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The pectoralis majorFlexor / Adductor Across upper chest; brings arm toward body and helps push forward. muscle is a fan-shaped muscle that covers much of the anteriorThe front of the body or toward the front when standing in the anatomical position. chest wall.
Use this 3D Viewer to Explore the Muscles of the Upper Body
“Open3DModel – Upper limb – English labels” by Open3D project, Jan Kooloos, RadboudUMC, Eungyeol Lee, LUMC et al, license: CC BY-SA

Photography, text, and labels by Rob Swatski, Assistant Professor of Biology, Harrisburg Area Community College – York Campus, York, PA.
Pectoralis major Origin
The clavicular part originates from the medialToward the midline of the body half of the clavicleS-shaped collarbone; connects sternum to scapula; helps brace the shoulder. (collarbone).
The sternal part originates from the sternumFlat bone forming the center of the chest; anchor for ribs and clavicles. Appears as a vertical dagg. It extends from the sternocostal joint of the first rib to the sixth rib. Sometimes it extends to the seventh rib.
Pectoralis major Insertion
It inserts into the lateralAway from the midline of the body. lip of the bicipital groove of the humerusLong bone of the upper arm; articulates with scapula at shoulder and radius/ulna at elbow..
It inserts into the lateral lip of the bicipital groove of the humerus.
Pectoralis major Actions
Assistance in Forced Inspiration
Medial Rotation of the Arm
Horizontal Adduction of the Arm
Shoulder Flexion
Interactive Materials
Identify More Muscles
Link to more Muscle Identification
Upper Arm Muscles
Forearm Muscles
Calf Muscles
Anterior Thigh Muscles
Posterior Thigh Muscles
Knee Structures
Chest Muscles
Back Muscles
Abdominal Muscles
Neck Muscles
Head Muscles
List of terms
- pectoralis major
- anterior
- superior
- medial
- clavicle
- sternum
- lateral
- humerus