What is the action of the deltoid muscle?

1 Answer
Dec 6, 2016

Main Abductor of the Arm

Explanation:

The deltoid muscle is a muscle that is shaped like an inverted triangle at the shoulder area (it gives your shoulder a round appearance). Unlike other muscles that usually produce one type of movement, the deltoid, due to its shape and direction of its muscle fibers is responsible for several actions of the arm:

  • Anterior (Clavicular) Deltoid = flexes and medially rotates the arm
  • Posterior (Spinal) Deltoid = extends and laterally rotates the arm
  • Middle (Acromial) Deltoid = adbucts the arm beyond initial 15 degrees done by the supraspinatus

Image taken from Google Search Function

*for a more detailed view of the actions of the deltoid muscle you may opt to watch Acland's Atlas of Human Anatomy videos - Upper Extremities

*The information above is taken from Netter's Atlas of Human Anatomy 6th Edition