Lecture Exam 3: Muscles

Question 1

Masseter (strongest jaw muscle)

Answer 1

Action: closes jaw/moves the mandible

Origin: zygomatic arch

Insertion: angle and ramus of mandible

Question 2

Sternocleidomastoid

Answer 2

Action: flexion of neck forward and rotation to the shoulder of opposite side

Origin: manubrium of sternum and the clavicle

Insertion: mastoid process of temporal bone

Question 3

Orbicularis Oris

“Kissing Muscle”

Answer 3

Action: closes mouth, protrudes lips

Origin: maxillary bone and mandible

Insertion: skin and muscle around mouth

Question 4

Diaphragm

Answer 4

Action: flattens to increase the volume of the thoracic cavity (inspiration)

Origin: inferior border of rib and sternum, costal cartilage of last 6 ribs and lumbar vertebrae

Insertion: central tendon

Question 5

Supraspinatus

Answer 5

Action: abduction at the shoulder

Origin: supraspinous fossa of scapula

Insertion: greater tubercle of humerus

Question 6

Gracilis

Answer 6

Action: flexion at knee, medial rotation and adduction at hip

Origin: inferior ramus and body of pubis

Insertion: medial side of distal tibia

Question 7

Gastrocnemius

Answer 7

Action: plantar flexion at ankle, inversion of foot, flexion at knee

Origin: medial and lateral condyles of femur via two heads

Insertion: calcaneus via calcaneal tendon

Question 8

Sartorius

Answer 8

Action: flexion at knee, flexion and lateral rotation at hip

Origin: anterior superior iliac spine

Insertion: medial side of proximal tibia

Question 9

Genioglossus

Answer 9

Action: depresses and protrudes the tongue

Origin: chin

Insertion: hyoid bone and the dorsum of the tongue