Obturator Nerve

Your obturator nerve carries signals that help your inner thigh feel and move. This nerve is part of your peripheral nervous system (PNS). The PNS helps your brain send messages to the rest of your body.

This nerve starts in a group of nerves in your lower back called the lumbar plexus. The group lets you move and feel your upper and lower legs and feet. It’s one of many nerves that pass through your groin as they travel down to communicate with your inner thigh.

What is the obturator nerve’s function?

This nerve provides movement (motor functions) and feeling (sensory functions) to your inner thigh.

Muscles along your obturator nerve help you:

• Move your leg in toward the middle of your body (adduction)
• Extend your leg at the hip
• Rotate your leg away from your body

This nerve provides feeling to:

• The skin covering the inside (middle) of your thighs
• Portions of your hip and knee joints

Where is the obturator nerve located?

Nerve roots branch off your spine. The nerve roots that make up your obturator nerve (as well as other nerves) come from the L2, L3 and L4 levels of your lumbar spine. These nerve roots come together from the lumbar plexus. The obturator nerve is a branch off of the lumbar plexus in your lower back.

From there, the nerve travels a long path:

1. It moves down through a muscle in your lower back called the psoas.
2. It passes behind a large blood vessel (iliac artery) and along the side of your pelvic wall.
3. It goes through a small opening in your pelvis (obturator canal) to your upper thigh.

Once it passes through your groin, it branches out.

What are the parts of the obturator nerve?

When your obturator nerve reaches your upper thigh, it splits into three main branches:

• Anterior branch (front): Helps the muscles that adduct your hip (bring it toward the middle of your body)
• Cutaneous branch (skin): Gives feeling to the skin on the upper part of your inner thigh
• Posterior branch (back): Rotates your hip outward and adducts the thigh (brings it toward the middle)

Sometimes, the anterior branch also helps move a muscle in your upper inner thigh called the pectineus. Usually, your femoral nerve controls this muscle. But in some people, the obturator nerve helps instead. This is a normal variation.

Which muscles receive nerve signals from the obturator nerve?

The following muscles receive nerve signals from (are innervated by) the obturator nerve:

• Adductor longus: Inner thigh
• Adductor brevis: Behind the adductor longus in your inner thigh
• Adductor magnus: Deepest in your inner thigh
• Gracilis: Inside of your inner thigh
• Obturator externus: Upper inner thigh, close to your hip joint
• Pectineus: Upper inner thigh, close to your groin

What conditions cause obturator nerve injury?

An obturator nerve injury happens when there’s damage to the nerve itself. It could cause pain, numbness or tingling in your groin or thigh. It could even cause weakness when you bring your thigh toward the middle (adduction).

It may happen with the following conditions:

• Nerve damage (obturator neuropathy): Nerve damage can happen from normal wear and tear over time or from a sudden injury, like one that causes stretching of the nerve.
• Obturator hernia: Abdominal tissue pushes through a small opening (obturator canal) and presses on your nerve.
• Obturator nerve entrapment: Nerves stop working because too much pressure is on nearby tissues. This can happen if ligaments swell. It may happen with endometriosis or pregnancy.
• Pelvic trauma: This can happen during childbirth or after an injury, like a car crash, when bleeding inside your body puts pressure on the nerve.
• Pelvic tumors or cancer: Growths can form on organs like your bladder, cervix or rectum.
• Sports injuries: These can happen in sports that involve a lot of kicking, like football. They can also happen in sports where you sit for a long time, like cycling or horseback riding.

Are there other issues that can affect the obturator nerve?

Because your pelvis has many important structures packed into a small space, your obturator nerve can sometimes be at risk during procedures. Surgeons are highly trained to work carefully in this area. Still, in rare cases, pressure or stretching can injure the nerve.

Before your procedure, your provider will talk with you about these risks so you know what to expect.

Childbirth can also affect this nerve. Moving your legs away from your body during delivery can put extra pressure or stretch on the nerve.

If a side effect or injury happens, your provider will offer treatments to help you feel better.

What is an obturator nerve block?

A nerve block is when a healthcare provider injects a medication to numb the nerve so you don’t feel sensations from it. Your provider may need to:

• Numb your groin before hip or knee procedures.
• Prevent involuntary leg jerks during pelvic surgery, including bladder cancer treatment.
• Relieve groin or thigh pain that doesn’t respond to standard therapies.
• Treat abnormal muscle tightness (spasticity) in your inner thigh.

When should I contact a healthcare provider about concerns with my obturator nerve?

Contact a healthcare provider if you notice:

• Constant aches near your pubic bone
• Discomfort that extends along your thigh
• A feeling of pins and needles in your groin
• Leg cramps
• Muscle weakness in your thigh
• Muscle pain when you’re active that stops when you rest (claudication)
• Numbness in your thigh
• Pain that gets worse with side-to-side leg movements