Muscle Actions and Origins

This video tutorial from Lehigh Carbon Community College covers key muscles in the head, neck, and back, detailing their origins, insertions, and actions. It includes a comprehensive look at muscles like the orbicularis oris, masseter, trapezius, and latissimus dorsi, among others. The tutorial is designed to aid students in understanding muscle anatomy and physiology, with a focus on practical applications. The video also highlights the support services available at LCCC, encouraging students to utilize walk-in tutoring and visit the science lab for further learning.

What is the primary action of the orbicularis oris muscle?

• To rotate the head

• To elevate the jaw

• To open the eyelids

• To close the lips

Which muscle is responsible for blinking and squinting?

• Temporalis

• Orbicularis oculi

• Sternocleidomastoid

• Masseter

Where does the masseter muscle insert?

• Hyoid bone

• Mastoid process

• Coronoid process of the mandible

• Angle and ramus of the mandible

What is the action of the sternocleidomastoid muscle?

• Flexion of the head

• Elevation of the jaw

• Extension of the arm

• Rotation of the scapula

Which muscle is involved in ADducting the scapula?

• Supraspinatus

• Infraspinatus

• Latissimus dorsi

• Trapezius

What is the primary action of the latissimus dorsi?

• To elevate the scapula

• To flex the elbow

• To rotate the head

• To extend, ADduct, and medially rotate the humerus

Where does the infraspinatus muscle originate?

• Supraspinous fossa

• Inferior angle of the scapula

• Lateral border of the scapula

• Infraspinous fossa of the scapula

What is the action of the teres minor muscle?

• To flex the elbow

• To extend the head

• To laterally rotate and weakly ADduct the humerus

• To medially rotate the humerus

Which muscle is responsible for elevating the scapula?

• Levator scapulae

• Rhomboid major

• Teres major

• Subscapularis

What is the action of the spinous group of muscles?

• To flex the elbow

• To medially rotate the humerus

• To extend and rotate the head

• To ADduct the scapula