Dominic Stone
The pectoralis muscle is one of the muscles that connect the front walls of the chest with the bones of the upper arm and shoulder. There are two pectoralis muscles on each side of the sternum (breastbone) in the human body: the pectoralis major and the pectoralis minor. The pectoralis major is the largest and most important of the chest muscles, while the pectoralis minor is situated beneath it to assist in key functions.
| Characteristics | Values |
|---|---|
| Number of muscles in the pectoral region | 3 |
| Names of muscles in the pectoral region | Pectoralis major, pectoralis minor, serratus anterior |
| Location of the pectoralis major | The upper part of the chest |
| Origin of the pectoralis major | The clavicle (collarbone), the sternum, the ribs, and a tendinous extension of the external oblique abdominal muscle |
| Attachment of the pectoralis major | A ridge at the rear of the humerus (the bone of the upper arm) |
| Actions of the pectoralis major | Adduction, or depression, of the arm (in opposition to the action of the deltoideus muscle), rotation of the arm forward about the axis of the body |
| Functions of the pectoralis major | When the raised arms are fixed (as in mountain climbing), it assists the latissimus dorsi and teres major muscles in pulling the trunk up |
| Location of the pectoralis minor | Beneath the pectoralis major |
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What You'll Learn
- The pectoralis major is the largest and most important chest muscle
- The pectoralis minor is situated beneath the pectoralis major
- The pectoralis major originates at the clavicle (collarbone)
- The pectoralis major can be injured during weight lifting
- The pectoralis major is attached to a ridge at the rear of the humerus
The pectoralis major is the largest and most important chest muscle
The pectoralis major is the biggest and strongest of the chest muscles. It is situated in the upper part of the chest and is attached to a ridge at the rear of the humerus (the bone of the upper arm). Its major actions are adduction, or depression, of the arm (in opposition to the action of the deltoideus muscle) and rotation of the arm forward about the axis of the body.
The pectoralis major is one of three muscles that lie in the pectoral region and exert a force on the upper limb. The other two are the pectoralis minor and the serratus anterior. The pectoralis minor is situated beneath the pectoralis major to assist in key functions. It is an important chest muscle but can also be problematic.
A pectoralis major tendon rupture is a rare shoulder injury, most commonly seen in weight lifters. This injury is becoming more common due to the increased emphasis on healthy lifestyles.
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The pectoralis minor is situated beneath the pectoralis major
The pectoralis muscle is any of the muscles that connect the front walls of the chest with the bones of the upper arm and shoulder. There are two such muscles on each side of the sternum (breastbone) in the human body: the pectoralis major and the pectoralis minor. The pectoralis major is the largest and most superior muscle of the anterior chest wall. It is a thick, fan-shaped muscle that lies underneath the breast tissue and forms the anterior wall of the axilla. The pectoralis major is the most superficial muscle in the pectoral region. It is also the biggest and strongest of the chest muscles.
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The pectoralis major originates at the clavicle (collarbone)
The pectoralis major is the largest and most important of the chest muscles. It is a thick, fan-shaped muscle that lies underneath the breast tissue and forms the anterior wall of the axilla. The pectoralis major originates at the clavicle (collarbone), the sternum, the ribs, and a tendinous extension of the external oblique abdominal muscle. It extends across the upper part of the chest and is attached to a ridge at the rear of the humerus (the bone of the upper arm).
The pectoralis major has two heads, the clavicular and the sternocostal, which reference their area of origin. The pectoralis major is the most superficial muscle in the pectoral region. It is the superior most muscle of the anterior chest wall.
The pectoralis major is responsible for the adduction or depression of the arm (in opposition to the action of the deltoideus muscle) and the rotation of the arm forward about the axis of the body. When the raised arms are fixed (as in mountain climbing), it assists the latissimus dorsi and teres major muscles in pulling the trunk up.
The pectoralis major tendon rupture is a rare shoulder injury, most commonly seen in weight lifters. This injury is becoming more prevalent due to the increased emphasis on healthy lifestyles.
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The pectoralis major can be injured during weight lifting
The pectoralis muscle is one of the muscles that connect the front walls of the chest with the bones of the upper arm and shoulder. There are two pectoralis muscles on each side of the sternum (breastbone): the pectoralis major and the pectoralis minor. The pectoralis major is the largest and strongest of the chest muscles. It is a thick, fan-shaped muscle that lies underneath the breast tissue and forms the anterior wall of the axilla. It has two heads, the clavicular and the sternocostal, which reference their area of origin.
The location of the tear is most commonly at the tendon insertion or the musculotendinous junction. Patients often describe an audible pop coupled with pain and ecchymosis at the time of injury. Physical examination demonstrates pain and weakness of the affected arm when tested in adduction and internal rotation. Diagnosis is often made clinically and confirmed with further imaging, chest MRI being the imaging modality of choice.
Injuries of the pectoralis major muscle can be classified according to three levels of severity: Type 1 (contusions and strains), Type 2 (partial tear), and Type 3 (complete tear). They can also be classified according to their location: tendon, myotendon juncture, or muscle.
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The pectoralis major is attached to a ridge at the rear of the humerus
The pectoralis muscle is any of the muscles that connect the front walls of the chest with the bones of the upper arm and shoulder. There are two such muscles on each side of the sternum (breastbone) in the human body: the pectoralis major and the pectoralis minor. The pectoralis major is the largest and strongest of the chest muscles. It is a thick, fan-shaped muscle that lies underneath the breast tissue and forms the anterior wall of the axilla. It has two heads, the clavicular and the sternocostal, which reference their area of origin. The pectoralis major originates at the clavicle (collarbone), the sternum, the ribs, and a tendinous extension of the external oblique abdominal muscle. It extends across the upper part of the chest and is attached to a ridge at the rear of the humerus (the bone of the upper arm). Its major actions are adduction, or depression, of the arm (in opposition to the action of the deltoideus muscle) and rotation of the arm forward about the axis of the body. When the raised arms are fixed (as in mountain climbing), it assists the latissimus dorsi and teres major muscles in pulling the trunk up.
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Frequently asked questions
The pec muscle is short for the pectoralis muscle, which connects the front walls of the chest with the bones of the upper arm and shoulder.
There are two pec muscles on each side of the sternum (breastbone) in the human body: the pectoralis major and the pectoralis minor.
The pectoralis major is the largest and most superior muscle of the anterior chest wall. It is a thick, fan-shaped muscle that lies underneath the breast tissue.
The pectoralis minor is situated beneath the pectoralis major to assist in key functions.
The pectoralis major's major actions are adduction, or depression, of the arm (in opposition to the action of the deltoideus muscle) and rotation of the arm forward about the axis of the body.
