Why Can’t I Curl My Toes? Causes and When to Worry

Difficulty curling your toes can stem from anything as benign as years of wearing stiff shoes to something as serious as nerve compression in the spine. The toe-curling motion depends on a surprisingly long chain of muscles, tendons, and nerves that runs from your lower back all the way to the tips of your feet, and a problem at any point along that chain can weaken or block the movement. Most causes are treatable once identified, but a few deserve urgent medical attention.

What Actually Has to Work for You to Curl Your Toes

Curling your toes is not as simple as it feels. The motion relies on two groups of muscles: the intrinsic muscles that live entirely inside the foot and the extrinsic muscles whose bellies sit in the calf but whose tendons travel down through the ankle to pull on the toe bones. The long toe flexors in the calf, for instance, cross both the ankle joint and the joints at the base of each toe, generating force during the push-off phase of every step you take.¹ The nerves commanding those muscles originate in the lumbar and sacral spine, travel down the leg as the sciatic nerve and its branches, and eventually thread through tight tunnels in the ankle before reaching the foot. A disruption in the muscles themselves, in the tendons that transmit their pull, in the nerves that carry the signal, or in the joints that the toes bend around can all result in an inability to curl.

Nerve Compression in and Around the Ankle

One of the more common reasons people lose the ability to curl their toes is compression of the tibial nerve or its branches as they pass through the tarsal tunnel, a narrow space on the inner side of the ankle. Tarsal tunnel syndrome produces pain, numbness, tingling, and weakness along the bottom of the foot and toes.² It is sometimes compared to carpal tunnel syndrome in the wrist: a nerve gets squeezed inside a bony-and-ligament corridor, and everything downstream suffers. Early on, tingling and burning are the main complaints, but as the compression worsens, motor function drops and curling or gripping with the toes becomes difficult or impossible.

Initial treatment is usually conservative. Rest, anti-inflammatory medication, orthotics, or a corticosteroid injection near the tunnel can relieve pressure on the nerve. Surgery is reserved for cases where conservative measures fail or where there is already measurable muscle wasting or motor nerve involvement.³ If you notice that numbness under your foot has been gradually joined by weakness in your toes, it is worth having the nerve evaluated sooner rather than later, because prolonged compression can cause damage that does not fully reverse.

Diabetic Neuropathy and Toe Deformity

Diabetes is one of the most widespread causes of nerve damage in the feet, and it deserves its own discussion because the mechanism is a bit different from simple compression. High blood sugar over time injures the small nerve fibers in the feet, leading to loss of sensation and, eventually, weakening of the small muscles inside the foot. Imaging studies of people with diabetic neuropathy have shown dramatic shrinkage of those intrinsic foot muscles, with muscle tissue making up only about 8% of the foot’s cross-sectional area compared with roughly 31% in people without neuropathy.⁴

The conventional explanation has been straightforward: the small muscles waste away, the long flexors and extensors in the calf overpower them, and the toes buckle into claw or hammer shapes. But the picture may be more nuanced than that. A follow-up study found that the degree of intrinsic muscle wasting did not reliably predict which neuropathic patients actually developed toe deformities and which did not, suggesting that other factors play a role in whether the toes become stiff and curled or simply weak.⁵ For you as a reader, the practical takeaway is this: if you have diabetes and notice your toes are getting harder to move, it may signal advancing neuropathy even before you notice much numbness.

Hammertoes and Other Toe Deformities

Sometimes the issue is not that your nerves or muscles are weak but that the joints in your toes have shifted into an abnormal position. Hammertoe is one of the most common foot deformities and involves an imbalance between the muscles and tendons that control toe movement. Over time, one or more of the lesser toes buckle upward at the middle joint and become stuck. Genetics, tight shoes, trauma, and underlying conditions like neuromuscular disease or diabetic neuropathy can all contribute.⁶ Early hammertoes are flexible, meaning you can still straighten the toe by hand, but with time the joint stiffens and the deformity becomes rigid. At that stage, actively curling the toe through its full range is essentially impossible.

The big toe has its own version of this problem. Hallux rigidus is arthritis of the big-toe joint, affecting roughly 2.5% of people over 50. Bone spurs and narrowing of the joint space produce pain and steadily restrict how much the toe can bend.⁷ As the condition advances, both upward and downward motion of the big toe become painful and limited.⁸ If curling your big toe specifically is the problem and you also feel a grinding stiffness at the base of that toe, arthritis is a strong suspect.

Tendon Injuries That Block Toe Flexion

Tendons are the cables that transmit muscle force to bone, and if a tendon ruptures, the muscle behind it can fire all it wants without moving the toe. The flexor hallucis longus tendon runs from the calf down behind the ankle and attaches to the tip of the big toe. It can tear even without obvious trauma. In one documented case, a 35-year-old woman ruptured this tendon completely during a lunge exercise and lost the ability to flex her big toe. Even a year after surgical repair, her flexion strength measured only about 70% of the other side, and her range of motion remained limited.⁹

Chronic inflammatory conditions raise the risk further. In a study of patients with rheumatoid arthritis, about 18% had a rupture of the flexor hallucis longus tendon, and the rupture was associated with joint damage at the base of the big toe and flat feet.¹⁰ If you have an inflammatory joint disease and notice that one particular toe suddenly will not curl even though the others still can, a tendon rupture is worth investigating.

Spinal Problems and Sciatica

Because the nerves controlling toe flexion originate in the lower spine, a disc herniation or spinal stenosis can impair your ability to curl your toes even though nothing is wrong with the foot itself. The sciatic nerve draws its fibers from the L4 through S2 nerve roots, exits the pelvis, and runs down the back of the leg before branching into the nerves that serve the foot. Compression of the S1 nerve root, for example, can specifically weaken the muscles that curl the toes and push the foot downward when you walk. You might notice this as difficulty rising onto your tiptoes or a feeling that your foot “gives out” during push-off.

After a stroke, spasticity in the lower limb can create the opposite problem: toes that curl involuntarily and won’t relax. Managing spasticity involves physical therapy, bracing, and sometimes medication or injections, with treatment goals defined around what the person actually needs to do functionally rather than simply reducing muscle tightness as measured on a scale.

Hereditary Nerve Conditions

Charcot-Marie-Tooth disease is the most common inherited nerve disorder, and the feet are often the first place it shows up. Over half of people with the condition develop foot and ankle problems including pain, weakness, and deformity.¹¹ The disease damages the peripheral nerves progressively, so the intrinsic foot muscles atrophy early, leading to high arches, hammer toes, and difficulty controlling toe movement. Because the onset is gradual, often beginning in adolescence or early adulthood, many people assume their foot shape is just how they are built and don’t realize a neurological condition is at work. If you have unusually high arches, frequently twisted ankles, and toes that have become progressively harder to move, a nerve conduction study can help determine whether an inherited neuropathy is responsible.

Trauma, Compartment Syndrome, and Ischemic Contracture

Severe injuries to the lower leg or foot can leave behind lasting damage that prevents normal toe movement. One particularly feared complication is compartment syndrome, in which swelling inside the tight muscle compartments of the leg cuts off blood flow. If the pressure is not relieved quickly, the muscle tissue dies and is replaced by scar tissue that contracts permanently. This is known as Volkmann’s ischemic contracture. The resulting deformity combines contracture and weakness, and the mix depends on which muscles and nerves were starved of blood.¹²

When the deep posterior compartment of the leg is involved, the flexor tendons to the toes can scar down. Patients develop a telltale pattern: the toes are supple when the foot is pointed downward, but as soon as the ankle bends upward, the toes claw involuntarily because the shortened tendons get pulled taut.¹³ The chief complaint in these cases is often not “I can’t curl my toes” but rather painful calluses on the toe pads from the constant gripping posture. Surgical release or lengthening of the scarred tendons is sometimes needed.

When You Should Seek Urgent Care

Most causes of toe weakness develop gradually and are not emergencies, but there is one scenario that demands same-day evaluation. Cauda equina syndrome occurs when the bundle of nerve roots at the bottom of the spinal canal is compressed, typically by a large disc herniation. The classic warning signs are numbness in the buttocks or groin (sometimes called saddle anesthesia), loss of bladder or bowel control, and weakness in the legs or feet. If sudden difficulty curling your toes is accompanied by any of those symptoms, treat it as a medical emergency. Delayed treatment can result in permanent nerve damage.

Outside of that urgent scenario, you should still see a doctor if toe weakness came on suddenly after an injury, if it is progressive rather than stable, if it is accompanied by spreading numbness, or if you also notice muscle wasting in the foot. The combination of numbness and weakness together tends to point to a nerve problem that benefits from early intervention.

How Doctors Figure Out the Cause

Your doctor will start with a physical exam, testing the strength of each toe individually, checking sensation, and looking for signs of muscle wasting, deformity, or swelling. They will likely also test your ankle reflexes and ask you to walk on your heels and toes, since these quick screening tests reveal a lot about which nerve levels are working.

If a nerve problem is suspected, electrodiagnostic testing is the standard next step. A complete study involves both nerve conduction studies, which measure how fast electrical signals travel along a nerve, and electromyography, which assesses whether the muscles themselves are receiving proper signals. The two complement each other and together give a fuller picture of where the problem lies than either one alone.¹⁴ Imaging, usually MRI, may follow if a disc herniation, tarsal tunnel mass, or tendon tear is suspected.

Exercises and Rehabilitation

For mild weakness or stiffness, especially the kind related to disuse or early hammertoe, toe-strengthening exercises can make a real difference. A common program involves towel scrunches: you sit with your foot flat on a towel and use your toes to gather the fabric toward you, three sets of 15 repetitions on each foot. Curling and spreading all toes without the towel is added on top. In a study using an eight-week program of these exercises done twice daily, patients saw meaningful improvements in toe function.¹⁵ Toe-grip insoles, which have a small raised bar under the toes that encourages gripping during normal walking, have also been shown to improve toe-grip strength and flexibility over time in a controlled trial.¹⁶

When surgery enters the conversation, the specific procedure depends entirely on the cause. A tendon transfer can rebalance a hammertoe or claw toe by rerouting the pull of a working tendon to compensate for a weak one.¹⁷ Decompression surgery can relieve a pinched nerve in the tarsal tunnel. Joint fusion or joint-sparing procedures address arthritis. In each case, the goal is restoring enough function and comfort for normal walking rather than giving you the toe dexterity of a concert pianist.

Why Modern Shoes May Be Part of the Problem

If your toes simply feel weak and clumsy rather than numb or painful, the culprit could be your footwear. Most conventional shoes have stiff soles and narrow toe boxes that effectively immobilize the toes for hours every day. Over years, this leads to measurable atrophy of the foot’s intrinsic muscles, much the way a muscle immobilized by a cast shrinks, just more slowly.¹⁸ The same study found that switching to minimal footwear for daily activity increased foot muscle strength, suggesting that the atrophy is at least partly reversible. If you spend all day in rigid shoes and then wonder why your toes barely respond when you try to curl them, disuse is a plausible explanation. Spending more time barefoot or in flexible, wide-toe-box shoes and doing regular toe exercises is a reasonable first step before assuming something medical is wrong.

The Evolutionary Backstory of Human Toe Weakness

It is worth knowing that human toes are, by primate standards, remarkably weak and stiff. Our ancestors traded grasping, prehensile feet for a rigid platform optimized for upright walking and running. Among all living and extinct primates, our lineage is the only one that completely abandoned the grasping big toe.¹⁹ The evolutionary record suggests the human foot passed through stages: first a foot still adapted partly for climbing trees, then one capable of effective bipedal walking but retaining some grasping ability, and finally the modern foot adapted for long-distance walking and running at the cost of prehensility.²⁰ So when you struggle to pick up a marble with your toes, part of the reason is that your species has been engineering those toes for stiff push-off power for millions of years, not for grip. That baseline awkwardness makes it harder to notice early genuine weakness, and it means that a certain degree of toe clumsiness is normal rather than pathological.

This evolutionary context also helps explain why the intrinsic foot muscles are so vulnerable to disuse atrophy. They were already trending smaller and weaker across evolutionary time compared with other primates’ foot muscles, so they have less margin before they stop functioning well. Add decades of stiff shoes, and the muscles that remain barely have to fire at all. When nerve damage or arthritis is then layered on top, the decline from “I can sort of curl my toes” to “I can’t curl them at all” happens faster than it would in a foot that started from a stronger baseline.