Multidirectional instability occurs when the capsule that
holds the shoulder in place is stretched, torn or naturally loose. This
situation results in less static stability (stability arising from the joint
itself) in the shoulder and results in greater aberrant movement in the
shoulder joint. This can result in impingement of the rotator cuff and result
in further injuries. Treatment of multidirectional instability requires
conditioning of the muscles that help keep the head of the humerus (the top of the arm in
the shoulder joint) in addition training of the muscles of the trunk and hip to provide
a foundation for shoulder stability is also extremely important.