Thoracic Wall Flashcards
How many pairs of ribs do we have and what do they all articulate with
12 and they all articulate with the thoracic vertebrae
What does the thoracic cage contain
- Ribs and costal cartilage
- Sternum
- Thoracic vertebrae
- Pectoral girdle
What are the boundaries of the superior thoracic aperture
- Body of T1
- 1st pair of ribs and costal cartilages
- Superior body of the manubrium
What are the boundaries of the inferior thoracic aperture
- Body of T12
- 11th and 12th pairs of ribs
- Costal cartilages of ribs 7-10 (costal margin)
- Xiphisternal joint
What vertebra/vertebrae does the head of the 7th rib articulate with
T6 and T7
What vertebra/vertebrae does the tubercle of the 7th rib articulate with
T7
What are the true ribs and describe their connection to the sternum
1-7 and they connect directly via their own costal cartilage
What are the false ribs and describe their connection to the sternum
8-10 and they connect indirectly via costal cartilage of the ribs above
What are the floating ribs and describe their connection to the sternum
11 and 12 and they have no connection
What are the typical ribs
3-9
What are the atypical ribs
1, 2, and 10-12
Describe the appearance of a typical rib head
Wedge shaped; contains 2 articular facets separated by crest
What does the head of a rib articulate with
Body of its own vertebra and of the vertebra above, and with the IV disc via the crest
What does the tubercle of a rib articulate with
Transverse process of their own vertebra
What is the costal angle
The most curved part of the body of the rib
Where is the costal groove located and what does it provide
Inferior and posterior part of the bone; provides protection for neurovascular structures
Describe the common difference in the 1st, 10th, 11th and 12th ribs
Contain a single facet as they only articulate with one vertebra each
What is a difference in the 2nd rib
Contains a tuberosity for the serratus anterior muscle
Describe the difference in just the 11th and 12th ribs
They are short with no neck or tubercle
What are the 3 parts of the sternum
- Manubrium
- Body
- Xiphoid process
What are the joints in the sternum
- Manubriosternal (sternal angle)
2. Xiphisternal
What rib attaches at the sternal angle
2nd
What rib attaches at the xiphisternal joint
7th
What joint forms between the vertebral bodies and what does it allow
A secondary cartilagenous joint; allows bodies to move against one another (IV disc)
What joint forms between the articular facets of the vertebra and what does it allow
A synovial plane joint (zygapophysial joint); allows for a lot of lateral rotation
Describe the different sternocostal joints
- Primary cartilagenous joint in rib 1
2. Synovial plane joints in ribs 2-7
Describe the different interchondral joints
- Synovial plane joints between ribs 6&7, 7&8 and 8&9
- Fibrous joint between ribs 9&10
What are the different respiratory movements in the ribs, and which ribs complete which movement
- Ribs 1-6 = pump handle movement
2. Ribs 7-12 = bucket handle movement
Describe the movement of the upper ribs
Happens anteriorly at the distal end of the ribs, anterior to the sternum; ribs move up and out
Describe the movement of the lower ribs
Occurs more laterally; ribs flare outwards
Describe the changes in dimension of structures during respiratory movement
- Sternum moves anteriorly and superiorly
- Lower ribcage moves laterally
- Diaphragm descends
What are the main thoracic wall muscles involved in respiratory movements
- Intercostal
- Subcostal
- Transversus thoracis
What are the secondary muscles involved in respiratory movements
- Scalene
2. Serratus posterior (superior and inferior)
What are the superficial muscles involved in respiratory movements
- Pectoral
- Serratus anterior (attachment to the 2nd rib)
- External oblique
- Rectus abdominis
Name the 5 upper limb and anterior abdominal wall muscles
- Pectoralis major
- Pectoralis minor
- External oblique
- Serratus anterior
- Rectus abdominis
Describe the attachment of the pectoralis major
Very broad attachment along the sternum and the ribs; distal attachment to the humerus
Describe the attachment of the pectoralis minor
Attaches to some of the ribs and the coracoid process of the scapula
Name the 5 posterior thoracic wall muscles
- Anterior scalene
- Middle scalene
- Posterior scalene
- Serratus posterior superior
- Serratus posterior inferior
What are the 3 layers of intercostal muscle (starting with the most superficial)
- External intercostal
- Internal intercostal
- Innermost intercostal
Describe the orientation of the external intercostal muscles and where they attach
- Fibres pass downwards and forwards
2. Attach to tubercles of ribs to costochondral junction
What is the function of the external intercostal muscles
They raise the ribs in inspiration
Describe the orientation of the internal intercostal muscles and where they attach
- Fibres pass downwards and backwards
2. Attach from the sternum to the angle of the ribs
What is the function of the internal intercostal muscles
- Interosseous part depresses the ribs
2. Interchondral part raises the ribs
Describe the orientation of the innermost intercostal muscles and where they are located
- Fibres pass downwards and backwards
2. Deep to the lateral part of the internal intercostal muscles
Where are the subcostal muscles located and how far do they span
- Near the angle of the ribs
2. Spans 1 or 2 intercostal spaces
Where does the transversus thoracis muscle span
Radiates from the sides of the sternum to costal cartilages 2-6
Where is the neurovascular plane located between the ribs
Between the internal and innermost muscles
What is the arrangement of vessels and nerves in the intercostal space
Intercostal 1. Vein (superior) 2. Artery 3. Nerve (inferior) run in the costal groove
Where do the posterior intercostal arteries originate from
The thoracic aorta; apart from 1 and 2
What does the anterior thoracic arteries supply and where does it originate from
- The anterior region of the thoracic cavity
2. The internal thoracic artery
Describe where the first 2 posterior intercostal arteries originate from
The supreme intercostal artery; branch of costocervical trunk from the subclavian artery
What does the superior epigastric artery supply
The anterior abdominal wall
Describe the anterior venous drainage system
Anterior intercostal veins -> internal thoracic vein -> brachiocephalic vein
Describe the posterior venous drainage system
Posterior intercostal veins -> azygous venous system -> superior vena cava
Where does the breast tissue anchor on the thoracic wall
At the connective tissue of the overlapping pectoral muscle
What nodes does the majority (75%) of lymph drain to from the breast
Axillary lymph nodes
Where does less than 25% of lymph drain to from the breast
Parasternal nodes and some to the abdominal nodes
Describe the venous drainage in the breast
Through the medial and lateral mammary veins
What vessels originate from the lateral thoracic artery that supply the breast
Lateral mammary branches
What vessels originate from the internal thoracic artery that supply the breast
Medial mammary branches
