Anatomy Booklet Questions Flashcards
How does contraction of pectoralis major assist in breathing?
The 2 pectoralis muscles form part of a ring of muscles which encircle the thoracic cage; the other muscles forming the ring are SCAPULA muscles. When the ring contracts the thoracic pressure rises to assist exhalation. (This only occurs in disease and during exercise, normal exhalation is a passive process)
Which bony structures lie subcutaneously in the anterior chest wall?
Clavicles
Sternum (manubrium, body, xiphi-sternum)
What are the articulations of the clavicle?
At the medial end to the manubrium of the sternum; the sternoclavicular joint and at the lateral end to the acromion of the scapula; the acromioclavicular joint.
What forms the anterior axillary fold?
The lower edge of the pectoralis major muscle
What lies deep to the pectoralis minor muscle?
The axilla
The majority of breast tissue is in the upper outer quadrant of the breast. Where does lymph from this part of the breast drain?
To the axillary lymph noes
Which costal cartilage connects to the sternum at the sternal angle? (angle of Louis)
2nd costal cartilage
Which nerves carry sensation from the parietal and visceral pleura?
The parietal pleura lines the inside of the thoracic wall and is supplied by the same nerves as the tissue of the thoracic wall; the spinal nerves, T1 and T2. The visceral pleura covers the surface of the lung and is supplied by the same nerves as the lung; the vagus and sympathetic nerves.
What is a bronchopulmonary segment?
A bronchopulmonary segment has a feeding artery and bronchus which run together through the centre of the segment and repeatedly branch to reach all parts of the segment. The veins which drain the segment run on the surface of the segment rather than through the centre. The ten segments on each side are separate dby layers of connective tissue and the fissures. Each segment is anatomically and functionally seperate and this influences how diseases may spread throughout the lungs.
What structures pass through the hilum of the lung?
Main bronchus Pulmonary artery Two pulmonary veins Bronchial artery Lymphatic vessels branches of the vagus and sympathetic nerves
How does contraction of the diaphragm assist in returning blood to the heart?
Contraction of the diaphragm decreases intra-thoracic pressure and increases intra-abdominal pressure. The net effect is for blood to flow from the abdomen into the chest.
What is the sensory and motor nerve supply to the diaphragm?
Sensory and motor supply are both from the phrenic nerve which arises from the spinal chord at C3, 4, 5 (C345 keeps the diaphrahm alive)
What is the surface markings of the lowest extent of the lungs?
At the midclavicular line to lowest part of the lung lies at the tip of the 6th rib, at the mid-axillary line the 8th rib and posteriorly the 10th rib.
What is intercostal recession?
When a patient is having difficulty taking a breath in and is having to create very negative pressure in the thorax the intercostal muscles get ‘sucked in’.
What is the developmental significance of the ligamentum arteriosum?
It is the remnant of a shunt between the pulmonary artery and aorta. The shunt carries all the blood from the pulmonary artery into the aorta before the lungs have developed and most of the blood after the lungs have developed. At birth it closes so that all the right ventricular blood passes to the lungs.
What are the main branches of the following arteries and what organs/tissues do these vessels supply:
1 - left common carotid artery
2 - left subclavian artery
Left common carotid artery
- Internal and external carotid arteries
External -> left side of the face and head
Internal -> most of the cerebral hemispheres
Left subclavian arteries
- Vertebral, thyro-cervical, axillary
Vertebral; cerebellum, brain stem, occipital lobe and the interior temporal lobe
Thyro-cervical; thyroid gland and neck
Axillary; upper limb
What are the nerve roots of the phrenic nerve? Why is this clinically important?
C3, 4, 5
Painful diseases affecting the diaphragm are felt by the patient in the side of the neck and onto the shoulder tip which is the dermatome supplied by C345.
What structures are supplied by the vagus nerve?
- Pharynx
- Larynx
- Heart
- Lungs
- Fore gut
- Mid gut
What are the vessels which connect the heart to other structures?
Aorta Pulmonary artery Four pulmonary veins Superior vena cava Inferior vena cava
What is the surface marking for the apex of the heart?
5th intercostal space
midclavicular line
How may the fibrous pericardium contribute to a reduction in ventricular filling?
Fibrous tissue is resistant to stretching, and so restricts the maximum end diastolic volume. Diseases which ‘take up volume’ in the pericardial sac (E.g. fluid, muscle, hypertrophy etc.) whill reduce diastolic filling and therefore reduce stroke volume. Cardiac output can then only increase by increasing the heart rate. Disease which progress very slowly (over years rather than days) can stretch the pericardium.
Describe the anatomy of the tricuspid and mitral valves. What happens if they are incompetent?
Both of these valves have a similar structure with the tricuspid having 3 cusps and the mitral having 2 cusps. The cusps are made of fibrous tissue covered with endothelium and are very flexible. The cusps are attached to a ring of fibrous tissue which forms the orifice between the atrium and ventricle, the myocardium is also attached to this fibrous ring. The free edge of the cusp has multiple tendinous cords attached, the cordi tendini; for each cusp these cords attach to a cylinder of myocardium, the papillary muscle, which contracts during systole to keep the cordi tendini taught.
Describe the anatomy of the aortic and pulmonary valves. What happens if they are incompetent?
Both of these valves have a similar structure with both having three cusps. The cusps are made of fibrous tissue covered with endothelium and are very flexibile. The cusps are attached to a ring of fibrous tissue which form the orifice between the ventricle and artery. The free edge of the cusps have a thickening, like a baton in a sail, which helps to shape the valve when it is closed.
At what phase of the cardiac cycle do the coronary arteries fill? Why?
Blood flows through the coronary arteries during ventricular dystole. Blood flows from high pressure to low pressure. During ventricular systole the highest pressure is in the ventricular lumen and in the myocardium surrounding the lumen. Pressure in the coronary arteries on the surface of the heart is initially lower so these fill with blood. However, most of the coronary arteries are inside the myocardium where the pressure is highest so these will be squeezed so that they are empty. Blood cannot flow from the surface arteries into the myocardium so there is no flow. During ventricular diastole, pressure in the aorta is high, pressure in the myocardium drops to zero; now the coronary arteries inside the muscle can fill and blood flow occurs.
Describe the conducting system of the heart and its function.
The 4 fibrous rings which support the four heart valves form a complete electrical isolation of the ventricles from the atria. In order for the ventricles to contract there has to be a system of carrying the electrical impulse across this barrier. Furthermore, the ventricles need to contrat from the apex towards the aortia and pulmonary valve for maximum efficiency.
As a result, the conducting system starts at the atrio-ventricular node, which is positioned in the atrial septum close to the fibrous rings. From the atrio-ventricular node modified myocardium (purkinje fibres) extends into the ventricular septum and travels down to the apex of the heart. In the ventricular septum it divides twice to provide a right bundle to the right ventricle and two bundles (an anterior and posterior) for the left ventricle. The right bundle crosses the lumen of the ventricle as the moderator band.
What is the blood supply of the sinoatrial node and the atrioventricular node?
The sino-atrial node is supplied by the right coronary artery in 60% of hearts and the left in 40%.
The atrioventricular node is supplied by the posterior intraventricular artery in all hearts. However, in 90% of hearts the posterior intraventricular artery arises from the right coronary artery and in 30% of hearts from the left coronary artery. In 20% of hearts there are 2 posterior intraventricular arteries, one from the left and one from the right.
What is the location of the sinoatrial node?
The sinoatrial node is located on the crista terminalis (a ridge of tissue on the inside between the right atrium and right atrial appendage) just where the superior vena cava enters the right atrium.
On a chest X-ray, which chambers and vessels form the right and left borders of the cardiac shadow?
Right heart border; right atrium
Left heart border; left auricular appendage superiorly and the left ventricle.
What is the thoracic duct and where does it join the vascular system?
The thoracic duct is the main lymphatic channel draining lymph from the lower half of the body and the bowel back to the bloodstream. The bowel component is important because fat is absorbed into the lymphatics so this is the only route for fat absorption.
It joins the vascular system at the confluence of the left subclavian and left internal jugular vein.
What structures are supplied by the three splanchnic nerves and where does a patient
appreciate pain felt by these nerves?
The greater splanchnic nerve supplies the foregut and pain is felt in the epigastrium.
The lesser splanchnic nerve supplies the midgut and pain is felt round the umbilicus.
The least splanchnic nerve supplies the hindgut and pain is felt in the suprapubic area.
What structure lies immediately behind the trachea in the upper thorax and the left atria in the lower thorax?
Oesophagus
What structures drain blood into the azygous system?
The lateral and posterior chest wall and the lateral and posterior abdominal wall
Why is the left recurrent laryngeal nerve at risk from thoracic disease, but not the right?
The LRL passes into the thorax, round the aortic arch and back into the neck. The RRL does not pass through the thorax.
Where do the sympathetic nerves attach to the CNS?
T1 - T12
L1
L2
What happens if the sympathetic nerves to the head and neck are damaged?
There will be no sweating on the face (anhidrosis)
The eye lid will droop (ptosis)
The pupil will be constricted (miosis)
Slightly withdrawn eye ball (enopthalmos)
Horner’s syndrome
What is the function of the extrinsic laryngeal muscles? (sternothyroid, thyrohyoid?)
They move the larynx up and down the neck and support its central position, this is particularly important for swallowing.
Where may you create an emergency airway?
Between the thyroid and cricoid cartilage, through the cricothyroid membrane.
Why does the thyroid gland have such a good blood supply?
Iodine is present in very low conc. in the blood so the gland needs a high blood flow to ensure adequate delivery of iodine.
Which structure may be compressed by an enlarged thyroid gland?
trachea
What is the location of the parathyroid glands and how many are there?
They are positioned on the posterior surface of the thyroid gland.
There are four.
What is the only complete cartilage ring around the airway?
The cricoid cartilage.
A patient may develop hypocalcaemia after thyroid surgery, why?
The parathyroid glands may be accidentally or deliberately removed during thyroid surgery which will cause acute hypoparathyroidism.
What forms the ganglia on the sympathetic chains and vagus nerves?
A collection of neuron cell bodies.
What is the name of the fused first thoracic and lower cervical sympathetic ganglia?
The stellate ganglion
What structures are supplied by the superior laryngeal nerve?
Sensation to the inside of the larynx down to the vocal cords and the cricothyroid muscle.
Which special sensation is carried in the glossopharyngeal nerve
Taste from the posterior 1/3rd of the tongue
What is the location of the carotid sinus and what sensation does it detect?
The origin of the internal carotid artery; blood pressure.
Which structures lie immediately behind the pharyngeal wall?
A thin layer of loose areolar tissue and then the cervical vertebral bodies.
Which parts of the pharynx lie below the lower border of the mandible?
The hypopharynx
Which structure stops liquid refluxing into the back of the nose during swallowing?
the soft palate
Which nerve carries sensation from the larynx below the vocal cords?
The recurrent laryngeal nerves
Describe the histology of the mucosa of the trachea
Simple ciliated pseudostratified columnar
+ goblet cells
Which nerve travels through the parotid gland?
Facial nerve C7
Where do the parotid and submandibular ducts enter the mouth?
Parotid; from the cheek adjacent to the second upper premolar
Submandibular; under the tongue
Which nerve supplies the muscles of the tongue?
Hypoglossal nerve
C12
What is the upper extent of the abdominal cavity?
Anteriorly the undersurface of the diaphragm reaches the 5th intercostal space.
Describe the 9 regions of the abdominal wall
Two vertical lines down from the midclavicular line.
A horizontal line across the lowest point on the thoracic cage.
A horizontal line across the tubercules of the iliac crest.
Three areas down the midline are; epigastrium, umbilical and suprapubic from top down.
The three lateral areas are hypochondrium, flank and iliac fossa from top down.
Describe the nerve supply to the skin of the abdominal wall
The dermatomes of the abdominal wall start at T5 in the upper epigastrium, with T10 being at the umbilicus and T12 being just above the hair bearing area in the lower suprapubic area. Each dermatome starts at the back at the level of the name vertebra; the dermatomes run towards as they pass round the trunk to the front.
How is the rectus sheath formed?
In the upper 2/3 of the abdomen, the aponeurosis of the external oblique muscle passes in front of the rectus abdominus and the aponeurosis of the transversus abdominus passes behind. The aponeurosis of internal oblique sends fibres both in front and behind rectus abdominus. In the lower 1/3 of the abdomen all three aponeuroses pass in front of the rectus abdominus.
What is the surface marking of the aortic bifurbication?
The level of the umbilicus
In which regions of the abdomen is pain from the 3 parts of the bowel felt?
Foregut - epigastrium
Midgut - umbilicus
Hindgut - suprapubic
Describe the anatomy of a ‘six pack’?
The rectus abdominus muscle runs vertically from the pubis up to the costal margin. Along its length there are 3 places where is becomes a tendon. When exercised the muscle hypertrophies (becomes bigger) but the tendinous part stays the same. The result is three bulges of muscle between the tendons. This occurs on either side of the midline; six bulges in all.
