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Arm Bones | Bones of the Arm

The Arm Bones

In anatomy, the entire arm is divided into two regions,

  • the upper portion above the elbow known as the upper arm
  • and the lower portion below the elbow known as the forearm.

Sometimes the the entire arm is referred to as the upper limb and the two portions are the arm and forearm. However, for our purposes we will use the terms upper arm and forearm.

Below are detailed diagrams and information regarding the arm bones (upper arm bones and forearm bones). Learn the names of the arm bones and arm anatomy trough the arm bones diagram.

Arm bones

List of all Arm Bones


  • Humerus (2)
  • Radius (2)
  • Ulna (2)



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  • The humerus is the bone of the upper arm extending from the shoulder to the elbow.
  • This long bone is essential for movement and support of the arm (upper extremity).
  • The humerus exists on both arms and thus accounts for 2 bones of the human body.
  • The humerus is divided into three portions, the rounded head, the narrow neck, and the processes known as the tubercles.
  • The humerus is essential for movement because it is the site of many muscle and ligament attachments.

Examples of muscles attaching to the humerus include

  • the deltoid
  • pectoralis major
  • teres major
  • latissimus dorsi
  • biceps brachii
  • brachialis
  • coracobrachialis
  • and the brachioradialis



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  • The radius is the bone of the forearm or lower arm, extending from the elbow to the wrist.
  • This bone is relatively long and curved, extending parallel to the ulna.
  • Like the humerus, the radius’ primary function includes motion of the arm and support of the arm.

The radius connects to many muscles, such as

  • the biceps,
  • supinator
  • flexor digitorum superficialis
  • flexor pollicis longus muscles
  • extensor ossis metacarpi pollicis
  • extensor primi internodii pollicis
  • and the pronator teres muscles

Furthermore, the radius is found on each arm thus contributing a total of two bones to the human body skeleton.



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  • The ulna is the third and final bone of the arm.
  • This bone runs parallel to the radius from the elbow to the wrist.
  • Like the other arm bones, the ulna is relatively long and slightly curved.

The primary function of the ulna is allowing motion and supporting the arm.

An ulna exists on each arm and thus contributes two bones to the total human body skeleton.

The ulna is also the site of attachment for many muscles and ligaments.

Examples of muscles attaching to the ulna include

  • the triceps brachii muscle
  • supinator muscle
  • pronator teres muscle
  • pronator quadratus muscle
  • and the flexor digitorum superficialis muscle

Above, a good idea of the Arm Bones for you.

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Test Your Knowledge

How Many Bones in the Human Body?

An adult has a total of 206 bones in their skeleton

How many Bones in a Child's Body?

A newborn baby has 270 bones in the skeletal system. Most of their skeleton is made up of cartilage which forms bone as it hardens over time. The bones in a child's skeleton fuse together as they grow, reducing the number, up until about 25 years old.

What is The Strongest Bone in the Human Body?

The femur or thigh bone is the strongest bone in the body. It is situated between the pelvis and the knee. It is also the longest bone in the body and is fully one quarter of your bodies' height.

What is the Weakest Bone in The Body?

The weakest bones in your body are the tiny bones inside your ear that enable you to hear. On the other hand; the most commonly fractured bone is the clavicle.

What is the Hardest Bone in the Body?

The hardest bone in the body is the petrous portion of the temporal bone. The temporal bones are found at the sides and base of the skull and the petrous portion is specifically the part at the base of the skull that contains the organs for hearing.

Where are the Smallest bones in Your Body Located?

The smallest bone in the body is called the stapes. It is a stirrup shaped bone found inside the ear drum that transmits vibrations enabling us to hear.

How many Bones are in the Leg?

A human leg contains 30 bones. There are 26 bones that make up the foot, and the four major bones of the leg, which are the thigh bone (femur), the shin bone (tibia), the calf bone (fibula) and the knee cap (patella)