Thorax Muscles

Question 1

Serratus Anterior Origin

Answer 1

Upper eight ribs and ant intercostal membranes from midclavicular line. Lower four interdigitating with external oblique

Question 2

Serratus Anterior Insertion

Answer 2

Inner med border scapula. 1 and 2: upper angle; 3 and 4: length of costal surface ; 5-8: inf angle

Question 3

Serratus Anterior Action

Answer 3

Lat rotates protracts scapula

Question 4

Serratus Anterior Innervation

Answer 4

Long thoracic Nerve (C5, 6, 7) (from roots) slips from ribs 1 and 2: C5; 3 and 4: C6; 5-8: C7)

Question 5

Diaphragm Origin

Answer 5

Vertebral:crura from bodies of L1, 2 (left), L1-3(right). Costal: med and lat arcuate ligs, inner aspect of lower six ribs . Sternal: two slips from post aspect of xiphoid

Question 6

Diaphragm Insertion

Answer 6

Trefoil central tendon

Question 7

Diaphragm Action

Answer 7

Inspiration and assists in raising intra-abdominal pressure

Question 8

Diaphragm Innervation

Answer 8

Phrenic N (motor) (C3, 4, 5). Sensory: phrenic, intercostals(6-12) and upper two lumbar N roots

Question 9

External Intercostals Origin

Answer 9

Inf border of ribs as far back as post angles

Question 10

External Intercostals Insertion

Answer 10

Sup border of ribs below, passing obliquely downwards and backwards

Question 11

External Intercostals Action

Answer 11

Fix intercostal spaces during respiration. Aids forced inspiration by elevating ribs

Question 12

External Intercostals Innervation

Answer 12

Muscular collateral brs of intercostal Ns

Question 13

Innermost Intercostals Origin

Answer 13

Int aspect of ribs above and below

Question 14

Innermost Intercostals Insertion

Answer 14

Int aspect of ribs above and below

Question 15

Innermost Intercostals Action

Answer 15

Fix intercostal spaces during respiration

Question 16

Innermost Intercostals Innervation

Answer 16

Muscular collateral brs of intercostal Ns

Question 17

Internal Intercostals Origin

Answer 17

Inf border of ribs as far back as post angles

Question 18

Internal Intercostals Insertion

Answer 18

Sup border of ribs below , passing obliquely downwards and backwards

Question 19

Internal Intercostals Action

Answer 19

Fix intercostal spaces during expiration. Aids forced inspiration by elevating ribs

Question 20

Internal Intercostals Innervation

Answer 20

Muscular collateral brs of intercostal Ns

Question 21

Levatores Costarum Origin

Answer 21

Transverse processes C7 to T11

Question 22

Levatores Costarum Insertion

Answer 22

Post surface and angle of rib below

Question 23

Levatores Costarum Action

Answer 23

Elevates ribs

Question 24

Levatores Costarum Innervation

Answer 24

Muscular collateral brs of intercostal Ns

Question 25

Pectoralis Major Origin

Answer 25

Clavicular head-med half clavicle. Sternocostal head -lat manubrium and sternum, six upper costal cartilages and ext oblique aponeurosis

Question 26

Pectoralis Major Insertion

Answer 26

Lat lip of bicipital groove of humerus and ant lip of deltoid tuberosity

Question 27

Pectoralis Major Action

Answer 27

Clavicular head:flexes and adducts arm. Sternal head: adducts and med rotates arm . Accessory for inspiration

Question 28

Pectoralis Major Innervation

Answer 28

Med pectoral nn(from med cord) and lat pectoral nn (from lat cord) (C6, 7, 8)

Question 29

Pectoralis Minor Origin

Answer 29

3, 4,5 ribs

Question 30

Pectoralis Minor Insertion

Answer 30

Med and upper surface of coracoid process of scapula

Question 31

Pectoralis Minor Action

Answer 31

Elevates ribs if scapula fixed, protracts scapula (assists serratus ant )

Question 32

Pectoralis Minor Innervation

Answer 32

Med pectoral N (C8, T1) (from med cord)

Question 33

Serratus Posterior Inferior Origin

Answer 33

Spinous processes and supraspinous ligs of T11-L2

Question 34

Serratus Posterior Inferior Insertion

Answer 34

Post aspect of ribs 9-12

Question 35

Serratus Posterior Inferior Action

Answer 35

Assists forced expiration

Question 36

Serratus Posterior Inferior Innervation

Answer 36

Ant primary rami (T9-12)

Question 37

Serratus Posterior Superior Origin

Answer 37

Spinous processes and supraspinous ligs of C7-T2

Question 38

Serratus Posterior Superior Insertion

Answer 38

Post aspect of ribs 2-5

Question 39

Serratus Posterior Superior Action

Answer 39

Assists forced inspiration

Question 40

Serratus Posterior Superior Innervation

Answer 40

Ant primary rami (T2-5)

Question 41

Subcostals Origin

Answer 41

Int post aspects of lower six ribs

Question 42

Subcostals Insertion

Answer 42

Int aspects of ribs two to three levels below

Question 43

Subcostals Action

Answer 43

Depresses lower ribs

Question 44

Subcostals Innervation

Answer 44

Muscular collateral brs of intercostal Ns

Question 45

Transversus Thoracis Origin

Answer 45

Lower third of inner aspect of sternum and lower three costosternal junctions

Question 46

Transversus Thoracis Insertion

Answer 46

Second to sixth costal cartilages

Question 47

Transversus Thoracis Action

Answer 47

Depresses upper ribs

Question 48

Transversus Thoracis Innervation

Answer 48

Muscular collateral brs of intercostal Ns