Chapter 11

Question 1

Differentiate between origin and insertion.

Answer 1

Origin – end of muscle attached to fixed bone
Insertion – moveable end of muscle attached to bone being pulled

Question 2

List and describe the patterns of muscle fascicle organization.

Answer 2

Parallel muscles – fascicles arranged in same direction of long axis of muscle
Circular muscles – concentric bundles that increase or decrease the size of an opening
Convergent- widespread expansion over sizeable area
Pennate muscles – blend with tendon that runs through central region of whole length

Question 3

List the muscles of facial expressions and their functions.

Answer 3

1) Orbicularis oris – move lips
2) orbicularis oculi – close eye
3) occipitofrontalis – move up scalp and eyebrows (frontal and occipital bellies)
4) buccinator – compress cheek – whistle, blow, suck, chew
5) corrugator supercilii – primary mover of eyebrows

Question 4

What muscles are responsible for chewing?

Answer 4

Masseter, temporalis, medial pterygoid, lateral pterygoid

Question 5

What do the extrinsic muscles of the tongue do? Intrinsic muscles?

Answer 5

Extrinsic muscles – move tongue in different directions
Intrinsic muscles – change tongue shape

Question 6

List the suprahyoid muscles and their functions.

Answer 6

Digastric – anterior and posterior bellies – lift hyoid bone and larynx when swallowing
Stylohyoid – move hyoid bone posteriorly and lift larynx
Mylohyoid – lift hyoid and press tongue to top of mouth
Geniohyoid – depress mandible and pull hyoid anteriorly

Question 7

List the infrahyoid muscles and their functions.

Answer 7

Omohyoid – superior and inferior bellies – depress hyoid with sternohyoid and thyrohyoid
Thyrohyoid – increase larynx’s thyroid cartilage
Sternohyoid – depress to create different tones of voice

Question 8

How do core muscles help to maintain posture?

Answer 8

Alternate between contraction and relaxation so that muscles do not fatigue

Question 9

What is the linea alba?

Answer 9

White fibrous band made of bilateral rectus sheaths join at anterior midline – enclose rectus abdominis – origin at pubic crest and symphysis

Question 10

What are the three openings in the diaphragm and what structures pass through?

Answer 10

Inferior vena cava – caval opening
Esophagus and nerves – esophageal hiatus
Aorta, thoracic duct, azygous vein – aortic hiatus

Question 11

What is the main function of the intercostal muscles?

Answer 11

Assist in breathing and change dimensions of rib cage

Question 12

What is the levator ani?

Answer 12

Most important muscle of the pelvic floor – supports pelvic viscera

Question 13

What happens when the rhomboids contract?

Answer 13

Scapula moves medially and pulls shoulder and limb posteriorly

Question 14

What muscles move the humerus and their function?

Answer 14

Axial – pectoralis major, latissimus dorsi
Scapula – Deltoid - Facilitate with flexing and medial rotation, extension, lateral rotation
Subscapularis - medially rotate arm
Supraspinatus and Infraspinatus - Abduct arm and laterally rotate the arm
Teres Major - Extends arms, adduction and rotation
Teres Minor - Laterally rotates and extends arm
Coracobrachialis - Flex and adduct arm

Question 15

What muscles compose the rotator cuff?

Answer 15

subscapularis, supraspinatus, infraspinatus, teres minor

Question 16

List the muscles that move the forearm and their function.

Answer 16

Flexion – biceps brachii, brachialis, brachioradialis
Extension – triceps brachii and aconeus
Pronation – pronator teres and pronator quadratus
Supination – supinator – turns forearm anteriorly

Question 17

What are the intrinsic muscles of the hand and which finger do they act upon?

Answer 17

Thenar – act on thumb
Hypothenar – act on little finger
Intermediate muscle – act on all fingers

Question 18

What muscles constitute the quadriceps?

Answer 18

Vastus lateralis, vastus intermedius, vastus medialis, rectus femoris

Question 19

Which muscles compose the hamstrings?

Answer 19

Semitendinosus, semimembranosus, biceps femoris

Question 20

What are the actions of the sartorius and gracilis?

Answer 20

Sartorius – flex leg at knee; flex, abduct, laterally rotate leg at hip
Gracilis – adduct thigh and flex leg at knee