Dominic Stone
The pectoralis muscle is a thick, fan-shaped muscle that makes up the bulk of the chest muscles. It is located on the front surface of the chest and 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: the pectoralis major and the pectoralis minor. The pectoralis major is the larger and more superficial of the two, and it lies underneath the pectoralis minor. The pectoralis muscles are commonly targeted in exercises such as the flat barbell bench press and the flat dumbbell bench press.
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What You'll Learn
The pectoralis major is the largest muscle in the pectoral region
The pectoral region is located on the anterior chest wall. It contains four muscles that exert a force on the upper limb: the pectoralis major, pectoralis minor, serratus anterior, and subclavius. The pectoralis major is the largest and most superficial muscle in the pectoral region. It is thick and fan-shaped, originating from multiple places along the medial and superior chest, including the anterior sternum, clavicular head, sternal end of rib 6, superior six costal cartilages, and the aponeurosis of the external oblique.
The pectoralis major has two heads: the clavicular head and the sternocostal head. The clavicular head is responsible for flexion, horizontal adduction, and inward rotation of the humerus. It contributes to adduction of the humerus when at an approximately 110-degree angle. The sternocostal head is antagonistic to the clavicular head, contributing to downward and forward movement of the arm, as well as inward rotation during adduction. It also permits horizontal and vertical adduction, extension, and internal rotation of the upper extremity.
The pectoralis major plays a crucial role in shoulder joint movement. For example, it allows for the flexion of the humerus, such as when throwing a ball underhand or lifting a child. Maximal activation of the pectoralis major occurs in the transverse plane through pressing motions. Exercises that include horizontal adduction and elbow extensions, such as the barbell bench press and dumbbell bench press, induce high activation of the pectoralis major in the sternocostal region.
Tears and ruptures of the pectoralis major are rare but can occur in weightlifters and athletes participating in high-impact contact sports. These injuries can result in pain, weakness, and disability. Poland syndrome is another rare condition associated with the pectoralis major, where the whole muscle is missing, usually on one side of the body.
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The pectoralis minor lies underneath the pectoralis major
The pectoralis minor lies underneath its larger counterpart muscle, the pectoralis major. 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. The pectoralis major consists of two heads: the clavicular and the sternocostal. The clavicular head originates from the anterior surface of the medial clavicle, while the sternocostal head originates from the anterior surface of the sternum, the superior six costal cartilages, and the aponeurosis of the external oblique muscle.
The pectoralis minor, on the other hand, is much thinner and triangular in shape. It originates from the third to fifth ribs adjacent to the costochondral junction. The fibres then pass upward and laterally to insert into the medial border and superior surface of the coracoid process. The pectoralis minor is important clinically and as a surgical landmark due to its relation to underlying structures.
Both the pectoralis major and minor muscles work together to produce various movements of the scapula. The pectoralis minor is involved in stabilising the scapula by pulling it downward and anteriorly against the thoracic wall. It also plays a role in respiration, assisting in raising ribs 3-5 during deep inspiration and aiding in expanding the thoracic cavity.
The primary nerve supply to the pectoralis minor comes via the medial pectoral nerve, with additional innervation from the lateral pectoral nerve. The vascular supply to the pectoralis minor is provided by branches of the axillary artery, including the thoracoacromial artery and the superior thoracic artery.
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The serratus anterior is located on the front of the chest
The serratus anterior is a muscle located on the front of the chest, also known as the "boxer's muscle" or the "big swing muscle". It is a 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 is a key scapular stabiliser, keeping the shoulder blades against the ribcage when at rest and during movement.
The serratus anterior has three parts: the upper/superior, middle/intermedius, and lower/inferior. The upper part involves the first to second ribs attaching to the superior angle of the scapula. The middle part involves the second to third ribs attaching to the medial border of the scapula. The lower part involves the fourth to ninth rib attaching to the medial border and inferior angle of the scapula. The lower part of the muscle is the most prominent and powerful.
The serratus anterior acts in concert with the upper and lower fibres of the trapezius muscle to sustain upward rotation of the scapula, allowing for overhead lifting. It is also 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.
The serratus anterior is an important muscle for the shoulder and upper limb. It is one of the three muscles that lie in the pectoral region and exert a force on the upper limb, along with the pectoralis major and pectoralis minor. The pectoralis major is a thick, fan-shaped muscle that originates from multiple places along the medial and superior chest, including the anterior sternum, clavicular head, and sternal end of rib six. The pectoralis minor lies underneath the pectoralis major and is much thinner and triangular in shape. It originates from the margins of the third to fifth ribs and inserts into the medial border and superior surface of the coracoid process.
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The subclavius is a small muscle located underneath the clavicle
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 larger and more superficial of the two, and it originates at the clavicle (collarbone), the sternum, the ribs, and a tendinous extension of the external oblique abdominal muscle.
The subclavius is a small, triangular muscle located underneath the clavicle. It is a short muscle of the shoulder girdle that helps to stabilise the clavicle during movements of the shoulder and arm. The subclavius originates from the first rib and its costal cartilage, inserting into the inferior surface of the middle third of the clavicle. Its main function is to actively stabilise the clavicle at the sternoclavicular joint, preventing dislocation. Additionally, the subclavius helps to protect the underlying neurovascular structures, such as the brachial plexus and subclavian vessels, in the event of a clavicular fracture.
The subclavius is enclosed in the clavipectoral fascia, along with the pectoralis minor, coracobrachialis, and short head of the biceps. It has been suggested that the subclavius may regulate the output of kinetic energy of the upper extremity's movement rather than solely acting as a stabilising muscle. The subclavius also aids in depressing the clavicle and elevating the first rib, contributing to the control of the scapula's position in relation to the thorax.
The serratus anterior is another muscle located on the front of the chest, and it moves the scapula forward around the torso, as when throwing a punch. It is involved in rotating the scapula and allowing the arm to be raised over 90 degrees. The serratus anterior forms the medial border of the axilla region, along with the pectoralis minor and major, which form part of the anterior wall of this region.
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Exercises to strengthen the pectoralis muscle
The pectoral muscles, also known as pecs, are a group of three muscles that lie in the pectoral region and exert a force on the upper limb. These are the pectoralis major, pectoralis minor, and the serratus anterior. The pectoralis major is the largest of the chest muscles, lying under the breastbone and assisting in the bending, straightening, and rotation of the arm at the shoulder joint. The pectoralis minor, on the other hand, is a thin muscle on either side of the upper chest that is involved in the movement and stabilization of the scapula or shoulder blade.
Basic Pectoral Strengthening Exercise
Start in a push-up position on your knees. Keeping your back and neck straight, slowly straighten your elbows until they are fully extended, tightening the pectoral muscles, and then return to the starting position. Perform 3 sets of 10 repetitions, provided the exercise is pain-free.
Resistance Band Adduction
Begin by standing or kneeling with your back straight and holding a resistance band. Keeping your back and elbows straight, slowly pull the resistance band to your hip, tightening your pectoral muscles. Perform 3 sets of 10 repetitions, ensuring the exercise is pain-free.
Bench Press
The bench press is a compound exercise that targets the pectoralis muscles. It involves lying on a bench and pushing a weight straight up and away from your chest, before lowering it back down.
Incline Pushups
Incline pushups are an excellent way to target the lower pecs. By performing pushups on an elevated surface, such as a box or bench, you can effectively work the lower chest and pectoralis major.
Shoulder Internal Rotation
This exercise targets the pectoralis major and helps with shoulder movements. Simply move your arm back behind your body, pull your raised arm down towards your body, and turn your arm inwards.
Stretching
Stretching the pectoralis muscles is crucial to improving flexibility, reducing tightness, and enhancing breathing. Stand facing a wall with your arm straight out to the side at shoulder height. Press your palm against the wall and slowly push your arm into it. Then, turn your body away from the wall, so your arm is behind you. Hold this position for 30 seconds before switching sides.
It is important to consult with a physiotherapist or certified trainer to ensure the suitability of these exercises for your specific needs and to avoid injury.
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Frequently asked questions
The pectoral 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 superior most, largest, and most superficial muscle of the anterior chest wall. It is a thick, fan-shaped muscle that lies underneath the breast tissue.
The pectoralis minor is a muscle that lies underneath its larger counterpart, the pectoralis major. It is thinner and triangular in shape and resides below the major. It originates from the margins of the third to fifth ribs adjacent to the costochondral junction.
Many exercises focus on the pectoralis muscle, including pressing exercises such as the flat barbell bench press and the flat dumbbell bench press.
