Section 3

Question 1

What is frontalis?

Answer 1

• the muscle that covers the frontal bone and lifts the eyebrows, causing the forehead to wrinkle

Question 2

What is orbicularis oculi?

Answer 2

• a muscle surrounding the eye that forcefully closes the eye when contracted
  -it originates on the frontal and maxillary bones

Question 3

What is zygomaticus?

Answer 3

• a muscle that extends from the zygomatic arch to the corners of the mouth
• it draws the angle of the mouth superiorly and posteriorly, causing one to smile :)

Question 4

What is orbicularis oris?

Answer 4

• a muscle that surrounds the mouth and enables the puckering of lips
• it originates on the maxillary bones or mandible bones
• sometimes referred as a kissing muscle

Question 5

What are the temporalis and masseter muscle used in?

Answer 5

Mastication (chewing)

Question 6

What is the temporalis?

Answer 6

• a fan-shaped muscle
• extends from the temporal fossa of the parietal bone to the coronoid process of the mandible
• elevates and pulls the mandible posteriorly (retract)

Question 7

What is the masseter?

Answer 7

• a powerful muscle
• extends from the zygomatic arch to the angle of the mandible (lower jaw)
• its action is to elevate and protract (move forward) the jaw

Question 8

Which muscle flexes the neck, and rotates the head to the opposite side

Answer 8

The sternocleidomastoid muscle flexes the neck with bilateral contraction, and rotates the head to the opposite side with unilateral contraction.

Question 9

Where is the sternocleidomastoid muscle attached?

Answer 9

“Sterno” and “cleido” mean that the inferior attachment of the muscle is at the sternum and the clavicle

“Mastoid” means that the superior attachment of the muscle is on the mastoid process of the temporal bone

Therefore the sternocleidomastoid has one attachment at the sternum and clavicle and another attachment at the mastoid process

Question 10

What does the sternocleidomastoid muscle do?

Answer 10

It flexes the neck with bilateral contraction, and rotates the head to the opposite site with unilateral contraction.

(It is an anterior muscle that moves the head)

Question 11

What two main posterior muscles move the head?

Answer 11

Semispinalis capitis and splenius capitis

Question 12

Where is the semispinalis capitis?

Answer 12

• “capitis” means head: referring to the fact that this muscle inserts to the occipital bone
• “spinalis” means half of the spine

Therefore the semispinalis capitis attaches at the occipital bone and lies on each side of the spine

Question 13

What does the semispinalis capitis do?

Answer 13

Extends the neck with bilateral contraction, and turns the face slightly to the opposite side with unilateral contraction

(its a posterior muscle that moves the head)

Question 14

Where is the splenius capitis?

Answer 14

• “capitis” means head referring to the insertion of the muscle on the occipital bone
• “splenius” means bandage, suggesting that the muscle looks like a bandage

Therefore the splenius capitis attaches at the occipital bone and is shaped like a bandage.

Question 15

What does the splenius capitis do?

Answer 15

Extends the neck with bilateral contraction, and causes flexion and lateral rotation of the neck with unilateral contraction.

(its a posterior muscle that moves the head)

Question 16

What are the external and internal intercostal muscles of the thorax?

Answer 16

External intercostals are the most superficial, and their fibers run anteriorly and inferiorly between the ribs. They aid in inspiration.

Internal intercostals lie deep to the externals, and their fibers run posteriorly and inferiorly. They aid in expiration.

Question 17

What do the intercostal muscles of the thorax do?

Answer 17

They aid in the process of breathing

Question 18

What are erector spinae muscles?

Answer 18

A group of muscles that help keep the spine erect.
They run down both side of the spinal column.

Question 19

What do the abdominal wall muscles do?

Answer 19

They facilitate movement of the trunk, and aid in breathing

Question 20

What are the four types of abdominal muscles?

Answer 20

1. External oblique
2. Internal oblique
3. Transversus abdominis
4. Rectus abdominis

Question 21

Where is the external oblique and how do its fibers run?

Answer 21

• the most superficial of the anterolateral abdominal wall musculature
• its fibers run anteriorly and inferiorly

Question 22

What are the functions of the external oblique?

Answer 22

• bilateral: flexes the vertebral column and compresses the abdominal wall. used in forced expiration
• unilateral: lateral flexion and rotation of the vertebral column

Question 23

Where is the internal oblique and how do its fibers run?

Answer 23

• lies deep to the external oblique
• its fibers run anteriorly and superiorly

Question 24

What are the functions of the internal oblique?

Answer 24

• bilateral: flexes the vertebral column and compresses the abdominal wall
• unilateral: lateral flexion and rotation of the vertebral column

Question 25

How does the transversus abdominis run (position)?

Answer 25

• runs horizontally, deep to the internal oblique

Question 26

What are the functions of the transversus abdominis?

Answer 26

• bilateral: flexes the vertebral column and compresses the abdominal wall. used in forced expiration
• unilateral: lateral flexion of the vertebral column

Question 27

Where does the rectus abdominis lie?

Answer 27

• it lies on either side of the linea alba and is separated by tendinous intersections

(linea alba = a line of connective tissue down the middle of the abdomen for muscle attachment)

Question 28

What is linea alba?

Answer 28

linea alba = a line of connective tissue down the middle of the abdomen for muscle attachment

Question 29

Compare bilateral and unilateral contraction.

Answer 29

Bilateral contraction is referring to the bilateral, paired muscles working simultaneously. So, for example, bilateral contraction of the left and right sternocleidomastoid work together to flex the neck.

Unilateral would then just be one.