The etiology of inguinal pain can be straightforward if a groin bulge is the chief complaint and a hernia is palpated on exam. Common exacerbating factors to note in the history include major lifting or coughing. Pain occurring later in the day, after prolonged standing or straining, is also consistent with a hernia.

Inguinal hernias are the most common, accounting for 70–75 % of all hernias [1]. They are divided into indirect and direct forms, with the indirect form being the most common. The pathophysiology behind an indirect hernia is a patent processus vaginalis that failed to degenerate after descent of testes during fetal development. This potential space allows intra-abdominal contents to pass from the deep inguinal ring to the superficial inguinal ring. Direct hernias are protrusions within Hasselbach’s triangle, directly through a weakened posterior wall of the inguinal canal. Finally, femoral hernias account for a small percentage of hernias. Classically quoted in textbooks as the third most common type of primary hernia, femoral hernias account for 20 % of hernias in females and 5 % in males [2]. They occur distal to the inguinal ligament through a defect in the femoral ring, which is bound anteriorly by the inguinal ligament, posteriorly by the iliopectineal ligament, medially by the lacunar ligament, and laterally by the femoral vein. Though altogether representing less than 10 % of all hernias, femoral hernias tend to present more emergently with strangulation or incarceration of bowel [3]. Definitive treatment of all hernias is surgical. Options include open repair with or without mesh and laparoscopic repair with mesh.

Athletes are a population of special consideration when it comes to hip and groin pain, a symptom not uncommonly experienced by those engaged in activities such as soccer, rugby, football, and ice hockey. The aforementioned sports involve extensive use of the adductors and hip flexors. Osteitis pubis, fractures, stress fractures, joint disorders producing referred hip pain, bursitis, hernias, muscular pain, tendonitis, tendon or ligament injury, and nerve impingement are just some of the afflictions that may result in groin pain [4]. Separating etiologies into extra- and intra-articular disease processes can help narrow the differential. Extra-articular causes include iliac apophysis injury, iliopsoas tendinosis, bursitis, snapping iliopsoas tendon, and athletic pubalgia. Intra-articular causes include acetabular labral tears and femoroacetabular impingement [5]. Fortunately, most groin pain is the result of muscle strain and will resolve with rest. When conservative management (including physical therapy) fails and other etiologies have been excluded, the diagnosis of a sports hernia is made as one of exclusion.

First described by Gilmore when three professional soccer players presented to him with unclear groin pain refractory to medical management, sports hernias, also known as “Gilmore’s groin,” “athletic pubalgia,” or “groin disruption,” represent a small subset of groin pain experienced by high-performance athletes [6]. It is a condition of chronic inguinal pain caused by weakness in the abdominal wall without a palpable hernia. Its true prevalence is difficult to pinpoint, as the diagnosis remains a clinical entity that is poorly understood, with estimates ranging from 5 to 28 % [7]. The etiology, pathophysiology, and surgical treatments have all been variously described in the literature. Pain is located at the confluence of the origin of the rectus abdominis muscle, the adductor longus tendon on the pubic bone, and the insertion of the inguinal ligament on the pubic bone [8]. Pain onset is typically insidious, exacerbated by activity and improved with rest. Various surgical techniques have been reported, ranging from standard inguinal hernia repair with or without mesh, to incorporation of rectus reattachment in combination with adductor release in select cases. A commonly found area of pathology reported in the literature is the posterior inguinal wall along the transversalis fascia [9].

Referred groin pain in the absence of low back or radicular pain is found in a small subset of patients with singular lumbar disc herniation. A retrospective study of 512 subjects diagnosed with singular lower lumbar disc herniation (L4-L5 and L5-S1) at Kakegawa City General Hospital between July 1990 and December 1993 reported a 4.1 % incidence of groin pain, especially in the subset of patients with L4-5 involvement [10]. A subsequent prospective study in 2010 found evidence supporting degenerated intervertebral disc as an etiology for referred groin pain: ten subjects with groin pain and single disc degeneration found on MR underwent evaluation of changes in pain scale after local hip joint block, pain provocation on discography, and anesthetic discoblock. All ten subjects had a negative hip joint block, while five showed pain on discography and improvement in pain with discoblock, and definitive improvement after surgical fusion [11]. The proposed mechanism based on physiology studies in rats is the existence of overlapping segments of dorsal root innervation for the sensory nerve endings in the lower lumbar discs, with some of the sensory nerves from the L5 intervertebral disc coming from upper dorsal root ganglions of L2, which supply the genitofemoral and ilioinguinal nerves [12]. Thus, it is possible for patients to feel referred groin pain corresponding to the L2 dermatome.

The urologic etiologies for groin pain are quite extensive, including but not limited to epididymitis, hematocele, hydrocele, varicocele, malignancy, orchitis, Fournier’s disease, and testicular torsion. Categorizing etiologies into urgent conditions and emergent conditions requiring surgical intervention helps to elucidate workup and management. Of the aforementioned etiologies, appendage torsion, epididymitis, and testicular torsion make up most of the presentations of an acute scrotum [13]. Appendage torsion occurs primarily in prepubescent males, while the latter two occur more commonly in adolescents [14]. The true frequency of these three conditions is difficult to describe due to variations in age distribution and study settings in the medical literature. A recent retrospective review of 523 pediatric emergency department visits presenting with an acute scrotum found only a 3.25 % incidence of testicular torsion, while epididymitis, appendage torsion, and scrotal pain of unknown etiology accounted for 32.3 %, 7.7 %, and 34 %, respectively [15]. In contrast, a prior retrospective review of 238 cases of acute scrotal pain encountered in a similar pediatric emergency department setting published in 1995 reported incidences of testicular torsion, torsion of a testicular appendage, and epididymitis to be 16 %, 46 %, and 35 %, respectively [16]. Despite the reported disparity, the final diagnosis of scrotal pain of unknown etiology is not uncommon as previously mentioned. Physical exam findings such as Prehn’s sign (relief of pain with scrotal elevation) and assessment of cremasteric reflex are used in combination with ultrasound Doppler imaging to make the appropriate diagnosis, though surgical exploration remains the only definitive modality for assessing testicular torsion [17]. When vasculature of the testicle is compromised, prompt surgical intervention within 6 h of pain onset has demonstrated greater than 90 % rate of salvage [18].