk. In coordination with the external oblique, the internal oblique can assist with forward and lateral flexion and rotation of the torso.
●Transversus abdominis – The transversus abdominis (figure 1 and figure 3) is the deepest muscle of the abdominal wall. It originates from the thoracolumbar fascia, inner portion of the iliac crest, 12th rib, lower six costal cartilages (where it interdigitates with the origins of the diaphragm), and lateral two-thirds of the inguinal ligament. The transversus muscle runs horizontally to insert into the linea alba via an aponeurosis that contributes to the posterior rectus sheath. The inferior fibers of the aponeurosis pass downwards with those of the internal oblique as the conjoint tendon and insert onto the pubic crest and pectineal line. The transversus abdominis provides support for the abdominal contents and has a significant role in lumbopelvic stability [10].
●Intercostal muscles – The intercostal muscles run between the ribs in three layers. Their action on the ribs is essential for respiration. The external intercostal muscles are continuous with the external oblique, as are the internal intercostal muscles with the internal oblique. These muscles are recruited in truncal twisting and flexion and susceptible to the same injuries as the other muscles involved in such movements.
●Quadratus lumborum – The quadratus lumborum muscle is a complex structure with a quadrangular shape. It consists of three layers: a thin superficial layer of iliocostal muscle and ilio-thoracic fibers (with attachments to the T-12 lateral vertebral body), a middle layer of lumbocostal muscle extending from the transverse processes of the lumbar vertebrae to the 12th rib, and a deep layer of lateral iliocostal muscle (with attachments to the thoracolumbar fascia) and medial iliolumbar muscle fibers (with attachments to transverse processes of the lumbar vertebrae). The arrangement of its fibers is highly variable [11].
There is disagreement regarding the primary roles of the quadratus lumborum. It is described as an extensor of the lumbar spine, a stabilizer of the lumbar region, and an accessory muscle of inspiration [12]. The muscle is integrated into the thoracolumbar fascia and, along with the multifidus and erector spinae, provides counterbalancing forces to the action of the abdominal wall muscles.
ABDOMINAL WALL INJURIES
Muscle contusions
Clinical presentation and initial management — Abdominal wall muscle contusions are caused by blunt trauma and may be sustained during a wide variety of recreational activities, including collision sports (eg, American football, rugby, ice hockey), contact sports (eg, basketball, soccer [ie, football], other ball sports), and combat sports (eg, boxing, wrestling). Impact may involve a body part (eg, shod foot, knee, shoulder) or equipment (eg, stick, bat, ball). The blow usually causes pain, swelling, and local ecchymosis but little damage to the overlying skin.
The force of the blow determines the severity and extent of injury. With severe blunt force trauma, internal organs may be injured, particularly if they are enlarged (eg, splenomegaly from infectious mononucleosis, hepatomegaly from infectious hepatitis). Distinguishing abdominal wall from intra-abdominal trauma is crucial, and a high index of suspicion should be maintained in high-force injuries. If an intra-abdominal injury is suspected, vital signs should be monitored, and the patient should be transported immediately to a hospital for further investigation. Assessment of possible intra-abdominal injury is discussed below. (See 'DO NOT MISS: Intra-abdominal organ injury' below.)
Most abdominal wall contusions are minor and heal uneventfully. Rest, application of ice, and activity modification until pain subsides are the mainstays of treatment. A large compression bandage applied to the abdomen can help to relieve symptoms with more severe contusions. Over-the-counter analgesics (eg, acetaminophen) as needed are generally sufficient for relief of more painful injuries.
In the hours to days following an abdominal wall injury, focal tenderness and possibly swelling are present at the area of impact. Ecchymosis of the surrounding area may develop over days. If the impact is severe, a hematoma may develop. Pain may be provoked by movement, particularly reaching upwards or rotating the trunk. Movement-related symptoms vary depending upon which muscles are injured. Most often, the rectus abdominis and external oblique are affected, as they are most superficial. Inspiration may be painful if the injury is more proximal.
Early recovery and rehabilitation — Once pain and swelling begin to subside, typically over the first couple of days, gentle range of motion exercises may commence, including gentle lumbar spine extension and trunk rotation. Pain is used as a guide; exercises should not cause anything more than mild discomfort. Patients may begin aerobic exercise (eg, walking, stationary bicycle, deep water running) as tolerated and then gradually increase weightbearing exercise over days to weeks as symptoms permit.
For more significant contusions, strengthening exercises for the abdominal wall may be prescribed. Exercises vary depending on the injury. Isometric exercises that engage the abdominal muscles are often prescribed. As an example, the patient may assume a supine position with their knees bent and then contract their abdominal muscles for 10 seconds at a time.
As healing of severe contusions progresses, patients begin trunk mobility exercises (eg lateral flexion, forward flexion, extension, and rotation). As an example, head and chest lifts can be performed (curl-ups involving lumbar spine flexion should be avoided). For this exercise, the patient lies supine with their feet on a wall placed hip-width apart, both the hips and knees are flexed to 90 degrees and the spine is kept in a neutral position. Maintaining this position, the patient lifts their head and chest a few centimeters off the ground. Repetitions are increased gradually over days to weeks, depending on the severity of the injury, building to three sets of 12 to 15 repetitions. The internal and external oblique muscles can be targeted by lifting the shoulder towards the contralateral hip. Other exercises may include bridges, planks, and side planks (picture 1 and picture 2). Exercises should not cause pain and should not be performed if they do.
Return to sport — Once full, pain-free motion of the trunk is achieved and basic isometric and floor-based exercises can be done without pain, the patient can begin to perform more functional and sport-specific exercises as appropriate. Activities progress gradually from jogging and running to side-stepping, twisting, and pivoting. Weight training should begin with lighter weights and advanced gradually. All exercises should be painless.
Cricket and baseball field players should resume swinging gradually, ideally using a bat that is at least 50 percent lighter than their standard bat. The number and intensity of swings and bat weight should be increased gradually over the ensuing weeks. Batting should be painless. Similarly, throwing and overhead athletes should resume activity gradually. Throwers can begin with a light ball, such as a tennis or soft rubber ball, and increase the weight of the ball over days to weeks as the injury heals and strength is regained. Rehabilitation programs for throwers are reviewed separately. (See "Throwing injuries of the upper extremity: Treatment, follow-up care, and prevention", section on 'Exercise and throwing programs for treatment and injury prevention'.)
Tennis and other outdoor racquet sport players can resume activity with easy ground strokes and serves from midcourt and gradually increase force and distance over a period of weeks.
Participants in contact sports should not return to full contact or collision drills until all noncontact movements (eg, sprinting, cutting) and skills (eg, throwing, shooting) can be performed painlessly [1,9]. Athletes may return to full sport when they have regained full mobility and strength and can perform all practice training at their baseline level of performance without symptoms.
Rectus abdominus sheath hematoma — Rectus sheath hematoma in sport is usually caused by blunt force trauma to the anterior abdomen. In most cases, the sheath surrounding the rectus abdominus muscles creates a tamponade effect and prevents blood from dispersing into adjacent tissues, resulting in a local hematoma. Bleeding is from torn muscle fibers or injury to the inferior or superior epigastric arteries or their various perforating branches [9].
Most rectus sheath hematomas are minor, particularly those sustained during sport. However, sometimes bleeding is severe and may cause hemodynamic instability, or in rare instances hypovolemic shock. Such severe bleeding is usually not caused by a sporting injury alone but occurs after a medical procedure or is associated with a bleeding diathesis or anticoagulant medication use [3]. Severe hematoma is more common in the right lower quadrant below the arcuate line. Patients with symptoms or signs of severe bleeding should be referred to the emergency department. The presentation and management of spontaneous or severe rectus sheath hematoma is reviewed separately. (See "Spontaneous retroperitoneal hematoma and rectus sheath hematoma".)
The usual presentation of rectus sheath hematoma involves pain and localized swelling with symptoms aggravated by abdominal extension and rotation away from the injury. Symptoms are relieved by trunk flexion. While not common, some patients may experience nausea and vomiting. Examination reveals a tender, swollen mass over the rectus abdominus, usually below the umbilicus. Pain is aggravated by resisted trunk or hip flexion. Abdominal guarding is sometimes present. Bruising may be evident after 48 to 72 hours.
When internal injury is a concern, point-of-care ultrasound is a useful tool for differentiating between superficial hematoma and intraperitoneal blood. Isolated intramuscular hematoma appears as a hypoechoic area within the rectus sheath (image 1) [9]. The use of ultrasound to assess abdominal and thoracic trauma is discussed separately. (See "Emergency ultrasound in adults with abdominal and thoracic trauma".)
When necessary, computed tomography (CT) (image 2) or magnetic resonance imaging (MRI) may be used to assess intra-abdominal trauma.
In a study of 13 cases, CT was used to classify rectus sheath hematoma as follows [13]:
●Type 1 (mild) injuries consist of small collections of blood confined within the rectus muscle without crossing the midline or dissecting into fascial planes (image 3).
●Type II (moderate) injuries involve blood largely within the muscle, but blood can dissect along the transversalis fascia or cross the midline (image 4).
●Type III (severe) injuries are large, usually below the arcuate line, with evidence of a hemoperitoneum or blood within the retropubic space (image 5). In all reported cases, patients with type III injuries were taking anticoagulants or had medical conditions that contributed to bleeding. Severe bleeding does not occur in athletes without such complicating factors.
The great majority of rectus sheath hematomas sustained during sport are self-limited and require minimal care. Management consists of relative rest, ice applied for the first day or so, and other-the-counter analgesics (eg, acetaminophen). Maintaining a position of slight trunk flexion when lying helps to reduce symptoms. In most cases, athletes can return to full sport as pain allows. Strength and mobility exercises can be introduced as needed in preparation for a full return to sport. This usually occurs over four to six weeks.
Severe hematoma with active bleeding may require interventional radiology or surgical intervention. After recovery from the acute injury, a large hematoma may require percutaneous drainage. Pain is the most common complication of a large, undrained hematoma, but there is a potential for abscess formation. Smaller hematomas do not require drainage.
Oblique muscle strain
Epidemiology — Oblique muscle strains are the most common abdominal muscle injury [1-9,14-22]. The internal oblique is injured most often [3,17,19], but the external oblique and transversus abdominis can also be affected (figure 1 and figure 2) [17,19]. Oblique muscle strains occur most often in throwers, such as fast bowlers in cricket [1,2,23] and pitchers in baseball [3,14,22]. However, oblique muscle strains have been reported in javelin throwers [1,9], gymnasts [4], soccer players [18], and tennis players [6] as well as hurdlers, rowers, and golfers [9].
A retrospective review of injuries among Major League Baseball players from 1991 to 2010 reported 393 abdominal muscle strains, constituting 5 percent of all injuries [3]. At least 92 percent involved strains of the internal or external oblique or intercostal muscles, and 44 percent were sustained by pitchers. An increase in the rate of strain injuries during the study period was noted. Pitchers averaged 35.4 days on the disabled list compared with 26.7 days for position players. Nearly 80 percent of injuries occurred contralateral to the pitcher's dominant arm, and over 70 percent were contralateral to the position player's dominant batting side.
In a 20-year review of injuries among professional cricket players, abdominal muscle strains involved the internal oblique in over one-half of the 46 cases where the injured muscle was specified, while 15 percent involved the rectus abdominus and 11 percent the external oblique [2]. As injury rates were higher earlier during the season, the authors speculate that lack of muscle conditioning may have contributed. Fast bowlers accounted for over 90 percent of injured players. Injury data from professional Australian cricket extending over 18 seasons to 2013 indicate that oblique strains had the second highest incidence and third highest prevalence of all injury types [24].
While data are limited, it appears that the internal oblique muscle is the most frequently strained muscle of the abdominal wall. Injury to the internal oblique can be isolated or occur in combination with the external oblique and less frequently has been reported with the transversus abdominis [17]. The injury is uncommon in most sports but relatively common among throwers, such as baseball pitchers and cricket fast bowlers [1,2,14,17]. In an observational study of a single Japanese professional baseball team over 10 years, internal oblique injuries accounted for 12.2 percent (n = 28 cases) of injuries [14]. Among field players, two-thirds sustained the injury while batting. Most injuries occurred on the side contralateral to the dominant hand.
The external oblique may be injured in isolation or concomitantly with other abdominal muscles, particularly the internal oblique. External oblique injuries have been reported in cricket fast bowlers [2,17,23], baseball players [3,14], and javelin throwers [1,9] as well as golfers, rowers, Australian football players [15], and soccer players, often in combination with an internal oblique injury [18]. Of 46 abdominal strains sustained by professional cricket players in one case series, five involved the external oblique [2].
Mechanism of injury — Published evidence related to oblique muscle strains is limited. Studies consist almost exclusively of case series [6,14-21,23].
Typically, athletes sustain oblique muscle strains during sudden, forceful movement of the torso involving rotation and hyperextension or hyperflexion [1-3,25]. The resulting forceful eccentric contractions of the involved abdominal muscles can cause tearing of the fibers. Such movement is most common in throwers and overhead athletes (eg, tennis players).
As an example, the bowling movement in cricket requires the nonthrowing (or leading) arm to be swung rapidly down and back as the trunk rotates and flexes laterally. The bowling arm then follows through and releases the ball overhead, placing a large eccentric load on the contralateral internal and external oblique muscles [1,17,22]. This forceful, asymmetric load predisposes to acute strain of the oblique muscles contralateral to the throwing arm. Thus, injury typically occurs on the side contralateral to the throwing arm in bowlers, pitchers, javelin throwers, and comparable athletes or to the swinging arm in tennis or golf players [3,6,19,26]. Other movements involving high-velocity thoracolumbar torque, such as rowing or baseball batting, can cause oblique muscle strains [27].
The internal oblique muscle on the side contralateral to the dominant (throwing) hand is approximately 10 percent thicker in elite cricket players, irrespective of player position [28]. Amateur fast bowlers display similar changes [29]. These findings suggest that regular, forceful throwing, bowling (pitching), and batting induce hypertrophy of the torque-generating muscles of the trunk involved in rotation and lateral flexion [30].
There is little discussion in the literature regarding risk factors for abdominal muscle strains. Studies of elite cricket fast bowlers [2] and baseball players [3] suggest that injury to the abdominal wall is more common during match play, particularly in the early part of the competitive season. In a review of injuries among professional cricket players, athletes under 24 years of age were approximately three times more likely to sustain an injury to the oblique muscles than those over 30 years of age [2]. This is likely due to the significantly higher physical demands of bowling at the highest level of competition, for which younger throwers may have been inadequately prepared.
Clinical presentation — Oblique muscle strains can present with vague findings, and the specific muscle group involved may not be evident without advanced diagnostic imaging. As many injuries are mild, and treatment is typically unaffected by the results, such imaging is usually unnecessary. An understanding of the mechanism, along with investigation of aggravating and relieving factors, can help to identify the likely muscles involved.
Commonly, an athlete with an oblique strain complains of pain at the lateral thoracoabdominal wall that began acutely with a high-force trunk movement (eg, swinging a bat) or gradually from repetitive movements (eg, cricket bowling, baseball pitching). Pain is focal and aggravated by twisting, flexion, or extension of the torso or some combination of these movements. Coughing, deep inspiration, or sneezing may exacerbate pain, as can rolling over in bed or arising from sitting.
Strains of the oblique muscles usually affect the lower four ribs on the anterolateral or posterolateral thoracic wall. In a small case series of cricket bowlers, pain was present roughly in the midaxillary line over the lower four ribs in all cases [2].
Injury is most common where the muscles attach to the ribs, and pain is usually experienced around the costal margin [19,26]. The muscle region just inferior to the ribs may be weaker and more vulnerable to injury than more distal muscle tissue further from the ribs [19]. However, strain may occur elsewhere in the muscle belly and has been reported at the distal insertion into the iliac crest and at the insertion into the thoracolumbar fascia [2,15,16,23]. While rare, cases of complete avulsion of the external or internal oblique muscles from the lower rib cage or the iliac crest have been reported [15,17].
Strains of the internal oblique, the muscle most often injured, usually involve anterolateral fibers at the 11th rib attachment, followed by the 10th, 9th, and 12th ribs [2,17,19,26]. Injuries associated with periosteal stripping from the bony or cartilaginous areas of the rib have been reported [19]. Such injuries appear to cause greater bleeding and pain.
Physical examination — Examination reveals localized tenderness at the injury site, usually the anterolateral or posterolateral thoracic wall [1,9,19]. Local swelling may be present. Pain is reproduced when the muscle is stretched, usually by rotating or bending away from the side of the injury. Over succeeding days, bruising may appear. With strains involving the lower abdomen, an active straight leg raise reproduces the pain. Severe strains can cause significant pain, particularly with movement involving the torso.
Reduced motion of the thoracic and lumbar spine, particularly rotation and lateral flexion, is often present due to localized pain. Patients may describe a jamming sensation when bending laterally towards the injured side.
Diagnostic imaging — If investigation is required for diagnostic or prognostic purposes, MRI is preferred [19,26]. Fat suppression images demonstrate high signal intensity in the area of the tear. High fluid signal intensity changes seen on short tau inversion recovery (STIR) or T2 images at the muscle rib or costal cartilage interface represent either a complete or partial muscle tear [19].
Point-of-care ultrasound may be useful where MRI is not easily accessible or for initial assessment [22,26]. Sonographic findings include disruption of the normally fibrillary pattern of the muscle with a hypoechoic area either at the rib or costal cartilage attachment of the internal oblique. A hypoechoic area between the internal and external oblique muscles suggests tracking of blood and edema [26]. Doppler flow may be increased at the injury site.
Management — Little research has been performed about the management of abdominal muscle strains. Management decisions, including restriction from play, are drawn from clinical experience and depend upon symptoms, the severity of injury, and whether taping or other forms of support and protection allow for adequate function.
Initial management is focused on reducing pain with cryotherapy, compression bandaging, over-the-counter analgesics (eg, acetaminophen), relative rest, and avoidance of aggravating activities.
Once pain is minimal, rehabilitation can begin. The initial goal is resumption of usual daily activities followed by gradual resumption of recreational activities and sport. As the muscles of the abdominal wall work together to stabilize and move the torso, rehabilitation should be targeted towards their integrated function. Aerobic exercise to maintain fitness should be included in any rehabilitation program.
Simple mobility exercises may begin as soon as they are tolerated. The introduction of strength exercises is guided by symptoms and sport-specific requirements. When the patient no longer experiences pain with deep inspiration, they can generally tolerate some light strength and aerobic exercises [1].
Initially, isometric exercises performed with a neutral trunk position (ie, no bending or rotating) are introduced. The goals are to minimize pain and muscle atrophy and to promote muscle healing [31]. Next, light stretching is added, followed by concentric exercises aimed at loading the injured muscles. As the injury heals and strength improves, power exercises, exercises involving larger eccentric loads, and plyometrics are introduced along with sport-specific skills [6,15]. Dynamic activities of the proposed sport should be started with low loads and volumes and increased gradually. When the athlete can perform such activities without difficulty or symptoms, they can return to training, where the intensity of drills is gradually increased and full sport resumed.
Some patients may experience reductions in thoracic spine motion. Physical therapy mobilization techniques may help patients regain full thoracic spine mobility.
Other treatments, including iontophoresis [27], local injection of glucocorticoid, anesthetic, dry needling, biologics [22], and Traumeel, have been reported [17,22,27], but their effectiveness is unproven, and we do not support the use of such interventions outside of clinical trials.
Transversus abdominus — Tears of the transversus abdominus muscle are rare [2,3,17]. When the muscle is torn, it is usually in combination with one or more of the oblique muscles (figure 1 and figure 2). This is likely because the transversus abdominis functions as a corset-like stabilizer of the torso between the thorax and the pelvis rather than a prime mover. Management is unchanged from other abdominal muscle strains. (See 'Management' above.)
Return to full activity and sport — Reports are limited, but full return to play following a significant abdominal muscle strain usually requires about four to five weeks in baseball pitchers, although baseball field players may return more rapidly [1-3,14,19,22]. In a small cohort study of elite cricket bowlers, return to play required as long as 70 days [17] while a tennis player returned after four weeks [6]. When such studies are obtained, patients with MRI findings demonstrating an oblique muscle strain require longer to return to play than those without such findings [2]. Athletes should be made aware that recovery may be prolonged and there is a significant risk of recurrence, particularly if the return to sport is premature. The risk of recurrence is highest among throwers [3].
Rectus abdominus muscle strain — Tears of the rectus abdominis muscles appear to be uncommon, but evidence is limited. In a retrospective study of abdominal muscle injuries among Major League Baseball players over 20 years, only four of 339 injuries involved the rectus abdominus [3]. Of 46 abdominal muscle strains sustained by cricket players and investigated with MRI, seven involved the rectus abdominis [2]. However, in a study of 100 consecutive MRIs performed for sport-related pubic pain ("sports hernia"), 76 percent of injuries involved the rectus abdominis, although most occurred in combination with injuries to other groin structures [32]. Thus, while rectus abdominis injury may be more common than previously thought, injuries of the distal muscle may present more often in patients with pubic pain. (See "Sports-related groin pain or 'sports hernia'".)
Rectus strains occur most often in throwers and overhead athletes, including baseball and cricket players [2]. They have been described in a 14-year-old softballer performing plyometric box jumps [33], tennis players, and a baseball player who sustained an inferior rectus avulsion [32]. Of the 11 elite tennis players included in a cohort study, all injuries occurred below the umbilicus on the side contralateral to the dominant hand [34]. Most injuries involved the deep surface of the muscle belly, with tears ranging from 6 to 72 mm. Six injuries occurred while serving, four during a forehand shot, and one during an overhead smash. Imaging with ultrasound and MRI revealed asymmetric hypertrophy of the rectus muscles on the side opposite the dominant arm. Such asymmetry may predispose to injury due to the imbalance of forces exerted across the abdominal musculature.
The predominant symptom among athletes with rectus strain is pain in the lower abdomen. Signs include pain provoked by coughing or Valsalva maneuvers. Examination reveals pain with hip flexion. Pain is often reproduced when the patient moves from lying supine to sitting or from sitting to standing. While the diagnosis can be made at the bedside with ultrasound [35], MRI remains the preferred imaging technique [34].
Rehabilitation for return to play is similar to that for oblique strains, typically requiring about four to six weeks. (See 'Management' above.)
Intercostal muscles — Intercostal muscles, while technically thoracic, are active in trunk stabilization. Intercostal strain injuries with mechanisms similar to those affecting the internal oblique muscles have been reported [2,25]. Such injuries are commonly referred to together as lateral strain injuries. Treatment and recovery times are similar for each type.
Trigger points and myofascial pain — Trigger points are a hallmark of myofascial pain and have been described as "hyperirritable spots, usually within a taut band of skeletal muscle or in the muscle's fascia that is painful on compression and can give rise to characteristic referred pain, tenderness, and autonomic phenomena" [36]. (See "Overview of soft tissue musculoskeletal disorders", section on 'Myofascial pain syndrome'.)
Trigger points may be found in the external oblique or along the sheath of the rectus abdominis laterally, usually centrally or in the lower end of the muscle, and have been reported in the quadratus lumborum. They can be caused by poor posture or voluntary muscle guarding around the diaphragm or excessive abdominal muscle training. Individuals with chronic cough have been reported to develop trigger points. Palpation may reveal small, discrete lumps that are firm and tender.
Treatment may consist of massage techniques to relieve spasm, other manual soft tissue therapy techniques, and correction of predisposing factors, such as poor posture, thoracic asymmetries, mobility restrictions, and poor weightlifting technique.
Rectus abdominus enthesopathy — Tendinopathy of the rectus abdominus insertion (ie, enthesopathy) usually occurs in combination with enthesopathy of the adductor muscles and is a common cause of groin pain, particularly in male soccer players. Pain in this region may stem from multiple injuries and can be difficult to diagnose. (See "Sports-related groin pain or 'sports hernia'".)
Pain from rectus abdominus enthesopathy is usually bad enough to impair performance and limit sporting activity. Whether from an isolated injury or concomitant with other soft tissue groin conditions, athletes usually complain of pain in the lower abdomen just proximal to the pubic bone. Pain may radiate into the lower abdomen. The condition is usually unilateral, involving the dominant leg, and is aggravated by activity, particularly running, twisting, pivoting, and kicking. A sit-up often elicits pain. There is focal tenderness at the tendon insertion.
Enthesopathy is thought to be an overuse injury from repetitive torsion and traction of the rectus abdominus tendon causing microtrauma at the insertion [37]. In some cases, it may be related to an acute incident, such as lifting or other activity associated with intense abdominal contraction.
Several factors may predispose to injury. Intrinsic risk factors may include weakness or strength imbalance among the abdominal muscles. Extrinsic factors may include training errors (eg, excessive running or kicking drills), poor lifting technique, unsuitable or unsupportive footwear, and inhospitable ground conditions (eg, uneven or excessively hard playing surface) [38].
Imaging is not always required, as the history and examination may be adequate for diagnosis. Plain radiographs may demonstrate bony changes consistent with osteitis pubis. Point-of-care ultrasound can be used to assess the integrity of the tendon and to exclude other pathology, such as an inguinal hernia. If necessary, MRI provides greater detail, including signs of bone stress response at the tendon insertion. High-intensity signal on T2 weighted and T2 fat suppressed images indicates edema of subchondral bone.
Management may vary depending upon the presence of associated pathologies but typically includes over-the-counter analgesics (eg, acetaminophen, ibuprofen), relative rest, and remediation of contributing factors. Once any acute symptoms have resolved, strengthening of the torso and hip musculature is often part of a rehabilitation program. When healing is complete and strength and mobility improved, the final stage of rehabilitation involves performance of sport-specific skills with a gradual increase in volume, intensity, and frequency.
Diastasis of rectus adominus — Diastases of the rectus abdominis is a pathologic separation of the muscle due to weakening of the linea alba (figure 6). While relatively common in pregnant patients, the condition can also occur in middle-aged and older men with central obesity and torso muscle weakness. Any separation greater than 2 cm is considered abnormal. In most cases, diastasis is readily apparent on examination. The condition is discussed in detail separately. (See "Rectus abdominis diastasis".)
Prevention of abdominal muscle strains — Strategies to reduce the risk for oblique and other abdominal muscle strains include resistance exercise programs emphasizing strength development of the torso musculature and gradual progression through the levels of competition. The approach taken by Australian cricket is to ensure a slow, graduated progression to the first 11 (top international team) to ensure that strength and endurance of the abdominal and flank muscles are sufficient to meet the demands of competition at the highest level, rather than sudden promotion to the top team due to outstanding performances at junior levels [39].
Differential diagnosis of soft tissue abdominal injuries
DO NOT MISS: Intra-abdominal organ injury
Epidemiology and mechanism — Blunt force injury of intra-abdominal viscera has been reported in a wide range of sports and recreational activities. Such injury may involve high-energy trauma such as a downhill skiing, cycling, or equestrian crash; ice hockey check; or impact from a baseball or cricket ball or lower-energy forces such as a tackle, stick check, or collision with a goalpost. Such blows may cause injury to the liver, spleen, kidneys, or other internal organs [40]. Given the life-threatening potential of bleeding from visceral injury, recognition is vitally important. Any athlete suspected of sustaining such an injury should be evaluated in the emergency department. Evaluation of such injury is reviewed separately. (See "Initial management of trauma in adults" and "Initial evaluation and management of blunt abdominal trauma in adults" and "Pediatric blunt abdominal trauma: Initial evaluation and stabilization".)
Overall, sport is not a common cause of intra-abdominal injury. Sports performed at high speed with a potential for high-energy trauma (such as horse-riding and downhill skiing) and collision sports (such as ice hockey, rugby, and American football) account for the majority of sports-related intra-abdominal injuries [40-47]. When injury occurs, the viscera most often affected are the spleen (about 25 percent) and liver (about 15 percent), the latter accounting for approximately one-half of deaths due to blunt force trauma in sport. While intestinal injury is rare in sport, it can occur when viscera is crushed between an object, such as the handlebars of a bicycle, and the pelvis or vertebrae [47]. Another mechanism may involve acceleration-deceleration injuries that create shearing forces at sites where a tethered segment of bowel is adjacent to a mobile segment, such as the duodenal-jejunal junction. Such mechanisms can occur during sports such as cycling, mountain biking, or horse riding and may cause intestinal tearing and possibly perforation.
Clinical presentation and examination — Intra-abdominal injury may be difficult to diagnose early, as the presenting symptoms and signs may be mild. The history should include questions about infections (eg, Epstein–Barr virus, cytomegalovirus, viral hepatitis, malaria) and other medical conditions (eg, sickle cell, hemochromatosis, other genetic disorders) that can cause hepatic or splenic enlargement, predisposing to injury.
The initial examination may reveal only mild tenderness without abnormalities in the vital signs or skin. Particularly in young, healthy athletes whose resting heart rate and blood pressure may be low at baseline, vital signs may be falsely reassuring, and hypotension may not manifest until a patient is in severe shock. The patient should be able to relax their abdominal musculature for examination; voluntary or involuntary guarding is concerning and should prompt more detailed assessment. Focal rib tenderness may be associated with one or more rib fractures, which may in turn cause laceration of the liver, spleen, or lung. Reassessment of vital signs and re-examination of the abdomen and chest are important. If there is uncertainty about the extent of injury, it is best that the patient be brought to the emergency department for further evaluation. Bedside ultrasound can be useful for distinguishing between muscle wall and intra-abdominal injury. (See "Emergency ultrasound in adults with abdominal and thoracic trauma".)
Bleeding from lacerated viscera may be slow, causing symptoms and signs to be delayed by days or weeks. Thus, close follow-up should be arranged and the patient instructed about signs to watch for and the need to be re-evaluated should they appear. Such signs include worsening pain or fatigue, increased anxiety, tachycardia at rest, increased difficulty breathing, hematuria, or significant flank ecchymosis. Although often delayed, signs the clinician should consider include associated shoulder pain (Kehr sign), suggesting irritation of the diaphragm by intraperitoneal blood, and ecchymosis at the periumbilical area (Cullen sign (picture 3)) or lateral flank (Gray-Turner sign (image 6)), which also suggest hemoperitoneum.
Hernia — Hernias of the abdominal wall are discussed in detail separately. Abdominal hernias are unlikely to be caused by trauma but may masquerade as a sports-related injury, as they can develop at sites such as an aponeurosis where activity-related strains may occur (figure 7 and figure 8 and figure 9). Careful palpation and possibly ultrasound or other imaging are sufficient means to distinguish hernia from soft tissue injuries of the abdomen and flank. (See "Overview of abdominal wall hernias in adults" and "Classification, clinical features, and diagnosis of inguinal and femoral hernias in adults" and "Spigelian hernias".)
Osteitis pubis — Osteitis pubis, a groin condition sustained primarily by athletes whose sports involve kicking, twisting, or running, causes pain that may radiate into the low abdomen. Performing a sit-up may cause such pain and radiation. Onset of osteitis pubis is usually gradual, and pain is localized to the pubic symphysis. In addition to the low abdomen, pain may radiate distally toward the adductor tendon origins (figure 10). The condition is caused by chronic overloading of the muscles, but sacroiliac joint dysfunction may contribute, particularly in athletes with hypermobility of that joint. Osteitis pubis may coexist with other groin conditions, including stress fracture and other soft tissue injury. There is ongoing debate about the term and nature of osteitis pubis. Some organizations consider it an umbrella term for multiple injuries related to the lower abdominal wall and pubic bone due to chronic overload from sport. (See "Osteitis pubis".)
Rib and costochondral joint injuries — Pain from rib fractures and costochondral injuries of the lower ribs can be like that caused by abdominal muscle strains or contusions, and it may refer to the upper abdomen. As the mechanisms too may overlap and muscle and rib injuries may occur concomitantly, distinguishing between them can be difficult. Rib fractures are reviewed in detail separately; aspects of their presentation that help to distinguish them from muscle injuries are discussed briefly below. (See "Initial evaluation and management of rib fractures" and "Initial evaluation and management of chest wall trauma in adults".)
Sport-related rib fractures are usually sustained from a direct blow or heavy impact with the ground or another player during collision sports, such as American football, rugby, and ice hockey, while injuries at the costochondral junction are usually the result of forceful twisting of the torso, as might occur in wrestling [48]. Blunt trauma can cause costochondral separation, but this is more common with the upper and middle ribs [49]. Most sport-related rib fractures are relatively minor, but associated injury of the lung, liver, spleen, or kidney may occur.
Patients with rib fractures or costochondral injuries complain of localized pain over the low ribs, which increases with inspiration, coughing, or sneezing. The athlete may recall feeling a "pop" when the injury occurred. Any truncal movement can aggravate symptoms, but flexion to the contralateral side in particular increases pain.
On examination, bony injury is often associated with more focal pain, which may be elicited by compression of the thorax, and localized tenderness at the affected rib or costochondral junction. Tenderness can be provoked by direct palpation, percussion of the rib, or application of a vibrating tuning fork. With muscle strains, diffuse tenderness is more common, and inspiration may not be as painful as it is with rib-related injuries. Isolated movements that stretch the injured muscle may elicit pain.
Plain radiographs are often adequate to diagnose rib fractures, but CT or MRI may be needed if there is concern for severe injury. Costochondral injuries are not seen on plain radiograph but may be evident on CT or MRI.
Other conditions and injuries
●Referred pain from spine — Nerve root impingement at the low thoracic (T8-12) or upper lumbar (L1) spine can cause referred pain at the abdominal wall. Impingement may be due to disc protrusion, degenerative change of the vertebrae, tumor, or cyst. The presence of referred symptoms and the absence of focal abdominal tenderness suggest that muscle injury is not the cause. (See "Acute lumbosacral radiculopathy: Etiology, clinical features, and diagnosis".)
●Shingles (prodromal pain) — The prodromal pain from herpes zoster (shingles) can cause significant burning, throbbing, or stabbing pain in the abdominal wall and flank along the T8 to L1 dermatomes. While only a small percentage of patients younger than 20 experience such a prodrome, among patients older than 50, up to 85 percent may do so. Until lesions manifest (picture 4), this pain can be mistaken for a soft tissue injury, particularly if the region has sustained minor trauma recently. The diagnosis usually becomes clear after two to three days when a unilateral, vesicular rash develops in one or two adjoining dermatomes (picture 5 and picture 6). (See "Epidemiology, clinical manifestations, and diagnosis of herpes zoster".)
●Ischemic bowel injury — Participants in prolonged endurance sports, such as marathons, long-distance triathlons, and ultra-endurance races, particularly in high heat and humidity, are susceptible to ischemic bowel injury. Dehydration and redistribution of blood from the splanchnic circulation to working muscle predispose to such injury. Presentation typically involves abdominal pain without muscle wall tenderness, which may be accompanied by diarrhea with occult or frank blood. While injury is usually reversible with appropriate treatment, there are reports of athletes requiring bowel resection [50]. (See "Overview of intestinal ischemia in adults".)
●Bladder injury — Forceful blunt trauma to a full bladder may cause the bladder to rupture, but such injury is rare in sport, as athletes typically do not participate with a full bladder. Symptoms include difficulty with urination and abdominal pain and fullness; signs include abdominal rigidity and marked tenderness as well as hematuria. (See "Blunt genitourinary trauma: Initial evaluation and management" and "Traumatic and iatrogenic bladder injury".)
FLANK INJURIES
Muscle contusion — Muscle contusions of the flank are caused by blunt trauma to the muscle and may be sustained during a wide variety of recreational activities and sports, as discussed above. (See 'Muscle contusions' above.)
Injuries at the flank may involve the oblique muscles (discussed above) but can affect the quadratus lumborum and sometimes the erector spinae muscles. Injury to the muscle fibers causes local pain and swelling and interstitial and intramuscular edema. Ecchymosis and possibly a hematoma may form. The area of injury is generally tender, and patients may complain of low back stiffness. Stretching or contraction of the affected muscles aggravates pain. Kidney injury should be considered in any patient who has sustained significant trauma at the flank or paralumbar region. (See 'DO NOT MISS: Traumatic kidney injury' below.)
In most cases, advanced diagnostic imaging is unnecessary. When necessary, magnetic resonance imaging (MRI) is ideal for assessing the extent of muscle injury and determining whether deeper structures (eg, kidney) are affected. MRI findings of muscle contusion range from disruption of muscle fibers to focal intramuscular edema and, in more severe cases, hematoma surrounded by interstitial hemorrhage. Signal intensity varies depending upon the duration and state (eg, active bleeding) of the hemorrhage.
Management of mild to moderate muscle contusions is largely identical to that described above for abdominal muscle contusions. (See 'Muscle contusions' above.)
Muscle strain — Strains involving the muscles of the flank, including the quadratus lumborum, involve mechanisms and present in a fashion similar to strains of the abdominal oblique muscles described above. The presumed mechanism involves forceful eccentric contraction (as occurs with throwers) causing injury most often at the musculotendinous junction. (See 'Oblique muscle strain' above.)
In most cases, advanced diagnostic imaging is unnecessary. When obtained, MRI appearance ranges from focal mild intramuscular edema to extensive fiber disruption. Muscle strain usually appears as feathery, high-intensity T2 signal that follows the course of the involved muscle fibers. The extent and duration of rehabilitation and time before return to full play vary depending upon the severity of injury.
Quadratus lumborum — While published literature is scant, strains to the quadratus lumborum appear to be uncommon. Forceful, eccentric loading of the muscle is the most likely mechanism. Cricket fast bowlers and other throwers may have asymmetrical development of the quadratus lumborum, but it is not clear whether this asymmetry predisposes a player to injury [51]. Management mirrors that described above for abdominal muscle strains. (See 'Management' above.)
As an example, a case report describes a 16-year-old soccer player who sustained the injury while kicking and landing on the kicking foot, causing ipsilateral flexion of the trunk with the pelvis tilted back, thereby causing eccentric contraction of the trunk [52]. The patient complained of a sudden onset of acute pain in the posterolateral flank, just above the iliac crest. There was moderate tenderness in this region, and pain was reproduced by lateral flexion or internal rotation of the hip toward the contralateral side. Passive hip range of motion was unaffected. Fat-saturated T2 weighted MRI images showed a high-signal-intensity area in the right quadratus lumborum at its attachment on the iliac crest that extended proximally along the muscle fibers. The player was treated with relative rest followed by rehabilitation and returned to play three weeks after injury. The authors speculated that tight hamstrings may have contributed to the injury.
The uncommon complications associated with muscle injuries (eg, myositis ossificans) may occur following flank muscle strains [53]. (See "Quadriceps muscle and tendon injuries", section on 'Myositis ossificans'.)
Erector spinae injury — Muscle strain of the erector spinae (figure 11) is theoretically possible, but there are no published case reports. There is one case reported of chronic exertional compartment syndrome of the erector spinae treated successfully with fasciotomy [54]. The patient presented with localized, exercise-induced low back pain relieved by rest without neurologic symptoms or signs.
Avulsion of muscular attachments from ribs 11 and 12 — Sudden vigorous contractions of muscle attachments to the lower ribs may cause avulsion fractures of the external oblique muscle posteriorly. Such injuries, which were first described in baseball players, are rare and have only been reported in sport [55].
Enthesopathy at iliac crest — Entheses are the portion of the tendon that inserts onto bone. Enthesopathy is a painful condition associated with pathologic changes in the tissue. Enthesopathy may be inflammatory (ie enthesitis), degenerative, traumatic, or related to underlying endocrine, metabolic, or rheumatologic disorders [56]. Radiographic features consistent with enthesopathy include bony erosions, hyperostosis, fragmentation, and crystal deposition. (See "Overview of soft tissue musculoskeletal disorders", section on 'Enthesitis'.)
Enthesopathy of the distal attachments of the oblique muscles and quadratus lumborum, also known as iliac crest syndrome, are relatively common in patients suffering from low and middle back pain. There may be a history of overuse, particularly with sports involving substantial throwing or twisting (eg, batting). The syndrome is associated with increased tone of the muscles that insert onto the iliac crest, causing traction at the insertion. Increased tone of the muscles may be associated with other pathology affecting the low back, including sacroiliac joint dysfunction or dysfunction of the thoracic rings. Detailed investigation including advanced imaging may be required to exclude medical causes for enthesopathy of the iliac crest, as ankylosing spondylitis and rheumatoid arthritis commonly cause such enthesopathy. (See "Clinical manifestations and diagnosis of peripheral spondyloarthritis in adults".)
Patients typically complain of nonspecific pain in the region of the iliac crest. Focal tenderness is present at the tendon insertion. Pain is aggravated by lateral flexion away from the side of the injury and by lateral flexion and rotation movements of the torso generally. Ultrasound may show hypoechogenicity and thickening of the muscle insertion, iliac enthesophytes, and bony erosions [57]. MRI may show marrow edema of the iliac crest at the muscle attachments.
Treatment typically involves relative rest, flexibility exercises, manual soft tissue therapy, and graduated strengthening exercises. As symptoms settle, patients may gradually resume activity and sport.
Differential diagnosis of soft tissue flank injuries
DO NOT MISS: Traumatic kidney injury — Of all trauma-related kidney injuries, approximately 11 percent are sustained during sport with blunt trauma as the usual cause [58]. Significant force is necessary to damage a kidney, and mechanisms typically involve a direct blow or compression against vertebral and paravertebral structures. Rapid deceleration is another possible mechanism.
Kidney injuries are more common in children, as the organs extend below the ribcage and the ribs are more pliable. Injuries in children are discussed separately. (See "Pediatric blunt abdominal trauma: Initial evaluation and stabilization" and "Approach to the initially stable child with blunt or penetrating injury".)
Sports such as skiing, snowboarding, and in-line skating account for more kidney injuries than collision sports. Kidney injuries sustained in collision sports are uncommon, and most such injuries heal completely without lasting impairment of renal function [59-61]. Once healed, most athletes can resume collision or contact sports.
Kidney injuries can be difficult to diagnose in the setting of field or court sports. Typically, patients will have sustained a blow to their flank and complain of pain. Nausea and vomiting may be present. The presence of any hemodynamic instability suggests internal injury and hemorrhage and warrants urgent evaluation. Associated rib fractures may be present. Point-of-care ultrasound can be useful for identifying internal hemorrhage and broken ribs. Frank or microscopic hematuria is present in 50 to 75 percent of cases [62]. The degree of hematuria does not appear to predict the severity of kidney injury following blunt trauma [63]. Bruising (Gray-Turner sign (image 6)) or flank hematoma may develop over time and may indicate retroperitoneal hemorrhage.
Any patient with a suspected kidney injury or retroperitoneal hemorrhage should be transferred to the emergency department for evaluation. Evaluation of kidney injuries sustained through blunt trauma is discussed separately. (See "Blunt genitourinary trauma: Initial evaluation and management" and "Overview of the diagnosis and initial management of traumatic retroperitoneal injury" and "Overview of traumatic upper genitourinary tract injuries in adults".)
Most traumatic kidney injuries sustained through field or court sports are mild, and athletes can return to activity without problems. Hematuria must be completely resolved prior to return to sport. The literature suggests a minimum of two to six weeks before sport can be resumed following mild injury [59]. Return to full contact sport typically takes significantly longer and, depending on the severity of the injury, a delay of 6 to 12 months may be required [64].
Other injuries and conditions
●Rib fracture — Fractures of the 11th or 12th rib can cause flank pain, sometimes with radiation anteriorly or inferiorly. Pain is exacerbated by deep inspiration, coughing, or sneezing. Radiographs or point-of-care ultrasound may reveal the location of the fracture. As rib fractures may be associated with internal injury, assessment for such injury is needed. (See "Initial evaluation and management of rib fractures".)
Distinguishing a rib or costochondral injury from a muscle strain or contusion involving the lateral abdomen or flank may be difficult. Bony injury is often associated with more focal pain, which may be elicited by compression of the thorax, and localized tenderness at the affected rib or costochondral junction. Tenderness can be provoked by direct palpation, percussion of the rib, or application of a vibrating tuning fork. With muscle strains, diffuse tenderness is more common, and inspiration may not be as painful as it is with rib-related injuries. Isolated movements that stretch the injured muscle may elicit pain.
●Referred pain from spine — Radicular pain from nerve root compression at lower thoracic or upper lumbar vertebrae may cause flank pain. The presence of referred symptoms and the absence of focal flank tenderness suggest that muscle injury is not the cause. (See "Acute lumbosacral radiculopathy: Etiology, clinical features, and diagnosis".)
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Nontraumatic abdominal pain in adults".)
SUMMARY AND RECOMMENDATIONS
●Epidemiology – Soft tissue musculoskeletal injuries of the abdominal wall and flank are relatively uncommon but occur most often in throwers and other overhead athletes as well as participants in collision and contact sports.
●Anatomy – The abdominal wall and flanks include several muscles with different orientations and functions. They include the rectus abdominis, external and internal obliques, transversus abdominis, intercostals, and quadratus lumborum (figure 1 and figure 2 and figure 3 and figure 4 and figure 5). An in-depth discussion of abdominal wall anatomy is provided separately; key features for understanding soft tissue injuries are discussed in the text. (See "Anatomy of the abdominal wall" and 'Clinical anatomy' above.)
●Muscle contusions – Contusions of the abdominal wall and flank muscles are caused by blunt trauma from contact sport or other activities. The force of the blow determines the severity and extent of injury. Focal tenderness and possibly swelling are present at the area of impact acutely; ecchymosis of the surrounding area may develop over days. Pain may be provoked by movement, particularly reaching upwards or rotating the trunk.
Distinguishing abdominal wall from intra-abdominal trauma is crucial. This may be difficult in healthy athletes, whose resting heart rate and blood pressure may be low at baseline. Bedside ultrasound can be useful in this setting. Most abdominal wall contusions are minor and heal uneventfully with supportive care, possibly including rehabilitation exercises. (See 'Muscle contusions' above and 'DO NOT MISS: Intra-abdominal organ injury' above.)
●Oblique muscle strain – Oblique strains, particularly of the internal oblique, are the most common abdominal muscle injury. They develop most often in throwers but can occur in participants in any sport involving rotational force (eg, tennis, rowing, golf, javelin). Strains occur most often during sudden, forceful movement of the torso involving rotation and hyperextension or hyperflexion. (See 'Epidemiology' above and 'Mechanism of injury' above.)
Commonly, an athlete complains of pain at the lateral thoracoabdominal wall that began acutely with a high-force movement (eg, swinging a bat) or gradually from repetitive, forceful movement (eg, cricket bowling, baseball pitching). Pain and tenderness are focal, usually affecting the lower four ribs on the anterolateral or posterolateral thoracic wall, and aggravated by twisting, flexion, or extension of the torso. (See 'Clinical presentation' above and 'Physical examination' above.)
Initial management is focused on reducing pain with cryotherapy, compression bandaging, over-the-counter analgesics (eg, acetaminophen), relative rest, and avoidance of aggravating activities. As symptoms permit, patients begin a progressive rehabilitation program to improve torso strength and coordinated movement. Return to full sport varies depending on the severity of the strain. Baseball pitchers often require four to five weeks. (See 'Management' above and 'Return to full activity and sport' above.)
●Less common injuries – Other, less common injuries of the abdominal wall and flank soft tissues include:
•Rectus abdominus hematoma (see 'Rectus abdominus sheath hematoma' above)
•Rectus abdominus muscle strain (see 'Rectus abdominus muscle strain' above)
•Intercostal muscle strain (see 'Intercostal muscles' above)
•Contusions and strains of flank musculature (eg, quadratus lumborum, erector spinae) (see 'Flank injuries' above)
●Differential diagnosis – Important causes of abdominal wall pain that should be considered when assessing possible soft tissue injury of the abdominal wall and flank include intra-abdominal injury, hernia, osteitis pubis, and rib and costochondral injury. The possibility of kidney injury must be considered in any patient who has sustained significant blunt trauma of the flank. Such injury is more common in children. (See 'Differential diagnosis of soft tissue abdominal injuries' above and 'Differential diagnosis of soft tissue flank injuries' above.)
آیا می خواهید مدیلیب را به صفحه اصلی خود اضافه کنید؟
