CHEST

GENERAL INFORMATION

The chest muscles, mainly the pectoralis major and minor, are responsible for movements of the shoulder joint and play a key role in upper body strength. Moreover, these muscles contribute to pushing movements, shoulder adduction, and rotation. They are essential in activities such as lifting, moving, and throwing, making them vital for athletes and fitness enthusiasts.

ORIGIN

• Pectoralis Major: The clavicular head originates from the medial half of the clavicle; the sternal head is from the sternum and cartilage of the first six ribs.
• Pectoralis Minor: From the anterior surfaces of ribs 3-5.
• Serratus Anterior: From the outer surfaces of ribs 1-8 or 9.
• Subclavius: From the first rib and its costal cartilage.

INSERTION POINT

• Pectoralis Major: Intertubercular groove of the humerus.
• Pectoralis Minor: Coracoid process of the scapula.
• Serratus Anterior: Anterior surface of the medial border of the scapula.
• Subclavius: Inferior surface of the clavicle.

MAJOR ARTERIES

• Thoracoacromial Artery: This artery supplies blood to the pectoralis, major and minor.
• Lateral Thoracic Artery: Provides blood to the serratus anterior and the lateral part of the chest.
• Subclavian Artery: This artery Supplies the subclavius muscle.

NEURAL INNERVATION

• Pectoralis Major: Medial and lateral pectoral nerves (C5-T1).
• Pectoralis Minor: Medial pectoral nerve (C8-T1).
• Serratus Anterior: Long thoracic nerve (C5-C7).
• Subclavius: Nerve to subclavius (C5-C6).

TRIGGER POINT

Trigger points in the pectoralis major and minor can cause referred pain in the shoulder, chest, and down the arm. This function often manifests as tightness or discomfort during pushing or lifting movements and is commonly aggravated by poor posture or overuse.

CONCENTRIC FUNCTION

• Pectoralis Major: Shoulder adduction, internal rotation, and flexion, such as when pushing a weight or performing a bench press.
• Pectoralis Minor: Draws the scapula forward and downward, stabilising the shoulder blade.
• Serratus Anterior: Protracts and stabilises the scapula, essential for overhead movements.
• Subclavius: Stabilises the clavicle, preventing excessive movement.

ECCENTRIC FUNCTION

• Pectoralis Major: Controls the lowering of the arm from a raised position, resisting abduction and external rotation.
• Pectoralis Minor: Assists in controlling upward movement of the scapula, especially during arm elevation.
• Serratus Anterior: Controls the retraction of the scapula during arm lowering.
• Subclavius: Prevents excessive upward movement of the clavicle during arm movements.

ISOMETRIC FUNCTION

Stabilises the shoulder and chest during static positions like holding a weight in place or during the plank position. The pectoralis major and minor work together to keep the upper body stable while resisting forces pulling the arm away from the midline.

RELATED MUSCLE – SCIENTIFIC NAMES

• Deltoid: Assists with shoulder abduction and stabilisation.
• Latissimus Dorsi: Works with the pectorals to perform shoulder extension and adduction.
• Trapezius: Involved in scapular stabilisation and movement.
• Teres Major: Assists with internal shoulder rotation and extension.
• Infraspinatus: A rotator cuff muscle involved in the external rotation of the shoulder.

ANTAGONIST

• Latissimus Dorsi: Opposes the pectoralis major by controlling shoulder extension and external rotation.
• Posterior Deltoid: Assists in shoulder extension, opposing the flexion role of the pectoralis major.
• Rhomboids: Oppose scapular protraction performed by the serratus anterior.
• Trapezius (lower fibres): Elevates the scapula, opposing the downward pull of the pectoralis minor.
• Infraspinatus: Performs external rotation, opposing the internal rotation caused by the pectoralis major.

COMMON INJURIES

• Pectoralis Major Tear: A tear in the muscle fibres, often occurring during heavy lifting, especially bench presses. Pain is immediate, and the muscle may show visible deformity.
• Costochondritis: Inflammation of the cartilage connecting the ribs to the sternum, often confused with chest pain from muscle strains.
• Shoulder Impingement: Occurs when the pectoralis minor tightens and presses against the shoulder blade, causing pain during overhead movements.
• Pectoral Strain: This is due to overstretching or tearing of the chest muscles, commonly due to overuse or improper warm-up before strength training.
• Bicipital Tendonitis: Inflammation of the biceps tendon, which can be aggravated by tight or overactive chest muscles pulling on the shoulder joint.

EXERCISES

• Bench Press: A staple chest exercise that works the pectoralis major by pressing a barbell or dumbbells from the chest upwards. This exercise builds strength and mass in the chest.
• Push-Ups: Push-ups are a bodyweight exercise that strengthens the chest, shoulders, and triceps. It works the pectoralis major and serratus anterior, promoting functional upper-body strength.
• Chest Flys: Using dumbbells or cables, this exercise isolates the pectoralis major by stretching the arms out wide and bringing them together, enhancing muscle definition.
• Cable Crossovers: Targets the chest by pulling cables from the sides of the body towards the midline, focusing on the pectoralis major’s adduction function.
• Dips: Dips are a compound movement that targets the lower pectoralis major and triceps by lowering and raising the body between parallel bars, building upper body strength.

STRETCHES

• Chest Doorway Stretch: Stand in a doorway with arms at shoulder height, then lean forward to stretch the pectoralis major. This stretch improves flexibility and opens up the chest.
• Seated Chest Stretch: Sit with hands behind your back, clasping them together, and lift the chest upwards, stretching the pectoralis major and minor while enhancing posture.
• Chest Wall Stretch: Stand sideways to a wall, placing one arm on the wall and gently turning the body away to stretch the chest muscles.
• Child’s Pose with Chest Stretch: Kneel and stretch your arms forward, then slide one arm under the other to stretch the serratus anterior and upper chest.
• Pectoralis Minor Stretch: Lie on your back with a foam roller between the shoulder blades and open the arms wide to stretch the minor chest muscles, improving shoulder mobility.