radius

Examples of radius in the following topics:

• Ulna and Radius (The Forearm)

  • Anatomically, the ulna is located medially to the radius, placing it near the little finger.
  • The ulna is slightly larger than the radius.
  • Anatomically, the radius is located laterally to the ulna placing it near the thumb.
  • Distally the radius expands, medially the ulnar notch articulates with the head of the ulnar.
  • Immediately adjacent to the ulnar notch, the radius articulates with the scaphoid and lunate carpal bones to form part of the wrist.

• Humerus (The Upper Arm)

  • Distally, the humerus articulates with the radius and ulna to form the elbow joint.
  • Distally, the humerus flattens to articulate with the ulna and radius at the elbow joint.
  • Located laterally to this is the capitulum that articulates with the radius.
  • The humerus attaches proximally to the scapula (shoulderblade) at the humeral head and distally with the radius and ulna (lower-arm bones) at the trochlea and capitulum, respectively.

• Factors Affecting Pulmonary Ventilation: Airway Resistance

  • Resistance in an airway is inversely proportional to the radius of the airway.
  • The most important part of this formula is radius of the airway (r).
  • A common example is that if one were to double the diameter of an airway  (thus doubling the radius as well) the resistance of the airway would drop by a factor of 16.
  • This mathematical property between radius and resistance is consistent for all tubes, and is often applied to the blood vessels in the cardiovascular system.
  • The radius of the airways of the conducting zone become smaller as air goes deeper into the lungs.

• Tennis Elbow, Little-League Elbow, and Dislocation of the Radial Head

  • The pathologic lesion is generally a tear in the attachment of the annular ligament to the periosteum of the radial neck, with the detached portion becoming trapped between the head of the radius and the capitellum.
  • If the forearm of a young child is pulled, it is possible for this traction to pull the radius into the annular ligament with enough force to cause it to be jammed therein.
  • The situation cannot arise in adults or in older children because the changing shape of the radius associated with growth prevents it.
  • Nursemaid's elbow involves the head of radius slipping out from the annular ligament of radius.

• Muscles of the Humerus that Act on the Forearm

  • Anatomically, it interacts with the scapula to form the shoulder joint and the radius and ulna of the lower arm to form the elbow joint.
  • It attaches to the mid region of the radius.
  • Attachments - Originates from the ulna and attaches to the radius.
  • Attachments - Originates from the humerus and attaches to the distal end of the radius.
  • Together they attach to the radius.

• Introduction to Blood Flow, Pressure, and Resistance

  • Numerous factors can alter resistance, but the three most important are vessel length, vessel radius, and blood viscosity.
  • With increasing length, increasing viscosity, and decreasing radius, resistance is increased.
  • Arterioles in particular are able to rapidly alter resistance by altering their radius through vasodilation or vasoconstriction.

• Muscles of the Wrist and Hand

  • It attaches to the mid region of the radius.
  • Attachments - Originates from the radius and attaches to the base of the thumb.
  • Attachments - Originates from the ulna and attaches to the radius.
  • Together they attach to the radius.
  • Attachments - Originates from radius and attaches to the base of the thumb.

• Overview of the Appendicular Skeleton

  • This consists of the left and right Humerus (two bones in the upper arm), the ulna (two bones), and the radius (two bones).
  • Both the ulna and the radius are in the forearm.

• Interosseous Membranes

  • The interosseous membrane in the arm extends between the radius and the ulna in the lower arm .
  • This image shows the interosseous membrane connecting the radius and the ulna.

• Syndesmoses

  • The interosseous membrane in the lower arm extends between the radius and the ulna.
  • Joints of this kind are found at several points in the human body, including the intermediate radioulnar joint where the radius and ulna meet above the wrist, in the spine between the spinous processes of various adjacent vertebra, and above the ankle joint where the tibia and fibula converge.