Week 11: Cardiorespiratory Care - Clinical Anatomy Flashcards
What level of vertebra is said to be heart shaped?
thoracic vertebra.
The vertebral foramen is surrounded by how many pedicles and laminae?
The vertebral foramen is surrounded by two pedicles and two laminae
At what vertebral level do the spinous process projects posteriorly (they are long and slope downwards)?
thoracic vertebra.
On thoracic vertebrae, the superior articular facets are flat and face directly posteriorly, while the inferior articular facets face anteriorly.
What movement(s) does this vertical orientation limit? What movement(s) does it help facilitate
Limits flexion and extension of the vertebral column, but facilitates rotation.
On thoracic vertebrae, how many demifacets does a typical vertebral body have? What articulates at these demifacets?
4 total: 2 demifacets on each side of the vertebral body (a superior and inferior costal facet) for the ribs to articulate.
thoracic vertebrae - Look at the transverse process of the vertebra and the articular facet there – what specific portion of the rib articulates at this area?
Tubercle of the rib.
What three anatomical structures can be found in the costal grooves?
Intercostal vein, artery and nerve.
Which rib articulates at the manubriosternal joint?
2nd rib
Fill in the blanks with the words inferior or superior.
Rib 5 articulates with the ____ costal facet of Vertebra 5 and the ______ costal facet of Vertebra 4.
superior
inferior
What forms the boundaries of the superior thoracic aperture?
T1 vertebral body, Rib 1, and the superior manubrium
What forms the boundaries of the inferior thoracic aperture?
T12 vertebral body, Rib 12, distal end of rib 11, cartilaginous ends of ribs 7-10, and xiphoid process. It is closed by the muscular diaphragm.
When you take a breath in, the dimensions of the thorax change. As the diaphragm contracts, it descends, and this increases the vertical dimension of the thoracic cavity. What causes the anteroposterior and lateral dimensions of the thorax to change during inspiration?
rib elevation
When you take a breath in, the dimensions of the thorax change. As the diaphragm contracts, it descends, and this increases the vertical dimension of the thoracic cavity. The increase in anteroposterior and lateral dimensions of the thorax are the result of rib elevation.
When you take a breath in, what causes the vertical dimension of the thoracic cavity to increase?
diaphragm
When you take a breath in, the dimensions of the thorax change. As the diaphragm contracts, it descends, and this increases the vertical dimension of the thoracic cavity. The increase in anteroposterior and lateral dimensions of the thorax are the result of rib elevation.
The diaphragm is the primary muscle of inspiration. Why might isometric contraction of the intercostal muscles be important as intrathoracic pressure falls?
Isometric contraction is when you have muscular tension without contraction, so this helps to keep the thorax open, even when pressure falls, so that you create a zone of negative pressure which allows air to flow into the thorax during inspiration with little effort
Why is the sterno-costal joint an important bony landmark?
A clinically useful feature of the manubriosternal joint is that it can be palpated easily. This is because the manubrium normally angles posteriorly on the body of sternum, forming a raised feature referred to as the sternal angle. This elevation marks the site of articulation of rib II with the sternum. Rib 1 is not palpable because it lies inferior to the clavicle and is embedded in
tissues at the base of the neck. Therefore, rib 2 is used as a reference for counting ribs and can be felt immediately lateral to the sternal angle. You can then use this rib reference to count ribs inferiorly to correctly place chest
drains or perform a thoracostomy/thoracotomy.
True or false?
the pleural cavity projects above the first costal cartilage
True.
the subclavian veins pass over the first rib, separated from the subclavian artery by what structure?
Scalenus anterior
Why is this close relationship between the veins, arteries and the lung important when placing a cannula into the subclavian vein by the sub-clavicular route?
You do not want to perforate/puncture the subclavian artery that resides immediately deep to this vein. You also want to avoid puncturing the apex of the lung so that you don’t cause a pneumothorax or a mediastinal hematoma.
A 60-year-old man attended A/E with pain in the left arm. An x-ray of his shoulder was requested, it showed Mass left apex likely to be carcinoma – Pancoast tumour.
Why might he have pain in his arm?
Infiltration of the brachial plexus.
A 60-year-old man attended A&E with pain in the left arm. An x-ray of his shoulder was requested, it showed Mass left apex likely to be carcinoma – Pancoast tumour.
What should you examine his face for?
Ptosis left eye
Small pupil
A 60-year-old man attended A/E with pain in the left arm. An x-ray of his shoulder was requested, it showed Mass left apex likely to be carcinoma – Pancoast tumour. You notice his left eye has ptosis and a small pupil.
What has happened to cause these signs?
Horner’s syndrome is characterized by a triad of symptoms - miosis (constriction of the pupil), partial ptosis (drooping of the superior eyelid), and anhydrosis (absence of sweating).
The mnemonic MAP is helpful in remembering the symptoms (M, miosis; A, anhydrosis; P, ptosis). The cause of these symptoms is disruption of the sympathetic
outflow to the dilator pupillae, smooth muscle of the levator palpebrae, and sweat glands.
This disruption is caused when the tumour involves the superior part of the sympathetic trunk and the first thoracic and inferior cervical ganglion. The inferior cervical ganglion is at level of the transverse process of vertebra CVII and is frequently fused with the first thoracic ganglion to form the cervicothoracic (stellate) ganglion.
On chest x ray, you see that the horizontal fissure is raised. This is an indication of what?
Horizontal fissure raised. Collapse of right upper lobe – volume loss elevating the horizontal fissure.
On CXR, you see opacity in right mid zone. What imaging would you ask for next if you saw this on an X-ray?
CT Thorax, likely to be neoplastic
What is consolidation?
Consolidation is a radiological sign that refers to non-specific air-space opacification on a chest radiograph or chest CT. Many things can fill the alveolar spaces, including fluid (heart failure), pus (pneumonia), blood
(pulmonary haemorrhage) and cells (lung cancer).
A 48-year-old woman presents to the GP with increasing shortness of breath. CXR shows opacification in left lower zone and a meniscus fluid level.
What is the diagnosis?
pleural effusion.
What are the common causes of pleural effusion? (Divide the causes into: exudates and transudates)?
Transudates occur when there is an increase of hydrostatic pressure or a decrease of capillary oncotic pressure
· cardiac failure
· nephrotic syndrome
· cirrhosis
Exudates occur due to the increase in permeability in microcirculation or alteration in the pleural space drainage to lymph nodes. · bronchial carcinoma · secondary (metastatic) malignancy · pulmonary embolism and infarction · pneumonia · tuberculosis · mesothelioma · rheumatoid arthritis · SLE · lymphoma
A 70-year-old man presents with malaise, loss of appetite and weight loss. The GP arranges a chest X-ray that shows multiple opacities. What is the most likely diagnosis?
most likely multiple pulmonary metastases.
CXR hows sternal wires and a raid right hemi-diaphragm. Can you explain a posible link between the two findings?
Thoracic surgery (sternal wires) and raised right hemidiaphragm – injury to right phrenic nerve.
The interior of the right atrium is divided into a smooth part (derived from the right horn of the sinus venosus} and a part covered in ridges - pectinate muscles. What structure divides these types of muscle?
the smooth muscular ridge (crista terminalis) marks this division.
What chamber forms the most anterior surface of the heart?
the right ventricle forms most of the anterior surface of the heart. The right ventricle lies anteriorly to the right atrium.
Function of papillary muscles in the heart
There are three papillary muscles (anterior, posterior and septal). Contraction of the papillary muscles prevent cusp eversion into the right atrium during ventricular contraction.
the walls of the inflow portion of the right ventricle have
muscular structures called…
trabeculae carneae
LV trabeculae carneae are similar to those in the
right ventricle.
The free edges of the tricuspid valve are attached to..
the chordae tendineae which arise from the tips of the papillary muscles.
True or false: The pulmonary valve has two semilunar cusps.
False. The pulmonary valve has three semilunar cusps.
What chamber of the heart forms the posterior surface?
the left atrium forms most of the posterior surface of the heart
Which three surfaces of the heart are formed by the left atrium?
The left ventricle forms the anterior, diaphragmatic and left pulmonary surfaces of the heart. It also forms the apex.
Note the left ventricle is somewhat posterior to the right ventricle.
How many cusps are there on the aortic valve?
consists of three semilunar cusps.
Describe the origin and course of the right coronary artery
RCA arises from the right aortic sinus of the ascending aorta. It descends in the sulcus between the right atrium and right ventricle.
List 4 structures supplied by the right coronary artery.
The right coronary artery supplies: right atrium, right
ventricle, SA node / AV node, Interatrial septum, part of left atrium, posterior inferior 1/3 of interventricular septum, posterior part of the left ventricle).
Describe the origin and course of the left coronary artery
LCA comes from left coronary sinus and passes between the pulmonary trunk and left auricle.
two terminal branches of left coronary artery
- Anterior interventricular (LAD – left anterior
descending) - Circumflex branch (in the coronary sulcus)
What coronary artery branch is found in the coronary sulcus?
Circumflex branch
List 3 structures supplied by the left coronary artery.
The left coronary supplies left atrium, left ventricle,
interventricular septum including AV bundle and branches.
ECG changes: Marked ST elevation in II, III and aVF with early Q-wave formation.
Reciprocal changes in aVL.
ST elevation in Lead III > II with reciprocal change present in lead I and ST
elevation in V1-2.
Which part of the heart is affected?
Which artery is most likely to be occluded?
Inferior
The vast majority are the result of the occlusion of the right coronary artery
80%) (Circumflex 20%
ECG changes: Marked ST elevation in II, III and aVF with early Q-wave formation. Reciprocal changes in aVL.
ST elevation in Lead III > II with reciprocal change present in lead I and ST elevation in V1-2.
You decide the inferior part of the heart is affected.
The patient receives intravenous nitrates and becomes severely hypotensive. i) Why might this have happened? Ii) What repeat ECG would you perform?
Right ventricular infarction.
ECG with right sided leads.
ST elevation in VR3-6.
Patient has inferior STEMI. The patient receives intravenous nitrates and becomes severely
hypotensive. The ECG monitor now shows Inferior STEMI with third degree heart block and slow junctional escape rhythm.
What has happened and why?
Up to 20% of patients with inferior STEMI will develop either second- or third degree heart block.
There are two presumed mechanisms for this:
Ischaemia of the AV node due to impaired blood flow via the AV nodal artery. This artery arises from the RCA 80% of the time, hence its involvement in inferior STEMI due to RCA occlusion.
Bezold-Jarisch reflex = increased vagal tone secondary to ischaemia. The conduction block may develop either as a step-wise progression from 1st degree heart block via Wenckebach to complete heart block (in 50% of cases) or as abrupt onset of second or third-degree heart block (in the remaining 50%).
Patient has inferior STEMI and undergoes an angiogram performed via the right wrist.
- What test do you perform to ensure the blood supply is intact to the hand prior to this procedure?
- What two arteries is it testing?
Allen’s test.
Ulnar artery and Radial artery.
When performing a coronary arteriogram from the right wrist which arteries does the guidewire traverse from beginning to “end”?
Radial, brachial, axillary, subclavian, brachiocephalic, ascending aorta
The heart is found in the middle mediastinum, name 2 structures that are found in the posterior mediastinum.
Posterior: oesophagus, thoracic aorta, thoracic duct, azygous veins, splanchnic nerves, sympathetic nerves.
The heart is found in the middle mediastinum, name 2 structures that are found in the anterior mediastinum.
Anterior: Internal mammary arteries (internal thoracic artery), lymphatics, fat, thymus gland.
A 75-year-old man was admitted following a myocardial infarction. Five days later he became severely short of breath. On examination, he had a loud pan
systolic murmur loudest at the apex and radiating to the axilla. His respiratory rate was 28.min-1. He was using accessory muscles of respiration. He had bilateral crepitations extending midway up the lung fields.
What is likely to be the valve defect causing the murmur, and what two ventricles is this valve found between?
Mitral regurgitation.
Valve between the Left atrium and ventricle
List FOUR different accessory muscles of respiration?
Sternomastoid, scalenus anterior, pectoralis major, pectoralis minor, inferior fibres of serratus anterior and latissimus dorsi.
What is the “Bat Wings” sign on CXR?
Bilateral peri-hilar shadowing likely to be pulmonary oedema. “Bat wings”
Usually the result of cardiogenic sudden onset pulmonary oedema.
What are the irregular muscular columns which project from the inner surface of the right and left ventricles of the heart called?
irregular muscular columns which project from the inner surface of the right and left ventricles of the heart.
Explain how a ruptured papillary muscle, an arteriogram showing 90% obstruction of LAD and a CXR showing “bats wings” are all connected.
Occlusion of coronary artery – leads to myocardial infarction – this then leads to ischaemia of the papillary muscle – a rupture of the papillary muscle – then this causes the valve to fail, thus mitral regurgitation – then an acute left ventricular failure – which led to severe pulmonary oedema.
A 55-year-old man presents to the Emergency Department with severe “ripping” chest pain radiating to his back. He is pale and sweaty. On examination he has a tachycardia, unequal blood pressures in his upper limbs and a diastolic murmur over the left sternal edge.
What are you suspecting or concerned about?
You think he has an aortic dissection and arrange a CT scan.
A 55-year-old man presents to the Emergency Department with severe “ripping” chest pain radiating to his back. He is pale and sweaty. On examination he has a tachycardia, unequal blood pressures in his upper limbs and a diastolic murmur over the left sternal edge. You think he has an aortic
dissection and arrange a CT scan.
Looking at the CT scan, is the ascending aorta anterior or posterior to the descending aorta?
ascending aorta is anterior to the descending aorta.
Describe the layers of the wall of the aorta?
The aorta is composed of the tunica intima, media, and adventitia. The intima, the innermost layer, is thin, delicate, lined by endothelium, and easily
traumatized. The outermost layer of the aorta is adventitia. This largely consists of collagen. The vasa vasorum, which supplies blood to the outer half of the aortic wall, lies within the adventitia.
How does the structure of the aorta differ from peripheral arteries?
The tunica media is responsible for imparting strength to the aorta and consists of laminated but intertwining sheets of elastic tissue. The arrangement of these sheets in a spiral provides the aorta with its maximum
allowable tensile strength. The aorta’s tunica media contains very little smooth muscle and collagen between the elastic layers and thus has increased distensibility, elasticity, and tensile strength. This contrasts with
peripheral arteries, which, in comparison, have more smooth muscle and collagen between the elastic layers.
What is a dissection of the aorta and how does it occur?
Aortic dissection is defined as separation of the layers within the aortic wall. Tears in the intimal layer result in the propagation of the dissection (proximally or distally) with secondary to blood entering the intima-media space
