Summary
ANATOMY CHEST
The anatomy of the pectoralis muscle consists of two muscles:
- the pectoral major muscle,
- The pectoral minor muscle.
The pectoralis major muscle
The pectoralis major has four origins, like a fan. These include:
- the clavicle,
- the sternum,
- the sixth and seventh ribs,
- the humerus.
The fibers at the top go parallel to the anterior deltoid. They make up the clavicular section of the pectoralis major or the top half of it.
The fibers linked to the sternum run horizontally. They make up the sternal part of the pectoralis major.
Lower fibers are connected to the sixth and seventh ribs. They are parallel to the abdominal oblique major.
The oblique abdominis fibers all terminate in a tendon. This tendon is about 8 cm broad. It rotates 180 degrees before connecting to the top arm. The upper fibers of the pectoralis major attach lower than the lower fibres as a result of this movement.
This feature facilitates the following muscle actions:
- extension: the motion that permits you to extend your arm down and in front of you from an above position;
Your arm does an internal rotation;
Adduction is the motion that allows you to lower and laterally extend your arm from a raised posture. - When you adduct your arm horizontally, you bring it in toward your body’s midline.
- arm is brought forward into a less extreme flexion position;
The small pectoralis
The pectoralis minor muscle is situated inferior to the pectoralis major muscle. The contribution of this particular activity on the development of the pectoral muscle mass is negligible. However, it does engage in the downward descent and rotational motion. Additionally, it offers a degree of stability to the scapula. Nevertheless, despite the coordinated functioning of the pectoralis major and minor, it is important to note that they are not directly implicated in the arm’s movement.
Primarily, the action of elevating the arm anteriorly is associated with the pectoralis minor muscle, which results in the abduction of the scapula. Subsequently, while descending the arm from an elevated posture, the pectoralis minor muscle facilitates the downward rotation of the scapula.
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