The axillary joints are two joints in the axillary region of the body, and include the shoulder joint and the acromioclavicular joint .
Shoulder joint
The shoulder joint also known as the glenohumeral joint is a synovial ball and socket joint . The shoulder joint involves articulation between the glenoid cavity of the scapula (shoulder blade) and the head of the upper arm bone (humerus ) and functions as a diarthrosis and multiaxial joint.
Due to the very loose joint capsule that gives a limited interface of the humerus and scapula, it is the most mobile joint of the human body.
Acromioclavicular joint
The acromioclavicular joint , is the joint at the top of the shoulder . It is the junction between the acromion (part of the scapula that forms the highest point of the shoulder) and the clavicle .[ 1] It is a plane synovial joint.
The acromioclavicular joint allows the arm to be raised above the head. This joint functions as a pivot point (although technically it is a gliding synovial joint), acting like a strut to help with movement of the scapula resulting in a greater degree of arm rotation.
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