The humerus is the bone in your upper arm. It’s located between your elbow and your shoulder, and consists of several parts that allow it to move freely in different directions.

Your humerus has important functions related to both movement and support.

Keep reading to learn more about your humerus, its different parts, why it’s important, and what types of injuries it can sustain.

  • Your humerus is classified as a long bone. Other types of long bones include the radius and ulna in your forearm and the femur in your upper leg.
  • Speaking of long, the humerus is the longest bone in your arm.
  • Despite its name, when you hit your “funny bone”, you’re not hitting your humerus. You’re actually hitting your ulnar nerve, which is located behind your elbow joint.
  • Bones in your arms or hands are more likely to be broken. This is because we commonly use these parts of our body to break a fall or reduce the impact of some kind of trauma or blow.

Your humerus is the only bone in your upper arm. It can be found between your elbow and your shoulder.

There are some important terms to know with regard to the anatomy of your humerus:

  • Proximal: This is the upper part of your humerus closest to your shoulder.
  • Body or shaft: This is long, middle portion of your humerus.
  • Distal: This is the lower area of your humerus that’s closest to your elbow.

In addition to the areas mentioned above, the humerus is made up of other parts, too. Let’s explore some of these.

Parts of the humerus

  • Head: This rounded area of the proximal humerus interacts with your shoulder blade (scapula) to form your shoulder joint.
  • Tubercles: These bony areas of the proximal humerus serve as attachment points for the muscles of your shoulder joint. You have two tubercles – the greater and lesser tubercle.
  • Surgical neck: This part is located at the base of the proximal humerus and is a common site for fractures.
  • Epicondyles: These are bony protrusions at the distal (lower end) of your humerus. You have two – the medial and lateral epicondyle. They serve as attachment points for the muscles of your lower arm, wrist, and hand.
  • Trochlea: This part of the your distal humerus interacts with the ulna bone in your lower arm.
  • Capitulum: The capitulum is the part of the humerus that interacts with the radius bone of your lower arm.
  • Fossae: You have three fossae, which are depressions that help to accommodate the bones of your lower arm when your elbow joint is moved.
Healthline

Your humerus has two important functions. These are movement and support. Let’s explore them in a little more detail.

The connections that the humerus makes at your shoulder and elbow allow for a wide variety of arm movements, such as:

  • rotation at the shoulder joint
  • raising your arms away from your body (abduction)
  • lowering your arms back toward your body (adduction)
  • moving your arm behind your torso (extension)
  • moving your arm in front of your torso (flexion)
  • straightening your elbow (extension)
  • bending your elbow (flexion)

In addition to being crucial for various arm movements, your humerus is also important for support. For example, parts of the humerus serve as a connection point for muscles in your shoulder and arm.

Fractures are one of the most common injuries to the humerus. Humerus fractures are classified by their location:

  • Proximal: A break that occurs at the end of your humerus closest to your shoulder.
  • Mid-shaft or middle: A break that occurs in the shaft or body of your humerus.
  • Distal: A break that happens at the end of your humerus that’s closest to your elbow.

Causes

A humerus fracture most often occurs due to a direct blow. This type of injury often happens in contact sports or car accidents. You can also break your humerus if you fall with your arm outstretched.

Sometimes a humerus fracture can happen due to an underlying health condition. This is called a pathologic fracture and can be caused by conditions such as osteoporosis or cancer.

Symptoms

Some of the most common signs that you may have fractured your humerus include:

  • arm pain, which can be severe and often gets worse with movement
  • a cracking or snapping sound that happens at the time of the injury
  • swelling
  • bruising
  • a visible lump or bump in your upper arm
  • decreased range of motion

Treatment

The type of treatment will depend on the severity of the fracture. Some treatment options may include one or a combination of the following:

  • medications to help ease pain and swelling
  • immobilization using a brace or splint to prevent movement of your upper arm
  • physical therapy to help you maintain or regain strength, flexibility, and movement in the affected arm
  • surgery for severe fractures, which can include plates and screws to help the bone to mend

Recovery time can also depend on the severity of your injury as well as your overall health.

Generally, it could take between 8 to 12 weeks to recover from a humerus fracture. Keep in mind that you may need to do physical therapy for several months afterward.

Other potential issues associated with the humerus include:

  • Radial nerve injury: The radial nerve runs through your arm. Radial nerve injury can be a complication of a humerus fracture, particularly middle or distal fractures.
  • Metastatic bone disease: Metastatic bone disease is when cancer that developed in one area of the body, such as the lungs or breast, spreads to the bones. According to the American Academy of Orthopaedic Surgeons, the humerus is commonly impacted.
  • Osteochondroses: This is a group of disorders in which bone growth is affected. One type, called Panner’s disease, can impact the distal area of the humerus, leading to pain in the elbow.

Your humerus is the long bone in your upper arm. The connections it makes at the shoulder and elbow enable you to make many different arm movements. The humerus is also a connection point for arm and shoulder muscles.

Humerus fractures are a common injury that are often caused by falls, car accidents, or contact sports. These fractures are typically treated with medications, immobilization, and physical therapy. Surgery may be needed in more severe cases.

Make an appointment to see your doctor if you have upper arm pain that is severe, unexplained by another health condition, or affects your range of motion. Your doctor can help diagnose what may be causing your pain and develop a treatment plan.