Osteology of the thorax - articulated thoracic skeleton, sternum and thoracic cage (dave's notes) Flashcards
What angle do the ribs slope at?
45’, extending out progressively lateral
Describe the anterior ends of the ribs
These fall progressively short of the midline, supplemented for by longer costal cartilages.
What makes up the sternum?
Main body, manubrium and xiphoid process
What is the joint between the manubrium and main body?
A secondary cartilaginous joint which rarely ossifies. NB a demifacet on the 2nd costal cartilage.
What does the xiphoid process represent?
The unossified lower end of the body. May ossify later in life.
Describe the ossification of the sternum.
Variable primary centres of ossification that appear in the 5th foetal month in 4-5 row. These fuse by 25 whats???
List the muscular attachments to the thoracic cage
Pectoralis major Serratus anterior Pectoralis minor External oblique Rectus abdominus Internal oblique Transversus abdominus Serratus posterior Scalene muscles Quadratus lumborum Lat dorsi The diaphragm
The costal artilages are higher than the vertebrae. At what level is the jugular notch? The sternal angle? The lower border of the sternum?
T3
T4
T8
What is the thoracic attachment of pectoralis major?
The upper 6 costal cartilages
What is the thoracic attachment of serratus anterior?
The upper 8 ribs
What is the thoracic attachment of pectoralis minor?
Ribs 3-5
What is the thoracic attachment of external oblique?
From the anterior angles of the lower 8 ribs, interdigitating with lat dorsi below serratus anterior to the lower four
What is the thoracic attachment of rectus abdominus?
To the anterior surface of the 5th to 7th costal cartilages
What is the thoracic attachment of internal oblique?
The lower borders of the last 6 costal cartilges
What is the thoracic attachment of transversus abdominus?
Transversus abdominus and the diaphragm interdigitate on the inner surface of the lower 6 ribs
