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The pectoralis muscle is a thick, fan-shaped muscle that connects the front or ventral 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 muscle of the chest and lies above the pectoralis minor. The pectoralis minor is situated in a sensitive area near the rib cage and is prone to painful tightness, which can disrupt posture.
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What You'll Learn
Pectoralis major and minor
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.
Pectoralis Major
The pectoralis major is the superior most and largest muscle of the anterior chest wall. It is a thick, fan-shaped or triangular convergent muscle that lies underneath the breast tissue. The pectoralis major arises from parts of the clavicle and sternum, costal cartilages of the true ribs, and the aponeurosis of the abdominal external oblique muscle. It has two heads: the clavicular and the sternocostal, which reference their area of origin. The clavicular head is smaller and originates from the anterior surface of the medial half of the clavicle. The sternocostal head, meanwhile, is the larger of the two and originates from the anterior surface of the manubrium and body of the sternum, the anterior surface of the superior six costal cartilages, and the superior part of the aponeurosis of the external oblique muscle. The upper and lower fibres of the pectoralis major insert into the crest of the greater tubercle of the humerus. The pectoralis major is active in deep or forced inspiration but not expiration. It is responsible for flexion, adduction, and internal rotation of the humerus, and it keeps the arm attached to the trunk of the body.
Pectoralis Minor
The pectoralis minor is a triangular-shaped muscle located under the pectoralis major. It arises from the margins of the third to fifth ribs adjacent to the costochondral junction, and its fibres pass upward and laterally to insert into the medial border and superior surface of the coracoid process of the scapula. The pectoralis minor is important clinically and as a surgical landmark. It is used as a reference point for the three divisions of the axillary artery. The pectoralis minor acts as an accessory muscle of inspiration and aids in drawing the shoulder forward and downward.
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The pectoralis major's heads
The pectoralis major is the largest muscle of the anterior chest wall. It is a thick, fan-shaped muscle that lies underneath the breast tissue. It is the most superficial muscle in the pectoral region. The pectoralis major is also referred to as "pecs" or "chest muscle". It is a paired, superficial muscle located on the anterior surface of the thoracic cage.
The pectoralis major consists of two heads: the clavicular and the sternocostal, which refer to their area of origin. The clavicular head is the smaller of the two heads and originates from the anterior surface of the medial half of the clavicle. The sternocostal head is the larger of the two heads and originates from the anterior surface of the manubrium and body of the sternum, the anterior surface of the superior six costal cartilages, and the superior part of the aponeurosis of the external oblique muscle. The upper and lower fibres of the pectoralis major insert into the crest of the greater tubercle of the humerus.
The two heads of the pectoralis major have different nerve supplies. The clavicular head receives its nerve supply from the lateral pectoral nerve, while the sternocostal head is innervated by the medial pectoral nerve. The pectoralis major receives dual motor innervation from the medial and lateral pectoral nerves. The medial pectoral nerve arises from the medial cord, while the lateral pectoral nerve arises from the lateral cord of the brachial plexus.
The pectoralis major is responsible for several actions, including flexion, adduction, and internal rotation of the humerus, as well as keeping the arm attached to the trunk of the body. The clavicular part contributes to flexion, horizontal adduction, and inward rotation of the humerus, while the sternocostal part contributes to downward and forward movement of the arm and inward rotation during adduction. The pectoralis major is also active during deep or forced inspiration, assisting in breathing when the diaphragm and intercostal muscles are insufficient.
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Pectoralis major tendon rupture
The pectoralis muscle connects 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 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 and pectoralis minor muscles provide strength and stability to the shoulder and assist with lifting heavy objects and moving the arm forward and backward.
Pectoralis major tendon tears can be partial or complete and are classified into four categories based on the severity of the injury. Type 1 is a common injury where the pectoralis major tendon is torn from the humerus and is often surgically repaired. Type 2 is also a common injury where the area where the pectoralis major muscle meets the tendon, the musculotendinous junction, is torn or strained, and is often surgically repaired as well. Type 3 is a tear that occurs within the pectoralis major muscle belly, while the tendon remains fully intact. Type 4 is when the pectoralis major tendon is torn from the sternocostal head.
The most common symptom of a pectoralis major tendon tear is sudden and severe pain at the time of injury, along with a "popping" or "snapping" sensation. Other symptoms include inflammation and bruising at the tendon attachment site and visual deformity of the chest wall muscle, such as a hollow arumpit. Diagnostic imaging, such as X-rays and MRIs, may be used to confirm the injury and assess damage to other structures within the arm or chest wall.
The recommended treatment for a pectoralis major tendon tear is surgical repair, although in some cases, non-surgical options may be considered. Post-surgical rehabilitation focuses on maintaining the structural integrity of the repaired soft tissues, gradually restoring full functional range of motion, and enhancing muscle control and stability. The ultimate goal is to return the patient to their previous level of activity as quickly and safely as possible.
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Pectoralis minor's role in shoulder movement
Pectoralis muscles are those 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): the pectoralis major and the pectoralis minor. 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 minor, on the other hand, plays a crucial role in shoulder movement and stability. It arises from the third, fourth, and fifth ribs near the costal cartilage and inserts into the coracoid process, which is part of the scapula (shoulder blade). A tight pectoralis minor muscle can cause pain and restrict shoulder movement. This tightness can be caused by various daily activities performed with poor posture, such as working at a computer, driving, or reaching forward.
The pectoralis minor muscle aids in drawing the shoulder forward and downward. It also assists in respiration by elevating the ribs for deep inspiration when the pectoral girdle is fixed or elevated. When the scapula is stabilized, the pectoralis minor acts as an accessory muscle of inspiration.
A shortened pectoralis minor restricts flexion of the shoulder joint by limiting scapular rotation. This can lead to issues such as pain and restriction in neck movements, stiffness in the upper back, and an increased risk of rotator cuff injuries.
To address tightness in the pectoralis minor, specific stretches and exercises can be performed. These include the serratus punch exercise, modified push-up plus exercise, and chest stretch for tight or sore muscles. Additionally, maintaining awareness of one's posture during daily activities can help prevent tightness and associated issues.
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Pectoralis muscle exercises
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 superior most and largest muscle of the anterior chest wall. It is a thick, fan-shaped muscle that lies underneath the breast tissue. The pectoralis minor lies, for the most part, beneath the pectoralis major, arising from the middle ribs and inserting into the scapula (shoulder blade).
Bench Press
One of the most popular chest exercises, the bench press is an excellent choice for overall chest development. It is a compound movement that works both the upper and lower pectoral muscles. Position yourself with your arms straight and resting on a bench. Keep your body in a straight line, with your bottom tucked under and your back flat. Drop your chest towards the bench by bending your elbows. Return to the starting position. Repeat 10-12 reps.
Barbell Bench Press Eccentric
Lie on a bench with your feet slightly wider than shoulder-width apart to create a stable base. Keep your head on the top of the bench, with your arms straight, your shoulder blades retracted, and your hands in an overhand grip on the bar. This exercise can be performed with a spotter.
Weighted/Push-ups
Push-ups are a great bodyweight exercise that can be done anywhere and are an effective way to target the chest muscles. Lie flat on the floor with your hands in a standard and comfortable press-up position on your toes with your shoulder blades retracted. Push yourself off the ground with a braced trunk, keeping your elbows tucked close to your body. At the top of the push-up, straighten your elbows but do not lock them. Slowly descend to the floor, maintaining tension on the chest and triceps. Repeat 10-12 reps. To make the exercise harder, place a weight plate on your back.
Dumbbell Fly
This exercise is great for sculpting and defining the chest muscles. Lie on a bench with your feet slightly wider than shoulder-width apart to create a stable base, with your head on the top of the bench.
Dumbbell Fly Decline Bench
Lie on a bench with your feet slightly wider than shoulder width apart to create a stable base, with your head on the top of the bench.
Alternating Cable Crossovers
Stand with one foot in front of the other to create a stable base and hold a cable machine handle in each hand. Bend your elbows slightly and retract your shoulder blades. Drive one handle towards your chest line, keeping tension on the pectoral muscle and ensuring the bicep muscle does not assist too much. Once the arm is at the chest line, bring it back out laterally, maintaining a slight bend in the elbow. Repeat with the opposite arm. Repeat for 10-12 reps.
Incline Dumbbell Bench Press
Lie on an inclined bench, holding a dumbbell in each hand with a neutral grip, and place your feet firmly on the ground.
Incline Pushups
Incline pushups are a great way to target the lower pecs.
Flat Barbell Bench Press
The individual lies supine on a bench with their feet flat on the ground. With a barbell, the individual extends their arms, lowering it slowly towards the nipple line, and then bringing the weight up approximately over the face at arm's length.
Flat Dumbbell Bench Press
Similar to the flat barbell bench press, but performed with a pair of dumbbells.
Dumbbell Flyes
This exercise targets the chest from multiple angles.
Cable Crossovers
This exercise allows your hand and the weight to move in front of and across the midline of your body, ensuring the pec is working through every range of motion.
Barbell Presses
This exercise overloads the pecs.
It is recommended that you perform a complete strength training routine two or three times a week. When adding chest exercises to your routine, remember to exercise muscles throughout the body for a well-rounded strength program. You can work the chest muscles with or without equipment, or even using your own body weight for resistance.
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Frequently asked questions
A pectoral 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 pectoral muscles on each side of the human body, the pectoralis major and the pectoralis minor.
The pectoralis major is the largest and strongest of the chest muscles. Its main function is to bring the arms closer to the body, but it also assists with moving the shoulders and rotating the arms.
The pectoralis minor is situated beneath the pectoralis major and assists in key functions such as shoulder movement, especially shoulder rotation.
