MUSCLES OF THE CHEST::
1.The pectoralis major muscle is found superficially on the anterior chest wall its origin is on the sternum and clavicle and its insertion is on the humerus it is involved in the movement of scapula and the upper limb
2. The pectoralis minor is found under the pectoralis major muscle and is placed between second and fifth ribs and the scapula it draws the scapula downward and forward
3. The subclavian muscle is situated between the first rib and the clavicle it draws the shoulder forward and downward
4. The serratus anterior is situated on the lateral surface of the thorax its origin looks like sawteeth on the upper eight ribs it draws the scapula forward and outward and turns it
5.The external and internal intercostal muscles are found in between the ribs the external intercostal muscles elevate the ribs and thereby take part in inhalation the internal intercostal muscles depress the ribs and thus take part in exhalation
6. The diaphragm separates the chest from the abdominal cavity it is dome shaped and has convexity upwards the diaphragm has its origin from the sternum ribs and lumbar vertebrae it has three openings for the aorta inferior venacava and oesophagus it descends as it contracts when the diaphragm relaxes it returns to its original position it takes part in respiration
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