The 'accessory muscles of respiration' consist of the
scalene muscles, which elevate the
sternocleidomastoid muscle; the
wing of the nose, which cause nasal flaring; and the small muscles in the neck and head.
Accessory muscles do not
contract during normal breathing, however, they do contract vigorously during exercise or when
airway obstruction is significant, and they actively pull up on the
rib cage. During normal breathing, they only anchor the
sternum and upper ribs.
See also
★
Muscles of respiration