A herniated disc occurs when the soft, gel-like center of a spinal disc pushes through a tear in the tougher outer ring. This displacement presses against nearby spinal nerve roots as they exit the vertebral column. The pain generated at the spine often travels along the nerve path, meaning discomfort can be felt far away from the lower back. This referred pain explains why a problem in the lumbar spine can manifest as pain in the hip or groin regions.
How a Herniated Disc Causes Referred Pain
The connection between a low back injury and pain in the hip or groin is explained by the anatomy of the nervous system. Nerve roots exiting the upper lumbar spine (L1, L2, and L3) provide sensory input to the front of the thigh, hip flexors, and groin. When a disc herniates at levels like L1-L2 or L2-L3, the extruded material irritates these specific nerve roots. This irritation causes radiculopathy, where pain is perceived along the entire distribution of the affected nerve.
The pain is described as “referred” because the brain interprets the distress signal as coming from the nerve’s destination point, such as the hip or groin, rather than its spinal origin. This sensation is often characterized by a sharp, shooting, or burning quality, sometimes accompanied by numbness or tingling. In contrast, mechanical lower back pain is localized to the spine and does not radiate into the extremities. The inner disc material also releases inflammatory chemicals that further irritate the nerve roots, increasing pain signals.
Compression of the L4-L5 disc is also a common source of hip pain, though it is traditionally associated with the sciatic nerve. About four percent of patients with lower lumbar disc herniations, particularly at the L4-L5 level, report groin pain. The discomfort may be constant or intermittent, often worsening with movements like sitting or bending, which increase pressure on the compromised nerve root. This mechanism highlights that the source of the hip and groin discomfort is the compromised nerve pathway originating from the spine, not the joint itself.
Identifying the Source of Hip and Groin Pain
Determining if hip and groin pain originates from the spine or the hip joint requires careful differential diagnosis, as symptoms can overlap. Pain from the hip joint is typically felt directly in the groin and worsens specifically with hip joint movement. Conversely, pain caused by lumbar radiculopathy is often positional, aggravated by sitting, standing, or spinal movements like coughing or sneezing. A key distinction is the presence of neurological symptoms, such as numbness, tingling, or muscle weakness, which strongly suggests nerve root involvement from the spine.
Physicians use specific physical examination maneuvers to isolate the pain generator. The Straight Leg Raise (SLR) test, where the examiner passively lifts the patient’s straight leg, is a foundational tool for assessing nerve root irritation. A positive SLR test, characterized by pain radiating down the leg between 30 and 70 degrees of hip flexion, is sensitive for lumbar disc protrusion causing nerve tension. This test attempts to provoke the irritated nerve roots (typically L4 through S1) and is a strong indicator of a spinal issue.
In contrast, tests like the FABER (Flexion, Abduction, and External Rotation) test specifically provoke pain originating from the hip joint or the sacroiliac joint. If pain is reproduced primarily by these hip-specific movements without neurological signs, it suggests a primary orthopedic issue, such as hip arthritis or a muscle strain. Imaging studies also play a role: an MRI of the lumbar spine reveals disc herniation and nerve compression, while an X-ray or MRI of the hip shows joint degeneration or soft tissue injury. The quality of the pain is also telling; radicular pain is often described as a sharp, electric, or burning sensation, while true hip joint pain is a dull, deep ache.
Targeted Treatment for Nerve-Related Pain
Treatment for hip and groin pain caused by a herniated disc focuses on relieving nerve root compression and inflammation. Conservative management is the initial approach, often involving physical therapy guided by methods like the McKenzie Method of Mechanical Diagnosis and Therapy (MDT). This approach uses repeated movements, such as specific back extensions, to shift the inner disc material away from the compromised nerve root. The goal is centralization, meaning the radiating symptoms move proximally toward the spine, indicating reduced pressure on the nerve.
Anti-inflammatory medications, such as non-steroidal anti-inflammatory drugs (NSAIDs), are used to manage the chemical irritation caused by the disc material. For persistent symptoms, an epidural steroid injection (ESI) may be recommended. During an ESI, a corticosteroid is injected directly into the epidural space surrounding the inflamed nerve roots. This injection aims to reduce the swelling and inflammation of the irritated nerve, decreasing the pain signals traveling to the hip and groin.
While an ESI will not correct the structural problem of the disc herniation, it can provide significant pain relief lasting several months, allowing the patient to engage effectively in physical therapy. For a minority of patients who experience severe, unremitting radiculopathy despite conservative care, surgery may be considered. A microdiscectomy is a common surgical procedure that involves removing the portion of the herniated disc material pressing directly on the nerve root, offering immediate decompression.