Acromioclavicular Joint - is responsible for the extended movement of the shoulder, most notably raising the arm above the head.

Bones: Scapula and clavicle.

Ligaments: The acromioclavicular ligament connecting the scapula to the clavicle.

Muscles: There are no major muscles that act here.

Joint type: Gliding joint that acts like a pivot.

Mechanics: As the scapula rotates to raise the arm the connection with the clavicle slides so that there is additional room to continue raising the arm.

Range of motion: Being able to raise the arm up next to the head.

Injury: This joint can be dislocated and is not the same as the glenohumeral dislocation, and usually had to do with ripping of the acromioclavicular ligament. This is commonly caused by falling on the shoulder or falling with the arm stretched out.

Manipulation: There is little specific manipulation of this joint as it allows for the full range of motion of the arm. A high amount of pressure say during a choke hold on the clavicle will extremely diminish the ability of the person to raise the arm above the head as the joint can not pivot to allow for extended motion of the arm.

To best understand this joint please read the Glenohumeral Joint (Common Movement) page as these two joints work together in moving the humerus.

For information on additional joints please refer back to the Joints page.