rotator cuff

Examples of rotator cuff in the following topics:

• Rotator Cuff Injury and Dislocated and Separated Shoulder

  • Rotator cuff tears are the most common conditions affecting the shoulder .
  • When shoulder trauma occurs, these functions can be attenuated, suggesting a rotator cuff tear .
  • 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.

• 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 of the Shoulder

  • It retracts and rotates the scapula.
  • There are six intrinsic muscles, four of which form the rotator cuff.
  • The rotator cuff is a group of four muscles that pull the ball of the humerus into the shallow socket of the scapula, adding required stability.
  • The rotator cuff complex is composed of the supraspinatus, infraspinatus, subscapularis, and teres minor all of which originate from the scapula and connect to the humerus.
  • Muscles of the rotator cuff and presented with the triceps brachii.

• 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.

• Humerus (The Upper Arm)

  • The four rotator cuff muscles attach to these tubercles, strengthening and maintaining the shoulder joint.

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

  • Disorders such as calcification of the rotator cuff, bicipital tendinitis, or carpal tunnel syndrome may increase chances of tennis elbow.

• Rotational Kinetic Energy: Work, Energy, and Power

  • The rotational kinetic energy is the kinetic energy due to the rotation of an object and is part of its total kinetic energy.
  • Rotational kinetic energy is the kinetic energy due to the rotation of an object and is part of its total kinetic energy .
  • Looking at rotational energy separately around an object's axis of rotation yields the following dependence on the object's moment of inertia:
  • The mechanical work applied during rotation is the torque ($\tau$) times the rotation angle ($\theta$): $W = \tau \theta$.
  • The earth's rotation is a prominent example of rotational kinetic energy.

• Rotational Angle and Angular Velocity

  • The rotational angle is a measure of how far an object rotates, and angular velocity measures how fast it rotates.
  • The amount the object rotates is called the rotational angle and may be measured in either degrees or radians.
  • The speed at which the object rotates is given by the angular velocity, which is the rate of change of the rotational angle with respect to time.
  • The radius of a circle is rotated through an angle $\Delta\theta$.
  • The angular velocity describes the speed of rotation and the orientation of the instantaneous axis about which the rotation occurs.

• Conservation of Energy in Rotational Motion

  • Energy is conserved in rotational motion just as in translational motion.
  • The simplest rotational situation is one in which the net force is exerted perpendicular to the radius of a disc and remains perpendicular as the disc starts to rotate.
  • Kinetic energy (K.E.) in rotational motion is related to moment of rotational inertia (I) and angular velocity (ω):
  • The final rotational kinetic energy equals the work done by the torque:
  • This confirms that the work done went into rotational kinetic energy.

• Angular Position, Theta

  • The angle of rotation is a measurement of the amount (the angle) that a figure is rotated about a fixed point— often the center of a circle.
  • When objects rotate about some axis—for example, when the CD (compact disc) rotates about its center—each point in the object follows a circular arc.
  • The rotation angle is the amount of rotation, and is analogous to linear distance.
  • Thus, for one complete revolution the rotation angle is:
  • The radius of a circle is rotated through an angle Δ.