An orthosis can comprise a first body member that can conform to a portion of a patient's body and a second body member that can conform to another portion of a patient's body. A closure unit having a first connector member with a first plurality of support posts can be operatively connected to the first body member, while a second connector member with a second plurality of support posts can be operatively connected to the second body member. An elongated flexible pull member can operatively extend between the respective first and second support posts so that when tightened by a patient, a pull member slides across the support posts to provide a mechanical force advantage to draw the first body member and the second body member against the patient's torso. A closure unit can be of a modular configuration for subjective mounting on various components of an orthosis to provide a highly adaptable closure unit.