Thorax 02: Thoracic wall Flashcards
Where does the body wall of the thoracic wall derive from?
Somites
Where do the ribs and sternum derive from?
Scleretome
Where do the intercostal muscles derive from?
Myotome
Mediastinum
The central compartment of the thoracic cavity surrounded by loose connective tissue, containing the heart, vessels, aorta esophagus, and trachea; extends from the superior thoracic aperture to the diaphragm
Pulmonary Cavities
A set of two cavities lateral to the mediastinum that contain the lungs, pleural sacs, arteries, veins, and bronchi
Inferior thoracic aperture
Diaphragm; lowest point of the mediastinum
Sternal Angle
The junction between the sternum manubrium and sternum body that levels off; it divides the mediastinum into superior and inferior
Superior mediastinum
The mediastinum between the superior thoracic aperture and the strernal angle
Inferior mediastinum
The mediastinum between the sternal angle and the inferior thoracic aperture; subdivided into anterior, middle and posterior mediastina
Ribs
Bones that articulate from the thoracic vertebra and into the sternum
Costal cartialge
The cartilage that connects the rib bone to the sternum
Intercostal muscles
Muscles that run between ribs; divided into external, internal, and innermost
What nerve innervates hypaxial muscle?
Ventral ramus
What nerve innervates epaxial muscle?
Dorsal ramus
Subcostalis
Muscle fibers that run in the same direction as internal intercostal muscles
Transversus thoracis
4 or 5 muscular slips arise from the xiphoid process and inferior part of the sternal body, run superolaterally to insert on the upper costal cartilages. Located anteriorly
Manubrium
The top part of the sternum, running up until the sternal angle
Sternal body
The middle section of the sternum
Xiphoid process
The bottom part of the sternum that sticks out
What is another name for the sternal angle?
Angle of Louis
Jugular notch
A notch at the top of the sternal manubrium; also known as the suprasternal notch
Intercostal nerve
Ventral ramus, because it runs through intercostal muscle (in a layer between inner and innermost)
Cutaneous branch
Branches of the intercostal nerve that branch up to the skin; there are lateral branches and anterior branches
Where do almost all of the thoracic veins drain to?
Superior vena cava
Intercostal artery
The artery that runs along the intercostal muscles; posterior and anterior joined by anastomosis
Superior Thoracic aperture
Top of the thorax and the neck, up to the top of the sternum
What structures traverse the superior thoracic aperture?
Esophagus, trachea, left carotid and subclavian arteries, lungs, brachiocephalic trunk, Sympathetic trunks, vagus nerve, recurrent laryngeal nerve, phrenic nerves, cervical cardiac nerves, brachiocephalic veins
Thoracic outlet syndrome
Compression of brachial plexus of nerves
What are the three locations structures can pass through the inferior thoracic aperture?
T8, T10, T12
What structures pass through the inferior thoracic aperture at T8
(Caval opening) IVC, branches of rt. phrenic n.
What structures pass through the inferior thoracic aperture at T10
(Esophageal hiatus) Esophagus, lymph channels, branches of lt. gastric vessels
What structures pass through the inferior thoracic aperture at T12
(Aortic hiatus) Aorta, thoracic duct, azygos v.
What vertebral marks is the sternal angle plane?
T4/T5
Mammary glands
Modified sweat glands embedded in the superficial fascia of the anterior thoracic wall
Secretory tubuloacinar mammary glands
Ducts and acini with columnar and cuboidal cells and myoepithelial cells
interlobular and intra-lobular CT of mammary glands
Fibroblasts, blood vessels, lymphatics, inflammatory cells, ECM
Nipple
The point where the lactiferous ducts of all the lobules converge
Lactiferous sinus
Dilation of the ducts just deep of the nipple
Areola
Circular pigmented tissue around the nipple, has sebaceous areolar glands
Are inverted nipples a sign of cancer?
If it appear de novo; otherwise, it is normal
Axillary tail
a superolateral extension of the mammary gland that reaches the armpit
What are the two layers of the lactiferous ducts
Tall columnar and myoepithelial (produces laminin)
How does breast tissue change with the menstrual cycle?
Lumen becomes more prominent late in cycle
How does breast tissue change with pregnancy?
New ductal branch points and lobules form
How does breast tissue change with age?
interlobular stroma becomes more adipose, glandular tissue involutes
Clockface regions of the breast
12/3/6/9. 3 is medial on right breast but lateral on left breast. Vice versa with 9
Quadrants of the breast
Breast divided into upper, medial, lower, lateral. Quadrants are defined from there
Retromammary space
Loose connective tissue plane that separates the breasts from deep fascia of the underlying muscles
Peau d’orange
A type of edema which gives breasts an orange-like look (like the fruit); supersensory ligaments prevent uniform swelling
What supplies blood to the lateral mammary tissue?
Lateral thoracic arteries/axillary arteries
What supplies blood to the medial mammary tissue?
Medial thoracic arteries/subclavian arteries
How is breast cancer staged?
The lymph nodes invaded relative to pectoralis minor
External Intercostal membrane
Replaces external intercostal muscles between the costochondral junction and the sternum
Internal intercostal membrane
Replaces internal intercostal muscles between the angle of the ribs and the vertebral column
Subcostalis
Muscles fibers that cross two intercostal spaces near the spinal cord and run in the same direction as internal intercostals
Transversus throacis
4-5 anterior muscles that originate from the xiphoid process and run superiolaterally to insert in the upper costal cartilages
What are the three throacic nerves?
Greater splanchnic nerve, lesser splanchnic nerve, least splanchnic nerve. They are in order from inside to outside
Posterior intercostal artery
Intersegmental artery + ventral ramus
Internal thoracic artery
An artery that runs longitudinally down the rib cage that supplies the anterior chest walls and breasts
Anterior intercostal arteries
Supply the upper 5 or 6 intercostal spaces
What nerves supply breast tissue?
Anterior and lateral cutaneous branches of 4th – 6th intercostal nerves
What are the three stages of breast cancer?
Level 1: lateral to pec minor
Level 2: deep of pec minor
Level 3: medial to pec minor
What four main structures are found at the sternal angle?
1) beginning and end or aortic arch
2) SVC enters the pericardial sac
3) Tracheal bifurcation
4) Pulmonary trunk bifurcation
What are the two inferior branches of the internal thoracic arteries?
1) Musculophrenic arteries
2) Superior epigastricarteries
Where do the intercostal neurovascular bundles of each thoracic segment travel with respect to the ribs?
Inferiorally to the respective rib in the costal groove
What is the arrangement of neurovascular bundles?
Vein, artery, nerve
What are the three general layers of tissue in the breast?
1) Mammary glands
2) Interlobular and intralobular connective tissue
3) Superficial fascia, fat, and skin
Subareolar plexus
The lymphatic plexus that anatomoses with the contralateral breast
