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Anatomy Encyclopedia Entry 1778233325

** The **Pectoralis Major** is a large, fan-shaped muscle in the chest that plays a crucial role in movements of the shoulder joint and arm. ## Overview The **Pectoralis Major** is a powerful, fan-shaped muscle located in the chest, extending from the **clavicle** (collarbone) and **sternum** (breastbone) to the **humerus** (upper arm bone). This muscle is divided into two parts: the **clavicular head** and the **sternal head**. The **Pectoralis Major** is responsible for movements of the shoulder joint and arm, including flexion, extension, and rotation. The **Pectoralis Major** is a key muscle in various daily activities, such as pushing, throwing, and carrying objects. It is also essential for athletic movements, such as swimming, rowing, and weightlifting. In addition, the **Pectoralis Major** helps maintain posture and stability of the shoulder joint. ## History/Background The study of human anatomy dates back to ancient civilizations, with evidence of anatomical studies found in ancient Egyptian, Greek, and Roman texts. The **Pectoralis Major** has been described in various anatomical texts throughout history, including the works of Galen (129-216 AD) and Andreas Vesalius (1514-1564 AD), who is considered the father of modern anatomy. In the 19th century, the discovery of the **Pectoralis Major** muscle's function and structure was further advanced through the work of anatomists such as Henry Gray (1827-1861 AD) and William Henry Flower (1831-1899 AD). Today, the **Pectoralis Major** is a well-understood muscle, with its anatomy and function studied in detail through various imaging techniques, including MRI and CT scans. ## Key Information The **Pectoralis Major** muscle has several key characteristics: - **Origin**: The **Pectoralis Major** muscle originates from the **clavicle** and **sternum**. - **Insertion**: The muscle inserts into the **humerus**. - **Function**: The **Pectoralis Major** muscle is responsible for movements of the shoulder joint and arm, including flexion, extension, and rotation. - **Blood Supply**: The muscle receives blood supply from the **pectoral branches** of the **axillary artery**. - **Nerve Supply**: The muscle is innervated by the **lateral pectoral nerve** and the **medial pectoral nerve**. ## Significance The **Pectoralis Major** muscle plays a crucial role in various aspects of human life, including: - **Athletic Performance**: The **Pectoralis Major** is essential for athletic movements, such as swimming, rowing, and weightlifting. - **Daily Activities**: The muscle is involved in various daily activities, such as pushing, throwing, and carrying objects. - **Posture and Stability**: The **Pectoralis Major** helps maintain posture and stability of the shoulder joint. INFOBOX: - **Name**: Pectoralis Major - **Type**: Muscle - **Date**: Ancient civilizations (e.g., Galen, 129-216 AD) - **Location**: Chest - **Known For**: Crucial role in movements of the shoulder joint and arm TAGS: **Pectoralis Major**, **Muscle**, **Anatomy**, **Shoulder Joint**, **Arm Movement**, **Athletic Performance**, **Daily Activities**, **Posture**, **Stability**