A humeral neck fracture is a break in the upper part of the arm bone (humerus), just below the shoulder joint. It’s one of the most common fractures in older adults, with an annual incidence of 60 to 80 per 100,000 people, and it accounts for roughly 5% of all fractures. Women are affected more often than men, largely because of higher rates of bone loss after menopause. Most of these fractures happen from a fall onto an outstretched hand or directly onto the shoulder.
Where Exactly the Break Occurs
The upper humerus has two distinct “neck” regions, and the location of the break matters for treatment and recovery. The anatomical neck sits immediately below the ball-shaped head of the bone that forms the shoulder joint. The surgical neck is slightly lower, just below two bony bumps called the greater and lesser tuberosities where muscles and tendons attach.
Fractures at the surgical neck are far more common. This area is a natural weak point because the bone narrows there, making it vulnerable to force transmitted up through the arm during a fall. Fractures at the anatomical neck are rare but more concerning because they can cut off the blood supply to the humeral head, raising the risk of bone tissue dying from lack of blood flow.
What It Feels Like
The most immediate symptom is sharp pain around the shoulder that worsens with any attempt to move the arm. You’ll typically feel a grinding sensation (crepitus) at the fracture site when the broken ends shift. Swelling develops quickly, and within a day or two, bruising often spreads well beyond the shoulder, tracking down the inner arm, across the chest wall, and sometimes as far as the forearm. This dramatic bruising pattern is normal for these fractures and doesn’t mean the injury is getting worse.
If the shoulder loses its normal rounded contour and appears flattened, that suggests the humeral head has also dislocated from the joint, which points to a higher-energy injury and a more complex treatment path.
How Doctors Classify the Fracture
Doctors use a system that categorizes the fracture by how many bone segments have shifted out of place. The upper humerus is divided into four potential segments: the humeral head, the greater tuberosity, the lesser tuberosity, and the shaft. A segment counts as “displaced” if it has separated by more than 1 centimeter or tilted more than 45 degrees.
- One-part fracture: The bone is cracked but no segment has shifted significantly. This is the most common type.
- Two-part fracture: One segment has displaced, most often at the surgical neck.
- Three-part fracture: A tuberosity and the surgical neck are both displaced, causing the remaining attached tuberosity to rotate the humeral head out of its normal position.
- Four-part fracture: All four segments are displaced. The humeral head is typically pushed to the side and loses contact with the shoulder socket entirely.
The number of displaced parts directly guides treatment decisions. Higher numbers generally mean more complex injuries with longer recovery timelines.
Diagnosis and Imaging
Standard shoulder X-rays taken from two angles, a front-facing view and a side view through the shoulder blade, are usually enough to identify the fracture and classify it. When the X-rays are hard to interpret or the fracture pattern looks complex, a CT scan provides a three-dimensional picture that helps surgeons plan their approach. CT is especially useful for three- and four-part fractures where the exact position of each fragment matters.
Why Bone Density Matters
Osteoporosis plays a central role in humeral neck fractures. People who sustain these fractures typically have bone density scores well into the osteoporotic range. In one study, patients with humeral fractures had average bone density scores of negative 2.7 at the spine and negative 2.63 at the hip, both below the threshold for osteoporosis (negative 2.5). This matters not just for understanding why the fracture happened but for preventing the next one. If you’ve broken your proximal humerus from a low-energy fall, bone density testing and treatment for osteoporosis can reduce the risk of future fractures at the hip, spine, or wrist.
Non-Surgical Treatment
The good news is that 80% to 90% of humeral neck fractures, particularly one-part fractures, heal well without surgery. Treatment involves wearing a sling to immobilize the shoulder, followed by a gradual transition to physical therapy.
How long you stay in the sling is evolving. Traditional protocols called for three to four weeks of immobilization, but several clinical trials have found that shorter immobilization periods produce equal or better results. In one randomized trial of 111 patients, those who began movement after just one week had the same functional outcomes as those immobilized for three weeks, regardless of fracture pattern. Other studies found that early movement led to less pain and better function at three months. The trend in treatment is moving toward shorter sling use, typically one to two weeks for stable fractures, followed by guided movement.
When Surgery Is Needed
Displaced two-part, three-part, and four-part fractures often require surgical repair, especially in younger, active patients. The two main surgical options are internal fixation (repairing and stabilizing the bone with plates and screws) and shoulder replacement.
For younger patients with good bone quality and an intact blood supply to the humeral head, internal fixation is generally preferred because it preserves the natural joint. For patients 65 and older with three- or four-part fractures, a reverse shoulder replacement tends to produce better outcomes. This is especially true when the rotator cuff tendons are already worn down, which is common in older patients, or when the humeral head is too damaged to reconstruct. A reverse shoulder replacement works by flipping the mechanics of the joint so that the deltoid muscle, rather than the rotator cuff, powers arm movement.
Recovery Timeline
Recovery from a humeral neck fracture is a months-long process, whether treated with or without surgery. After surgical repair with plates and screws, rehabilitation follows a structured progression.
During the first four weeks, the arm stays in a sling and a therapist gently moves the shoulder through its range of motion while you keep the muscles relaxed. The goal is to prevent the joint from stiffening. Lifting is restricted to no more than one pound. Between weeks four and eight, you start assisting with movement and then gradually begin moving the arm on your own, with a two-pound lifting limit until week six. From weeks eight through twelve, light strengthening begins, though lifting remains capped at ten pounds. After twelve weeks, more normal activities can resume.
Non-surgical recovery follows a similar arc but often progresses slightly faster since there’s no surgical wound to protect. Most people regain functional use of the arm by three to four months, though full strength and range of motion can take six months to a year.
Potential Complications
The most serious complication is avascular necrosis, where the blood supply to the humeral head is disrupted and the bone gradually dies. This is most common in fracture-dislocations and multi-part fractures. In one study of fracture-dislocations, 33% of patients developed symptomatic avascular necrosis. Timing of surgery mattered significantly: among patients who had surgery promptly, 20% developed avascular necrosis, while those whose surgery was delayed all developed it. When avascular necrosis occurs, it typically requires a second surgery, often a shoulder replacement.
Nerve injury is another concern. The axillary nerve runs close to the surgical neck, and a fracture in this area can bruise or stretch it, causing numbness over the outer shoulder and weakness when lifting the arm away from the body. Most nerve injuries from fractures recover on their own over weeks to months. Non-union, where the bone fails to heal, occurs in a small percentage of cases and is more likely in displaced fractures treated non-surgically or in patients with poor bone density.
Shoulder stiffness is the most common long-term issue across all treatment types. This is why early, guided movement is emphasized even while the fracture is still healing. Consistent physical therapy is the single most important factor in regaining range of motion.