Thorax Flashcards
Pectoralis Major Orgin
Clavicular Head:anterior surface of medial half of clavicle
Sternocostal Head: anterior surface of sternum, costal cartilages of ribs 1-6 and aponeurosis of external oblique mm.
Pec Major Insertion
Lateral lip of the intertubercular suluc on humerus
Pec major Innervation
Lateral and Medial Pectoral N. (CH: C5,C6/ SH: C7-T1)
Pec Major Action
Adducts and medially rotates humerus , draws scapula anteriorly and inferiorly. Acting alone the CH flexes the humerus and the SH extends it from the flexed position
Pec Minor Orgin
ribs 3-5 near their costal cartilages
Pec Minor Insertion
medial and superior surface of the coracoid process of the scpaula
Pec Minor Innevation
Medial Pectoral N (C8, T1)
Pec Minor Action
stabilizes the scapula by drawing it inferiorly and anteriorly against the thoracic wall
External Intercostal Origin
Inferior Borders of the ribs, run INFEROANTERIORLY between successive ribs between the tubercles and costochondral junctions
External Intercostal insertion
superior borders of the ribs between the tubercles and costochondral junctions
External Intercostal Innervation
Intercostal Nerve
External Intercostal Action
most active during INSPIRATION maintaining the tone of the muscles in the intercostal space and ELEVATING the ribs during forced inspiration.
Internal Intercostal Origin
Inferior Borders of the ribs, run deep and INFEROPOSTERIORLY from rib angle to sternum
Internal Intercostal Insertion
superior borders of ribs from rib angle to sternum
Internal Intercostal innervation
Intercostal nerve
Internal Intercostal Action
most active during EXPIRATION, maintaining the tone of the intercostal space. During forced expiration, Interosseous part depress ribs, Interchondral part elevates ribs
Innermost Intercostal Origin
inferior border of ribs
Innermost Intercostal Insertion
superior border of ribs
Innermost Intercostal Innervation
Intercostal N.
Innermost Intercotal Action
most active during EXPIRATION, maintaining the tone of the intercostal space. During forced expiration, Interosseous part depress ribs, Interchondral part elevates ribs
Subcostal Origin
Internal surface of lower ribs near their angles
Subcostal Insertion
Superior borders of 2nd or 3rd rib below (spans 2-3 ribs)
Subcostal Innervation
Intercostal N.
Subcostal Action
prob same as Internal Intercostal; help to maintain tone in expiration and depress ribs in forced exipration
Transversus Thoracis Origin
Posterior Surface of lower Sternum ( body and Xiphoid process)
Tranversus Thoracis Insertion
internal surface of costal cartilages of ribs 2-6
Transversus Thoracis Innervation
Intercostal N
Transversus Thoracis Action
weakly depresses ribs and proprioception
