Percussion is a foundational technique used during a physical examination to assess the density of underlying body structures. This method involves tapping the body surface to produce vibrations, generating sounds the examiner interprets. The resulting sound quality provides information about the composition of the tissue beneath the tapped area. Tympany is one distinct sound heard, which is significant in evaluating a patient’s internal status.
Understanding Tympany: The Sound Quality and Mechanism
Tympany is recognized as a high-pitched, loud, and drum-like sound with a relatively long duration. This unique acoustic quality is created when a hollow organ or space containing a large amount of air or gas is struck. The sound occurs because the gas inside the structure vibrates easily, similar to the skin of a drum when tapped.
The presence of air makes the structure highly resonant, producing the characteristic musical note of tympany. In contrast, percussion over a dense, solid structure, such as the liver, produces dullness. Dullness is lower-pitched, quieter, and thud-like. The difference between tympany and dullness helps map out the boundaries of organs and air-filled spaces.
Physiological Locations of Tympany in the Body
Tympany is expected to be the predominant sound heard across most of the abdominal area during a standard physical examination. This is because the intestines, which occupy a large portion of the abdominal cavity, are naturally filled with air and gas from digestion. Percussion over the loops of the small and large bowel typically yields this drum-like note, confirming the normal presence of intestinal gas.
A specific location where tympany is reliably heard is over the gastric bubble, the air-filled space in the stomach. This area is generally located in the left upper quadrant, just below the ribs. Eliciting tympany here is a normal finding indicating a healthy, air-filled stomach.
The abdomen is characterized by generalized tympany, interspersed with small areas of dullness where solid organs like the liver or spleen are located. The boundaries of solid organs are identified by the transition from tympany to dullness. For example, percussing upward toward the right rib cage, the sound changes from tympany over the bowel to dullness over the liver, indicating the organ’s lower border.
When Tympany Signals a Problem
While tympany is normal over the bowel, its presence in an unexpected location or its excessive nature can signal an underlying health issue. Generalized, excessive tympany throughout the entire abdomen suggests significant gaseous distension. This finding may indicate conditions where gas accumulates abnormally, such as a bowel obstruction or paralytic ileus.
Tympany heard outside of the abdomen, specifically over the chest, points to a pneumothorax. This condition occurs when air leaks into the pleural space, the area between the lung and the chest wall. Percussing over this air-filled space produces a loud, hyper-resonant, tympanic sound instead of the normal resonant sound of a healthy lung.
The absence of expected tympany can also be a pathological sign. For instance, in a patient with ascites, fluid accumulates in the abdominal cavity and displaces the air-filled bowel. This causes the flanks to sound dull instead of tympanic, as the percussion is over fluid rather than gas. This shift helps clinicians detect abnormal fluid accumulation.