The Muscular System


Trunk Muscles


Perhaps the most important muscles of the body, those of the trunk are and upper limbs are crucial for complex movement and bodily manipulation. The trunk muscles are essential in:
-moving the vertebral column
-manipulating the movement of the arms, head, and ribs
-forming the 'muscle girdle' of the body

Name of Muscle
Origin
Insertion
Primary Action(s)
Pectoralis major
Clavicle, Sternum, and Upper Ribs
Humerus (Proximal)
Flexes and abducts the humerus.
Rectus abdominus
Pubis
Sternum and Lower Ribs
Flexes the spine.
Biceps brachii
Scapula
Radius (Proximal)
Flexes the elbow and supinates the forearm
Brachialis
Humerus (Distal)
Ulna (Proximal)
Flexes the elbow.
Deltoid
Scapula and Clavicle
Humerus (deltoid tuberosity)
Abducts arm and humerus.
Trapezius
Occipital Bone and the Cervical and Thoracic Vertebrae
Scapula and Clavicle
Extends the neck and abducts the scapula.
Latissimus dorsi
Lower Spine
Humerus (Proximal)
Extends and abducts the humerus.
Triceps brachii
Shoulder girdle and Humerus (Proximal)
Ulna (Olecranon Process)
Extends the elbow.
Flexor carpi radialis
Humerus (Distal)
Second and Third Metacarpals
Flexes the wrist and abducts the hand.
Flexor carpi ulnaris
Humerus (Distal) and Ulna (Posterior)
Carpals of Wrist and Fifth Metacarpal
Flexes the wrist and abducts the hand.