Groin pain affects athletes across a wide range of sports, including football, ice hockey, rugby, track and field, volleyball, and ski racing, wherever abrupt changes of direction or forceful kicking place repeated strain on the pelvis1. Football alone accounts for 10 to 18% of all injuries in the sport, with rates reported as high as approximately two groin injuries per 1,000 hours of play2. Nearly a third of football players will experience groin pain at some point in their careers3, often resulting in prolonged absence from competition, reduced performance, and, in some cases, early retirement3,4.
Despite this burden, groin pain remains one of the least standardized diagnoses in sports medicine. Bone, cartilage, ligament, tendon, and muscle converge within centimeters of the pubic symphysis, and any of these structures may fail in isolation or in combination1. Clinical history and physical examination alone yield a pre-test probability of correct diagnosis of approximately 62%; a dedicated MRI protocol raises this figure to above 90%5.
The 2015 Doha agreement was a first step toward a shared clinical vocabulary, replacing vague labels with defined clinical entities based on history and physical examination and discouraging imprecise terms such as osteitis pubis6. Imaging was deliberately left for future work at that meeting. In the decade since, cadaveric studies, MRI-surgical correlation series, and refined classification systems have advanced the imaging-based understanding of groin pain.
This review summarizes the anatomy, biomechanics, classification, and imaging findings relevant to groin pain in athletes, using MRI as the primary diagnostic reference and distinguishing areas of established consensus from those where the evidence remains divided.
CLARIFYING ANATOMY AND BIOMECHANICS
The pubic symphysis
The pubic symphysis is an amphiarthrodial joint formed by two pubic bones joined by a fibrocartilaginous disc, creating a nonsynovial joint encased in a fibrous capsule2,3,7. The disc is stabilized by four capsular ligaments: the superior, inferior (arcuate), anterior, and posterior pubic ligaments2,3,7. It may contain a small physiological fluid-filled cleft, the primary cleft, present in an estimated 10% of adults and distinct from pathological cleft signs7.
The anterior and inferior pubic ligaments carry particular biomechanical weight. The anterior pubic ligament anchors both the superficial aponeurotic and deep musculotendinous layers of the symphyseal region, acting as its fulcrum, while the inferior pubic ligament, thicker and more heavily invested with muscular connections, is considered the principal stabilizer of the joint2,8. Only the superior pubic ligament is thought to retain elastic fibers, which may explain why the symphysis tolerates horizontal displacement more readily than vertical displacement2 (Figure 1).
Apophyseal maturation
There are two secondary ossification centers, or apophysis, and they serve different structures: a superior apophysis that anchors the adductor longus and the rectus abdominis aponeurosis, and a lower separate center that anchors the adductor brevis and gracilis instead. This split is the reason apophyseal changes at superior apophysis can be mistaken for superior cleft sign and changes at the inferior apophysis can be mistaken for the secondary cleft sign.
The maturation of the ossification center is slow, and a staged process rather than a single event14. Radiologically, four stages can be distinguished on CT or MRI according to whether the growth plate is still open and whether a separate ossification center is visible within it (Table 1 / Figure 2 and 3)14.
CT data from an asymptomatic cohort aged 9–30 years show why this staging matters clinically: complete closure was not observed before age 21, and some individuals still had an incompletely fused apophysis in their mid-twenties14. Because many competitive athletes fall within this age range, the pubic apophysis can remain a site of physeal weakness well into a professional career; a point revisited in the section on pubic apophysitis7,14.
The PLAC complex
For decades, the anatomy of the prepubic region was described according to a single model: direct fusion of the rectus abdominis and adductor longus through a shared aponeurotic plate, known as the prepubic aponeurotic complex (P-PAC). More recent cadaveric, histological, and MRI-surgical correlation studies have shown that any direct connection between these two structures is, at most, vestigial.
The alternative, the pyramidalis–anterior pubic ligament–adductor longus complex (PLAC), assigns this anchoring role to the pyramidalis — a small, anatomically variable muscle lying directly anterior to the pubic body that is continuous with the adductor longus tendon via the anterior pubic ligament9. In this model the rectus abdominis plays little part at the pubic attachment. It crosses the midline along its own course and ends on the fascia lata and gracilis, without joining the adductor longus. MRI and surgical studies have since shown that proximal adductor avulsions usually involve both the PLAC and the pectineus, and this pattern forms the six-type classification used later in this review10–12. One cadaveric and micro-CT study has described a different model, with two complexes, in which the external oblique rather than the pyramidalis anchors the adductor longus13 (Table 2). The models disagree about which structure provides the anchor, but both accept that any remaining link between the rectus abdominis and adductor longus is small and mechanically unimportant7.
For the purposes of this review, PLAC is used as the reference term; the classic P-PAC terminology remains in wide clinical use and is noted where relevant. Recognizing PLAC anatomy, rather than assuming direct rectus abdominis–adductor fusion, changes how adductor-region tears should be interpreted and reported on MRI.
2. CLASSIFICATION SYSTEMS
Classifying PLAC injuries
PLAC injury patterns are organized into a six-type classification based on three MRI variables: adductor longus fibrocartilage status, pyramidalis–adductor longus separation, and pectineus involvement9,10 (Table 3, Figure 4).
Classifying adductor lesions
A complementary classification addresses adductor lesions directly on MRI: strain, tendon avulsion, tendinopathy, and secondary cleft sign, of which the first two are acute and the latter two chronic16 (Table 4).
IMAGING TECHNIQUE AND MRI PROTOCOL
MRI is the first-line imaging modality for groin pain in athletes2,3,7. Although no single protocol is universal, approaches converge on a common two-stage strategy: a large-field-of-view sequence (approximately 30–40 cm) to survey the whole pelvis and localize the injury, followed by high-resolution, small-field-of-view sequences (approximately 15–24 cm, 2–3.5 mm slices) centered on the symphysis, using coronal and axial T1 and fluid-sensitive (T2 fat-saturated or STIR) images1–3,7. Critically, an oblique plane, axial, coronal, or both, oriented parallel to the pubic bone or pelvic arcuate line is essential for assessing the PLAC complex and proximal adductor origin; standard orthogonal planes alone are insufficient for this purpose1–3,7. A dedicated PLAC-specific protocol has also been described, using thin (3 mm) slices with the oblique axial plane oriented perpendicular to the adductor longus fibrocartilage; gadolinium is not required in the acute setting10.
Complementary modalities
CT-like MRI: When a bone lesion needs CT-level detail without the added radiation dose, a fast 3D gradient-echo sequence such as VIBE or ZTE can stand in for a conventional CT acquisition (Figure 3A).
Dynamic ultrasound: offers real-time correlation with the exact point of the athlete’s tenderness, scanned with a high-frequency linear probe as the examiner palpates the adductor origin, the iliopsoas tendon, or the inguinal canal in turn. Its trade-off is operator dependence, and it resolves the PLAC complex and the symphysis itself less reliably than MRI. For inguinal wall weakness and hernia, however, static MRI is frequently unremarkable, and dynamic ultrasound with a Valsalva maneuver is the diagnostic test of choice2,3,7. (Figure 14 C-E)
X-ray: an AP pelvis view plus a lateral of the proximal femur can flag cortical irregularity, an osseous avulsion, apophyseal change, calcification, or a narrowed symphyseal joint space as we can see at the Figure 5.
IMAGING FINDINGS
Muscle injuries
Adductor group injuries
The adductor group comprises six muscles along the medial thigh: adductor longus, adductor brevis, adductor magnus, pectineus, gracilis, and obturator externus17 (Figure 6). The adductor longus is by far the most commonly affected, accounting for 90% of adductor injuries overall and an estimated 10% of all injuries in soccer players7. Injuries typically occur at the myotendinous junction but may also involve the bone-tendon junction (enthesopathy)7. Reported distribution is approximately 25% proximal (75% of which are avulsions), 31% at the proximal myotendinous junction, 37% at the distal tendon, and 7% intramuscular, at the middle third of the muscle2.
Adductor longus tendinopathy, among the most common causes of groin pain in athletes, appears on MRI as diffuse tendon thickening and/or increased signal intensity, at times with focal bone marrow edema along the anteroinferior symphysis. Progression to partial or complete rupture appears as discontinuity of the tendon fibers, usually with surrounding edema or hemorrhage2,7. Adductor longus tendinopathy carried an odds ratio of 3.88 for concurrent direct inguinal hernia or posterior inguinal wall weakness, without excluding the possibility that MRI detects adductor tendinopathy in the absence of any inguinal pathology2.
Rectus abdominis injuries
Isolated rectus abdominis injury is uncommon (Figure 7); most cases are better described as rectus abdominis/adductor aponeurosis injuries, reflecting the close proximity of these structures on imaging2. As with any indirect muscle injuries, the key MRI indicator is increased intramuscular signal on fluid-sensitive sequences; avulsion of the rectus abdominis can itself produce a PLAC lesion2. Rectus abdominis tendinopathy is rare and follows the same principle, with increased signal at the myotendinous junction and/or tendon thickening2.
Iliopsoas injuries
Iliopsoas injury is considerably less common than adductor injury and typically also affects the myotendinous junction. Iliopsoas bursitis, from overuse or friction between the tendon and bursa, is a further possible cause of groin pain, appearing on MRI as fluid distension of the thin-walled bursa, often in direct communication with the hip joint (Figure 8).
PLAC injuries and cleft signs
PLAC tears have a typical MRI appearance (Figures 4, 9, 10 and 13). Fluid runs along the front of the pubic periosteum and collects in a cleft, sometimes extending into the adductor longus insertion. Patients usually describe pain that spreads up into the lower abdomen rather than staying in the groin7.
Three clefts can be seen on MRI. These are separate from the PLAC injury types listed in Table 5, and each point to a different structure, so they are worth distinguishing.
The primary cleft is a normal gap in the central disc, present in about 1 in 10 adults. On its own it means nothing, and the main risk is reading it as an injury. The other two clefts do indicate tears. The superior cleft runs along the underside of the superior pubic ramus and indicates a PLAC tear. The secondary cleft runs along the underside of the inferior ramus and indicates a tear of the short adductors (gracilis, adductor brevis). Both appear as a thin line of high T2/STIR signal, and both are easily mistaken for each other or for adductor tendinopathy unless their exact position along the ramus is checked (Table 5).
The anatomy explains the clinical pattern. The superior cleft lies close to the superficial inguinal ring, which is why it is associated with inguinal-related pain, and the secondary cleft lies among the short adductors, which is why it is associated with adductor-related pain2,7. Not every area of high signal fits these two categories. Atypical clefts that meet neither the superior nor the secondary criteria may still represent PLAC injury7,18, and subperiosteal bone reaction near the PLAC can look like a tendon tear when it actually reflects chronic stress-related bone edema7. Either cleft sign also carries prognostic weight: in one cohort, median return to play was 24.7 weeks when a superior or secondary cleft was present compared with 11.9 weeks when it was not, and the cleft sign was the only imaging finding that independently predicted this delay19 (Figures 9 and 10).
Pubic bone: marrow edema, osteopathy and apophysitis
Bone marrow edema (BME) is one of the most common findings on groin MRI. It appears as an area of high signal on fat-suppressed T2 or STIR sequences and often extends beyond the bone into the adductor and rectus abdominis attachments (Figure 11). The pattern can point to the source. Edema spread diffusely around the symphysis suggests a pubic-related process, whereas edema that stays focal around a single tendon attachment suggests an adductor-related process7. BME is not diagnostic on its own, and it may reflect normal adaptive remodeling of bone2. No grading system has been universally adopted, and none has been shown to be better for clinical decision-making2,18,20–22.
Pubic degenerative changes (erosion, sclerosis, cysts, joint space narrowing, disc protrusion, and osteophytes) can be seen in players without symptoms2,7. On plain radiographs, 75% or more of players with no groin complaints show degenerative change, compared with 45–65% of non-players. MRI separates the groups even less well: reported prevalence ranges from 20% to 98% in symptomatic athletes but still reaches 50% in athletes without symptoms7. Because these findings overlap so widely, a diagnosis of pubic degenerative changes should require at least three of five signs: pubic ramus BME, bone resorption or sclerosis, symphyseal irregularity or erosion, subchondral cysts or osteophytes, and central disc protrusion2. Fatigue fractures develop when repetitive loading exceeds the resistance of cortical bone, appearing on MRI as a linear hypointensity oriented obliquely to the joint surface, with associated BME (Figure 12).
Adolescent athletes are the population at risk for pubic apophysitis, particularly in kicking-heavy or high-mileage sports where sudden changes of direction load the pelvis repeatedly; on exam, the symphysis is tender to palpation, and resisted adduction or hip abduction reproduces the pain7. On MRI the immature plate reacts to this stress with a fairly consistent triad: marrow edema, irregularity just beneath the apophysis, and small cyst-like changes23. Because its clinical picture overlaps so much with muscle and tendon injury, apophysitis is easy to miss, and the resulting bone irregularity can be misread as a superior or secondary cleft sign unless the examiner first confirms whether the apophysis itself is unfused or asymmetric14.
Inguinal canal: hernias and posterior wall weakness
The true prevalence of inguinal-related pain is unclear, with reported rates ranging from none to 50% across studies. Surgically, posterior wall involvement affects the conjoint tendon and transversalis fascia, while anterior wall involvement affects the rectus abdominis, inguinal ligament, and external oblique aponeurosis. Static MRI is frequently unremarkable, and MRI’s role here is mainly to exclude alternative or coexisting pathology rather than to confirm wall weakness itself.
The diagnosis is built in two steps. Clinically, the pattern is tenderness in the inguinal canal without a palpable hernia, worse with abdominal resistance, coughing, or Valsalva. That suspicion is then tested with dynamic ultrasound during a Valsalva maneuver, examined both supine and standing; weakness without a true hernia is identified by anterior pre-peritoneal fat protrusion and, critically, by reproduction of the athlete’s actual symptoms, not by size alone3,6.
Indirect inguinal hernias develop at the internal inguinal ring and are lateral to the inferior epigastric artery (Figure 14). Direct inguinal hernias occur through Hesselbach's triangle, bounded by the inguinal ligament inferiorly, the inferior epigastric vessels laterally, and the rectus abdominis muscle medially. Femoral hernias develop in the empty space at the medial aspect of the femoral canal, inferior to the inguinal ligament.
One proposed grading scheme distinguishes flattening (posterior wall bulges without true protrusion), ballooning (dilation of the inguinal ring beyond 1 cm without a peritoneal sac), and true hernia (the herniating arc exceeds the radius of the ring during Valsalva)15; comparison with the asymptomatic contralateral side improves confidence in borderline cases.
Hip joint
Hip pathology is classified separately from the four core Doha entities, as a differential diagnosis rather than a groin pain subtype6, since hip and groin pain frequently coexist, radiate into one another, and share risk factors. Femoroacetabular impingement, classified as cam (reduced femoral head–neck offset) or pincer (acetabular overcoverage) morphology, and labral tears, most often located antero-superiorly2 should be actively considered in any groin pain assessment1,2.
CONCLUSION
Although groin pain in athletes remains a diagnostic challenge, terminology is converging. The Doha agreement established a shared clinical vocabulary6. Imprecise labels such as “osteitis pubis” and “sportsman’s hernia” are being replaced by anatomically precise description7, although consensus on terminology has not yet produced consensus on anatomy, as reflected in the ongoing debate between the P-PAC and PLAC nomenclature.
Imaging now plays a central role in the diagnostic pathway, moving from a supporting role to a primary diagnostic tool5. A solid understanding of the differential diagnosis, characteristic imaging patterns, and common diagnostic pitfalls is essential for the accurate evaluation of groin pain in athletes, supporting timely diagnosis and appropriate treatment planning.
Maisa Hernandes Pardo MD
“Guided” Clinic
Sao Jose do Rio Preto, Brazil
Natalia Magero MD
Paulo Victor Partezani Helito MD, PhD
Marcelo Bordalo MD, PhD
Aspetar Orthopaedic and Sports Medicine Hospital
Doha, Qatar
Contact: pardomaisa@gmail.com
References
1. Weber MA, Rehnitz C, Ott H, Streich N. Groin Pain in Athletes. Fortschr Röntgenstr. 2013;185:1139–1148.
2. Bisciotti GN, Di Pietto F, Rusconi G, Bisciotti A, Auci A, Zappia M, Romano S. The Role of MRI in Groin Pain Syndrome in Athletes. Diagnostics. 2024;14:814.
3. Calatayud Moscoso del Prado J, Fernández-Gil MÁ, Bueno Horcajadas Á, Kassarjian A. Groin pain in soccer players: anatomy, clinical presentation, biomechanics, pathology and imaging findings. Skeletal Radiol. 2025;54:763–778.
4. Candela V, De Carli A, Longo UG, Sturm S, Bruni G, Salvatore G, Denaro V. Hip and Groin Pain in Soccer Players. Joints. 2019;7:182–187.
5. Hynes JP, O’Flaherty M, Glynn D, Eustace S, Kavanagh EC. Imaging of groin pain in athletes: patterns of injury at MRI and gender differences therein. Ir J Med Sci. 2023;192(3):1411–1418.
6. Weir A, Brukner P, Delahunt E, Ekstrand J, Griffin D, Khan KM, Lovell G, Meyers WC, Muschaweck U, Orchard J, Paajanen H, Philippon M, Reboul G, Robinson P, Schache AG, Schilders E, Serner A, Silvers H, Thorborg K, Tyler T, Verrall G, de Vos RJ, Vuckovic Z, Hölmich P. Doha agreement meeting on terminology and definitions in groin pain in athletes. Br J Sports Med. 2015;49(12):768–774.
7. Rodrigues TC, Cunha Filho GAR. Common Mistakes in Groin Pain Classification. Semin Musculoskelet Radiol. 2025; Epub ahead of print (published online 07 October 2025).
8. Pieroh P, Li ZL, Kawata S, Ogawa Y, Josten C, Steinke H, Dehghani F, Itoh M. The topography and morphometrics of the pubic ligaments. Ann Anat. 2021;236:151698.
9. Schilders E, Bharam S, Golan E, Dimitrakopoulou A, Mitchell A, Spaepen M, Beggs C, Cooke C, Holmich P. The pyramidalis–anterior pubic ligament–adductor longus complex (PLAC) and its role with adductor injuries: a new anatomical concept. Knee Surg Sports Traumatol Arthrosc. 2017;25:3969–3977.
10. Schilders E, Mitchell AWM, Johnson R, Dimitrakopoulou A, Kartsonaki C, Lee JC. Proximal adductor avulsions are rarely isolated but usually involve injury to the PLAC and pectineus: descriptive MRI findings in 145 athletes. Knee Surg Sports Traumatol Arthrosc. 2021;29:2424–2436.
11. Begum FA, Kayani B, Ahmad SA, Fontalis A, Plastow R, Haddad FS. Return to Preoperative Level of Sporting Function after Surgical Repair of the Pyramidalis–Anterior Pubic Ligament–Adductor Longus Complex in Professional Athletes. Am J Sports Med. 2025;53:1878–1884.
12. Johnson R, Cooke C, Jones G, Isern-Kebschull J, Schilders E. Correlation Between a 3-Step MRI Assessment and Surgical Findings in Classifying PLAC Injuries in 161 Athletes. Am J Sports Med. 2025;53:2915–2923.
13. Tharnmanularp S, Muro S, Nimura A, Ibara T, Akita K. Significant relationship between musculoaponeurotic attachment of the abdominal and thigh adductor muscles to the pubis: implications for the diagnosis of groin pain. Anat Sci Int. 2024;99:190–201.
14. Sailly M, Whiteley R, Read JW, Giuffre B, Johnson A, Hölmich P. Pubic apophysitis: a previously undescribed clinical entity of groin pain in athletes. Br J Sports Med. 2015;49(12):828–834.
15. Bisciotti GN, Zini R, Aluigi M, Aprato A, Auci A, Bellinzona E, Benelli P, Bigoni M, Bisciotti A, et al. Groin Pain Syndrome Italian Consensus Conference update 2023. J Sports Med Phys Fitness. 2023;64:402–414.
16. Eraslan A, Kose O. Prevalence and patterns of adductor lesions on MRI in athletes with osteitis pubis. J Orthop Traumatol. 2025;26:65.
17. McHugh MP, Nicholas SJ, Tyler TF. Adductor Strains in Athletes. Int J Sports Phys Ther. 2023;18(2):288–292.
18. Holl N, Gerhardt JS, Tischer T, et al. Comparison between dedicated MRI and symphyseal fluoroscopic guided contrast agent injection in the diagnosis of cleft sign in athletic groin pain and association with pelvic ring instability. Eur Radiol. 2023;33(10):7321–7329.
19. Saito M, Niga S, Nihei T, Uomizu M, Ikezawa Y, Tsukada S. The cleft sign may be an independent factor of magnetic resonance imaging findings associated with a delayed return-to-play time in athletes with groin pain. Knee Surg Sports Traumatol Arthrosc. 2021;29(5):1474–1482.
20. Verrall GM, Slavotinek JP, Fon GT. Incidence of pubic bone marrow oedema in Australian rules football players: relation to groin pain. Br J Sports Med. 2001;35(1):28–33.
21. Branci S, Thorborg K, Bech BH, Boesen M, Nielsen MB, Hölmich P. MRI findings in soccer players with long-standing adductor-related groin pain and asymptomatic controls. Br J Sports Med. 2015;49(10):681–691.
22. Gaudino F, Spira D, Bangert Y, Ott H, Beomonte Zobel B, Kauczor HU, Weber MA. Osteitis pubis in professional football players: MRI findings and correlation with clinical outcome. Eur J Radiol. 2017;94:46–52.
23. Koh E, Boyle J. Pubic apophysitis in elite Australian Rules football players: MRI findings and the utility of VIBE sequences in evaluating athletes with groin pain. Clin Radiol. 2020;75(4):293–301.
24. Dempsey PJ, Power JW, MacMahon PJ, Eustace S, Kavanagh EC. Nomenclature for groin pain in athletes. Br J Radiol. 2021;94(1126):20201333.
Header Image by Goran Has (Cropped)