37 - Thoracic Walls Flashcards
Tissue types in the breast 1) 2) 3) 4) 5) 6)
1) Glandular 2) Fibrous 3) Adipose 4) Blood vessels 5) Nerves 6) Lymphatics
Anatomical delineation of breast
From lateral border of sternum to mid-axillary line From second to sixth rib.
Name for elongated part of breast towards armpit
Superolateral extension or axillary tail
Why are most carcinomas of the breast found in the upper outer quadrant?
Because this quadrant has the most glandular tissue, because of the axillary tail of the breast.
Muscles that breast overlies
2/3 of breast overlies pec major 1/3 of breast overlies serratus anterior
How do breasts sit against torso?
Retro-mammary space separates breast and underlying muscle. This is where breast implants can be inserted.
Blood supply of breasts 1) 2) 3)
1) Medial breast gets branches from internal thoracic arteries. 2) Superior aspect of breast gets branches from lateral thoracic artery, which is a branch of axillary artery, which is from the subclavian artery. 3) Lateral breast gets branches from posterior intercostal.
Blood supply of medial breast
Medial breast gets branches from internal thoracic arteries.
Blood supply of superior lateral breast
Superior aspect of breast gets branches from lateral thoracic artery, which is a branch of axillary artery, which is from the subclavian artery.
Blood supply of lateral breast
Lateral gets branches from posterior intercostal arteries (lateral mammary branches)
Venous drainage of breasts 1) 2) 3)
1) Medial - Internal thoracic vein 2) Lateral - Lateral mammary vein, which drains to lateral thoracic vein, which drains to axillary vein, which drains to subclavian vein
Lymphatic drainage of breasts 1) 2) 3)
Drain to: 1) Axillary 2) Intercostal 3) Parasternal lymph nodes
Components of sternal complex 1) 2)
1) Manubrium (superior) 2) Sternum (inferior)
Ribs whose costal cartilage articulate with sternal complex
Upper 7 ribs
Ribs whose costal cartilage join costal cartilage of rib immediately superior
Ribs 8, 9 and 10
Ribs whose costal cartilage doesn’t articulate with anything
Ribs 11 and 12 (floating ribs)
Description of two articular facets of tuberculae
Medal facet is smooth, articular. Lateral facet is rough, attachment for ligament of intercostal muscle
Which part of rib are the tuberculae near?
Vertebral end (near head with articular facets
Number of articular facets on vertebral head of rib
Two (both smooth)
Orientation of rib bodies
Almost vertical (therefore have superior and inferior aspects)
Structures on inferior border or ribs
Costal groove. Contains (in superior to inferior order) intercostal vein, intercostal artery, intercostal nerve
Shape of first rib 1) 2) 3)
1) Shorter, more curved, flatter than other ribs. 2) Very deep groove for subclavian vessels. 3) Single articular facet on head, as only articulates with T1 vertebra.
Defining characteristics of T vertebra 1) 2)
1) Facets on body and transverse processes for ribs. 2) Long, almost vertical spinous process 3) Body has articular facets for ribs on posterolateral superior and inferior surfaces.
How do ribs join to vertebrae?
Join two adjacent vertebrae.
Name for joints between ribs and vertebrae
Costovertebral joints and costotransverse joints
Which parts of vertebrae do ribs attach to?
To body at costovertebral joints. To transverse processes at costotransverse joints.
Costotransverse joints
Ribs join transverse process with a three-part costotransverse ligament
Can ribs be dislocated from vertebral column?
No. Rib will break before costotransverse or costovertebral joints break
Locations of apertures of thorax 1) 2)
1) Superior aperture is bounded by rib 1. 2) Inferior aperture is bounded by rib 12 posteriorally, rib 11 and 12 laterally, costal cartilage of ribs 7-10 anteriorally, xiphoid body.
Superior aperture of thorax 1) 2) 3)
1) Bounded by rib 1. Runs around interior aspect of rib 1. 2) Covered by supra-pleural membrane (or Sibson’s fascia) 3) There is an opening for airways, etc.
Inferior aperture of thorax 1) 2)
1) Bounded by diaphragm.
2) Lateral and medial arcurate ligaments are posterior baoundaries.
3) Bounded laterally by ribs 11 and 12.
4) Bounded anteriorally by costal cartillage of ribs 7-10, and xiphoid process
Lateral and medial arcurate ligaments 1) 2) 3)
1) In inferior aperture of thorax. 2) Lateral arcurate ligament overlies quadratus lumborum 3) Medial arcurate ligament overlies psoas
Diaphragm anatomical delineation 1) 2) 3)
1) Posterior - Rib 12 2) Lateral - Rib 11 and 12 3) Anterior - Costal cartilage of ribs 7-10
How does the diaphragm attach to vertebrae?
With right and left cruses. Right crus joins to L1, L2, L3. Left crus joins to L1, L2
Origin and insertion of diaphragm
Circumferential origin. Central insertion.
Shape of diaphragm
Two domes. Right dome is higher than left
Objects passing through diaphragm 1) 2) 3)
1) Oesophagus passes through muscular diaphragm, about at midline at T10. 2) IVC passes through central tendon right of midline at T8 3) Aorta passes behind diaphragm between crura at T12, slightly left of midline
Vertebra where oesophagus passes through diaphragm
T10
Vertebra where IVC passes through diaphragm
T8
Vertebra where aorta passes behind diaphragm
T12
Innervation of diaphragm
Left and right phrenic nerves innervate respective domes of diaphragm
Layers of intercostal muscles
1) External intercostal 2) Internal intercostal 3) Innermost intercostal
Direction of muscle fibres in external intercostal muscle
Downwards, forwards (‘front pocket muscles’)
Function of external intercostal muscles
When contract, elevate and expand ribcage. Involved in inspiration.
Makeup of external intercostal muscles
Muscle on posterior and lateral aspects. Intercostal membrane on anterior aspect
Direction of muscle fibres in internal intercostal muscles
Downwards, outwards (‘back pocket muscles’)
Makeup of internal intercostal muscles
Anterior, lateral aspects are muscular. Posterior aspect is intercostal membrane
Function of internal intercostal muscles
Stabilise ribs during movement
Direction of muscle fibres in innermost intercostal muscles
Downwards
Distribution of innermost intercostal muscles
Mostly lateral. Some on posterior and anterior, but not many
Where does neurovascular bundle in costal groove run relative to intercostal muscles?
Lies between internal and innermost intercostal muscles
What does the neurovsacular bundle in costal groove supply?
Supplies rib inferior to rib in which groove runs. Can have collateral branches to supply superior rib (these are smaller than main branch)
When inserting an intercostal needle, where do you insert it?
At inferior part of intercostal space. Better to hit smaller, less vital collateral branches of neurovascular bundle than main neurovascular bundle (which is at the superior part)
Innervation of ribs
Anterior ramus of thoracic spinal nerve becomes intercostal nerve. Intercostal nerve innervates anterior skin, collateral nerves supply posterior and lateral skin.
Dimensions of thorax that change during inspiration
Vertical, lateral, anterior-posterior directions
Muscles of respiration
Any muscle attaching to ribs can potentially affect respiration. (EG: sternocleidomastoid, scalenes, abdominal muscles)
How can anterior-posterior dimensions of thorax be changed?
Elevate upper 7 ribs.
