Muscle Notes Part 2

Question 1

Masseter

Answer 1

Origin: Zygomatic

Insertion:Ramus and angle of mandible

Action:Closes jaw

Question 2

What two muscles are necessary to close the jaw?

Answer 2

Temporalis and masseter

Question 3

How many pounds of pressure per square inch can the human jaw exert?

Answer 3

About 200 pounds of pressure per square inch

Think of Mike Tyson when he bit off another boxer’s ear

Question 4

Can other animal’s jaws exert more pounds of pressure per square inch that a human jaw?

Answer 4

A Rottweiler can exert about 330 pounds of pressure per square inch

A snapping turtle can exert even more pressure than a Rottweiler

Question 5

Sternocleidomastoid (prayer muscle)

Answer 5

Origin:Sternum and clavicle

Insertion:Mastoid process of temporal bone

Action:Pulls head to one side when only one contracts; flexes neck when both contract like you bowing your head to pray

Question 6

Trapezius (named for trapezoid; has two parallel sides; on superior and posterior portion of back)

Answer 6

Origin: Occipital bone and ligamentum nuchae

Insertion:Spine of scapula and lateral third of clavicle

Action:Four actions 1 adducts scapula 2 depresses scapula 3 raises or elevates scapula 4 extends the head

Question 7

Latissimus Dorsi (on inferior and posterior back)

Answer 7

Origin: Thoracolumbar fascia, all lumbar spines, lower thoracic spines

Insertion: Humeris

Action: Medial rotate, adduct, and depress humerus

Question 8

Pectoralis major (chest muscle)

Answer 8

Origin:Sternum, medial clavicle, 2-6 costal cartilages

Insertion: Humerus

Action: Adduct and medial rotate the humerus

Question 9

Deltoid (gives definition to the shoulder; is both anterior and posterior )

Answer 9

Origin:Lateral clavicle and spine of scapula

Insertion:Humerus

Action:Abducts humerus, assists the biceps and triceps

Question 10

Rotator Cuffs

Answer 10

Four muscles associated with the scapula and having the same O, I, and A

Form a protective “cuff” around the ball and socket joint of the shoulder

Question 11

Supraspinatus

Answer 11

(above spine of posterior scapula)

Question 12

Infraspinatus

Answer 12

(below spine of posterior scapula)

Question 13

Subscapularis

Answer 13

(covers anterior scapula)

Question 14

Teres Minor

Answer 14

(on small portion of posterior scapula)

Question 15

Rotator Cuffs

Answer 15

Origin:Scapula

Insertion:Proximal humerus

Action:Adduct and abduct humerus, mediallu, and laterally rotate humerus

Question 16

Biceps Brachii (anterior arm muscle with two heads)

Answer 16

Origin: Short head -coracoid process of scapula; long head-superior lip of glenoid cavity

Insertion:Radius

Action:Supinator (turns hand palm up) and flexes forearm

Question 17

Triceps Brachii (posterior arm muscle with three heads)

Answer 17

Origin: 1 head on scapula; 2 heads on proximal humerus

Insertion: Olecranon process of ulna

Action: Extends forearm, stabilizes the hinge joint of the elbow

Question 18

Forearm muscles in general

Answer 18

Anterior forearm muscles are flexors of wrists and fingers

Posterior forearm muscles are extensors of wrists and fingers

Question 19

Rectus abdominis (also called the six pack)

Answer 19

Origin: 5th, 6th, and 7th costal cartilages; xiphoid process of sternum

Insertion: Pubic bone; pubic symphysis

Action: Supports and protects abdominal and pelvic viscera; flexes vertebral column;hold in your gut)

Question 20

The ____ ____ (white line of connective tissue going down midline of rectus abdominis) and umbilicus (belly button) are both landmarks of the rectus abdominis. The linea alba has no blood vessels so incisions are commonly made her to lessen bleeding

Answer 20

linea alba

Question 21

The ____ _____has three muscles associated with it: transversus abdominis (innermost layer with muscle fibers extending around the midline); internal oblique (middle layer with muscle fibers running up at an angle) and external oblique (outermost layer with fibers running down at an angle )

Answer 21

rectus abdominis

Question 22

External Oblique

Answer 22

Origin: Lower 8 ribs

Insertion: Linea alba

Action:Support and protect abdominal and pelvic viscera; flex vertebral column; aid in breathing, vomintting, defecating, childbirth, laughing, coughing, sneezing