The triangle of auscultation is a relative thinning of the

musculature Skeletal muscle (commonly referred to as muscle) is one of the three types of vertebrate muscle tissue, the others being cardiac muscle and smooth muscle. They are part of the somatic nervous system, voluntary muscular system and typically are a ...

of the

back The human back, also called the dorsum (: dorsa), 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 c ...

, situated along the medial border of the

scapula The scapula (: 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 either side ...

which allows for improved

listening Listening is the act of attention, paying attention to sounds. It includes listening to the sounds of Natural environment, nature, listening to music, and perhaps most importantly, Interpersonal communication, interpersonal listening, i.e. liste ...

to the

lung The lungs are the primary Organ (biology), organs of the respiratory system in many animals, including humans. In mammals and most other tetrapods, two lungs are located near the Vertebral column, backbone on either side of the heart. Their ...

Boundaries

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

latissimus dorsi The latissimus dorsi () is a large, flat muscle on the back that stretches to the sides, behind the arm, and is partly covered by the trapezius on the back near the midline. The word latissimus dorsi (plural: ''latissimi dorsi'') comes from L ...

* 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 and the internal and external

intercostal muscle The intercostal muscles comprise many different groups of muscle Muscle is a soft tissue, one of the four basic types of animal tissue. There are three types of muscle tissue in vertebrates: skeletal muscle, cardiac muscle, and smooth muscle ...

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 audible more clearly with a

stethoscope The stethoscope is a medicine, medical device for auscultation, or listening to internal sounds of an animal or human body. It typically has a small disc-shaped resonator that is placed against the skin, with either one or two tubes connected t ...

. On the left side, the cardiac orifice of the stomach lies deep to the triangle. In days before

X-ray An X-ray (also known in many languages as Röntgen radiation) is a form of high-energy electromagnetic radiation with a wavelength shorter than those of ultraviolet rays and longer than those of gamma rays. Roughly, X-rays have a wavelength ran ...

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 (: thoraces or thoraxes) or chest is a part of the anatomy of 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 di ...

, 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, Local anesthetic nerve block (sometimes referred to as simply "nerve b ...

known as the rhomboid intercostal block, which can be used to relieve pain after rib fractures, and a thoracotomy. This nerve block is usually achieved by injection of the local anesthetic agent into the fascial plane between the rhomboid upper intercostal muscle and the rhombic muscles.

References

External links

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