THORAX: Muscles of thoracic cage

Question 1

Pectoralis major [clavicular head]: - origin

Answer 1

Anterior surface of clavicle (medial half)

Question 2

Pectoralis major [sternocostal head]: - origin

Answer 2

Anterior surface of sternum, Costal cartilages of ribs 1-6

Question 3

Pectoralis major [abdominal head]: - origin

Answer 3

Anterior layer of rectus sheath

Question 4

Pectoralis major - insertion

Answer 4

Crest of greater tubercle of humerus (all heads)

Question 5

Pectoralis major - innervation

Answer 5

Lateral and medial pectoral nerves (C5-T1)

Question 6

Pectoralis major - function

Answer 6

Shoulder joint: Arm adduction, Arm internal rotation, Arm flexion (clavicular head), arm extension (sternocostal head);
Scapulothoracic joint: Draws scapula anteroinferiorly

Question 7

Pectoralis minor - origin

Answer 7

Anterior surface, Costal cartilages of ribs 3-5

Question 8

Pectoralis minor - insertion

Answer 8

Medial border and coracoid process of scapula

Question 9

Pectoralis minor - innervation

Answer 9

Lateral and medial pectoral nerves (C5-T1)

Question 10

Pectoralis minor - function

Answer 10

Scapulothoracic joint: Draws scapula anteroinferiorly, stabilises scapula on thoracic wall

Question 11

Serratus anterior [superior part] - origin

Answer 11

Ribs 1-2, Intercostal fascia

Question 12

Serratus anterior [middle part] - origin

Answer 12

Ribs 3-6

Question 13

Serratus anterior [inferior part] - origin

Answer 13

Ribs 7-8/9/10 (+ external oblique muscle)

Question 14

Serratus anterior [superior part] - insertion

Answer 14

Anterior surface of superior angle of scapula

Question 15

Serratus anterior [middle part] - insertion

Answer 15

Anterior surface of medial border of scapula

Question 16

Serratus anterior [inferior part] - insertion

Answer 16

Anterior surface of inferior angle of scapula

Question 17

Serratus anterior - innervation

Answer 17

Long thoracic nerve (C5-C7)

Question 18

Serratus anterior - function

Answer 18

Scapulothoracic joint: Draws scapula anterolaterally, Suspends scapula on thoracic wall, Rotates scapula (draws inferiorly angle laterally)

Question 19

Subclavius - origin

Answer 19

Costal cartilage, Sternal end of rib 1

Question 20

Subclavius - insertion

Answer 20

Anteroinferior surface of middle third of clavicle

Question 21

Subclavius - innervation

Answer 21

Subclavian nerve (C5-C6)

Question 22

Subclavius - function

Answer 22

Sternoclavicular joint: Anchors and depresses clavicle

Question 23

External intercostals - origin

Answer 23

Inferior border of ribs

Question 24

External intercostals - insertion

Answer 24

Superior border of immediate rib below

Question 25

External intercostals - innervation

Answer 25

Intercostal nerves

Question 26

External intercostals - function

Answer 26

Elevate ribs during forced inspiration; Supports intercostal spaces and thoracic cage

Question 27

Internal intercostals - origin

Answer 27

Costal groove of ribs

Question 28

Internal intercostals - insertion

Answer 28

Superior border of immediate rib below

Question 29

Internal intercostals - innervation

Answer 29

Intercostal nerves

Question 30

Internal intercostals - function

Answer 30

Depresses ribs during forced expiration; Supports intercostal spaces and thoracic cage

Question 31

Innermost intercostals - origin

Answer 31

Costal groove of ribs

Question 32

Innermost intercostals - insertion

Answer 32

Superior border of immediate rib below

Question 33

Innermost intercostals - innervation

Answer 33

Intercostal nerves

Question 34

Innermost intercostals - function

Answer 34

Depresses ribs during forced expiration; Supports intercostal spaces and thoracic cage

Question 35

Subcostal muscles - origin

Answer 35

Internal surface of ribs (near angle of rib)

Question 36

Subcostal muscles - insertion

Answer 36

Internal surface of rib (2-3 levels below origin)

Question 37

Subcostal muscles - function

Answer 37

Depresses ribs during forced expiration; Supports intercostal spaces and thoracic cage

Question 38

Subcostal muscles - innervation

Answer 38

Intercostal nerves

Question 39

Transversus thoracis - origin

Answer 39

Sternal ends of costal cartilages of ribs 4-7, Inferoposterior surface of body of sternum and xiphoid process

Question 40

Transversus thoracis - insertion

Answer 40

Internal surface of costal cartilages of ribs 2-6

Question 41

Transversus thoracis - innervation

Answer 41

Intercostal nerves

Question 42

Transversus thoracis - function

Answer 42

Depresses costal cartilages

Question 43

Respiratory diaphragm [sternal part] - origin

Answer 43

Posterior aspect of xiphoid process

Question 44

Respiratory diaphragm [costal part] - origin

Answer 44

Internal surfaces of lower costal cartilages and ribs 7-12

Question 45

Respiratory diaphragm [lumbar part] - origin

Answer 45

Medial and lateral arcuate ligaments (lumbocostal arches), Bodies of vertebrae L1-L3 (+ intervertebral discs), Anterior longitudinal ligament

Question 46

Respiratory diaphragm - insertion

Answer 46

Central tendon of diaphragm

Question 47

Respiratory diaphragm - innervation

Answer 47

Phrenic nerves (C3-C5) (Sensory innervation of peripheries via 6th-11th intercostal nerves)

Question 48

Respiratory diaphragm - function

Answer 48

Depresses costal cartilages, Primary muscle of breathing (inspiration)