Muscles of Thorax (Left)

Description

There are many different muscles within the thoracic region, some of these muscles:

- only originate from thoracic structures and insert onto other regions (e.g., the upper limb and abdominal regions);

- only insert onto thoracic structures and originate from other regions (e.g., the head and neck regions);

- both originate from and insert onto thoracic structures.

Muscles that only originate from or only insert onto thoracic structures are described as “muscles overlying the thoracic wall.” These muscles are not classified as muscles of the thorax, but are instead classified as muscles of the head, neck, upper limb, and abdomen. Such muscles include the sternocleidomastoid, scalenes, pectoralis major, pectoralis minor, serratus anterior, external abdominal oblique, and rectus abdominis muscles.

Muscles that both originate from and insert onto thoracic structures are described as “muscles within the thoracic wall.” These muscles are classified as the muscles of the thorax, and consist of the:

- intercostals;

- subcostals;

- transversus thoracis;

- levatores costarum.

These muscles elevate and depress the ribs and provide support to the structures of the thorax.

For classification purposes, the diaphragm is also considered one of the muscles of the thorax.