Trigger points can form in almost any skeletal muscle, but they cluster in predictable locations, particularly in the muscles of the neck, shoulders, upper back, lower back, and hips. These small, hyperirritable knots sit within taut bands of muscle fiber and are remarkably common. The estimated lifetime prevalence of myofascial pain syndrome, the condition defined by trigger points, is around 85% in the general population. Knowing where these knots tend to develop, and where they send pain, can help you identify the actual source of discomfort that often feels like it’s coming from somewhere else entirely.
What a Trigger Point Actually Is
A trigger point is a tiny segment of muscle fiber where the contractile units have locked into an extremely shortened state, increasing the diameter of that fiber segment and creating a palpable nodule. You can often feel it as a small, hard bump or “knot” embedded in a band of muscle that feels tighter than the tissue around it. These contraction knots develop when excessive signaling at the nerve-muscle junction increases muscle tension, compresses local blood vessels, and starves the area of oxygen and energy. That creates a self-reinforcing cycle: the muscle can’t release because it lacks the energy to do so, and the sustained contraction keeps blood flow restricted.
Trigger points come in two varieties. Active trigger points produce pain on their own, even when you’re not touching them. Latent trigger points are painless until someone presses on them, but they still stiffen the muscle, restrict your range of motion, and can become active under stress or overuse. Nearly 79% of healthy people carry latent trigger points in the upper trapezius alone, which means you can harbor these knots without realizing it.
Neck and Shoulders
The upper trapezius is the single most common site for trigger points in the entire body. This broad, diamond-shaped muscle runs from the base of your skull down to your mid-back and out to your shoulder blade. The point most likely to develop a knot sits roughly midway between the bony tip of your shoulder and the base of your neck. When active, this trigger point sends pain up the side of the neck and into the temple, which is why so many tension headaches originate from the shoulder rather than the head itself.
The levator scapulae, a smaller muscle that connects the upper neck vertebrae to the inner corner of the shoulder blade, is another frequent offender. Trigger points here create a stiff, aching neck and make it painful to turn your head. The suboccipital muscles at the base of the skull are a common source of headaches that wrap around the head toward the eye. In the shoulder itself, the infraspinatus (on the back of the shoulder blade) hosts active trigger points in up to 78% of people with shoulder pain, often producing deep aching in the front of the shoulder and down the arm, far from the actual source.
Upper and Mid-Back
The rhomboid muscles, which sit between the spine and the inner edge of each shoulder blade, develop trigger points that create a burning or aching sensation right along the shoulder blade’s border. People often describe this as a knot “under the shoulder blade” that they can’t quite reach. The middle and lower trapezius fibers in this same region can produce similar patterns.
The erector spinae, the long columns of muscle running along both sides of the spine, are prone to trigger points throughout their length. In the mid-back (thoracic region), these knots tend to produce localized aching that worsens with prolonged sitting or standing. The multifidus, a series of small, deep muscles that stabilize individual vertebrae, can also develop trigger points that feel like the pain is coming from the spine itself rather than the muscle beside it.
Lower Back and Abdomen
Lower back pain is one of the most common complaints tied to trigger points, and the gluteus medius is by far the leading culprit. In one clinical study of 115 patients with low back and leg pain, the gluteus medius was the most frequent source of trigger points across all groups: responsible in 19 of 23 low-back-pain cases, 6 of 8 leg-pain cases, and 15 of 22 cases involving both. This muscle sits on the outer surface of the hip, just below the rim of the pelvis, yet its trigger points send pain across the lower back and into the buttock in a pattern that mimics disc or joint problems.
The quadratus lumborum, a deep muscle connecting the top of the hip to the lowest rib on each side, is another major contributor. Trigger points here produce a deep, aching pain in the lower back that often worsens when you stand up from a chair or roll over in bed. The iliopsoas, a hip flexor that runs from the front of the lumbar spine through the pelvis to the upper thigh, refers pain to the lower back and inner buttock and is frequently overlooked because it’s difficult to palpate from the surface.
Perhaps the most surprising location is the abdominal wall. Trigger points in the upper rectus abdominis (the “six-pack” muscle) can produce a horizontal band of pain across the mid-back and sometimes mimic heartburn or indigestion. Trigger points in the lower portion of the same muscle refer pain as a band across the lower back. Because the pain shows up in the back, these abdominal trigger points are rarely suspected.
Hips and Glutes
Beyond the gluteus medius, several other hip muscles are common trigger point sites. The piriformis, a small muscle deep in the buttock that runs from the sacrum to the top of the thigh bone, sits directly over the sciatic nerve in most people. When its trigger points are active, the resulting tightness and pain can radiate down the back of the leg in a pattern that closely resembles sciatica. The gluteus minimus, a deeper layer beneath the medius, refers pain down the outside or back of the thigh and even into the calf, making it another common mimicker of nerve-related leg pain.
The gluteus maximus, the largest muscle in the body, develops trigger points that produce a deep ache in the buttock itself, sometimes making sitting uncomfortable. The tensor fasciae latae, a small muscle on the front-outer hip, can contribute to pain along the outer thigh when its trigger points are active.
Legs and Feet
In the thigh, the quadriceps group on the front and the hamstrings on the back both develop trigger points, particularly in runners and people who sit for long periods. Quadriceps trigger points, especially in the vastus medialis near the inner knee, can produce knee pain that gets mistakenly attributed to joint damage. Hamstring trigger points tend to cause a deep ache in the back of the thigh and can refer pain into the back of the knee.
The calf muscles, particularly the gastrocnemius and soleus, are frequent sites as well. Trigger points in the gastrocnemius refer pain into the back of the knee and the arch of the foot. Soleus trigger points can send pain deep into the heel and are sometimes confused with plantar fasciitis. Even the small intrinsic muscles of the foot can harbor trigger points that create localized pain in the arch or ball of the foot.
Jaw and Head
The masseter, the primary chewing muscle along the side of the jaw, is one of the densest muscles in the body relative to its size and a frequent trigger point location. Knots here contribute to jaw pain, tooth pain, and earaches. The temporalis muscle, which fans across the temple, refers pain across the side of the head and into the upper teeth. The sternocleidomastoid, the prominent muscle running from behind the ear to the collarbone, produces an unusual variety of referred symptoms: dizziness, eye pain, and headaches over the forehead or behind the eye.
Why the Pain Often Shows Up Somewhere Else
One of the defining features of trigger points is referred pain, meaning the discomfort you feel is often in a completely different location from the knot causing it. An infraspinatus trigger point on the back of the shoulder blade causes pain in the front of the shoulder. A gluteus minimus trigger point in the hip sends pain down to the calf. This happens because the nervous system processes pain signals from muscle, skin, and deeper structures through overlapping pathways, so the brain sometimes misidentifies where the signal originated.
This referral pattern is what makes trigger points so frequently misdiagnosed. Lower back pain caused by a gluteus medius trigger point may be treated as a disc problem. A headache from the upper trapezius may be treated as a migraine. Jaw trigger points may lead to unnecessary dental work. Understanding that the location of your pain and the location of its source are often different is the most practical thing trigger points teach us about the body.
How Trigger Points Differ From Fibromyalgia Tender Points
Trigger points are sometimes confused with the tender points associated with fibromyalgia, but they behave differently. Trigger points occur in specific muscles, sit within a taut band you can feel, and produce referred pain in characteristic patterns. They tend to show up in a regional pattern, affecting one area of the body more than others. Fibromyalgia tender points are areas of generalized tenderness that can occur in muscle, tendon junctions, or fat pads, and they appear in a widespread, symmetrical distribution across the body. A trigger point is a localized muscle problem; widespread tender points suggest a systemic pain-processing condition.
How They’re Identified
Trigger points are diagnosed primarily through physical examination. A clinician presses into the muscle looking for a taut band and a hypersensitive nodule within it. If pressing on the nodule reproduces or worsens the patient’s familiar pain pattern, it’s classified as an active trigger point. A useful confirmation is the local twitch response: when a needle or firm pressure hits the trigger point precisely, the taut band contracts in a brief, involuntary twitch visible under the skin. This reflex confirms the location and is considered a key marker during treatment with dry needling.
Diagnosis remains largely a hands-on process. Pressure algometers can measure the force needed to produce pain (a threshold below about 4 kg/cm² at a suspected site suggests an active trigger point), but most clinicians still rely on palpation. The subjective nature of this assessment means that experience matters: a skilled practitioner can identify knots that a less experienced one might miss.