A big toe that curves or points upward instead of lying flat is usually the result of a muscle or tendon imbalance around the toe’s joints, though injuries, arthritis, nerve conditions, and even prior surgeries can trigger it too. Doctors call this presentation “hallux extensus” when the upward bend occurs at the joint where the toe meets the foot, or interphalangeal hyperextension when it happens at the toe’s middle joint. While it can look alarming, the causes range from easily manageable to medically significant, and understanding which category yours falls into determines what you should actually do about it.
How the Big Toe Normally Works
Your big toe does more biomechanical work than most people realize. The extensor hallucis longus (EHL), a tendon running along the top of the foot, pulls the toe upward. On the underside, the flexor hallucis longus pulls it down. These two forces stay in balance during normal walking: the toe lifts to clear the ground during the swing phase, then presses down to help you push off. The EHL doesn’t just extend the toe in isolation. It dynamically adjusts forefoot positioning and pressure distribution across the first ray, playing a direct role in balance during standing and transitions between phases of your stride.1PubMed Central. Revisiting the Extensor Hallucis Longus Tendon: Anatomical Classification and Orthopedic Implications
Meanwhile, the plantar fascia, a thick band of tissue along the sole of your foot, connects your heel to your toes and helps maintain your arch. When you bend your toes upward during push-off, the plantar fascia tightens and stiffens the arch, a process sometimes called the windlass mechanism. Research into this system shows the plantar fascia is not a rigid cable but actually stretches and shortens as the arch stores and releases elastic energy during movement.2PubMed Central. The extensibility of the plantar fascia influences the windlass mechanism during human running When any part of this finely tuned system gets disrupted, the big toe can end up stuck in an upward position.
Muscle and Tendon Imbalance
The single most common reason a big toe curves upward is that the muscles and tendons pulling the toe up overpower those pulling it down. This can happen gradually. If the EHL tendon becomes tight or overactive, perhaps from a high-arched foot, a neurological condition, or simply from habitual compensation patterns, the toe gets tugged into extension without enough opposing force to keep it neutral. People with cavus (high-arched) feet are especially prone to this because the arch shape alters how the tendons pull on the toe.
In some cases the flexor tendons on the underside become weak or ineffective rather than the extensors becoming too strong. The result is the same: the balance tips in favor of extension, and the toe drifts upward. This is why surgeons have used the EHL tendon in transfer and tenodesis procedures to correct various deformities, including dynamic hyperextension of the hallux and clawed toes associated with cavus feet.3PubMed Central. A Review of Extensor Hallucis Longus Variants Featuring a Novel Extensor Primi Internodii Hallucis Muscle Merging With Extensor Hallucis Brevis Another surgical approach involves shortening the flexor hallucis longus tendon to correct interphalangeal hyperextension deformity, essentially rebalancing the system from the other side.4PubMed Central. Flexor hallucis longus shortening for interphalangeal joint hyperextension deformity of the hallux: technique tip
Prior Surgery or Trauma to the Foot
A big toe that starts curving up after a foot or ankle surgery is a recognized complication, not a coincidence. One well-documented scenario involves ankle arthrodesis (fusion). When the ankle joint is fused, the foot loses some of its normal motion, and surrounding structures compensate. That compensation can redirect forces through the big toe, pushing it into hyperextension. One case report describes hallux extensus developing after ankle fusion, with the patient experiencing pain, impaired gait, and difficulty wearing normal shoes. Physical examination showed flexible hyperextension at the MTP joint, and imaging confirmed the deformity without underlying bony abnormalities. After surgical correction, the patient achieved complete correction, significant pain relief, and a return to walking in regular footwear within eight weeks.5Cureus. Surgical Management of Hallux Extensus Following Ankle Arthrodesis: A Case Report
Trauma to the toe itself can also set this up. If a fracture heals in a slightly altered alignment, or if tendons are damaged and scar in a shortened position, the biomechanical balance shifts. Even a bad stub or a crush injury can damage the structures that keep the toe in its normal resting position. People who have had bunion surgery sometimes notice changes in the big toe’s alignment afterward for similar reasons: altering one part of the foot’s architecture has ripple effects.
Plantar Plate and Ligament Damage
Underneath each toe joint is a thick, fibrous structure called the plantar plate that acts as a floor, preventing the toe from bending too far upward. When this structure tears or weakens, the toe can drift into hyperextension because there is nothing resisting the pull of the extensor tendons from above. Plantar plate injuries are more commonly discussed in the lesser toes, but they do occur at the big toe as well.
A case report in a pediatric patient documented chronic plantar plate rupture of the first interphalangeal joint. The patient experienced worsening pain in the great toe despite conservative treatment and developed progressive hyperextension of the IP joint.6PubMed Central. Plantar Plate Repair using Suture Anchors for Chronic Plantar Plate Rupture of the first Interphalangeal Joint in a Pediatric Patient: A Case Report This type of injury can result from a single acute event, like hyperextending the toe forcefully (think of “turf toe” injuries in athletes), or from repetitive low-grade stress over time. The key point: if your big toe’s upward curve developed after a specific injury or gradually worsened alongside pain on the bottom of the joint, a plantar plate issue is worth investigating.
Inflammatory and Systemic Conditions
Rheumatoid arthritis is one of the less obvious but very real causes of big toe deformities. In rheumatoid disease, chronic inflammation (synovitis) eats away at joint cartilage and erodes bone at the metatarsal heads and the bases of the toe bones. But the damage extends beyond the joint surfaces. The inflamed tissue stretches and weakens the capsules and ligaments that hold the joint together, while erosions at ligament attachment points cause further loosening. The balance between the intrinsic foot muscles and the longer extrinsic tendons breaks down, and the joint can eventually subluxate or dislocate.7PubMed Central. Rheumatoid forefoot deformity: pathophysiology, evaluation and operative treatment options
At the first MTP joint, rheumatoid changes most commonly produce hallux valgus (the bunion deformity where the toe drifts sideways), but the same destructive process can produce upward deviation when the pattern of ligament and capsule damage favors extension over lateral drift. If your upward-curving toe is accompanied by joint swelling, warmth, stiffness that is worst in the morning, or if other joints in your hands or feet are affected, an inflammatory condition deserves to be ruled out. Other systemic causes worth mentioning include gout, which tends to attack the big toe joint and can cause structural changes over time, and psoriatic arthritis, which has a particular affinity for the digits.
Neurological Causes
Conditions that affect the nerves controlling foot muscles frequently produce toe deformities. Charcot-Marie-Tooth disease, peripheral neuropathy from diabetes, stroke affecting one side of the body, and spinal cord issues can all alter the nerve signals reaching the small muscles of the foot. When certain muscles weaken or become spastic while others remain functional, the resulting imbalance pulls the toe into an abnormal position. A big toe curving upward alongside foot drop (difficulty lifting the front of the foot), a high arch that developed over time, or weakness in the lower leg muscles points toward a neurological workup. In these cases, the toe itself is a symptom, not the primary problem.
Footwear and Everyday Habits
Shoes do not typically cause the big toe to curve upward in the same direct way they contribute to bunions, but footwear can worsen an existing tendency or create the conditions for one. Narrow, pointed toe boxes compress the toes and alter muscle activation patterns. Research on high-heeled shoes has found striking associations with hallux valgus: in one study, 90% of high-heel wearers had hallux valgus, and 97.8% of those wearing shoes with a narrow toe box did.8International Journal of Medical and Biomedical Studies. The use of High Heels Causes Hallux Valgus in Women Aged 20-40 Years While hallux valgus (lateral deviation) is not the same as hallux extensus (upward deviation), the underlying mechanism of cramped toe positioning, altered tendon angles, and joint stress overlaps. Shoes that pitch your weight forward onto the ball of the foot force the toes to grip and compensate in ways they were not designed for, and over years this can contribute to a range of first-toe deformities.
On the other end of the spectrum, going barefoot on hard surfaces for long periods or wearing completely flat, unsupportive shoes can overwork the extensor tendons as they try to stabilize the foot without help from a shoe’s structure. Neither extreme is ideal if you already have a tendency toward toe hyperextension.
Why an Upward-Curving Big Toe Matters
A mildly elevated big toe that causes no pain might seem like a cosmetic quirk, but it can have real consequences. The big toe bears a large share of your body weight during push-off, and when it sits in hyperextension, pressure shifts to the tip or the top of the toe rather than distributing evenly across the pad. This can cause calluses, blisters, and pain at the top of the toe where it rubs against footwear. More importantly, it changes the mechanics of your entire gait: the foot cannot push off as efficiently, and other structures, particularly the lesser toes, the ball of the foot, and the plantar fascia, pick up the slack.
For people with diabetes, this issue is more urgent. Research on diabetic patients with foot skin lesions found that abnormal extension of the big toe was a direct cause of ulceration. Out of 272 diabetic patients with foot lesions, 18 had this specific problem. Fifteen of those ulcers healed, but four legs required below-knee amputation due to underlying vascular disease.9PubMed Central. Abnormal extension of the big toe as a cause of ulceration in diabetic feet That is a small proportion of the overall group, but for the individuals affected, what might seem like a minor toe position issue cascaded into a limb-threatening complication. If you have diabetes and notice your big toe riding higher than it used to, bring it up with your care team promptly.
What You Can Do About It
The right approach depends entirely on why the toe is curving up, how long it has been happening, and whether the joint is still flexible or has become rigid.
- Stretching: If the EHL tendon is tight, gentle stretching can help. Sit with your foot crossed over your opposite knee and use your hand to slowly flex the big toe downward, holding for 20 to 30 seconds. Repeat several times daily. This works best when the deformity is flexible, meaning you can push the toe back down with your hand.
- Strengthening: Exercises that target the toe flexors can restore some balance. Towel scrunches (placing a towel on the floor and pulling it toward you with your toes), marble pickups, and pressing the big toe firmly into the floor while keeping it straight all engage the muscles that oppose the extensors.
- Footwear changes: Switch to shoes with a wide, deep toe box that does not press down on the top of the toe. A rigid or semi-rigid sole can also help by limiting how much the toe needs to bend during walking, reducing the demand on the overactive extensors.
- Taping or splinting: For mild cases, taping the big toe in a slightly flexed position during the day can remind the toe where it should be and reduce strain. Over-the-counter toe splints that hold the toe in a corrected position at night are also available, though evidence for their long-term effectiveness is limited.
- Orthotic insoles: Custom or over-the-counter insoles with a built-up area under the first metatarsal head can change how forces travel through the big toe joint, reducing the extension moment. If your arch shape is contributing to the problem, an orthotic that supports the arch can address the root cause.
These conservative measures work best for flexible deformities caught early. If the joint has become rigid, meaning you cannot passively push the toe back to a neutral position, or if conservative treatment has failed after several months, it may be time to discuss surgical options with a foot and ankle specialist.
When Surgery Comes Into Play
Surgical correction for an upward-curving big toe varies based on the cause. For tendon imbalance, surgeons may lengthen the EHL tendon, transfer it to a different attachment point, or shorten the flexor tendon on the underside to restore balance.3PubMed Central. A Review of Extensor Hallucis Longus Variants Featuring a Novel Extensor Primi Internodii Hallucis Muscle Merging With Extensor Hallucis Brevis For plantar plate tears, repair using suture anchors has been described even in younger patients.6PubMed Central. Plantar Plate Repair using Suture Anchors for Chronic Plantar Plate Rupture of the first Interphalangeal Joint in a Pediatric Patient: A Case Report For rigid deformities or those caused by joint damage, procedures may include joint fusion (arthrodesis) of the affected joint or bone cuts (osteotomies) to realign the toe. In the post-ankle-fusion case described earlier, surgical correction of the hallux extensus restored normal alignment and function within two months.5Cureus. Surgical Management of Hallux Extensus Following Ankle Arthrodesis: A Case Report
Recovery time depends on the procedure. Soft tissue work like tendon transfers typically allows weight-bearing sooner, while bone work often requires a period in a walking boot or cast. Most people return to regular shoes within two to three months, though full recovery of strength and flexibility takes longer.
When to See a Doctor
Not every upward-curving big toe needs medical attention. If the toe is flexible, painless, and not interfering with your footwear or walking, monitoring it and trying conservative measures at home is reasonable. But certain signs warrant a professional evaluation:
- Pain at the joint: especially pain that worsens with walking or limits what shoes you can wear.
- Rigidity: if you cannot push the toe back down to neutral with your hand, the window for conservative treatment may be closing.
- Skin breakdown: calluses, blisters, or open sores on the top of the toe from rubbing against shoes, particularly concerning in people with diabetes or poor circulation.
- Associated symptoms: numbness, tingling, or weakness in the foot or lower leg suggesting a neurological cause.
- Rapid onset: a toe that curves up suddenly over days or weeks rather than gradually over months may indicate an acute injury or a flare of inflammatory disease.
A podiatrist or orthopedic foot and ankle specialist can assess whether the deformity is flexible or rigid, identify the underlying cause through examination and imaging, and tailor treatment accordingly. For most people, catching the problem early and addressing the contributing factors, whether that is tight tendons, weak muscles, inappropriate footwear, or an underlying medical condition, prevents the need for surgery down the line.
The Foot’s Elastic Architecture
One reason toe deformities can develop so insidiously is that the foot is designed to be adaptive. The plantar fascia, tendons, and ligaments work together as a compliant, spring-like system. During walking and running, the arch compresses at ground contact and stiffens at push-off as the toes bend upward and engage the windlass mechanism. Research using ultrasound and motion capture has shown that the plantar fascia is not the rigid lever it was once assumed to be. It stretches and recoils, storing and releasing elastic energy with each step.2PubMed Central. The extensibility of the plantar fascia influences the windlass mechanism during human running This adaptability is a strength, letting the foot handle uneven terrain and varying speeds, but it also means that gradual changes in one component can be silently compensated for by others until the compensation itself becomes the problem. A slightly tight extensor tendon might cause no symptoms for years because the rest of the system adjusts. By the time the toe visibly curves upward, the imbalance may have been building quietly for a long time, which is precisely why early intervention, even just stretching and appropriate footwear, is worth the effort.