A significant number of providers have difficulty identifying the 2nd intercostal space. In many patients the first rib is not palpable under the patient's clavicle. It has been recommended to start at the midclavicular clavicle and palpate downwards to identify the correct space.
The right place in the right space? Awareness of site for needle thoracocentesis.
Ferrie EP, Collum N, McGovern S.
Emerg Med J. 2005 Nov;22(11):788-9.