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)



  • The humerus is the bone of the upper arm extending from the shoulder to the elbow.humerus 2Humerus arm bones
  • 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 includetriceps-muscles

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



  • The radius is the bone of the forearm or lower arm, extending from the elbow to the wrist.radius_and_ulna
  • 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 asradius muscles

  • 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.


  • The ulna is the third and final bone of the arm.ulna
  • 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 includeulna muscles

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

For more information on arm bones click here.

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