cardiac anatomy - inc coronaries Flashcards
describe the gross anatomy of the heart…
muscular structure that lies in the **middle mediastinum **
wraped in a 2 layered serous sac, the **pericardium **
consists of 4 muscular chambers - 2 atria and 2 ventricles on left and right side with the atria located superiorly.
separated by thin walled septum including intra -atrial, intraventricular and atrioventricular septum
AV valves - tricuspid (R), mitral (L
semilunar valves - pulmonary and aortic
R atria receives blood from SVC and IVC and drainage from coronary vessels.
L Atrium recieves blood from 4 pulmonary veins - left right upper and lower.
L ventricle drains into aorta, R atrium into pulm a.
LV wall is thicker than right
describe inner surface of heart
trabeculae carnae - rough irregular muscle columns
RVOT and LVOT are smooth
atria dont have trabeculae but still have roughened walls from pectinate muscles - more prominent in right.
what are the borders of the heart?
anterior border = RV and part of RA
posterior = LA and pulmonary veins
right border = RA, SVC, IVC, right pulmonary veins
left border = LV, left pulmonary veins and aorta
inferior = RV
what is the function of the fibrous skeleton of the heart
complex arrangmenet of connective tissue
supports function e.g. structure and support to valves, attachment of muscle
include 4 fibrous rings - found at orifices e.g. between V+A and entry and exit points.
also some fibrous septum
describe the structure of tricuspid valve…
located between RA and RV
3 leaflets of unequal size - base of each is attached to the fibrous ring (tricuspid annulus)
free edge are attached to chordae tendinae (fibrous) which inturn are attached to papillary muscles located on ventricles
during systole, the papillary muscles contract and prevent valves collapsing into atria
describe the structure of mitral valve
located between LA and LV
bicuspid valve - 2 leaflets - asymmetric
attached to mitral annulus - fibrous skeleton
2 chordae tendinae attaching to papillary muscles in ventricles
describe the aortic valve
located between aorta and LV
3 cusps of similar size and shape (some people have 2)
originate from the aortic annulus
and are attached to walls of aorta
sit in front of the aortic sinus of valsalva - where coronaries emerge
arrangment ensures coronaries are not occluded in diastole.
describe the structure of the pulmonary valve…
located between RV and pulmonary trunk
3 leaflets - originate from pulmonary annulus and attached to the walls of pulmonary artery.
also have sinuses like aorta
what are the sinuses of valsalva
anatomical structures found as pockets behind the valve leaflets of the aorta,
They are three small pouch-like dilations
play an important role in the circulation of coronaries blood flow. - during diastole, blood flows back, closes aortic valve and dilates/ fills sinus and coronary vessels.
(also present behind pulmonary valve leaflets but less significant)
left = posterior aortic sinus
right = anterior aortic sinus
what is the pericardium, describe its structure…
2 layered sac
outer fibrous - tough non distensible connective tissue. continous with diaphraghm inferiorly and adventitia of great vessles superiorly
inner serous- made of visceral and parietal layers - parietal is continuous with fibrous pericardium and visceral is continous with cardiac muscle thin layer of serous fluid between them - reduces friction to contraction.
what are the 2 sinuses of the heart?
transverse - between pulmonary a and aorta
oblique - behind the atrium
describe the anatomy of the right coronary circulation…
RCA recieves blood from anterior aortic sinus
RCA runs in AV groove - supplies RA and SAN (60%)
divides into right marginal and posterior intraventricular branch.
right marginal - supplies inferior right heart
posterior interventricular - supplies post 1/3 septum and gives of AV nodal branch in 90% to supply AVN
describe the anatomy of left coronary circulation
originates from posterior aortic sinus
LCA travels in LV groove but soon divides into left circumflex and left anterior descending
LAD - descends in interventricular groove to the apex
* supplies LV
* anterior interventricular branch - 2/3 septum
* anastomoses with posterior intraventricular branch of RCA.
circumflex follows AV groove
* supplies LA
* gives rise to left marginal - supplies LV
* continues in coronary sulcus on posterior surface - sometimes supplies SAN. anastomoses with RCA.
* LAD also gives of septal and diagonal branches
what supplies the AVN and SAN?
usually RCA
in 60% SAN
in 90% for AVN
otherwise LCA (circumflex)
describe the venous drainage of the heart…
predominately via the coronary sinus - 60% which drains directly into RA.
the tributaries of coronary sinus are…
* great cardiac vein - originates at apex and travels up anterior interventricular groove curves to left and around back of heart before reaching right A.
* small cardiac vein - anterior surface of AV groove, goes around the back of heart to RA.
* middle cardiac vein - bagins at apex but travels in posterior IV groove
* posterior cardiac vein - travels to left of middle cardiac vein
all eventually drain into coronary sinus.
there are also anterior cardiac veins which drain directly into RA - these drain RV.
a small amount also drains via thebesian veins direclty into all heart chambers. thaose that drain to left side are acting as a physiological shunt
what is meant by coronary dominance?
defined by which coronary vessel supplies AVN
in 70% this is right , in 10% left and co-dominance in 20%
important when assessing coronary artery disease
which nodes does cardiac lymph drain into
tracheo-bronchial
mediastinal
describe the conducting system of the heart..
this is a network of specialised cardiac muscle cells that initiate and transmit electrical impulses to coordinate muscle contraction
originates in SAN (found between RA and SVC)
travels to AVN via 3 bundles e.g. bachman bundle (anterior nodal tract), middle and posterior nodal tracts. and also to the LA (bachman)
from AVN to bundle of his into left and right bundles.
left consists of 2 fascicles (anterior and posterior), right 1
to purkinje fibres which carry from apex to ventricles
runs in endocardium
what is the aorta?
largest artery
originates from LV and supplies the rest of the systemic circulation with oxygenated blood.
it is split into 3 parts - ascending, arch and descending.
terminates at the bifurcation into R and L iliac arteries at level L4.
ascending aorta - gives off coronary branches.
arch of aorta - arches towards the left and gives of right brachiocephalic branch, left common carotid and left subclavian branch.
descending aorta - divided into thoracic and abdominal parts and has various branches e.g SMA, IMA, coeliac, renal, gonadal etc.
becomes abdominal aorta when it passes through aortic hiatus of diaphragm at level of T12
what is the common carotid artery?
major branch of aorta on left and arises from brachiocephalic artery on right. supplies head and neck with oxygenated bloood
travels behind sternoclavicular joint into the neck and is contained in carotid sheath with IJV and vagus
divides into external and internal carotid arteries around level of C4 / thyroid cartilage
internal carotid artery - enters cranium via carotid canal (found in petrous part of temporal bone)
what is the significance of anatomical variations of thyroid ima arteries
thyroid ima artery is present in 10% of population and will be an accessory supply to thyroid. sometimes this is significant and sometimes just small blood supply in addition to inferior and superior thyroid arteries.
significant for thyroid surgery / tracheostomy - always good to USS before trachy
describe upper limb arterial system
Subclavian –> axillary –> brachial artery
Brachial artery divides in arm into radial and ulnar arteries
Ulnar artery runs medially in forearm and enters wrist superficial to flexor retinaculum
Radial artery runs lateral
Anatomoses within hand (deep and superficial palmar arch) and supply digital branches
describe the arterial supply of lower limb
Aorta divides into L and R common iliac arteries
Divides into internal and external iliac arteries
Internal supply pelvic organs and gluteal muscles
External supply leg
External femoral a popliteal a
Popliteal a divides into fibular a, posterior tibial a and anterior tibial a
Anterior tibial artery gives rise to dorsalis pedis.
describe anatomy of femoral triangle..
triangle formed by ASIS, pubic tubercle and crossing point of adductor longus and sartorius.
inguinal ligament makes superior border.
within it lies the femoral nerve, artery and vein
from lateral to medial = nerve, artery, vein
femoral artery usually mid way between ASIS and pubic symphysis = mid inguinal point
mid point of inguinal ligament = half way between ASIS and pubic turbercle
describe the venous drainage of lower limb…
Deep and superficial veins
Deep veins accompany arteries e.g. tibial, popliteal, femoral and external iliac vein
Superficial veins include
Great saphenous – long saphenous – runs up medial leg and thigh. Drains into femoral vein
Small saphenous – lateral – drains into popliteal.
perforating veins communicate between deep and superficial - valves present preventing deep draining into superficial
label the following
1.Radial artery.
2.Ulnar artery.
3. Ulnar nerve.
4. Deep palmar branch of the ulnar artery.
5. Superficial palmar branch of the radial artery.
what does this image show
coronary angiogram
dye has been injected into left main stem and xray images taken to view coronary perfusion
can see there is an occlusion in LAD artery
this may result in downstream angina/ ischaemia
what are the structures labelled here…
A = lateral cutaneous nerve of the thigh
B = femoral nerve
C =common femoral artery
D = common femoral vein
E = saphenous vein
F = lymphatics.
name muscles the femoral nerve supplies
quadriceps femoris = rectus femoris, vastus medialis, vastus lateralis, vastus intermedius
sartorius
iliacus
pectinus
how is the fascia iliaca nerve block performed using landmark tecnique
preparation - monitoring, IV access, consent, trained assistent, emergency drugs available
landmarks - ASIS and pubic turbercle. draw a line and divide into 3rds.
needle inserted between lateral and middle thirds
pop pop sensation
aspirate and inject 20mls of anaesthetics
