Muscular overview

Question 1

What is smooth muscle?

Answer 1

Involuntary muscle that cannot be consciously controlled.

Found in blood vessels where ‘vaso-constriction and vaso-dilation’ cause changes in blood flow.

Question 2

What is cardiac muscle?

Answer 2

Highly specialised muscle found only in the heart. It has characteristics of both cardiac and skeletal muscles.

Involuntary.

Question 3

What is skeletal muscle?

Answer 3

Muscle that is under conscious control, allowing voluntary movement.

Various shapes allow for different amounts of force production.

Question 4

What are the types of skeletal muscles?

Answer 4

Fusiform, Convergent (Triangular), Parallel/strap, and Pennate.

Pennate has three subcategories: Unipennate, Bipennate, and Multipennate.

Question 5

Describe fusiform muscles.

Answer 5

Long, parallel fibres typically involved in movement over a large range, with tendons on either side.

Question 6

Describe convergent (triangular) muscles.

Answer 6

Origin is typically wider than insertion, allowing for large production of forces.

Question 7

Describe parallel/strap muscles.

Answer 7

Muscles that run parallel to each other, typically long and more suited for endurance rather than strength.

Question 8

What is unipennate muscle?

Answer 8

One row of muscle fibres arranged diagonally into a tendon on one side only.

Question 9

What is bipennate muscle?

Answer 9

Two rows of muscle fibres arranged diagonally into a tendon on either side, resembling a feather.

Question 10

What is multipennate muscle?

Answer 10

Multiple rows of muscle fibres converging into a central tendon.

Question 11

What is the origin of the trapezius muscle?

Answer 11

Occipital aspect of skull, nuchal ligament, spinous processes of C7 –T12.

Question 12

What is the action of the trapezius muscle?

Answer 12

Elevates, depresses, retracts, rotates, and fixes scapula; extends neck.

Question 13

What is the origin of the levator scapulae muscle?

Answer 13

Upper spine (C1 –C4).

Question 14

What is the action of the levator scapulae muscle?

Answer 14

Elevates, retracts, and rotates scapula; laterally flexes neck.

Question 15

What is the action of the rhomboids (major & minor)?

Answer 15

Major - retracts, rotates, and fixes scapula; Minor - retracts slightly, elevates, rotates, and fixes scapula.

Question 16

What is the origin of the latissimus dorsi muscle?

Answer 16

T7 –L5, sacrum, and iliac crest.

Question 17

What is the action of the latissimus dorsi muscle?

Answer 17

Adducts, flexes, and extends the arm.

Question 18

What is the origin of the teres major muscle?

Answer 18

Lateral border of scapula.

Question 19

What is the action of the teres major muscle?

Answer 19

Adducts, extends, and medially rotates the arm.

Question 20

What is the action of the erector spinae muscle?

Answer 20

Extends the vertebral column; Iliocostalis also laterally flexes and rotates the vertebral column.

Question 21

What is the origin of the quadratus lumborum muscle?

Answer 21

Iliac crest & lower lumbar vertebrae.

Question 22

What is the action of the quadratus lumborum muscle?

Answer 22

Laterally flexes vertebral column & depresses the 12th rib.

Question 23

What is the origin of the sternocleidomastoid muscle?

Answer 23

Upper sternum (manubrium) and medial clavicle.

Question 24

What is the action of the sternocleidomastoid muscle?

Answer 24

One contracting alone laterally flexes & rotates on the same side; two together cause neck extension.

Question 25

What is the origin of the pectoralis major muscle?

Answer 25

Clavicle, sternum, & upper 6 ribs (costal cartilages).

Question 26

What is the action of the pectoralis major muscle?

Answer 26

Adducts, flexes, & medially rotates arm; extends arm from flexed position.

Question 27

What is the origin of the serratus anterior muscle?

Answer 27

1st to 9th ribs.

Question 28

What is the action of the serratus anterior muscle?

Answer 28

Rotates & protracts scapula; elevates ribs.

Question 29

What is the origin of the pectoralis minor muscle?

Answer 29

3rd to 5th ribs.

Question 30

What is the action of the pectoralis minor muscle?

Answer 30

Depresses scapula or elevates ribs.

Question 31

What is the origin of the external intercostals?

Answer 31

Inferior margin of each rib.

Question 32

What is the action of the external intercostals?

Answer 32

Inspiration - elevates ribs.

Question 33

What is the origin of the internal intercostals?

Answer 33

Superior margin of each rib.

Question 34

What is the action of the internal intercostals?

Answer 34

Expiration - depresses ribs.

Question 35

What is the origin of the diaphragm?

Answer 35

Xiphoid process, cartilage of last 7 ribs, lateral aspect of L1-L4.

Question 36

What is the action of the diaphragm?

Answer 36

Inspiration – depresses floor of thorax.

Question 37

What is the origin of the supraspinatus muscle?

Answer 37

Supraspinous fossa of scapula.

Question 38

What is the action of the supraspinatus muscle?

Answer 38

Abducts arm.

Question 39

What is the origin of the infraspinatus muscle?

Answer 39

Infraspinous fossa of scapula.

Question 40

What is the action of the infraspinatus muscle?

Answer 40

Extends and laterally rotates arm.

Question 41

What is the origin of the teres minor muscle?

Answer 41

Lateral border of scapula.

Question 42

What is the action of the teres minor muscle?

Answer 42

Extension and laterally rotates arm.

Question 43

What is the origin of the subscapularis muscle?

Answer 43

Subscapular fossa.

Question 44

What is the action of the subscapularis muscle?

Answer 44

Flexion and medial rotation of the arm.

Question 45

What is the origin of the anterior head of the deltoid muscle?

Answer 45

Lateral portion of the anterior aspect of the clavicle.

Question 46

What is the action of the anterior head of the deltoid muscle?

Answer 46

Adduction, flexion, and internal rotation.

Question 47

What is the origin of the lateral head of the deltoid muscle?

Answer 47

Lateral portion of the acromion process.

Question 48

What is the action of the lateral head of the deltoid muscle?

Answer 48

Adduction.

Question 49

What is the origin of the posterior head of the deltoid muscle?

Answer 49

Inferior portion of the spine of scapula.

Question 50

What is the action of the posterior head of the deltoid muscle?

Answer 50

Adduction, extension, and external rotation.

Question 51

What is the origin of the triceps brachii muscle?

Answer 51

Long head – lateral border of scapula; Lateral head – lateral and posterior surface of humerus; Medial head – posterior humerus.

Question 52

What is the action of the triceps brachii muscle?

Answer 52

Extends forearm; extends and adducts arm.

Question 53

What is the origin of the biceps brachii muscle?

Answer 53

Long head – supraglenoid tubercle; Short head – coracoid process.

Question 54

What is the action of the biceps brachii muscle?

Answer 54

Shoulder: Long head triggers flexion and abduction; Short head does flexion, adduction, and medial rotation; Elbow flexion.

Question 55

What is the origin of the coracobrachialis muscle?

Answer 55

Coracoid process of scapula.

Question 56

What is the action of the coracobrachialis muscle?

Answer 56

Adducts and flexes the shoulder joint.

Question 57

What is the origin of the brachialis muscle?

Answer 57

Middle of the anterior shaft of humerus.

Question 58

What is the action of the brachialis muscle?

Answer 58

Flexes forearm.

Question 59

What is the origin of the pronator teres muscle?

Answer 59

Coronoid process of ulna.

Question 60

What is the action of the pronator teres muscle?

Answer 60

Pronates forearm.

Question 61

What is the origin of the pronator quadratus muscle?

Answer 61

Ulna.

Question 62

What is the action of the pronator quadratus muscle?

Answer 62

Pronates forearm.

Question 63

What is the origin of the brachioradialis muscle?

Answer 63

Lateral epicondyle of humerus.

Question 64

What is the action of the brachioradialis muscle?

Answer 64

Flexes forearm.

Question 65

What is the action of the wrist flexors?

Answer 65

Flexes wrist.

Question 66

What is the action of the wrist extensors?

Answer 66

Extends wrist.

Question 67

What is the origin of the supinator muscle?

Answer 67

Lateral epicondyle of humerus.

Question 68

What is the action of the supinator muscle?

Answer 68

Supinates forearm.

Question 69

What is the origin of the rectus abdominus muscle?

Answer 69

Pubic crest & pubic symphysis.

Question 70

What is the action of the rectus abdominus muscle?

Answer 70

Flexes vertebral column; compresses abdomen.

Question 71

What is the origin of the transverse abdominus muscle?

Answer 71

7th to 12th costal cartilages, iliac crest, and inguinal ligament.

Question 72

What is the action of the transverse abdominus muscle?

Answer 72

Compresses abdomen.

Question 73

What is the origin of the internal oblique muscle?

Answer 73

Outer edge of the middle two thirds of the iliac crest.

Question 74

What is the action of the internal oblique muscle?

Answer 74

Bilateral contraction compresses the abdomen (lumbar flexion); unilateral contraction ipsilaterally rotates the torso.

Question 75

What is the origin of the external oblique muscle?

Answer 75

5th to 12th ribs.

Question 76

What is the action of the external oblique muscle?

Answer 76

Flexes and contralaterally rotates the thoracic spine.