Anatomy of the thorax Flashcards
Blood flow to areas of the heart
LAD: left atrium, ventricle and IVS
Left circumflex: Left atrium and left ventricle
Left marginal: Left ventricle
RCA: Right atrium and ventricle
Right circumflex: Right ventricle and apex
What are the deep muscular relations of the breast
Pec major and serratus anterior
The lower medial edge just overlaps the upper part of the rectus sheath
How many lobules does the breast tissue have
15-20 lobules within the breast, each extends into the lactiferous duct and they all converge to the nipple
The lactiferous sinus acts as a reservoir and it lies beneath the areola
What are the coopers ligaments
Fibrous septa which extend from the subcutaneous tissue to the fascia of the chest wall (the pectoralis fascia)
These are responsible for the peau d’orange. invasion of the axillary lymphatics by tumour causes obstruction and subsequent oedema of the overlying skin. Parts of the skin that are tethered to the coopers ligaments appear as dimples. Hence, giving the appearance of an orange peel
What is the blood supply to the breast
Internal thoracic which is a branch of the subclavian
lateral thoracic which is a branch of the 2nd part of the axillary artery
Thoracoacromial artery which is a branch of the 2nd part of the axillary artery
Intercostal artery
What is the sensory innervation of the breast
4th to 6th intercostal nerves provides sensory and autonomic innervation
Where should a subclavian line catheter tip be
In the SVC and above the pericardial reflection
Describe the anatomy of the neurovascular bundle
Superior to inferior it is VAN in the intercostal groove
What is the superior limit of the pleura
The pleura projects 2.5cm above the middle third of the clavicle
What is the role of the thymus
important for the maturation of T cells and also releases hormones involved in T cell proliferation.
It atrophies after puberty
What ribs are considered atypical
1,2,10,11,12
The first is short and wide and has a single facet and the scalene tubercle
The second is thinner and longer and has a tuberosity on its upper surface for attachment with the serratus anterior
The 10th has only a single facet
11 and 12 also have single facets with no neck
What is the lymph drainage of the breast
What are the surface markings of the heart
Inf: 5th intercostal space midclavicular line on the left to the 6th costal cartilage on the right
Sup: 3rd costal cartilage on the right to the second intercostal space 2cm on the left of the sternum
What chambers of the heart form its boundaries
How many layers does the pericardium have
3 layers
Outer fibrous
Inner serous parietal and visceral layers
Where do the LCA and RCA arise from
From the aortic sinuses, there are 3
the LCA comes from the left and the left posterior AS
the RCA comes from the right coronary sinus
What is the venous drainage of the heart
Great, middle and small cardiac veins as well as the oblique and posterior veins. This forms 2/3rd of the venous drainage
The remaining 1/3rd is from venae cordis minimae and drain into each individual chamber.
The coronary sinus opens on the inferior border of the right atrium between the IVC and the tricuspid valve
What is the anatomically safe insertion site of the chest drain
Anterior: Posterior border of the pec major
Posterior: Midaxiallary line
Superior: Apex
Inferior: Line drawn above the 6th rib
Then put a needle in the 5th intercostal space above the 6th rib just anterior to the mid-axillary line.
What is the arterial blood supply of the chest wall
Posterior intercostals: 1 and 2 are supplied by the superior intercostal which is a branch of the costocervical trunk of the subclavian artery. Lower 9 are supplied by branches of the descending thoracic aorta
Anterior: Arises from the internal thoracic (1-6), superior and lateral and thoracic. Muscolophrenic artery supply 7-9.
Subcostal supplies spaces beneath the 12th rib
venous drainage of the thorax
Follows the arteries normally. Anterior is drained into the internal thoracic vein and the BCV and then the SVC. Posterior is azygous venous system.
Define thoracic outlet syndrome
Compression of the subclavian vessels or branches of the brachial plexus as they pass from the thorax into the arm
What are the clinical features of thoracic outlet syndrome
Nervous such as pain, parasthesia, muscle weakness
Arteries: Ischemia UL and emboli
Venous: Swelling UL
What are soem causes of thoracic outlet syndrome
cervical rib, fibrous band, malignancy, trauma
What are the contents of the superior mediastinum
Muscles: Sterno thyroid and sternohyoid
Vessels: Aortic arch, BCV, LCC and LSC, BC and SVC
Nerves: Phrenic, vagus and left recurrent laryngeal
Viscera: Oesophagus and trachea
Others: Thoracic duct, thymus and lymph nodes
What are the contents of the posterior mediastinum
Vessels: Thoracic part od descending aorta and azygous veins
Nerves: Vagus and splanchnic
Viscera: Oesophagus
Others: Lymph nodes and thoracic duct
What are the contents of the middle mediastinum
Vessels: Ascending aorta, lower half of SVC, azygous vein and pulmonary artery and veins
Nerves: Phrenic
Viscera: heart and pericardium
Others: Bronchial lymph nodes
SUbclavian steal syndrome
Patients have the steno-occlusive nature proximal to the origin of the vertebral artery, Hence the retrograde flow.
Can lead to ischemia of thee upper limbs and symptoms of dizziness, vertigo, syncope and other symptoms of potential vertebrobasilar insufficiency.
What type of joint is the manubrium sternii
Secondary cartilagenous joint
What important anatomical structures lie at the manubriosternal joint
SVC entering right atrium
Bif of trachea and pulmonary trunk
Arch of aorta
What are the surface markings of the pleura
It starts at the midclavicular line, then runs along the sternal edge up to the 6th rib, then 8th rib midclav line, then 10th mid ax line and then 12th post ax line
Surface marking of the horizontal fissure
4th intercostal space
Surface marking of oblique fissure
Hands-on head, line drawn from T3 to the lateral sternal border 6th rib along the medial scapular border