that may obstruct the vibrations of the larynx. Chest percussion Percussion is the act of tapping on the surface of the body in order to assess the structures that lie beneath the skin. Percussion and resonance (the quality and feeling of sound) are used to examine lung movement and possible lung conditions. Specifically, percussion is performed by first placing the middle finger of one hand over the area of interest. The middle finger of the other hand is used to strike the last joint of the placed finger. Percussion is performed in a systematic matter, from the upper chest to the lower ribs, and resonance is compared between the left and right sides of the chest. This is done from the front and back of the thorax. Percussion over different body tissues results in five common "notes". Resonance: Loud and low pitched. Normal lung sound. Dullness: Medium intensity and pitch. Experienced with fluid. A dull, muffled sound may replace resonance in conditions like pneumonia or hemothorax. Hyper-resonance: Very loud, very low pitch, and longer in duration. Abnormal. Hyper-resonance can result from asthma or emphysema Tympany: Loud and high pitched. Common for percussion over gas-filled spaces. Tympany may result in pneumothorax. Flatness: Soft and high pitched. Auscultation The areas of the lungs that can be listened to using a stethoscope are called the lung fields, and these are the posterior, lateral, and anterior lung fields. The posterior fields can be listened to from the back and include: the lower lobes (taking up three quarters of the posterior fields); the anterior fields taking up the other quarter; and the lateral fields under the axillae, the left axilla for the lingual, the right axilla for the middle right lobe. The anterior fields can also be auscultated from the front. An area of thinner musculature on the back where sounds may be more audible is called the triangle of auscultation. During auscultation, deep breaths are taken through the mouth and abnormal sounds listened for. Abnormal sounds include: Wheezes, describing a continuous musical sound on expiration or inspiration. A wheeze is the result of narrowed airways. Common causes include asthma and emphysema. Rhonchi (an increasingly obsolete term) characterised by low pitched, musical bubbly sounds heard on inspiration and expiration. Rhonchi are the result of viscous fluid in the airways. Crackles or rales. Intermittent, non-musical and brief sounds heard during inspiration only. They may be described