The hip and pelvis are connected by a complex web of deep muscles that maintain stability and facilitate movement. The obturator internus plays a significant role in lower body mechanics and pelvic floor function. When this deep hip rotator becomes tight, it can restrict mobility and generate chronic discomfort. Learning to properly stretch this muscle is a practical step toward restoring range of motion and improving pelvic health. This article provides the anatomical context and steps to safely target the obturator internus.
Understanding the Obturator Internus
The obturator internus is a thick, fan-shaped muscle located deep within the pelvis, covering the large opening known as the obturator foramen. It originates from the inner surface of the pelvis and passes out of the pelvic cavity through the lesser sciatic foramen. Its tendon then crosses the hip joint to attach to the greater trochanter of the femur, which is the bony prominence on the outside of the thigh.
Its primary mechanical function is to act as a lateral, or external, rotator of the hip, especially when the hip is extended, and to assist in hip abduction when the hip is flexed. The muscle works with other deep gluteal muscles to dynamically stabilize the hip joint, ensuring the head of the femur remains centered during activities like walking and standing. Due to its location, the obturator internus also forms part of the lateral wall of the pelvic floor.
Recognizing Signs of Tightness
Tightness or dysfunction in the obturator internus often manifests as persistent, localized pain deep in the buttock and gluteal region. This discomfort is frequently felt around the ischial tuberosity, commonly known as the “sit bone,” making it difficult and painful to sit for prolonged periods. The pressure from sitting directly irritates the muscle and surrounding structures.
A tight obturator internus can also mimic conditions such as sciatica because of its close proximity to surrounding nerves. Patients may experience pain that radiates down the back of the thigh. The tightness can also impact the pudendal nerve, potentially leading to symptoms like groin pain, tailbone discomfort, or urinary urgency. Difficulty with movements that require significant hip rotation, such as crossing the legs, is another common indicator of a shortened muscle.
Targeted Stretches and Techniques
Targeting a deep muscle like the obturator internus requires stretching techniques that emphasize hip flexion and internal rotation, as this combination works to lengthen the muscle against its primary function of external rotation.
Supine Figure Four Stretch
The Supine Figure Four stretch is a foundational exercise that effectively targets the deep hip rotators. To perform this, lie on your back with your knees bent and feet flat on the floor. Cross the ankle of the leg you wish to stretch over the opposite thigh, just above the knee. Gently draw the non-stretched thigh toward your chest, using your hands to grasp the back of the thigh or the front of the shin. The key is to keep your hips level and avoid tilting the pelvis, ensuring the stretch is focused deep in the buttock of the crossed leg. Breathe deeply for 30 seconds, allowing the muscle to slowly release tension, and repeat this movement three to five times on each side.
Seated 90/90 Internal Rotation
A more direct and active technique is the Seated 90/90 Internal Rotation stretch, which isolates the internal rotation component. Begin by sitting on the floor and positioning both legs so the hips and knees are bent at roughly 90-degree angles, creating a “Z” shape with your legs. The front leg should be externally rotated with the shin perpendicular to the body, and the back leg should be internally rotated. The internally rotated back leg is the one being targeted. To deepen the stretch, maintain contact between the internally rotated knee and the floor, and gently lean your torso forward or twist slightly toward the front leg. Focus on pushing the sit bone of the back leg down into the floor to anchor the stretch at the muscle’s origin. Hold this position for 30 seconds, feeling the sensation deep in the hip and gluteal region, then slowly release and switch sides.
Passive Internal Rotation
For a specific myofascial release, consider a passive stretch that involves active internal rotation. While lying on your back, bend the knee of the leg you want to stretch and let your foot rest flat on the floor. Allow the knee to slowly fall inward and across the midline of your body, which encourages internal rotation of the hip. You can gently assist the movement by using the opposite foot to stabilize the outside of the thigh or knee, carefully pushing it toward the floor. Smooth, controlled movement is necessary, avoiding any bouncing or jerky motions that could cause reflexive tightening of the muscle.
Guidelines for Safety and Professional Consultation
When incorporating these stretches into a routine, consistency is more beneficial than intensity for long-term relief. Aim to hold each stretch for at least 30 seconds, which is the duration generally required for the muscle’s connective tissue to respond to lengthening forces. A frequency of three to four times per week is often sufficient to maintain flexibility and alleviate symptoms.
Stop immediately if you feel any sharp, stabbing, or shooting pain, as this indicates irritation rather than a beneficial stretch. Self-stretching may not be enough if symptoms persist or worsen, especially if you experience numbness, tingling, or chronic pain that limits daily activities. In such cases, consulting a physical therapist, particularly one specializing in pelvic health, is advisable for a professional assessment. A therapist can use hands-on techniques and specific exercises to address deeper muscle imbalances and nerve involvement.