Understanding SI Joint?
The sacroiliac joint, commonly referred to as the SI joint (SIJ), is the junction where the sacrum meets the ilium. Situated just below the beltline, this joint exists on both the left and right sides where the hip connects with the tailbone. Notably, a substantial nerve passes through this joint and the buttocks. When this joint becomes unstable, it has the potential to induce discomfort in the lower back and legs.
The primary function of the SI joint is to offer stability and serve as a shock absorber for the spine and pelvis. It plays a crucial role in bearing the load of the upper body during activities such as standing, sitting, walking, or jumping, ensuring that the forces are absorbed before reaching the legs. This joint is an indispensable element for transferring energy efficiently between the legs and the torso.
Signs and Symptoms
Dysfunction in the sacroiliac (SI) joint typically manifests as a persistent, dull ache in the lower back on one side, potentially extending to the leg and buttock. Symptoms akin to sciatica may be experienced, including sensations of leg pain, burning, numbness, and tingling. The discomfort is commonly characterized as a mild to moderate ache centered around the dimple region of the lower back.
Aggravation of the pain often occurs during certain activities, particularly when standing up from a seated position or lifting the knee toward the chest during stair climbing or walking uphill. Although the pain is generally unilateral, it can occasionally manifest on both sides. Individuals may observe that the discomfort is more pronounced in the morning, gradually improving throughout the day.
In cases of severe SI joint pain, there may be associated referred pain radiating into the hip, groin, and occasionally down the leg, but rarely extending below the knee. Additionally, individuals may experience muscle tightness and tenderness in the hips or buttocks. The pain may be referred from the SI joint to the buttock or the back of the thigh, and in rare instances, even to the foot.
Common symptoms also include low back pain and stiffness, often concentrated on one side, which tends to intensify with prolonged periods of sitting and walking. Disruptions in sleep patterns and sitting discomfort may occur due to pain, leading to an inability to sit for extended periods or favoring one side while sitting. Some individuals may also report a feeling of leg instability, characterized by sensations of buckling or giving way.