Thorax introduction (ribs, sternum, muscles) Flashcards
What is the trunk?
What’s left after removing the head, neck, tail, and limbs
What cavities are part of the trunk?
- Thoracic cavity
- Abdominal cavity
- Pelvic cavity
What are cavities lined with?
All cavities are lined with mesothelium
Importance of thorax in terms of systems, diagnosis, and treatment
Systems- cardiovascular system, respiratory system
Diagnosis- auscultation (stethoscope), radiographs, percussion (listening for resonance)
Treatment- centesis
Thoracic cavity
Cranial-most body cavity; cranial to diaphragm
Pleural cavity
2 (right or left) within the thoracic cavity which hold the lungs
Thoracic cage
Area within the ribs, above sternum, and below vertebral column
“space embraced by rib cage”
Thoracic cavity varies between species
Ex. Pug vs. greyhound
Greyhound has larger lung capacity and is faster because more sleek and narrow (less muscle)
Looking at outlines of the thoracic cavity
The outlines of the back, sternum (brisket), and costal arch do not equal the thoracic cavity because the diaphragm extends cranially into area encased in rib cage
What changes the size of the thoracic cavity
- Musculature of the forelimb
- Shape of the diaphragm
Diaphragm
Concave dome muscle within rib cage occupied by abdominal viscera (not thoracic viscera)
Important for separation of thorax and abdomen, and is the muscle for respiration
The effect of the Musculature of forelimbs on the thoracic cavity
Limb strength is a function of area whereas respiratory capacity is a function of volume.
Therefore larger animal will have a larger proportion of musculoskeletal tissue and lungs will be much smaller.
Ex. Lungs of dog relatively much larger than that of the horse and cow
Mediastinum
Middle wall separating the right and left pleural cavities
Why is the mediastinum shifted to the left?
The right lung has an extra lung lobe (3 instead of 2)
Movement of diaphragm and ribs during inspiration
- Ribs move cranially
- Diaphragm moves caudally
Ribs
Arranged in pairs and articulate with 2 successive vertebrate
Two parts that meet at costochondral junction:
1. Bony dorsal part= rib proper
2. Cartilaginous ventral part= costal cartilage
Numerical designation of ribs and vertebra
Caudal vertebra and rib will have the same numerical designation
Costochondral junction
Connection between the rib and its costal cartilage
Articulations of the ribs
- Dorsal part of rib articulates with vertebral column
- Ventral cartilaginous part articulates with the sternum (directly by true ribs, and indirectly by false ribs)
- Costal arch- the caudal ribs cartilaginous part will form the arch
Costal arch
Combination of the cartilages of the false ribs