Thorax

• What are the muscles of the posterior thorax?

  Latissimus dorsi

  Serratus posterior superior

  Serratus posterior inferior

  Levatores costarum
• What are the actions of the muscles of the posterior thorax?

  Stabilises thoracic cage

  Accessory muscles of respiration
• What is the action of latissimus dorsi?

  When arm is fixed, elevates ribs 9-12 during deep inspiration
• What is the action of serratus posterior (both superior & inferior)?

  Accessory muscles of respiration

  Superior

  • elevates ribs during inspiration

  Inferior

  • depresses ribs during expiration
• What is the action of levatores costarum?

  Elevate ribs during respiration

  Stabilises ribs against vertebral column
• What are the muscles of the anterior thorax?

  Pectoralis major

  Pectoralis minor

  Serratus anterior

  Rectus abdominis

  External oblique
• What is the action of the pectoralis major & minor?

  Major

  • expands thoracic cage when arms are fixed

  Minor

  • deep inspiration -> lifts chest up & out
• What is the action of serratus anterior?

  Stabilises thorax & accessory muscles of respiration
• What is the action of rectus abdominis?

  Depresses ribs during expiration

  Flexes trunk
• What is the action of external oblique?

  Assists during forced expiration

  Rotates trunk
• What are the intercostals? What part of respiration do they aid in?

  External -> inspiration

  Internal -> expiration

  Innermost -> expiration
• What is the main muscle of respiration?

  Diaphragm
• What are the muscles situated within the thoracic cage? What are their actions?

  Transversus thoracis -> depresses ribs & costal cartilages

  Subcostal muscle -> depresses ribs, opposes levatores costarum
• Fill in the blanks

  A) Subcostal

  B) Transversus thoracis

  
• Where are the breasts?

  Lateral border of sternum -> mid-axillary line

  2nd-6th costal cartilages
• What are mammary glands? What do they drain into?

  Modified sweat glands

  Series of ducts & lobules

  Drain into lactiferous ducts -> converge at the nipple
• Where is the thymus located?

  Deep to manubrium

  NOTE: Becomes redundant & degenerates after puberty and becomes replaced by fat