WEEK 10 (Thoracic muscles) Flashcards
What are the properties of Intercostal spaces?
- Lie between adjacent ribs and are filled by intercostal muscles
- Intercostal nerves and associated major arteries and veins lie in the costal groove along the inferior margin of the superior rib and pass in the plane between the inner two layers of muscles
- In each space, the vein is the most superior structure and is therefore highest in the costal groove. The artery is inferior to the vein, and the nerve is inferior to the artery and often not protected by the groove
What do intercostal nerves carry in the thorax?
- Somatic motor innervation to the muscles of the thoracic wall
- Somatic sensory innervation from the skin and parietal pleura
- Postganglionic sympathetic fibers to the periphery
Where do the posterior and anterior intercostal arteries originate from?
The aorta and internal thoracic arteries, which in turn arise from the SUBCLAVIAN ARTERIES
Lymphatic vessels of the thoracic wall drain mainly into lymph nodes of what?
- Internal thoracic arteries
- Head and necks of ribs
- Diaphragm
What are the different thoracic muscles?
- External intercostal
- Internal intercostal
- Innermost intercostal
- Subcostales
- Transversus thoracis
What is the function of the External intercostal muscle?
- Most active during inspiration
- Supports intercostal space
- Moves ribs superiorly
What is the function of the Internal intercostal muscle?
- Most active during expiration
- Supports intercostal space
- Moves ribs inferiorly
What is the function of the Innermost intercostal muscle?
Acts with internal intercostal muscles
What is the function of the Subcostales?
Depresses ribs
What is the function of the Transversus thoracis?
Depresses costal cartilages
What is the function of the Lavatores Costarum?
Elevates ribs
What is the function of the Serratus posterior superior?
Elevates ribs
What is the function of the Serratus posterior inferior?
Depresses ribs
What is the function of the Pectoralis Major?
- Flexion
- Adduction
- Medial rotation of arm at glenohumeral joint
What is the function of the Pectoralis Minor?
- Pulls tip of shoulder down
- Protracts scapula
What is the function of the Subclavius muscle?
- Pulls tip of shoulder down
- Pulls clavicle medially to stabilise sternoclavicular joint
What is the function of the Serratus Anterior?
- Protraction and rotation of the scapula
- Keeps medial border and inferior angle of scapula opposed to thoracic wall
What is the function of the Subscapularis?
- Rotator cuff muscle
- Medial rotation of the arm at the glenohumeral joint
What is the function of the Teres Major?
Medial rotation and extension of the arm at the glenohumeral joint
What is the function of the Latissmus dorsi?
- Adduction
- Medial rotation
- Extension of the arm at the glenohumeral joint
Describe the structure if the diaphragm
- C-shaped thin MUSCULOTENDINOUS STRUCTURE that fills the INFERIOR THORACIC APERTURE and separates the THORACIC CAVITY from the ABDOMINAL CAVITY
- Forms a dome between two cavities
- Superior surface becomes floor of thoracic cavity & inferior surface makes the roof of the abdominal cavity
- Anatomically, diaphragm is divided into RIGHT and LEFT HEMIDIAPHRAGM
- RIGHT HEMIDIAPHRAGM is HIGHER than the left due to the presence of the liver
What is the diaphragm attached peripherally to?
- Xiphoid process of the sternum
- Costal margin of the thoracic wall
- Ends of ribs XI and XII
- Vertebrae of the lumbar region
What is the Crura of the diaphragm?
Musculotendinous bundles that attach to the anterior surface of the vertebral column, intervertebral disc and the anterior longitudinal ligament
STRUCTURE:
Right crura is LONGER and Left crura is SHORTER;
Right and Left crura join together via the MEDIAN ARCUATE LIGAMENT
Where is the Central tendon of the diaphragm?
Point of convergence of the peripherally located muscles that make up the diaphragm