Thorax and Abdomen Flashcards
Chambers of the Heart
- right atrium
- right ventricle
- left atrium
- left ventricle
Vessels to and from the Heart
- superior vena cava
- inferior vena cava
- pulmonary trunk/pulmonary arteries
- pulmonary veins
- aorta
Valves of the Heart
- tricuspid valve - RA and RV
- pulmonary valve - RV and pulmonary trunk
- bicuspid/mitral valve - LA and LV
- aortic valve - LV and aorta
Blood Circulation Through Heart
- venous/pulmonary system:
- inferior and superior vena cava + coronary sinus
- right atrium
- tricuspid valve
- right ventricle
- pulmonary valve
- pulmonary trunk/arteries
- lungs
- arterial system
- pulmonary veins
- left atrium
- bicuspid/mitral valve
- left ventricle
- aortic valve
- aorta
- body
2 Phases of Heartbeat
- diastole
- systole
Diastole
- relaxation and filling of ventricles with blood
- ventricle walls relax
- pulmonary and aortic valves close
- tricuspid and bicuspid valves open (atrial pressure > ventricular pressure)
- end of diastole: atria conract and push blood in ventricles
Systole
- ventricular contraction - emptying of blood from ventricles into aorta or pulmonary trunk
- walls of ventricles contract
- tricuspid and bicuspid valves close
- pulmonary and aortic valves open (ventricular pressure > atrial pressure)
- end systole: ventricles contract further, blood flows into aorta/pulmonary trunk until vessel pressure > ventricular pressure
- blood fills atria
Borders of the Heart (Anterior)
- superior border
- pulmonary trunk
- ascending aorta/arch of aorta
- atrioventricular groove
- anterior interventricular groove
- left border
- left ventricle
- apex
- inferior border
- right ventricle
- right border
- right atrium and auricle
- superior and inferior vena cava
Borders of the Heart (posterior)
- superior border
- pulmonary veins
- left border
- left ventricle
- apex
- inferior border
- left atrium
- right border
- superior and inferior vena cava
- right atrium
Atrioventricular Groove/Coronary Sulcus
separates atriums and ventricles, visible both posteriorly and anteriorly
Anterior Interventricular Groove
separates left and right ventricles, visible only anteriorly
Auscultation of Heart Valves
- aortic - 2nd intercostal space, right of sternum
- pulmonary - 2nd intercostal space, left of sternum
- tricuspid - 5th intercostal space, left of sternum
- mitral/bicuspid - 5th intercostal space, left midclavicular line
Characteristics and Function of Thoracic Wall
- rigid
- protect organs from external forces
- resist negative internal pressure
- flexible
- allow for breathing movement
- provides attachment and support for upper limbs and muscles
Bones of Thoracic Wall
- thoracic vertebrae
- ribs
- sternum
Thoracic Vertebrae

- Costal facet - tubercle of rib
- Costal demifacets - head of rib
- head of one rib articulates with demifacet of 2 adjacent vertebrae
Costal Cartilage

anterior portion of rib attached to sternum
Costal Margin

upturned cartilages of ribs 8-10, connected to the costal cartilage of rib 7
Types of Ribs
- 1-7: true ribs
- 8-10: false ribs
- 11-12: floating ribs
- 3-9: typical ribs
- 1-2, 10-12: atypical ribs
True Ribs
articulate directly with sternum via costal cartilage
False Ribs
articular with sternum indirectly via costal margin
Floating Ribs
no articulation with sternum
Typical Rib Structure

- head - articulates with costal demifacets on verterbral body
- neck
- tubercle - articulates with costal facet on transverse process
- shaft/body
- costal groove
Costal Groove
depression on inferior border of rib where intercostal veins, arteries, and nerves reside
Costovertebral Joints
- head of ribs to vertebrae - articulates with 2 adjacent vertebral bodies at demifacets
- costotransverse joint - tubercle of rib articulates with costal facet on transverse process
- ligaments restrict rotation of ribs
Sternocostal Joints
- via costal cartilage
- synovial joints
- except rib 1 + manubrium - synchondrosis
Parts of the Sternum
- jugular notch
- manubrium
- sternal angle
- body
- costal notches
- xiphoid process
Sternal Angle
- junction of the manubrium with body of sternum
- articulates with rib 2
- often palpable
Xiphisternal Junction
- junction of the body and xiphoid process
- articulates with rib 7
Thoracic Inlet/Superior Thoracic Aperture
- passage between neck and thorax
- first vertebral body, first rib, manubrium
Thoracic Outlet/Inferior Thoracic Aperture
- filled by diaphragm
- body of T12, rib 12, costal margins, xiphisternal joint
Landmarks on Thoracic Wall

- midaxillary line
- midscapular line
- midclavicular line
Muscles of Thoracic Wall
- intercostal muscles
- external
- internal
- innermost
- transversus thoracis
- subcostals
- serratus posterior superior and inferior
External Intercostal Muscles and Membrane

- most superficial
- “hands in pocket”
- muscles run from tubercle to midclavicular line
- membrane runs from midclavicular line to sternum
Internal Intercostal Muscles and Membrane

- oriented at right angle to external intercostal muscles
- muscles run from sternum to midaxillary line
- membrane runs from midaxillary line to neck of rib
Innermost Intercostal Muscles and Membrane
- same orientation as internal layer
- separated from internal layer by nerves
- muscles - at midaxillary line
- membrane posteriorly and anteriorly
Transversus Thoracis

- located on posterior surface of anterior ribs
- span multiple intercostal spaces
- same level as innermost costals
Subcostal Muscle

- on anterior surface of posterior ribs
- span multiple intercostal spaces (how you differentiated from innermost)
- same level as innermost
Accessory Muscles of Respiration

- pectoralis major and minor
- serratus anterior
- scalenes
Intercostal Nerves
ventral rami of spinal nerves 1-11
Subcostal Nerve
ventral ramus of spinal nerve 12
Branches of Intercostal Nerves

- muscular branches - between internal and innermost
- anterior cutaneous branch - superficial
- lateral cutaneous branch - superficial
- rami communicans
- collateral branches
Arteries of Thoracic Wall

- subclavian artery
- internal thoracic artery
- anterior and posterior intercostal arteries
- superior epigastric artery
- musculophrenic artery
Internal Thoracic Artery
- branch of the first part of the subclavian
- runs laterally to sternum
- gives off pericardiacophrenic branch
- terminal branches - musculophrenic nerve, superior epigastric nerve
- held against ribs by transversus thoracis
Superior Epigastric Artery
branch of internal thoracic artery that continues to anterior abdominal wall
Musculophrenic Artery
lateral branch of internal thoracic that supplies diaphragm
Anterior Intercostal Arteries
- 1-6: internal thoracic artery branches
- 7-9: musculophrenic artery branches
- 10-11: absent
Posterior Intercostal Arteries

- 1-2: subclavian 3rd part –> costocervical trunk –> supreme intercostal artery –> 1st and 2nd intercostal arteries
- 3-11: branches of descending aorta
Veins of Thoracic Wall

- brachiocephalic vein
- internal thoracic vein
- anterior and posterior intercostal veins
Right Side Venous Drainage

- intercostal veins
- azygos vein
- superior vena cava
Left Side Venous Drainage

- intercostal veins
- hemiazygos vein
- azygos vein
Intercostal Neurovascular Bundle
- VAN - vein, artery, nerve
- between innermost and internal muscle layers
Diaphragm
- chief muscle of respiration
- separates thoracic and abdominal cavities
- central tendon and muscular portions
Openings in Diaphragm

- vena caval foramen - inferior vena cava, T8
- esophageal hiatus - esophagus and vagal trunks, T10
- aortic hiatus - aorta, thoracic duct, and azygos vein, T12
Blood Supply to Diaphragm
- pericardiacophrenic artery
- musculophrenic artery
- inferior phrenic artery (from abdominal aorta)
Innervation to Diaphragm
- phrenic nerves (C3-5)
Visceral Pleura
- attached to lungs
- continuous with parietal pleura at root of lung
Parietal Pleura
lines thoracic wall, diaphragm, and mediastinum
Parts of Parietal Pleura

- cervical part - cupla
- costal part
- diaphragmatic part
- mediastinal part
Pleural Cavity
- between visceral and parietal pleura
- contains pleural fluid
Pleural Recesses

- areas where two layers of parietal pleura are not separated by lung during quiet respiration
- right and left costodiaphragmatic
- left costomediastinal recess
Lines of Pleural Reflection
where one type of parietal pleura becomes continuous with another
Innervation of Visceral Pleura
- autonomic - vagus and sympathetic trunk
- insensitive to pain
Innervation of Parietal Pleura
- somatic innervation
- costal - intercostal nerves
- diaphragmatic and mediastinal - phrenic nerve
- pain - dermatomes
Locations of Lungs and Pleura during Quiet Respiration at Thoracic Wall Landmarks
- midclavicular line - lungs at 6, pleura at 8
- midaxillary line - lungs at 8, pleura at 10
- midscapular line - lungs at 10, pleura at 12
Right Lung Structure

- wider and heavier than left
- right inferior part limited by liver
- superior, middle, and inferior lobes
- oblique and horizontal fissures
Left Lung Structure

- superior and middle lobes
- cardiac notch
- lingula
- oblique fissure
Hilum of the Lung
- bronchi
- pulmonary arteries and veins
- bronchial arteries and veins
- pulmonary plexus
- lymph vessels and nodes
- left and right side differences
Hila of Right Lung

- superior lobar bronchus superior to main bronchus
- 2 pulmonary arteries = superior and anterior to bronchus
- pulmonary veins - anterior and inferior to bronchi and arteries
Hila of Left Lung

- 1 pulmonary artery superior to main bronchus
- pulmonary veins anterior and inferior
Bronchial Branches
- principal - main
- right is wider, shorter, more verticle (more likely for objects to lodge here)
- secondary - lobar
- 2 left, 3 right
- tertiary - segmental
- bronchopulmonary segments
- bronchioles
Bronchial Arteries
- right: right bronchial artery from first intercostal or superior left bronchial
- left: aorta –> superior left bronchial and inferior left bronchila artery
Bronchial Veins
- right: azygos
- left: hemiazygos
Movement of Planes during Respiration
- vertical plane - diaphragm contracts and moves inferiorly
- transverse plane - rib 2-10 elevate, lateral edges of ribs move away from midline
- anteroposterior plane - sternum moves superiorly, anterior ends of ribs elevate
Muscular Movement during Inspiration
- quiet - diaphragm
- forced - elevate ribs and sternum
- primary: scalenes and SCM
- secondary: pec major and minor, serratus anterior, serratus posterior superior and inferior
Muscular Movement during Expiration
- quiet - diaphragm, lung elastic recoil
- forced - contract of abdominal muscles to pull ribs and sternum inferiorly and diaphragm superiorly
Mediastinum
space between the pleural cavities, end of retropharyngeal space
Transverse Thoracic Plane
from sternal angle of sternum to T4-5 intervertebral disc
Structures Defined at Transverse Thoracic Plane

- tracheal bifuration at carina
- aortic arch above thoracic plane, ascending/descending aorta below this line
- superior extent of pericardium
Borders of Superior Mediastinum
- superior: thoracic inlet
- inferior: transverse thoracic plane
Viscera of Superior Mediastinum
- thymus
- trachea
- esophagus - between trachea and vertebral column
Thymus (arteries and veins)
- large in children, regresses in adults
- artery: anterior mediastinal branches of internal thoracic arteries
- veins: drain into left brachiocephalic, internal thoracic, and inferior thyroid veins
Trachea

- anterior and to the right of the esophagus
- starts at cricoid cartilage
- ends at carina
- tracheal cartilage - C-shaped rings open posteriorly (connected with muscle and connective tissue
- annular ligaments - fibrous cartilage connecting rings of tracheal cartilage
Arteries of Superior Mediastinum

- arch of the aorta
- brachiocephalic trunk (branches into right common carotid and subclavian in the neck)
- left common carotid artery
- left subclavian artery
Veins of the Superior Mediastinum

- all drain into superior vena cava
- superiorly: subclavian and internal jugular (not in superior mediastinum) drain into right and left brachiocephalic veins
- inferiorly: azygos vein
Left vs. Right Brachiocephalic Veins
left is longer and crosses aortic arch
Nerves in the Superior Mediastinum
- vagus (CN X) - posterior to hiatus of lung
- left recurrent laryngeal (not right) - wraps under aortic arch and ligamentum arteriosum
- phrenic - from cervical plexus, anterior to hilum of lung
Anterior Mediastinum (Borders and Contents)
- borders
- anterior: sternum
- posterior: pericardium
- superior: transthoracic plane
- contents:
- thymus in children
- remnants of thymus and fat in adults
Middle Mediastinum (Borders and Contents)
- borders: pericardium
- contents: heart
- also roots of great vessels, phrenic nerves, pericariacophrenic vessels (branch of internal thoracic artery, run with phrenic nerves to diaphragm)
Borders of Posterior Mediastinum
- superior: transthoracic plane
- anterior: pericardium and diaphragm
- posterior: bodies of T5-12
Arteries of Posterior Mediastinum

- descending aorta/thoracic aorta - from T4 (transthoracic plane) to T12 (aortic hiatus)
- posterior intercostal arteries
Veins of Posterior Mediastinum

- posterior intercostal veins - drain into azygos and hemiazygos
- hemiazygos veins (left) - drains into azygos
- azygos vein (right) - drains into superior vena cava
Nerves of Posterior Mediastinum
- vagus (X) - posterior to root of lung
- esophageal plexus - on esophagus from vagus
- anterior vagal trunk - from left vagus
- posterior vagal trunk - from right vagus
- splanchnic nerves (greater, lesser, least) - branch off sympathetic trunks, run anterior to vertebral bodies
- sympathetic trunks not in posterior mediastinum because not anterior to vertebral bodies
Viscera of Posterior Mediastinum
- esophagus
Lymphatics of Posterior Mediastinum
thoracic duct
Branches of Thoracic Aorta
- visceral branches
- unpaired: esophageal, pericardial, mediastinal
- paired: bronchial
- parietal branches
- posterior intercostal arteries
- superior phrenic arteries
Esophagus

- posterior and to the left of the trachea
- anterior and to the right of the descending aorta
- muscular tube between pharynx and stomach
- exits at esophageal hiatus in diaphragm
Constrictions of the Esophagus

- pharynx (C5)
- left root of the lung and arch of aorta (T4)
- esophageal hiatus (T10)
Sympathetic Nervous System

- columnar arrangement
- preganglionic nerves from lateral horn gray matter in T1-L2/3
- innervate according to body organization
Course of Sympathetic Nerves

- preganglionic neuron leaves ventral root
- meets dorsal root to form dorsal root ganglion and spinal nerve
- quickly incorporated into rami communicantes and is connected to sympathetic trunk
- some go back out to the skin, some become splanchnic nerves, some become intercostal nerves
Rami Communicantes

- white - carry preganglionic sympathetic fibers from intercostal nerves to sympathetic trunk
- gray - carry postganglionic sympathetic fibers from sympathetic trunk to intercostal nerves
Splanchnic Nerves

- carry preganglionic sympathetics fom sympathetic trunk to abdominal viscera
- greater - T5-9
- lesser - T10-11
- least - T12
Mammary Glands
- both males and females have but more pronounced in females due to hormonal differences
- women proliferates glandular tissue, lactiferous ducts, fat
Path of Milk
alveoli (milk producing cells) –> lobule of gland –> lactiferous duct –> lactiferous sinus –> nipple
External Breast

- nipple
- areola
- pectoralis major
- serratus anterior

- retromammary space - loose connective tissue between the breast and deep pectoral fascia, allows limited movement
- suspensory ligaments of cooper - between skin and deep pectoral fascia to support breast
Arteries of Breast
- internal thoracic artery - gives off medial mammary branches
- posterior intercostal arteries - lateral cutaneous branches give off lateral mammary branches
- lateral thoracic arter y - also give off lateral mammary branches
- thoracoacromial artery
- axillary artery
Innervation of Breast
- lateral cutaneous branch of T4-T6 intercostal nerves - give off lateral mammary branches
- anterior cutaneous branch of T4-T6 intercostal nerves - give off medial mammary branches
Lymphatic Drainage of Breast
- 75% axillary nodes (lateral)
- parasternal lymph nodes (medial)
Functions of Lymphatic System
- drainage of extracellular fluid
- carries proteins and cell materials that can’t pass through capillaries
- absorption and transport of dietary fat
- defense
Lymphatic Vessels
- right lymphatic duct - drains right side of head and right arm
- drains at right venous angle (internal jugular + subclavian)
- thoracic duct - drains rest of body
- drains at left venous angle
- usually on right side
Lymph Nodes
- small masses of lymphatic tissue
- contain macrophages
- afferent and efferent vessels
- skin above umbilicus –> axillary nodes
- below umbilicus –> inguinal nodes
- head and neck –> cervical nodes
Axillary Dissection

- done in cases of breast cancer metastasis into axillary lymph nodes
- tons of nerves in axilla could be damaged
- long thoracic nerve –> reduced movement of upper lumb
- intercostobrachial nerve –> pain
- thoracodorsal nerve
- lymphoedema
Pericardium

- fibrous pericardium
- serous pericardium - secretes fluid into pericardial cavity
- parietal layer - stuck to fibrous pericardium
- visceral layer - stuck to heart, also the epicardium
Innervation of Pericardium
phrenic nerves
Blood Supply to Pericardium
pericardiacophrenic arteries (branch of internal thoracic)
Transverse Pericardial Sinus
space between major vessels of the heart
(posterior to ascending aorta and pulmonary trunk
anterior to inferior vena cava)
Oblique Pericardial Sinus

between pulmonary arteries
Fibrous Skeleton of the Heart
- provides attachment and support for muscles of the heart and valves
- functions as insulator between atria and ventricles
- parts:
- fibrous rings around valves
- 2 trigones connect the rings
- membranous portion of interatrial and interventricular septa
Right Atrium

- smooth region
- superior and inferior vena cava
- coronary sinus opening
- fossa ovalis - remnant of fetal foramen ovale
- tricuspid valve (right AV valve)
- rough region
- pectinate muscles
- right auricle
- crista terminalis - separates smooth and rough regions
Right Ventricle

- trabeculae carnae - like pectinate muscles but in ventricle
- papillary muscles - attached to tricuspid valve
- chordae tendinae - connect papillary muscles to valve cusps
- septomarginal trabecula - moderator band, from interventricular wall to base of anterior papillary muscle, contraction
- conus arteriosus - leading into pulmonary valve, also infundibulum
Tricuspid Valve
- 3 cusps: anterior, posterior, septal
- each attached to a papillary muscle via chordae tendinae
- open during diastole - ventricles filling
- closed during systole - ventricular contraction –> papillary muscle contraction –> closure of valve
Pulmonary Valve
- semilunar valve with 3 cusps: anterior, right, left
- closed during diastole
- open during systole when ventricle pumps
Left Atrium
- smooth region
- pulmonary veins
- fossa ovalis
- rough region
- pectinate muscle in left auricle
Left Ventricle
- trabeculae carnae
- papillary muscles - anterior and posterior
- chordae tendinae
- aortic valve and mitral valve
Mitral Valve
- also bicuspid and left AV valve
- anterior and posterior cusps attached to papillary muscles via chordae tendinae
Aortic Valve
- 3 cusps: right, left, posterior
- open during systole: blood pressure in ventricle is high so cups pressed against the wall
- cups made of nodule and lunula around the edges
- diastole: when blood pressure in ventricle decreases, blood starts to flow back into ventricle and goes into the cups and closes the valve
- right coronary artery from right cusp
- left coronary artery from left cusp
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Coronary Arteries
right and left branching from ascending aorta to supply myocardium
Right Coronary Artery

- runs in coronary sulcus/AV groove
- branches:
- right atrial branch
- marginal branch - along border of right ventricle
- posterior interventricular branch in posterior interventricular groove
- referred to as posterior descending artery (PDA)
- sinoatrial nodal and atrioventricular nodal branches
Left Coronary Artery

- bifurcates into
- anterior interventricular branch in anterior interventricular groove
- referred to as left anterior descending artery (LAD)
- circumflex branch - runs in coronary sulcus
- anterior interventricular branch in anterior interventricular groove
Balanced Distribution of Coronary Arteries
- right coronary artery supplies right lateral wall, most of right posterior wall and some of posterior septa
- left coronary artery supplies most
- variations: left coronary dominance, right coronary dominance

Coronary Veins
arise from myocardium and drain into right atrium at coronary sinus
Coronary Veins Path

- small cardiac vein - runs with marginal artery branch of right coronary artery
- great cardiac vein - runs with anterior AV artery
- middle cardiac vein - runs with posterior AV artery
- anterior cardiac veins - arise from anterior surface of RV
Intrinsic Impulse Conducting System

- SA node
- AV node
- AV bundle
- Purkinje fibers/subendocardial branches
Sinoatrial (SA) Node
- in wall of right atrium at superior end of crista terminalis
- pacemaker for heart
- impulse spreads through atria and causes contraction
Atrioventricular (AV) Node
- in floor fo right atrium
- distribuets impulses to atriventricular bundle
Atrioventricular Bundle
- also bundle of His
- bridges fibrous skeleton to bring conduction to ventricles
- divides into left and right branches to go to ventricles
- right bundle goes via septomarginal trabecular to reach anterior papillary muscle
Cardiac Plexus
- sympathetic: from sympathetic trunks to increase heart rate and contraction, dilate coronary arteries
- cervical sympathetic ganglia, cervicothoracic ganglion, thoracal sympathic ganglia
- parasympathetic: from vagus, decreases heart rate and contraction, constricts coronary arteries
Cardiac Tamponade
build-up of blood or other fluid in pericardial sac that puts pressure on the heart and can prevent it from pumping effectively
fixed with pericardiocentesis
Constrictive Pericarditis
after extensive inflammation, pericardium can scar and limit heart contractions
fixed with pericardiectomy (pericardial stripping)
Myocardial Infarction
blockage in coronary arteries causes muscle damage
Coronary Catheterization
insert stent and balloon into coronary artery to allow blood flow
Post-Myocardial Infarction Ventricular Septal Defects
muscle death causes a hole between the ventricles
get mitral regurgitation
long term: volume overload to right ventricle, increased presure in pulmonary vessels and pulmonary edema
Blockage in RCA
serves inferior wall, right ventricle, and conduction system
can have issues with arrythmias due to damage to conduction system and papillary muscles
Biventricular Pacemaker
right atrial lead, right ventricular lead, LV coronary sinus lead
Chest X-ray (CXR) Views
- PA - posterior anterior, frontal, standing
- lateral - standing
- AP - anteiror posterior, frontal, supine
Measuring Heart Size on CXR

- PA view only
- cardiothoracic ratio = heart size/thoracic diameter
- normal <50%
Cardiac Silhouette Borders on CXR (Frontal PA)

- right: RA
- left: aortic arch, pulmonary artery, left auricle, left ventricle
Cardiac Silhouette Borders on XCR (Lateral)

- anterior: RV
- posterior: LA

Mediastinum on CXR

Mediastinum on CXR (Lateral)

Thymic Tumor

Aorta on frontal CXR

Aorta on lateral CXR

Aorta on frontal and lateral CT

Aorta on CT cross sections

Aortic dissection on CXR- enlargement

Aortic dissection CT - diagnostic intimal flap

Pulmonary arteries on CXR

Pulmonary arteries on CT

Superior vena cava - right superior mediastinal border
Azygos Vein - oval density in angle between trachea and right main stem brochus

trachea - midline air containing structure
carina - important landmark
bronchi - right is wider, shorter, more vertically oriented
Endotracheal Intubation

placement confirmed with CXR
want it to go into right or above carina
Lungs on CXR
not usually recognizable so surmise based on adjacent structures
- right and left upper lobe - adjacent to thoracic apex
- right middle lobe - adjacent to right heart border, anterior on lateral
- right and left lower lobe - adjacent to right hemodiaphragm

Left Lung on CXR

Right Lung on CXR
Pneumothorax on CXR

can see thin line or edge
Pleural Recesses

- where the two layers of parietal pleura are not separated by lung during quiet respiration
- costodiaphragmatic angles
- anterior - 8th rib
- lateral - 10th rib
- posterior - 12th rib

Pleural Fluid in Costodiaphragmatic Angle

- right slightly higher than left usually
- convex upward
Anterior Abdominal Wall Bony Landmarks
arae between xiphoid process and costal margin
xiphoid process, costal margin, pubis, ilium
Features of Anterior Abdominal Wall
umbilicus
tendinous intersections
linea alba
semilunar lines
Sagittal Planes of the Anterior Abdomen
median - through umbilicus
midclavicular
Transverse Planes
subcostal - inferior border of 10th costal cartilage
transtubercular - level of iliac tubercles, L5
transpyloric - level of pylorus of stomach, ~L1, midpoint between superior aspect of manubrium and superior aspect of pubis
transumbilical - about level of umbilicus, iliac crests, L3/4
Quadrants of Anterior Abdomen
formed by median sagittal plane and transumbilical plane
right and left upper, right and left lower, periumbilical
Regions of Anterior Abdomen

formed by the midclavicular, subcostal, and transtubercular planes
subcostal regions: right and left hypochondriac, epigastric
lumbar regions: right and left lateral, umbilical
iliac regions: right and left inguinal, hypogastric
Functions of Anterior Abdominal Wall
- support and protection for abdominal viscera
- increase intra-abdominal pressure - forced expiration, defecation, micturition, coughing, parturition
- flexion and rotation of trunk
Layers of the Anterior Abdominal Wall
- skin
- superficial fascia (Campers fascia, Scarpas fascia)
- external oblique
- internal oblique
- transversus abdominis
- transversalis fascia
- extraperitoneal fat
- parietal peritoneum
Superficial Fascia

Campers fascia - outer fatty layer
Scarpas fascia - inner membranous layer inferior to umbilicus; connections to scrotum, penis, and perineum
External Abdominal Oblique

- lateral muscle, aponeurosis anteriorly
- hands in pocket fibers: lateral to medial
- contributes to rectus sheath
- free lower edge - forms inguinal ligament
Internal Abdominal Oblique

fibers run perpendicular to external oblique
aponeurosis contributes to rectus sheath inferior to arcuate line; goes anterior and posterior superior to arcuate line
contributes to inguinal canal
Transversus Abdominus
- innermost muscle layer
- fibers run horizontally
- aponeurosis contributes to anterior wall of rectus sheath inferior to arcuate line, contributes to posterior wall superior to arcuate line
- nerves/blood vessels travel between internal oblique and transversus abdominus
Transversalis Fascia

- part of endoabdominal fascia - lines abdominal cavity, continuous with pelvic fascia
- forms deep inguinal ring
Rectus Abdominis

- O: medial pubis
- I: costal margin/inferior sternum
- A: flexion of lumbar spine, compresses abdominal viscera, stabilizes pelvis
- I: thoracoabdominal nerves (ventral primary rami T7-12)
- A: superior and inferior epigastric artery anastamose
Arcuate Line

posterior to rectus muscle, 1/3 between umbilicus and pubic crest
Rectus Sheath

- above arcuate line:
- anterior - ext. and int. oblique
- posterior - int. oblique and transversus abdominus
- below arcuate line
- anterior - ext. and int. oblique, transversus abdominus
- posterir - only transversalis fascia
Hernias of the Abdominal Wall
- outpouching of peritoneum through an acquired weakness or defect in the abdominal wall
- types: epigastric, spigelian, inguinal, incisional
Epigastric Hernia
between sternum and umbilicus through linea alba
Spigelian Hernia
occur along semilunar lines
Umbilical Hernia
through umbilical ring
most common in women and obese individuals
Inguinal Hernia
- direct/acquired - projection into area of superficial inguinal ring
- often through Hesselbach’s Triangle (inguinal ligament, lateral border of rectus abdominis, inferior epigastric vessels)
- medial to inferior epigastric artery
- indirect/congenital - projection into deep inguinal ring, down the inguinal canal, and through superficial inguinal ring into scrotum
- lateral to inferior epigastric artery
Nerves of Anteiror Abdominal Wall

- ventral primary rami from T7-L1
- thoracoabdominal nerves (T7-11)
- subcostal nerve (T12)
- iliohypogastric (L1)
- ilioinguinal (L1)
- genitofemoral (L1-2)
Thoracoabdominal Nerves (T7-11)
sensory: skin
motor: abdominal muscles
Subcostal Nerve (T12)
sensory: skin
motor: abdominal musculature
Iliohypogastric Nerve (L1)
sensory: skin over iliac crest to pubic region
motor: internal bolique, transversus abdominis
Ilioinguinal Nerve (L1)
sensory: external genitalia, medial thigh
motor: internal oblique, transversus abdominus
Genitofemoral Nerve (L1-2)
genital branch: cremaster muscle and scrotum, skin of mons pubis and labia majora
femoral branch: skin on anterior superior thigh
Landmarks for Dermatome Levels In Abdomen

xiphoid process: T5-6
umbilicus: T10
pubis: L1
Arteries of Anterior Abdominal Wall
complex anastomotic network - internal thoracic (superior epigastric, musculophrenic), thoracic aorta, abdominal aorta (external iliac, femoral, inferior epigastric)
superior epigastric (internal thoracic) and inferior epigastric (abdominal aorta and external iliac) provides collateral circulation
Veins of the Anterior Abdominal Wall
- complex venous plexus
- deeper veins follow arteries
- collateral circulation is important!
Lymphatics of Anterior Abdominal Wall
- superior to transumbilical plane: superficial lymphatic vessels, drain to axillary lymph nodes
- inferior to transumbilical plane: superficial inguinal lymph nodes, converge to thoracic duct
Internal Surface of Anterior Abdominal Wall

- median umbilical fold - bladder to umbilicus, parietal peritoneum over urachus ligament
- medial umbilical folds - parietal peritoneum over obliterated umbilical arteries
- lateral umbilical folds - parietal peritoneum over inferior epigastric vessels
Inguinal Region

region between anterior superior iliac spine and pubic tubercle
site for inguinal hernias
Inguinal Ligament

- created by free inferior edge of ext. oblique
- anterior superior iliac spine to pubic tubercle
- forms inguinal canal
- boundary between atenrior abdominal wall and thigh
- maintains the integrity of the muscles and vessels
Inguinal Canal

- superior-lateral opening - deep/internal inguinal ring in transversalis fascia
- inferior-medial opening - superficial/external inguinal ring in ext. oblique aponeurosis
- males: spermatic cord; females: round ligament
- ilioinguinal nerve and genital branch of genitofemoral
Scrotum
- fibromuscular sac developed as an outpouching of the anterior abdominal wall
- skin and Dartos fascia (continuation of Scarpas fascia, includes small muscle fibers)
- scrotal septum - separates scrotum into 2 non-communicating compartment
Scrotal Ligament
anchors inferior pole of testis to bottom of scrotum, remnant of gubernaculum
Spermatic Cord
carries blood, nerves, and lymphatics for testis and transports sperm from testis to inside pelvic cavity via ductus deferens
Coverings of Spermatic Cord
- external spermatic fascia - continuation of ext. oblique aponeurosis
- cremaster muscle and fascia - continuation of int. oblique and fascia
- internal spermatic fascia - continuatoin of transversalis fascia
Cremaster Muscle
innervated by genital branch of genitofemoral
elevate testes in response to cold, fear, or sexual stimulation
Contents of Spermatic Cord

- ductus deferens and artery - transport sperm from testis to pelvic cavity
- testicular artery - supplies testis and epididymis, from abdominal aorta
- pampiniform plexus of veins
- autonomic nerves and genital branch
- lymphatics
Testis

- seminiferous tubules - sperm formed
- travel in efferent ductules
- stored in epidiymis
- tunica albuginea - capsule, septa separate blocks of seminiferous tubules
- tunica vaginalis - closed peritoneal sac, pareital and visceral parts
Lymphatic Drainage of Male Genitals
- scrotum - to superficial inguinal lymph nodes
- testis - to lumbar and pre-aortic lymph nodes
Descent of the Testis and Ovary
- both originate on posterior abdominal wall then pulled inferiorly by relative shortening of gubernaculum
- ovary stops at pelvic brim
- gubernaculum –> round ligament of the utereus, proper ligament of the ovary
- testis continues to scrotum
Opened Peritoneal Cavity

- opens greater sac of peritoneum
- falciform ligament - anterior body wall to liver
- ligamentum teres
- can see right and left lobe of liver and some gallbladder
- part of stomach
- greater omentum - covers all organs located inferior to stomach
Layer 2: Liver Reflected

- lesser omentum - made of hepatogastric and hepatoduodenal ligaments, connect liver to stomach and duodenum
- portal triad runs through
- omental foramen - opening deep to free edge of lesser opening, into lesser sac of peritoneum
- spleen to the left of the stomach
Layer 3: Greater Omentum and Stomach Reflected

- small intestine and large intestine
- ascending colon along right body wall
- transverse colon inferior to stomach, attached to greater omentum
- descending colon along left body wall
Layer 4: Most of GI Tract Removed

- pancreas
- inferior vena cava
- abdominal aorta
- kidneys
Liver

- diaphragmatic and visceral surfaces
- diaphragmatic surface with bare area
Anatomical Lobes

- right, left, caudate, quadrate lobes
- falciform ligament and ligamentum teres divide left and right
- posterior division at left sagittal fissure - ligament venosum
Functional Lobes of Liver

- right sagittal fissure - gallbladder and inferior vena cava
- right, left, caudate lobes
- 8 surfically resectable hepatic segments - each with portal vein, hepatic artery, biliary drainage
Right Sagittal Fissure
inferior vena cava, gallbladder
Left Sagittal Fissure
ligamentum teres and venosum
Porta Hepatis
portal triad - common bile dict, proper hepatic artery, portal vein
Biliary System

- bile produced in liver
- drains through hepatic ducts (right and left) into ccommon bile duct
- then to cystic duct to be stored in gallbladder
- during digestion, gallbladder contracts and forces bile down common bile duct
- bile duct and main pancreatic duct join to form main hepatopancreatic ampulla
- then opens into duodenum and major duodenal papilla
Gallstones
- cholesterol stones - yellow and large
- pigmented stones - small and dark
Spleen
- left upper quadrant, posterior
- largest lymphatic organ
- removes old RBC
Pancreas

- secondarily retroperitoneal
- parts:
- head - tucked into C loop of duodenum
- neck - anterior to superior mesenteric artery
- body - between neck and tail
- tail - near spleen
- main pancreatic duct joins bile duct –> hepatopancreatic ampulla
- hepatopancreatic sphincter of Oddi surrounds ampulla
- opens into descending duodenum at major duodenal papilla
Stomach

- cardia - near esophagus
- fundus - dilated superior portion
- body - major portion
- pyloric part - outflow region, antrum + canal
- pyloric sphincter
- greater and lesser curvature
Small Intestine
- duodenum, jejunum, ileum
Duodenum
- 4 parts
- superior - intraperitoneal, horizontal
- descending - bile and pancreatic ducts
- horizontal
- ascending
- ligament of Treitz - suspensory ligament, suports duodenal-jejunal junction
Jejunum vs Ileum
- jejunum is more red - more vascularization
- jejunum has thicker wall
- jejunum has larger, talller, more closely packed internal folds
- jejunum arcades are fewer and larger
- jejunum vasa recta are longer
Large Intestine

- cecum - enlarged area that receives material from small intestine
- appendix (McBurney’s point)
- ascending colon - right body wall, ends at right colic/hepatic flexure
- transverse colon - between right colic/hepatic and left colic/splenic flexures
- descending colon - left body wall, ends in sigmoid
- sigmoid colon - S-shaped, meets rectum
- teniae coli, haustra, omental appendices
Arterial Supply to GI Tract
- 3 major branches from abdominal aorta
- celiac trunk - foregut
- superior mesenteric artery - midgut
- inferior mesenteric artery - hindgut
Parts of Gut and Divisions
- foregut and midgut - duodenum
- midgut and hindgut - transverse colon
Celiac Trunk

- 3 branches
- splenic artery
- left gastric artery
- common hepatic artery
Branches of Common Hepatic Artery
- gastroduodenal
- right gastro-omental - greater curvature of stomach
- superior pancreaticoduodenal - duodenum and head of pancreas
- proper hepatic artery
- right gastric - lesser curvature of stomach
- left hepatic - left lobe of liver
- right hepatic - right lobe
- cystic branch - gallbaldder
Left Gastric Artery
supplies esphagus and lesser curvature of stomach
Branches of Splenic Artery
- pancreatic branches - to pancreas
- left gastro-omental - greater curvature of stomach
- short gastrics - fundus
Superior Mesenteric Artery

- inferior pancreaticoduodenal - distal duodenum and head of pancreas
- intestinal branches - small intestine
- form arcades and vasa recta
- ileocolic artery - distal ileum, cecum, appendix
- right colic - ascending colon
- middle colic - transverse colon
Inferior Mesenteric Artery

- left colic - transverse colon, descending colon
- sigmoid arteries - sigmoid colon, descending colon
- superior rectal artery - proximal rectum
Marginal Artery
between superior and inferior mesenteric arteries
Portal Venous System

- portal vein - carries blood from GI tract to liver
- distal branches - same names as arteries, except no celiac trunk vein
- splenic vein - spleen, stomach, pancreas
- superior mesenteric vein - stomach, ancreas, small intestine, cecum, ascending and transverse colon
- inferior mesenteric vein - transverse colon, descending colon, sigmoid colon, proximal rectum
- inferior mesenteric drains to splenic
- splenic joins superior mesenteric to form portal vein
- after liver, blood drains via right, middle, left, hepatic veins into inferior vena cava
Portal/Caval Anastomoses
- portal system lacks valves!
- gastroesophageal region - system esophageal veins to left gastric branch
- anal canal - systemic middle and inferior rectal veins to superior rectal branch
- hemorrhoids
- paraumbilical region - small cutnaeous veins with paraumbilical veins of falciform ligament to drain into portal vein
- caput medusae
- retroperitoneal region - posterior aspects of secondarily retroperitoneal viscera or liver with systemic retroperitoneal veins
Visceral Motor Innervation to GI Tract
- provided by autonomic nervous system
- sympathetics - vasoconstriction
- parasympathetics - rest and digest
- preganglionic sympathetics synapse at prevertebral ganglion
- postganglionic sympathetics + preganglionic parasympathetics –> peri-arterial plexuses –> travel to targets via blood vessels
Sympathetic Visceral Motor
- preganglionic
- thoracic splanchnics from T5-12
- greater T5-9
- lesser T10-11
- least T12
- lumbar splanchnics from L1-2
- contribute to aortic plexus
- thoracic splanchnics from T5-12
- synapse at prevertebral sympathetic ganglia near roots of central arteries
- greater –> celiac ganglion
- lesser - superior mesenteric ganglion
- least - aorticorenal ganglion
- lumbar - inferior mesenteric ganglion
- postganglionic fibers distributed to nearby arteries and go to target organs
Parasympathetic Visceral Motor
- preganglionic
- vagus nerve - anterior and posterior vagal trunks
- distal esophagus to left colic flexure
- contribute to aortic plexus
- distributed via peri-arterial plexuses
- pelvic splanchnics from S2-4
- distal to left colic flexure
- distribued by inferior hypogastric plexus
- vagus nerve - anterior and posterior vagal trunks
- synpase near targets
Visceral Sensory Innervation to GI Tract
- internal stimuli, reflexes - follow parasympathetic
- pain -
- distal esophagus to midpoint of sigmoid
- follows sympathetic (thoracic or lumbar splanchnics)
- goes to thoracolumbar spinal sensory ganglia
Referred Pain
- pain in GI tract is referred to dermatome levels supplised by the same spinal cord levels from which the specific sympathetic/parasympathetic nerves
- ex: appendix
- supplied by T10 - referred to paraumbilical region
- later pain is from irritation of parietal peritoneum localized to area of skin superficial - right lower quadrant
Diaphragm (Abdominal Perspective)

- central tendon
- sternal, costal, lumbar portions
- right and left crura - musculotendinous extensions of the diaphragm from bodies L1-3 and interior longitudinal ligament
- right crus loops and forms esophageal hiatus
- right crus + left crus + median arcuate ligament forms aortic hiatus
Arcuate Ligament

- median arcuate ligament - connects right and left crus
- medial arcuate ligament - over psoas major
- lateral arcuate ligament - over quadratus lumborum
Openings in the Diaphragm

- “I 8 10 Eggs At 12”
- vena caval foramen - T8
- inferior vena cava
- esophageal hiatus - T10
- esophagus, anterior and posterior vagal trunks
- aortic hiatus - T12
- aorta, thoracic duct, azygos vein
Branches of Abdominal Aorta
- anterior unpaired - to GI
- celiac trunk
- superior mesentery
- inferior mesentery
- lateral paired - to glands
- renal arteries
- middle suprarenals
- gonadal
- posterior paired - to body wall
- inferior phrenic
- lumbar arteries - 4 pairs
- terminal branches
- right and left common iliac - L4 bifurcation
- external iliac and internal iliac
- median sacral
- right and left common iliac - L4 bifurcation
Abdominal Aortic Aneurysm
dilations of arteries
may burst if it gets too big
Branches of Inferior Vena Cava

- left and right renal veins
- left gonadal vein branches from left renal
- right gonadal
- common iliac veins - bifurcation at L5
- external and internal iliac veins
Left vs. Right Renal Veins
- left is longer than right
- left gonadal comes directly from left renal
- right gonadal comes from IVC
Kidneys
- primarily retroperitoneal
- T12-L3 on posterior abdominal wall
- right slightly inferior to left - liver on right
- perinephric fat - goes around kidneys
- 2 layers separated by Gerota’s fascia/renal fascia
Structure of Kidney

- renal hilum - indentation on medial surface, where arteries enter and veins and renal pelvis leave
- fibrous capsule
Sagittal Section of Kidney

- cortex and renal columns
- renal pyramids with renal papillae - medulla
- minor and major calyx
- renal pelvis
- ureter
Areas of Constriction on Ureters

- where renal pelvis drains into ureter
- where ureter crosses the common iliac artery
- where ureter enters the bladder
Adrenal/Suprarenal Glands
endocrine glands surrounded by renal fascia and attached primarily to the diaphragmatic crura
Arterial Supply to Suprarenal Glands
- superior suprarenal - from inferior phrenic
- middle suprarenal - from aorta
- inferior suprarenal - from renal artery
Venous Drainage of Suprarenal Glands
- suprarenal veins
- left is longer and drains directly to left renal vein
- shorter right one drains to IVC
Muscles of Posterior Abdominal Wall

- quadratus lumborum
- psoas major and minor
- iliacus
- transversus abdominus
Quadratus Lumborum (QL)
- iliac crest to lumbar vertebrae and 12th rib
- ventral primary rami T12-14
- draws pelvis towards ribs, lateral flexion of vertebral column
Psoas Major
- extends from vertebral bodies of T12-L5 to lesser trochanter of femur
- flexes thigh and trunk
- ventral primary rami L1-3
Iliacus
- extends form sacrum to femur
- flexes thigh
- innervated by femoral nerve
Nerves of Posterior Abdominal Wall

- subcostal (T12)
- lumbar plexus branches
- iliohypogastric (L1)
- ilioinguinal (L1)
- genitofemoral (L1-2)
- lateral femoral cutaneous (L2-3)
- femoral (L2-4)
- Obturator (L2-4)
- lumbosacral trunk (L4-5)
- sympathetic trunk
Testicular Torsion
- twist in the spermatic cord –> cut off blood supply –> testes can die
- check for cremasteric reflex - touch inner thigh (L1 does cutaneous), goes to spinal cord, L1 component of genitofemoral –> cremaster contracts
- if there is no reflex, then you have a case of testicular torsion