Week 1 - Thoracic Osteology Flashcards
Identify the main features & functions of the thoracic cavity - A typical rib - First rib - Sternum - Thoracic vertebrae (alongside cervical & lumbar) Describe how the ribs articulate with the vertebrae and the sternum, and understand the movement the movements which occur at these joints
Structure of Thoracic Vertebrae
Body
Vertebrae Foramen
Laminae
Articular Processes
Types of ribs
True
False
Floating
Typical Ribs
Head has 2 articular facets
Neck
Body is thin flattened and curved
which ribs are atypical ribs?
Ribs 1, 2, 10, 11, & 12
Why is Rib 1 atypical?
Shorter & wider with only 1 facet for articulation with its corresponding vertebrae
The superior surface is marked by two grooves, whcih make way for the subclavian vessels
Why is Rib 2 atypical?
Longer and thinner than rib 1
Two articular facets on the head as “normal”
Why is Rib 10 atypical?
Only has one facet for articulation with its numerically corresponding vertebrae
Why is Rib 11 & 12 atypical?
Have no neck & only contain one facet
What are the muscles located within the intercostal space?
- External intercostal muscles
- Internal intercostal muscles
- Innermost intercostal muscles
- Pectoralis major
- Pectoralis minor
What does the term ‘intercostal’ mean?
Between ribs
What is the function of the external intercostal muscles?
Lifts the rib to increase lung volume
What are the characteristics of the external intercostal muscle?
- Most superficial muscle
- Fibers directed downward & forward
- Extends from rib tubercle to costochondral junction
What is the origin and insertion of the internal intercostal muscle?
- Origin: Inferior margin of costal cartilage and inner lip of costal groove
- Insertion: Superior border of the rib below
What is the role of the intercartilaginous internal intercostal muscles?
Elevates the ribs
Which artery is known as the internal thoracic artery?
Arises from the first part of the subclavian artery
At which intercostal space does the internal thoracic artery divide?
Sixth intercostal space
What are the main branches of the internal thoracic artery?
- Superior epigastric artery
- Musculophrenic artery
What is the significance of intercostal nerves?
Supply intercostal muscles, skin of the anterolateral chest, and abdominal wall
True or False: The intercostal nerves arise from the anterior rami of thoracic spinal nerves T1 to T11.
True
What is the function of the collateral branch of the intercostal nerve?
Runs parallel to the main nerve on the upper border of the rib below
What is the purpose of an intercostal nerve block?
Deliver anesthetic agent to the nerve
Fill in the blank: The _______ and _______ intercostal arteries supply the upper six intercostal spaces.
Anterior intercostal arteries, internal thoracic artery
What do posterior intercostal veins drain into?
- Brachiocephalic vein
- Superior intercostal vein
- Azygos vein
- Hemiazygos vein
What is the thoracic inlet?
The superior opening of the thoracic cage
What are the boundaries of the thoracic inlet?
- Anterior: Suprasternal notch of the manubrium
- Lateral: First rib
- Posterior: 1st thoracic vertebra
What is the thoracic outlet?
The inferior opening of the thoracic cage
What are the boundaries of the thoracic outlet?
- Anterior: Xiphoid process
- Lateral: Lower six costal cartilages and last two ribs
- Posterior: Last thoracic vertebra
True or False: The diaphragm closes the thoracic outlet and separates it from the abdominal cavity.
True
What is the role of the transversus thoracis muscle?
Originates from the xiphoid process and body of sternum and inserts into the 2nd to the 6th rib
What is the innervation pattern for the thorax?
Ventral rami T1-T11 (intercostal and T12 subcostal nerves)
What are the main components of thoracic osteology?
Ribs, sternum, thoracic vertebrae
Includes features and functions of each component.
How many thoracic vertebrae are there?
12 thoracic vertebrae
What are the three categories of ribs?
True, False, Floating
What characterizes a typical rib?
Head with 2 articular facets, neck with a facet for transverse process, thin/flattened body, costal groove
Typical ribs articulate with corresponding vertebrae and the vertebrae above.
Which ribs are considered atypical?
Ribs 1, 2, 10, 11, & 12
What is unique about rib 1?
Shorter and wider with only 1 facet for articulation
The superior surface has two grooves for subclavian vessels.
What distinguishes rib 2 from rib 1?
Longer and thinner with two articular facets on the head
What is the characteristic of ribs 11 and 12?
Have no neck and only contain one facet
What is the embryologic origin of thoracic vertebrae?
Costal elements form ribs
What is a cervical rib?
A costal element of C7 that forms a rib, found in 1% of people
What are homologous structures?
Structures in different animals with a common developmental origin
May have different functions or become vestigial.
What are the main parts of the sternum?
Manubrium, body, xiphoid process
What type of joint is the costovertebral joint?
Synovial joint
What articulates at the sternocostal joint?
Costal cartilages (I-VII) and the sternum
What muscles are involved in quiet breathing?
Diaphragm and external intercostal muscles
Fill in the blank: During forceful breathing in, the _______ muscles contract.
accessory
What happens to the diaphragm during quiet breathing?
Contracts and dome lowers
How do the ribs, vertebrae, and sternum function together?
They move in conjunction to aid respiration
True or False: Ribs vary in features and functions.
True
