Thorachumeral muscles :
① Pectoralis major
- clavicular / sternocostal / Abdominal
- O: clavicle medial part / sternum (1st-7th ribs) / aponeuroses of the lateral muscles
- I : Humerus - intratubercle
- N: Pectoralis n. (lateral & media
- F: adduction, flexion & internal rotation of the arm
- B.S: thoracoacromial art
- ↳ branch of axillary art.
② Pectoralis minor
- O: 3rd - 5th ribs
- I : Scapula - coracoid process
- N: medial pectoral n.
- F: Protraction + depression of the scapula.
- B.S: Thoracoacromial art.
③ Serratus anterior m.
- O: Outer surface of the upper 8 ribs
- I :→ super. angle of the scapula
- → medial border " "
- → infer. angle " "
- N: long thoracic n.
- B.S: Sup. & lateral thoracic. alt.s
- ↳ branches of the axillary alt.
④ Subclavian
- O: 1st rib
- I : clavicle
- N: subclavian n.
Proper muscles :
① External intercostal m. → for exhalation.
- O: ribs - caudal margin of rib
- I: ribs - cranial " " "
- N: Intercostal n.
- F: Elevates the ribs
- * Fibers direction: hands to pocket.
- * absent in the region of the costal cartilage
② Internal intercostal m. → for inhalation
- O: ribs - caudal "
- I: ribs - cranial "
- N: intercostal n.
- F: Depression of the ribs
- * F.D = Hands to chest
- * absent from the vertebral column.
③ Innermost intercostal m.
- O: " "
- I: " "
- N: Intercostal n.
- F: Depression
- F.D = Hands to che
- * absent " vertebral column.
B.S.: Ant. + Post. intercostal art.
④ Transverse thoracis
- O: → Sternum → Cartilage of the 4th-7th ribs
- I: cartilage of 2nd - 6th ribs
- N: intercostal n.
- F: Depression of the ribs
- B.S: Sternal branches of internal thoracic (branch of the subclavian).
⑤ Levatores costarum
B.S : Posterior intercostal art.