The humerus is your upper arm bone. It’s connected to 13 muscles and helps you move your arm. When you injure your humerus, it’s likely the muscles and nerves attached to it will be damaged, too. If your bones are weakened by osteoporosis, you have an increased risk for fractures you might not even know about.


An illustration showing the labeled anatomy of the humerus
The humerus is the only bone in your upper arm. It runs from your shoulder to your elbow.

What is the humerus?

The humerus is your upper arm bone. Other than the bones in your leg, it’s the longest bone in your body. It’s a critical part of your ability to move your arm. Your humerus also supports lots of important muscles, tendons, ligaments and parts of your circulatory system.

If you experience a fractured (broken) humerus, you might need surgery to repair your bone and physical therapy to help you regain your strength and ability to move.

Your humerus — like all bones — can be affected by osteoporosis.

Because your humerus is connected to so many muscles and nerves, injuries to one can often affect the others.


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What does the humerus do?

Your humerus has several important jobs, including:

  • Helping your arm move, flex and rotate.
  • Holding 13 muscles in place.
  • Stabilizing the rest of your arm, including your elbow and hand.


Where is the humerus located?

The humerus is the only bone in your upper arm. It runs from your shoulder to your elbow.


What does the humerus look like?

The humerus has a rounded end where it meets your shoulder, a long shaft in the middle and a flatter end that forms your elbow joint. The upper end has a ball shape that fits into your shoulder socket.

Even though it’s one long bone, your humerus is made up of several parts. These include:

Humerus proximal aspect

The upper (proximal) end of your humerus connects to your shoulder joint. The proximal end (aspect) contains the:

  • Head (sometimes called the humeral head or humeral ball).
  • Greater tuberosity.
  • Lesser tuberosity.
  • Intertubercular sulcus (biceps groove).

Humerus shaft

The shaft is the long middle portion of the humerus that supports the weight of your upper arm and gives it its shape. It’s slightly rounded at the top near your shoulder and flatter at the bottom near your elbow. The shaft of your humerus includes the:

  • Deltoid tuberosity.
  • Radial groove.

Humerus distal aspect

The lower (distal) end of your humerus forms the top of your elbow joint. It meets your forearm bones (radius and ulna). It includes the:

  • Supracondylar ridges.
  • Epicondyles.
  • Trochlea.
  • Capitulum.
  • Coronoid, radial and olecranon fossae.

All these parts and labels are usually more for your healthcare provider to use as they describe where you’re having pain or issues. If you ever break your humerus — a humeral fracture — your provider might use some of these terms to describe where your bone was damaged.

How big is the humerus?

Other than the bones in your legs, your humerus is the largest bone in your body. Most adults’ humerus bones are around a foot long.


Conditions and Disorders

What are the common conditions and disorders that affect the humerus?

The most common issues that affect the humerus are fractures, osteoporosis and damage to nerves or muscles attached to it.

Humerus fractures

A bone fracture is the medical term for breaking a bone. You can break your humerus during trauma, like a fall or car accident. Some people also experience humerus fractures playing sports. Symptoms of a fracture include:

  • Pain.
  • Swelling.
  • Tenderness.
  • Inability to move your arm like you usually can.
  • Bruising or discoloration.
  • A deformity or bump that’s not usually on your body.

Go to the emergency room right away if you’ve experienced trauma or think you have a fracture.


Osteoporosis weakens bones, making them more susceptible to sudden and unexpected fractures. Many people don’t know they have osteoporosis until after it causes them to break a bone. There usually aren’t obvious symptoms.

Women or people assigned female at birth (AFAB) and adults older than 50 have an increased risk for developing osteoporosis. Talk to your provider about a bone density test that can catch osteoporosis before it causes a fracture.

Nerve and muscle damage

When you injure your humerus, it’s likely the muscles and nerves attached to it will be damaged, too. Some of the most common nerve and muscle damage includes:

  • Rotator cuff injuries: The rotator cuff is a group of muscles and tendons that keep your shoulder joint stable and help it move. Sports injuries and traumas (like falls and car accidents) are the most common causes of rotator cuff injuries.
  • Dislocated shoulders: A dislocated shoulder happens when the head of your humerus is pushed out of the socket in your shoulder. Any hard push or pull on your shoulder can cause a dislocation.
  • Radial nerve damage: Your radial nerve helps you move your elbow, wrist, hand and fingers. It runs down the back of your arm from your armpit to your hand. People who experience a humerus fracture often damage their radial nerve during that injury.

Talk to your provider if you’re experiencing new pain in your arm or shoulder.

What tests are done on the humerus?

The most common test done to check the health of your humerus is a bone density test. It’s sometimes called a DEXA or DXA scan. A bone density test measures how strong your bones are with low levels of X-rays. It’s a way to measure bone loss as you age.

If you’ve experienced a humeral fracture, your provider or surgeon might need imaging tests, including:

What are common treatments for the humerus?

Usually, your humerus won’t need treatment unless you’ve experienced a fracture or other injury to your arm. You might need treatment if you’ve been diagnosed with osteoporosis.

Humerus fracture treatment

How your fracture is treated depends on what caused it and where the break is in your humerus. You’ll need some form of immobilization — like a splint or cast — and might need surgery to realign (set) your bone to its correct position and secure it in place so it can heal.

Osteoporosis treatment

Treatments for osteoporosis can include vitamin and mineral supplements, exercise and medications.

Exercise and taking supplements are usually all you’ll need to prevent osteoporosis. Your provider will help you develop a treatment plan that’s customized for you and your bone health.

Rotator cuff and shoulder dislocation treatment

A healthcare provider will diagnose and treat shoulder dislocations and rotator cuff injuries. Most people who experience a shoulder dislocation need to wear a sling for a few weeks. You’ll need surgery to repair a torn rotator cuff.


Keeping your humerus healthy

Following a good diet and exercise plan and seeing your healthcare provider for regular checkups will help you maintain your bone (and overall) health. If you’re older than 50 or have a family history of osteoporosis, talk to you provider about a bone density scan.

Follow these general safety tips to reduce your risk of an injury:

  • Always wear your seatbelt.
  • Wear the right protective equipment for all activities and sports.
  • Make sure your home and workspace are free from clutter that could trip you or others.
  • Always use the proper tools or equipment at home to reach things. Never stand on chairs, tables or countertops.
  • Follow a diet and exercise plan that will help you maintain good bone health.
  • Use a cane or walker if you have difficulty walking or have an increased risk for falls.

A note from Cleveland Clinic

Your humerus is an important bone that lets you use your arms the way you do every day. Talk to your provider about your osteoporosis risk. Anything you do to improve your overall health will also help keep your bones strong.

Medically Reviewed

Last reviewed on 01/03/2023.

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