Muscles of the trunk

Question 1

The trunk is made of the..

Answer 1

Thorax
Abdomen
Pelvis

Question 2

The functions of the muscles of the trunk are..

Answer 2

Movement and maintaining posture
Respiration
Support and compression of the abdominal and pelvic viscera

Question 3

4 main muscle groups of the trunk

Answer 3

1. Intrinsic (deep) muscles of the back
2. Respiratory muscles of the thorax
3. Muscles of the anterolateral abdominal wall
   4 Muscles of the pelvic flood

Question 4

Primer movers or agonists

Answer 4

Muscles that have a major responsibility for producing a specific movement

Question 5

Antagonists

Answer 5

Produce opposite movements (usually lie on opposite sides of a joint)

Question 6

Synergists

Answer 6

Work together with other muscles

Help the primer movers

Question 7

Fixators

Answer 7

Hold a bone firmly in place so that a prime mover can exert its function

Question 8

Erector spinae (what is it, how many parts, function)

Answer 8

Largest deep muscle of the back
3 parts
Extends trunk/spine (bilateral action) responsible for our erect posture
Lateral flexion of trunk (unilateral action)
Comes from ilium to skull

Question 9

Quadratus lumborum

Answer 9

Deep muscle of the back in the lumbar region
Lateral flexion of the trunk
Comes from ilium to rib

Question 10

Diaphragm

Answer 10

Dome shaped
Separates thoracic from abdominal cavity
Penetrated by 3 structures

Question 11

What 3 structures penetrate the diaphragm

Answer 11

Aorta
Inferior vena cava
Esophagus

Question 12

Intercostal muscles (3)

Answer 12

Maintain the spacing between ribs
Involved in elevation and depression of the ribs during respiration
1. External intercostal muscle (outermost, direction of fibers is “fingers in pockets”)
2. Internal intercostal muscle (perpendicular to above)
3. Innermost intercostal (same as internal)

Question 13

Pectoralis minor

Answer 13

Attaches to the scapula and to to ribs 3-5

Elevates ribs in inspiration

Question 14

4 abdominal wall muscles

Answer 14

3 lateral flat muscles - similar orientation to intercostal muscles
External and internal obliques, transversus abdominis
1 anterior vertical muscle
Rectus abdominis

Question 15

Functions of the abdominal wall muscles

Answer 15

Support the abdominal viscera
Compress the abdomen and increase the pressure upon abdominal viscera
Movements of the trunk

Question 16

Aponeurosis

Answer 16

Membrane that joins two muscles

Question 17

Transversus abdominis muscle

Answer 17

Innermost abdominal muscle
Compresses abdominal contents
Runs horizontally
Becomes an aponeurosis that meets at the midline

Question 18

Rectus abdominis muscle

Answer 18

Important flexor

Gives 6 pack appearance

Question 19

2 muscles that form the pelvic floor

Answer 19

Levator ani

Coccygeus

Question 20

Levator ani

Answer 20

Main muscle of the pelvic floor
Regulates sphincters - urinary bladder
Funnel shaped
Resists downward movement of the pelvic viscera