Epidural injections are given into the epidural space, a narrow gap that surrounds the spinal cord just inside the spinal column. Depending on the condition being treated, the needle can enter at four general regions of the spine: the neck (cervical), mid-back (thoracic), lower back (lumbar), or the base of the spine near the tailbone (caudal). The lumbar region is by far the most common site, used both for pain management of lower back conditions and for labor anesthesia.
What the Epidural Space Actually Is
The spinal cord is wrapped in protective layers called meninges. The outermost layer, the dura mater, is separated from the bones and ligaments of the spinal column by a small fat-filled gap. That gap is the epidural space, and it runs the full length of the spine from the skull down to the sacrum near the tailbone. Medication delivered here bathes the spinal nerve roots without entering the fluid around the spinal cord itself, which makes it useful for both pain relief and anesthesia.
The Four Spine Regions Used
Lumbar (Lower Back)
Most epidural injections target the lumbar spine, the five vertebrae in your lower back. For steroid injections treating sciatica or spinal stenosis, the needle enters between two vertebrae at or near the level where the problem disc or narrowing is located. For labor epidurals, the catheter is typically placed in the lower lumbar area for the same reason: the nerves carrying pain signals from the uterus exit the spine in this region.
Caudal (Tailbone)
The caudal approach enters the epidural space through a small natural opening at the very bottom of the sacrum called the sacral hiatus. This is a gap where the lowest segments of the sacrum never fully fused during development, creating a bony window near the tailbone. It is commonly used for surgical anesthesia in children and for chronic pain management in adults, particularly in people who have altered spinal anatomy from previous back surgery that makes a standard lumbar approach difficult.
Thoracic (Mid-Back)
Thoracic epidurals are placed between the shoulder blades, most often between the T4 and T6 vertebrae. They are considered the gold standard for pain control after major chest surgery, including lung cancer operations and lung transplants. Because the ribs connect to the thoracic spine, numbing this region controls the intense pain that follows a surgical incision through the chest wall.
Cervical (Neck)
Cervical epidural injections deliver steroid medication into the epidural space around the spinal nerves in the neck. They treat cervical radiculopathy, the type of chronic pain that starts with an irritated nerve root in the neck and radiates down into the shoulders, arms, or hands. Common causes include herniated discs and bone spurs narrowing the nerve openings.
How the Needle Reaches the Epidural Space
For the most common approach, called the interlaminar technique, the needle passes straight through the midline of the back. It travels through skin, a layer of fat beneath the skin, and then two tough ligaments that connect adjacent vertebrae. The final layer before the epidural space is a thick elastic ligament called the ligamentum flavum. Providers often feel a distinct “give” or loss of resistance when the needle tip passes through this ligament and enters the epidural space.
The second major approach is called transforaminal. Instead of going through the midline, the needle enters from the side, about 5 to 8 centimeters off center, and threads through the small bony opening (foramen) where a nerve root exits the spine. This delivers a high concentration of medication right next to the specific nerve that is inflamed, which many pain specialists prefer when a single nerve root is clearly the source of the problem. You typically lie face down for this approach rather than sitting up.
How Providers Find the Right Spot
Locating the correct vertebral level on a living person is harder than it sounds. One study testing experienced clinicians found they correctly identified a specific thoracic vertebra only 29% of the time using surface landmarks alone. Accuracy improved to about 78% when they only needed to be within one level of the target, but only in patients with a BMI under 25. In patients with higher body weight, surface landmarks became unreliable.
This is why many epidural steroid injections are done under fluoroscopy, a form of real-time X-ray. The provider can watch the needle on a screen, confirm the vertebral level, and inject a small amount of contrast dye to verify the medication will spread where intended. Research comparing fluoroscopy-guided injections to “blind” (landmark-only) injections found similar pain relief overall, but the image-guided group had roughly half the complication rate: 4.3% versus 9.6%. The most common complication in both groups was accidental puncture of the deeper membrane surrounding the spinal fluid, which occurred in about 3 to 5% of cases.
How You’re Positioned During the Injection
For a lumbar or thoracic epidural using the interlaminar approach, you’ll most likely sit on the edge of a table with your feet on a stool, knees bent, and your back rounded forward as much as possible. This curled position widens the gaps between your vertebrae and brings the epidural space closer to the surface of your skin, giving the needle a clearer path. Some providers use a side-lying (lateral) position instead, with your knees drawn up toward your chest to achieve the same spinal flexion.
For transforaminal injections, you lie face down on a special table that allows X-ray imaging from multiple angles. The provider tilts the X-ray beam to get a clear view of the nerve opening they need to target.
Who Should Not Get an Epidural Injection
Certain conditions make epidural injections unsafe regardless of the spine level. Active infection, whether systemic or at the skin where the needle would enter, is an absolute contraindication. So is being on full blood-thinning therapy, because the epidural space contains small blood vessels and a bleed in this confined area can compress the spinal cord. A known severe allergy to the steroid, anesthetic, or contrast dye used also rules out the procedure. Uncontrolled diabetes is a relative concern because steroid injections can spike blood sugar levels for days afterward. Pregnancy is another relative contraindication for steroid injections specifically, due to the X-ray guidance typically involved.
For injections in the neck or upper back, providers take extra care to avoid major arteries that supply the spinal cord. The largest of these, called the artery of Adamkiewicz, typically branches off around the T9 vertebra but can originate as low as L5 and sits in the upper portion of the nerve opening. Accidental injection of certain steroid formulations into this artery has been linked to neurological injury in animal studies, which is one reason cervical and thoracic transforaminal injections are almost always performed under fluoroscopy with specific safety protocols.