Dominic Stone
The pectoral 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 pectoral muscles on each side of the human body. The pectoralis major is the largest muscle of the anterior chest wall and lies underneath the breast tissue. The pectoralis minor is much thinner and triangular in shape and resides below the pectoralis major.
| Characteristics | Values |
|---|---|
| Definition | Any of the muscles which connect the front/ventral walls of the chest with the bones of the upper arm and shoulder |
| Number of muscles | 2 on each side of the human body |
| Types | Pectoralis major, pectoralis minor, serratus anterior, subclavius, sternalist muscle |
| Pectoralis major | Thick, fan-shaped, and originates from multiple places along the medial and superior chest |
| Pectoralis minor | Much thinner and triangular in shape, originates from the margins of the third to fifth ribs |
| Serratus anterior | A thin muscular sheet originating from the outer surface of the first to eighth ribs |
| Subclavius | A small muscle located directly underneath the clavicle, running horizontally |
| Sternalis muscle | A strip of anterior and lateral muscle to the sternum and lateral to the pectoralis major muscle |
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What You'll Learn
- The pectoralis major is the largest muscle in the pectoral region
- The pectoralis minor lies underneath the pectoralis major
- The subclavius is a small muscle located directly underneath the clavicle
- The serratus anterior moves the scapula forward around the torso
- The pectoralis major tendon rupture is a rare shoulder injury
The pectoralis major is the largest muscle in the pectoral region
The pectoralis major is responsible for various movements of the shoulder and upper arm. The clavicular head allows for the flexion of the humerus, such as lifting a glass for a toast. The sternocostal head permits the horizontal and vertical adduction, extension, and internal rotation of the upper extremity. For example, when the arm is raised overhead, the pectoralis major assists in bringing it back down to the side.
The pectoralis major is a common site of injury, especially in weight lifters. A pectoralis major tendon rupture is a rare shoulder injury that can occur during pressing exercises such as the bench press. This injury is becoming more prevalent due to the increasing popularity of weightlifting and healthy lifestyles.
The pectoralis major can be strengthened through various pressing exercises. The flat barbell bench press and the flat dumbbell bench press are common exercises that utilise the pectoralis major. In these exercises, the individual lies supine on a bench with their feet flat on the ground and uses weights to perform controlled movements.
The pectoralis major is a crucial muscle in the pectoral region, providing structural support and enabling a wide range of movements in the shoulder and upper arm. Its strength and proper function are essential for activities such as weightlifting and throwing sports.
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The pectoralis minor lies underneath the pectoralis major
The pectoralis muscle is any of the muscles that connect the front or ventral walls of the chest with the bones of the upper arm and shoulder. There are two pectoralis muscles on each side of the human body. The pectoralis major is the superior most and largest muscle of the anterior chest wall. It is thick and fan-shaped, lying underneath the breast tissue. The pectoralis minor lies underneath its larger counterpart muscle, the pectoralis major. Both muscles form part of the anterior wall of the axilla region.
The pectoralis minor is much thinner and triangular in shape compared to the pectoralis major. It originates from the margins of the third to fifth ribs adjacent to the costochondral junction. The fibres pass upward and laterally to insert into the medial border and superior surface of the coracoid process. The pectoralis minor is crucial in stabilising the scapula by pulling it downward and anteriorly against the thoracic wall.
The pectoralis major also has a role in stabilising the scapula. It originates from multiple places along the medial and superior chest: anterior sternum, clavicular head, sternal end of rib 6, superior six costal cartilages, and from the aponeurosis of the external oblique. The actions of the pectoralis major depend on which parts of the muscle are activated. The fibres attaching to the clavicular head allow for the flexion of the humerus, as seen when lifting a glass for a toast. However, the muscle fibres attaching to the sternocostal head permit the horizontal and vertical adduction, extension, and internal rotation of the upper extremity.
The pectoralis major can be strengthened through various exercises, including pressing exercises such as the flat barbell bench press and the flat dumbbell bench press. These exercises involve the individual lying supine on a bench with their feet flat on the ground, extending their arms with either a barbell or a pair of dumbbells, and slowly lowering the weight towards the nipple line before bringing the weight up again to arm's length.
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The subclavius is a small muscle located directly underneath the clavicle
The pectoralis muscles are those 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 human body. The three muscles that lie in the pectoral region and exert a force on the upper limb are the pectoralis major, pectoralis minor, and the serratus anterior.
The pectoralis major is the superior and largest muscle of the anterior chest wall. It is thick and fan-shaped, lying underneath the breast tissue. The pectoralis minor is much thinner and triangular in shape, residing below the pectoralis major.
The pectoralis major and minor muscles have different functions. The pectoralis major's actions depend on which parts of the muscle are activated. The fibers attaching to the clavicular head allow for the flexion of the humerus, as in lifting a glass for a toast. However, the muscle fibers attaching to the sternocostal head permit the horizontal and vertical adduction, extension, and internal rotation of the upper extremity. The pectoralis minor stabilises the scapula by drawing it anteroinferiorly against the thoracic wall.
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The serratus anterior moves the scapula forward around the torso
The pectoralis major is the superior and largest 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.
The serratus anterior is a thin, fan-shaped muscle that originates on the superolateral surfaces of the first to eighth or ninth ribs at the lateral wall of the thorax. Its main part lies deep under the scapula and the pectoral muscles. It acts on the scapula and is the prime mover in both scapular protraction and scapular upward rotation. It is a key scapular stabiliser, keeping the shoulder blades against the ribcage when at rest and during movement.
The serratus anterior is also known as the "boxer's muscle" as it is largely responsible for the protraction of the scapula which occurs when throwing a punch. The contraction of the entire serratus anterior leads to an anterolateral movement of the scapula along the ribs. Due to the pull of the inferior part at the lower scapula, the shoulder joint is shifted superiorly. This shifting now enables the lift of the arm above 90 degrees (elevation).
The serratus anterior is located more laterally in the chest wall and forms the medial border of the axilla region. It originates from the first to eighth ribs and inserts at the anterior surface of the scapula. Due to its course, it has a "'serrated" or "saw-toothed" appearance. The lowest attachment may alternatively extend to the tenth rib in approximately 10% of the population.
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The pectoralis major tendon rupture is a rare shoulder injury
The pectoralis major is the superior most and largest 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. There are two heads of the pectoralis major: the clavicular and the sternalcostal, which reference their area of origin. The pectoralis major is a very powerful shoulder muscle and functions as the shoulder adductor, internal rotator, and flexor of the humerus.
The diagnosis of pectoralis tears is usually straightforward. Patients often report feeling a "'snap" or "pop" during a maximal lift or effort, followed by mild swelling and ecchymosis. An MRI can be helpful in assessing the location and severity of the tear.
Treatment options for pectoralis major tendon rupture include surgical and non-surgical approaches. Surgical repair is generally recommended for athletes and those wishing to return to recreational athletic activity, as it provides superior outcomes in terms of strength recovery. Nonsurgical treatment may be considered for older or less active individuals or those with medical conditions that increase the risk of surgical complications. However, patients treated without surgery will likely experience a strength deficit and cosmetic changes.
The goals of post-operative rehabilitation are to maintain the structural integrity of the repaired soft tissues, restore full functional range of motion and muscle control, and return the patient to their previous level of activity as quickly and safely as possible.
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Frequently asked questions
The peck muscle is any of the muscles that connect the front or ventral walls of the chest with the bones of the upper arm and shoulder. There are two on each side of the human body.
The three muscles in the pectoral region are the pectoralis major, pectoralis minor, and the serratus anterior.
The pectoralis major is the largest muscle of the anterior chest wall. It is thick and fan-shaped and lies underneath the breast tissue.
The pectoralis major is active in deep or forced inspiration, but not expiration. It also assists in breathing when the diaphragm and intercostal muscles are insufficient.
Common exercises that utilise the pectoralis major include pressing exercises like the flat barbell bench press and the flat dumbbell bench press.
