The triangle of auscultation is a relative thinning of the

musculature Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscle ...

of the

back The human back, also called the dorsum, is the large posterior area of the human body, rising from the top of the buttocks to the back of the neck. It is the surface of the body opposite from the chest and the abdomen. The vertebral column runs ...

, situated along the medial border of the

scapula The scapula (plural scapulae or scapulas), also known as the shoulder blade, is the bone that connects the humerus (upper arm bone) with the clavicle (collar bone). Like their connected bones, the scapulae are paired, with each scapula on eith ...

which allows for improved

listening Listening is giving attention to a sound or action. When listening, a person hears what others are saying and tries to understand what it means. The act of listening involves complex affective, cognitive and behavioral processes. Affective proce ...

to the lungs.

Boundaries

It has the following boundaries: * medially, by the inferior portion of the

trapezius The trapezius is a large paired trapezoid-shaped surface muscle that extends longitudinally from the occipital bone to the lower thoracic vertebrae of the spine and laterally to the spine of the scapula. It moves the scapula and supports th ...

* inferiorly, by the latissimus dorsi * laterally, by the medial border of the

The superficial floor of the triangle is formed by the lateral portion of the erector spinae muscles. Deep to these muscles are the osseous portions of the 6th and 7th

ribs The rib cage, as an enclosure that comprises the ribs, vertebral column and sternum in the thorax of most vertebrates, protects vital organs such as the heart, lungs and great vessels. The sternum, together known as the thoracic cage, is a semi- ...

and the internal and external

intercostal muscles Intercostal muscles are many different groups of muscles that run between the ribs, and help form and move the chest wall. The intercostal muscles are mainly involved in the mechanical aspect of breathing by helping expand and shrink the size of ...

Clinical significance

The triangle of auscultation is useful for assessment using a pulmonary auscultation and thoracic procedures. Due to the relative thinning of the musculature of the back in the triangle, the posterior thoracic wall is closer to the skin surface, making

respiratory sounds Respiratory sounds, also known as lung sounds or breath sounds, refer to the specific sounds generated by the movement of air through the respiratory system. These may be easily audible or identified through auscultation of the respiratory system ...

audible more clearly with a stethoscope. On the left side, the cardiac orifice of the stomach lies deep to the triangle. In days before

X-ray An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...

s were discovered, the sound of swallowed liquids were auscultated over this triangle to confirm an oesophageal tumour. To better expose the floor of the triangle up of the posterior thoracic wall in the 6th and 7th intercostal space, a patient is asked to fold their arms across their

chest The thorax or chest is a part of the anatomy of humans, mammals, and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the crea ...

, laterally rotating the scapulae, while bending forward at the trunk, somewhat resembling the fetal position. The triangle of auscultation can be used as a surgical approach path. It can also be used for applying a

nerve block Nerve block or regional nerve blockade is any deliberate interruption of signals traveling along a nerve, often for the purpose of pain relief. Local anesthetic nerve block (sometimes referred to as simply "nerve block") is a short-term block, ...

known as the rhomboid intercostal block, which can be used to relieve pain after

rib fracture A rib fracture is a break in a rib bone. This typically results in chest pain that is worse with inspiration. Bruising may occur at the site of the break. When several ribs are broken in several places a flail chest results. Potential complicatio ...

s, and a

thoracotomy A thoracotomy is a surgical procedure to gain access into the pleural space of the chest. It is performed by surgeons (emergency physicians or paramedics under certain circumstances) to gain access to the thoracic organs, most commonly the hea ...

. This nerve block is usually appled by injection into the upper intercostal muscle plane and below the rhombic muscles.

References

External links

*
Overview and diagram at ithaca.edu
{{Authority control Anatomy