Humerus Fracture, Causes and Symptoms
The upper arm bone (called the humerus) is the bone that runs between the elbow and the shoulder. Humerus fractures account for a remarkably small proportion of total bone fractures: only 3%. The humerus is a strong bone – analogous to the femur in the leg (which is the strongest bone in the body). The humerus does not absorb the intensity of stress that the forearm bones (known as the radius and the ulna) do when you fall and catch yourself with your hands, since the humerus is further up the chain of bones. Nonetheless, falling down is responsible for the bulk of humerus fractures. People with osteoporosis (whose bones have been made thin and porous through mineral loss) are especially vulnerable to humerus fractures.
Of all humerus fractures, only 10% cause substantial bone displacement. This means that the vast majority of humerus fractures can be treated non-operatively. They can be immobilized and stabilized without surgery. Of the humerus fractures that do need surgery, many are toward the elbow (i.e., toward the humerus’ distal end).
Anatomy of the Upper Arm
The bone of the upper arm articulates with the shoulder blade at its proximal end and with the radius and ulna (the forearm bones) at its distal end. It consists of the following:
- The humerus (this is the upper arm bone; it is a very strong bone)
- The radius (this is the forearm bone on the inside of your arm)
- The ulna (this is the forearm bone on the outside of your arm)
- The scapula (this the shoulder blade; this triangular bone is protected by a lot of muscle)
Types of Humerus Fractures
Humerus Fractures can be divided into three main types:
- Proximal humerus fracture – If your fracture is near the shoulder joint (i.e., where the humerus connects with the scapula), then you have a proximal humerus fracture. Since this type of fracture can mean that the humerus’ ball, which inserts into the shoulder blade’s socket, is broken, rotator-cuff damage is sometimes associated with it.
- Diaphyseal humerus fracture – Diaphyseal humerus fractures are mid-shaft fractures. This type of humerus fracture generally will be treated non-surgically.
- Distal humerus fracture – Distal humerus fractures – fracture of the humerus at or near the elbow – are far more common in children than in adults. This type of humerus fracture generally does require surgery in order to heal properly.
Causes of Humerus Fractures
A humerus fracture is generally the result of a fall or a blow to the arm. The following are the causes of humerus fractures:
- Indirect blow to the humerus – If you fall down and land on your arm, and it is outstretched with the elbow locked, the ulna can be forced into the distal humerus (the portion of the humerus that makes up a part of the elbow). This can cause a distal humerus fracture.
- Direct blow to the humerus – If you fall directly on any area of your humerus, or are hit there by an object or in an automobile accident, you can fracture it at that point.
Symptoms of Humerus Fractures
Different types of humerus fracture have somewhat different symptoms, since they occur in different locations. But they are generalizable. If you fracture your humerus, the portion of it that you have fractured will hurt intensely, swell and feel stiff. If your nerves have been damaged by the fracture, your hand and wrist will likely be weak and experience strange sensations. If you have fractured your distal humerus, you elbow may feel unstable – like the joint is going to separate.
The following are common humerus fracture symptoms:
The symptoms of humerus fracture may be mistaken for the symptoms of other medical conditions (proximal ulna fracture, rotator cuff tear, etc.). Make sure you consult a doctor in order to determine if you have a humerus fracture and get the appropriate treatment.
The multidisciplinary team of orthopaedic experts at North Shore-LIJ Orthopaedic Institute's Trauma Services in New York treats humerus fractures as well as a broad range of conditions that affect the bones within the body.