rotation

(noun)

The act of turning around a centre or an axis.

Related Terms

  • Levers can also vary based on the relative position of the load, pivot, and point of force application.
  • Flexion
  • extensors
  • Abduction
  • adduction
  • third-class lever
  • second-class lever
  • first class lever
  • abduction
  • origin
  • insertion
  • flexion
  • extension
  • flexor
  • extensor

Examples of rotation in the following topics:

  • Rotator Cuff Injury and Dislocated and Separated Shoulder

    • Rotator cuff tears are the most common conditions affecting the shoulder .
    • The tears occur in one or more of the four tendons of the rotator cuff muscles.
    • The tendons of the rotator cuff, not the muscles, are most commonly torn.
    • Once a tear happens in the rotator cuff, it is much more likely to recur.
    • After injury, it is hard to do a 180 degree rotation.
  • Muscles that Cause Movement at the Hip Joint

    • Actions – Extends of the thigh and assists with rotation.
    • The muscles of the lateral rotator group are deeply located and as the name suggests, act to laterally rotate the thigh at the hip.
    • Actions - Lateral rotation and abduction of the thigh at the hip.
    • Actions - Lateral rotation and abduction of the thigh at the hip.
    • Actions: Extends and laterally rotates at the hip.
  • Muscles of the Shoulder

    • Actions – The superior region supports the arm and elevates and rotates the scapula, the intermediate region retracts the scapula, and the inferior region rotates and depresses the scapula.
    • It retracts and rotates the scapula.
    • There are six intrinsic muscles, four of which form the rotator cuff.
    • Actions – Adducts the shoulder and assists in rotation of the arm.
    • Muscles of the rotator cuff and presented with the triceps brachii.
  • Posterior Muscles

    • Actions – The superior region supports the arm and elevates and rotates the scapula, the intermediate region retracts the scapula, and the inferior region rotates and depresses the scapula.
    • Rhomboid Minor – Sits between the levator scapulae and rhomboid major, with which it is paired in action and function, this retracts and rotates the scapula.
    • Two muscles in the superficial layer are responsible for rotation of the head.
    • Two muscles in the deep layer are responsible for maintenance of posture and rotation of the neck.
  • Neck Muscles

    • Two muscles in the superficial layer are responsible for rotation of the head.
    • Two muscles in the deep layer are responsible for maintenance of posture and rotation of the neck.
    • Actions – The superior region supports the arm and elevates and rotates the scapula.
    • It controls adduction, abduction and rotation of the head, the intermediate region retracts the scapula, and the inferior region rotates and depresses the scapula.
    • Actions – Abduction, adduction, extension, flexion, and rotation of the neck depending on intra and inter-muscle contractions.
  • Impingement Syndrome

    • Shoulder impingement syndrome occurs when the tendons of the rotator cuff muscles become irritated and inflamed.
    • The rotator cuff muscle tendons pass through a narrow space between the acromion process of the scapula and the head of the humerus.
    • Loss of function of the rotator cuff muscles, due to injury or loss of strength, may cause the humerus to move superiorly, resulting in impingement.
    • Ultrasonography, arthrography, and MRI can be used to detect rotator cuff muscle pathology .
    • Also damaged rotator cuff muscles can be surgically repaired.
  • Muscles that Cause Movement at the Knee Joint

    • When the knee is fully extended the femur rotates slightly on the tibia to lock the joint into place, allowing for efficient load bearing.
    • The rectus femoris additionally facilitates rotation at the hip.
    • Actions: Extends and laterally rotates at the hip, main action is flexing of the lower leg at the knee.
    • Actions: Laterally rotates the femur on the tibia “unlocking” the knee joint so that flexion can occur.
    • The knee joint allows for slight rotation when flexed, which is produced by the biceps femoris, semitendinosus, semimembranosus, gracilis, and sartorius.
  • Synovial Joint Movements

    • Rotation is a circular movement around a fixed point.
  • Lever Systems

    • Internal or medial rotation is specific to the shoulder or hip and brings the distal portions of the limbs inwards towards the midline.
    • Internal rotation can also move the humerus and femur inward.
    • External or lateral rotation is the opposite movement, pointing the distal portion of limbs as well as the humerus and femur away from the mid-line.
  • How Skeletal Muscles Produce Movements

    • The muscles of the rotator cuff are also synergists in that they fix the shoulder joint allowing the bicepps brachii to exert a greater force.
    • The brachioradialis and brachialis are synergist muscles, and the rotator cuff (not shown) fixes the shoulder joint allowing the biceps brachii to exert greater force.
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