Muscles of the Torso

Trapezius Origin External occipital bone Spinous process of C7- T12 Insertion Clavicle Spine and acromion process of scapula Function Elevates scapula Trapezius

Latissimus dorsi Origin Spines of the sacral, lumbar and T7 – T12 Spines of the sacral, lumbar and T7 – T12 Iliac crest Iliac crestInsertion Intertubercular groove of humerus Intertubercular groove of humerusFunction Extends, adducts and medially rotates arm Extends, adducts and medially rotates arm Latissimus Dorsi

Sternocleidomastoid Origin Sternum clavicle Insertion Mastoid process Function Pulls head to one side (Lateral flexion) Sternocleidomastoid

Pectoralis Major Origin Clavicle Sternum Costal cartilage of 2 nd – 6 th ribs Insertion Lateral lip of the intertubercular groove Function Flexes, adducts and medially rotates arm Pectoralis Major

Pectoralis minor Origin Ribs 3-5 Insertion Coracoid process of the scapula Function Depresses scapula Pectoralis minor

Serratus anterior Origin Outer surface of the upper ribs Insertion Anterior surface of the scapula Function Pulls the scapula forward and downward Serratus Anterior

External intercostals Origin Inferior border of each rib Insertion Superior border of the rib below Function Elevates for inspiration External Intercostals

Internal Intercostals Origin Superior border of each rib Insertion Inferior border of the rib above Function Depresses the ribs for exhalation Internal Intercostals

Rectus abdominus Origin Pubic crest and pubic symphasis Insertion Cartilage of ribs 5-7 Xiphoid process Function Flexes vertebral column Rectus abdominus

External Obliques Origin Lower eight ribs Insertion Anterior iliac crest Abdominal aponeurosis Function Tenses abdominal wall Lateral flexion External Obliques

Internal Obliques Origin Crest of ilium inquinal ligament Insertion Costal cartilage of lower pubis Function Tenses abdominal wall and compresses contents Internal Obliques

Transverse abdominal Function Compresses abdomen Transverse Abdominus

Temporalis Origin Temporal fossa Insertion Coronoid process of the mandible Function Closes jaw Temporalis

Masseter Origin Zygomatic arch Insertion Angle and ramus of the mandible Coronoid process of the mandible Function Closes jaw and clenches teeth Masseter

Occipitalis Function Tenses and retract scalp Occipitalis

Frontalis Function Raises eyebrows and wrinkles forehead Frontalis

Platysma Function Tenses skin of the neck and depresses mandible Platysma

Mentalis Function Elevates and protrudes lower lip Mentalis

Procerus Function Wrinkles skin between the eyes “serious” look Procerus

Nasalis Function Elevates the corners of the nostrils Nasalis

Orbicularis oris Function Closes and purses lips Orbicularis oris

Orbicularis oculi Function Closes eye Orbicularis oculi

Temporoparietalis Function Wriggles ears Temporoparietalis