Anatomy

==Block 8 - Lecture 15 & 16 (Thoracic viscera 1 & 2) - Khanna==

Thoracic viscera 1

List three major compartments of the thoracic cavity
- Right and left pleural cavities, mediastinum (cardiac window)
Describe the topography of the lungs
- Superior: apices extend 2.5 cm above the clavicle to vertebrae prominens
- Inferior: depends upon the line of the axis
  - Mid-clavicular: Rib 6
  - Mid-axillary: Rib 8
  - Paravertebral: Rib 10
- Right lung has three lobes, left lung has two lobes
Describe the boundaries and divisions of the mediastinum
1. Boundaries
  - Anterior: sternum
  - Posterior: T1-T-12
  - Superior: jugular notch → T1
  - Inferior: diaphragm → T12
2. Divisions: separated by line connecting jugular notch → T4/T5
  - Superior
  - Inferior: anterior, middle, posterior subdivisions
List the major viscera located in each of the divisions of the mediastinum
- Superior mediastinum: trachea, esophagus, & thymus (anterior)
- Middle mediastinum: pericardium, heart, initial segments of great vessels
- Posterior mediastinum: esophagus continued & primary bronchi
Describe the surface topography for the auscultation of cardiac valves
- Right 2nd intercostal space - aortic valve
- Left 2nd intercostal space - pulmonary valve
- Left 4th intercostal space - right AV valve
- Left 5th intercostal space - left AV valve
Describe the general function of the thymus gland and its mediastinal location
- Superior/anterior mediastinum = educates T lymphocytes to recognize self antigens & then involutes (peak mass of 35 g @ puberty)
Describe the movements of the heart during inspiration and expiration
- Fibrous pericardium is attached to the diaphragm, heart moves up and down with each breath

Thoracic viscera 2

Compare & contrast the anatomy of the four cardiac chambers
- RA: pectinate muscle (derived from primitive atrium), sinus venarum (smooth; derived from sinus venosus), fossa ovalis, openings for coronary sinus/SVC/IVC, crista terminalis
- RV: trabeculae carneae (muscular ridges), papillary muscles, chordae tendinae
- LA: mostly smooth, 4 x pulmonary veins, valve of foramen ovale, some pectinate muscle
- LV: trabeculae carneae, papillary muscles, chordae tendinae
List the great vessels and the cardiac chambers that receive or issue from them
- SVC & IVC → RA
- 4 pulmonary veins → LA
- 2 pulmonary arteries (send blood from RV → lungs via pulmonary trunk)
- LV → aorta
Describe the sulci, surfaces, base and apex
- 3 sulci: one separating A/V & 2 separating the ventricles
  - Atrioventricular/coronary sulcus: separates atria and ventricles → RCA
  - Anterior IV → LCA
  - Posterior IV → circumflex & RCA
- Surfaces: anterior/sternocostal (RA, RV, part of LV & L auricle); right pulmonary (RA); left pulmonary (LV & part of LA); diaphragmatic (RV & LV)
- Base: receives pulmonary veins, SVC & IVC
- Apex: formed by LV, 7-9 cm left of midline, 5th intercostal space
Describe the cardiac valves with regard to location and numbers of cusps
- Right AV valve = tricuspid valve; 3 cusps (anterior, posterior, septal)
- Left AV valve = bicuspid/mitral valve; 2 cusps (anterior, posterior)
- Pulmonic valve (more anterior): 3 cusps (anterior, right, left)
- Aortic valve: 3 cusps (left, right, posterior); posterior is non coronary w/ right and left giving off branches of coronary arteries

%%Block 9. Thoracic viscera 3 & 4 - Khanna%%

Thoracic viscera 3

Describe the coronary circulation with regard to dominance and arterial distribution and venous drainage
- Right cusp of aortic artery → RCA
- Left cups of aortic artery → LCA
- Dominance patterns: depends which artery is supplying the posterior IV sulcus
- Right dominant pattern
  - 70-80% of people; RCA → posterior IV sulcus (as posterior descending artery)
- Left dominant pattern
  - 8-10% of people: Left circumflex → posterior IV sulcus
- Balanced pattern
  - 1% of patients: 2 posterior IV arteries (RCA & LCx)
- Venous drainage:
  - Great cardiac vein (anterior IV) → coronary sinus
  - Middle cardiac vein (posterior IV) → coronary sinus
  - Anterior cardiac veins → drain directly into right atrium
  - drains primarily right ventricle
  - Venae cordis minimae → run deep w/ muscle tissue
Describe the cardiac conduction system and the clinical relevance of Koch’s triangle
- Koch’s triangle borders
  - Todaro’s tendon, ostium of coronary sinus, base of septal cusp
  - Location of the AV node
  - SA → AV → Bundle of His → RBB and LBB → Purkinje
Describe the pleural membranes and associated recesses
- Parietal pleura
  - Regions of parietal pleura
  - Costovertebral or costal pleura: along the ribcage & vertebral column
  - Diaphragmatic pleura
  - Cervical pleura: covers apical lung
  - Mediastinal pleura
  - Recesses: points of reflection -- potential spaces
  - Costodiaphragmatic recess = potential space which can accumulate fluid, where costal and diaphragmatic pleura meet
  - Costomediastinal recess = parietal pleura meets mediastinum
  - Vertebromediastinal recess = lungs to vertebral
- Visceral pleura - up against the organ
- Potential space between parietal and visceral pleura = pleural cavity
Describe the trachea, its wall, and bronchial branching pattern
- Starts at C6
- Bifurcates T4, T5
  - Right main bronchus: more vertical, wider
- 10-11 cm in length
- 16-20 cartilaginous incomplete rings
- Layers (internal to external)
  - Mucosa - epithelium
  - Tunica mucosa or submucosa - glands
  - Cartilaginous/fibromuscular - trachealis muscle
  - Adventitia - connective tissue coat
- Bronchi → bronchioles
  - 2 primary (right and left)
  - Right has 3 lobes → 3 secondary/lobar bronchi
  - 10 tertiary/segmental
  - Left has 2 lobes → 2 secondary/lobar bronchi
  - 8 tertiary/segmental

Thoracic 4

Compare and contrast the features of the right and left lungs
Describe the applied anatomy in performing a thoracentesis
Describe the esophageal segments, constrictions, and layers forming its wall
Describe the locations of esophageal diverticula and the relevance of Killian’s triangle
Describe the arteries of the thorax, the parent vessels that issue them, and their distribution

^^Block 10. Thoracic viscera 5 & 6 - Khanna^^

Thoracic 5

List he parts of the aorta found in the thorax
Describe the normal and variant branching pattern of the aortic arch
Describe the veins of the thorax, the vessels they empty into, and their drainage

Thoracic 6

Describe the distributions of the phrenic nerve and the sympathetic and parasympathetic divisions of the autonomic nervous system
Compare and contrast the general functions of the ANS
Describe the clinically applied anatomy of vocal cord paralysis and achalasia
Describe the clinically applied anatomy of asthma, Pancoast tumor, and cardiac referred pain

@@Block 11. Abdomen 1 & 2 - Lutfi@@

Abdominal wall 1

Locate the surface landmarks, regions, reference planes and positions of organs (appendix and liver) for the abdomen
Surface anatomy:

Umbilicus: L3 - L4 intervertebral disc
Linea alba: xiphoid process → pubis (separates into right and left abdomen)
Linea semilunaris: curved line (convex laterally) approx. 5-8 cm from median plane; 9th costal cartilage → pubis; represents lateral border of rectus abdominis muscle
Tendinous intersections: transverse lines over the rectus abdominis muscle
Inguinal groove: division between the anterior abdominal wall and anterior thigh region
Pubic symphysis: firm resistance felt at the inferior end of the linea alba at the anterior aspect of the median plane
Pubic crest and tubercle: bony landmark located 2.5 cm laterally of pubic symphysis (inguinal ligament attaches here)
Iliac crest: extends posteriorly from ASIS, the iliac tubercle can be palpated 6 cm posterior to the ASIS
Epigastric fossa: slight depression in epigastrium just inferior to xiphoid, best seen supine
SUPERIOR ABDOMEN
- Xiphoid process
- Costal cartilages of 7-10th ribs
INFERIOR ABDOMEN
- Inguinal ligament
- Pubic crest and pubic symphysis
PLANES AND REGIONS
- Horizontal planes
- Transpyloric plane = thru L1
- Subcostal plane = joins the inferior margins of the 10th costal cartilage passing thru L2-L3
- Transtubercular plane (TTP) or inter-tubercular plane = thru iliac tubercles, usually passes thru body at L5
- Transumbilical plane (TUP) = thru umbilicus; indicates the level of the intervertebral disc between L3 - L4
- Vertical planes
- Mid-clavicular lines: from mid clavicle → mid-inguinal point in the sagittal plane
- Median plane
Position of appendix: 1/3 the distance from the ASIS → McBurney’s point
- Right inguinal region
Position of the liver: right hypochondriac region
- Typically can’t feel it in a healthy person because it is protected by the ribs

Define the sensory distribution of the abdomen
List the layers of the abdominal wall from superficial to deep
Locate the origin and insertion of the abdominal wall muscles (external oblique, rectus abdominus, internal oblique, transversus abdominus) and define their innervation and describe their actions

Abdominal wall 2

List the components of the rectus sheath
Distinguish the differences between the rectus sheath above and below the umbilicus
Locate the arcuate line in the posterior view of the abdominal wall and define its significance
Label the blood supply (epigastric vessels) of the abdominal wall and its branches
Identify the spinal nerve branches that innervate the abdomen
Describe the movements of the abdomen (lateral, flexion, extension, and rotation)
Describe the boundaries of the surface anatomy of the inguinal canal
Identify the origin, insertion, nerve and blood supply, and action of the abdominal wall muscles
Identify the layer of the abdominal wall. Be able to list these layers in order from superficial to deep

B12. Inguinal region + inguinal hernias & Abdominal organs - Lutfi

Inguinal region and hernias

Define the boundaries of the inguinal canal (anterior wall, posterior wall, roof and floor)
- Surface anatomy of inguinal region: ASIS → pubic tubercle
- Inguinal canal = 4-5 cm, oblique passage, runs inferomedially just superior and parallel to medial half of the inguinal ligament
- Boundaries of inguinal canal
  - Anterior: aponeurosis of EOM and lateral 1/3 IOM
  - Posterior: fascia transversalis, reinforced by conjoint tendon
  - Roof: arching fibers of IOM and transversus abdominis (intercrural fibers)
  - Floor: lacunar ligament
Differentiate the contents of the inguinal canal male vs. female
- Male: spermatic cord + its contents
- Female: round ligament of uterus
- Both sexes: Ilioinguinal nerve (L1) ** content of inguinal canal, but not of spermatic cord!
Describe the layers of the spermatic cord from superficial to deep
- Spermatic cord passed thru IOM, TA and IOM pass over it, and TA and IOM converge behind the superior inguinal ring → conjoint tendon
- Coverings of spermatic cord (sup to deep)
  - Internal spermatic fascia from (TF) transversalis fascia
  - Cremasteric fascia and muscle from IOMA and muscle fibers
  - External spermatic fascia from EOMA
Define an inguinal hernia and explain its possible causes & sites of weakness
- Inguinal canal has an opening at either end
  - Deep inguinal ring: slit in TF
  - Superficial inguinal ring: triangular opening in EOMA
  - Hernia = abdominal protrusion of tissue thru an opening from the cavity in which it belongs
  - Inguinal hernia: males > females
    - Indirect (congenital) 75% of cases
    - Direct (acquired)
Differentiate between an indirect and direct hernia
- Indirect inguinal hernia: LATERAL to inferior epigastric artery → deep inguinal ring → canal → superficial inguinal ring
  - hernial sac w/i spermatic cord
  - can be palpated lateral to pubic tubercle
- Direct inguinal hernia: protrude ANTERIORLY through posterior wall of inguinal canal and leave abdominal canal MEDIAL to the inferior epigastric artery
  - pass thru Hesselbach’s triangle (aka inguinal triangle)
  - located posteriorly to superficial inguinal ring
  - hernial sac parallels spermatic cod
Identify the efferent and afferent arms of the cremasteric reflex
- Afferent: ilioinguinal nerve L1 → supplies anterosuperior skin of the thigh
- Efferent: genital branch of the genitofemoral nerve L1/L2 thru superficial inguinal ring
  - genital branch supplies the cremaster muscle
- Absent reflex → corticospinal tract injury
List the contents of the spermatic cord
- Begins at deep inguinal ring and ends in the testis
- Contents (3 arteries, 2 nerves, 1 venous plexus, VD, lymph, remnant)
  - Vas deferens
  - Testicular artery (abdominal aorta)
  - Testicular veins
  - Lymphatic vessels → lumbar lymph nodes
  - Sympathetic nerves (run w/ testicular artery)
  - Remnant of processus vaginalis
  - Cremasteric artery → cremasteric muscle
  - Genital branch of genitofemoral nerve (L1-L2)
  - Arteries to vas deferens (from superior or inferior vesical artery)
Identify the boundaries of Hesselbach’s triangle
- Inferior: inguinal ligament
- Medial: rectus abdominis muscle
- Lateral: inferior epigastric artery
Describe the venous drainage of the testicles
- Testicular veins begin in testes as extensive venous plexus (Pampiniform)
  - Pampiniform plexus
  - Right testicular vein leaves plexus as single vein → IVC at L1 (directly)
  - Left testicular vein leaves plexus as single vein → left renal vein at L1
1. Define varicocele and its pathogenesis
- abnormality in the testicular venous drainage system, valve problem
- dilated/tortuous pampiniform plexus or cremasteric plexus → infertility

Abdominal organs

Describe the embryology of the GI tract
- split into foregut, midgut, and hind gut
Define foregut, midgut, and hind gut
- Foregut: cranial portion which ends at second part of duodenum where the common bile duct enters
  - esophagus, stomach, duodenum, liver, pancreas, biliary passages, gallbladder
  - PSD: vagus
  - SD: pre greater splanchnic → post celiac ganglion
  - Blood supply: celiac trunk
  - Referred pain → epigastrium
- Midgut: second part of the duodenum and ends at left colic flexure
  - 2/3/4 duodenum, jejunum, ilium, cecum, appendix, ascending colon, proximal 2/3 transverse colon
  - PSD: vagus
  - SD: pre lesser splanchnic → post superior mesenteric ganglion
  - Blood supply: SMA
  - Referred pain → umbilical
- Hind gut: starts at left colic flexure → ends at upper anal canal
  - distal 1/3 transverse colon, descending colon, sigmoid, rectum, upper anal canal (above pectinate line)
  - PSD: pelvic splanchnic
  - SD: pre lumbar splanchnic → post inferior mesenteric ganglion
  - Blood supply: IMA
  - Referred pain → hypogastrium
Define the blood supply & nerve supply: esophagus, stomach, duodenum, small intestine
- Esophagus: short abdominal segment which measures 1-2 cm, enters at cardiac region of stomach posterior to level of 7th costal cartilage
  - Arteries: left gastric and left inferior phrenic artery
  - Venous: azygos and left gastric vein (portal system)
  - Nerves: vagus, sympathetic trunks, greater splanchnic, plexuses around left gastric and inferior phrenic arteries (periarterial plexuses)
- Stomach
  - Arteries: celiac trunk, common hepatic artery → right gastric artery and gastroduodenal artery, splenic artery → left gastroomental and short gastric artery
  - Veins: right and left gastric veins, right and left gastroomental veins, short gastric veins
  - Nerves: PSD vagus & a/p vagal branches; SD celiac plexus and T6-T9 efferent, greater splanchnic (T5-T9)
- Duodenum
  - Arteries: celiac trunk via common hepatic artery through superior pancreaticoduodenal artery (gastroduodenal artery) and SMA via the interior pancreaticoduodenal artery
  - Veins: portal system of veins and SMV
  - Nerves: Foregut section → vagus (PSD) and greater splanchnic (SD); midgut section → vagus (PSD) and lesser splanchnic (SD)
- Small intestine: proximal 2/5 = jejunum and distal 3/5 = ileum
  - Arteries: SMA (abdominal aorta L1 via jejunal and ileal branches
  - Veins: portal vein (SMV joins with splenic vein)
  - Nerves: Vagus (PD) and lesser splanchnic (SD)
List branches of the celiac trunk, superior and inferior mesenteric arteries
Celiac trunk
- Left gastric artery
  - 3 branches: ventral → anterior surface of stomach, dorsal → lesser curvature, cardioesophageal → cardia and esophagus
- Common hepatic artery
  - Gastroduodenal artery
  - Retroduodenal artery
  - Right gastroepiploic artery
  - Superior pancreaticoduodenal artery
  - Right gastric artery → lesser omentum and pylorus
  - Proper hepatic artery
  - Right hepatic artery → cystic artery
  - Left hepatic artery → capsule of liver
  - Middle hepatic artery → quadrate lobe of liver
- Splenic artery
  - Pancreatic artery, dorsal pancreatic artery, great pancreatic artery, caudal pancreatic artery
  - Left gastroepiploic artery → greater curvature
  - Short gastric arteries → fundus of stomach
  - Splenic artery → spleen

Superior mesenteric artery (RIIM)

Right colic
Ileocolic
Ileal and jejunal branches
Middle colic

Inferior mesenteric artery (LESS)

Left colic artery
Sigmoid artery
Superior rectal artery
1. List the two veins that join to form the hepatic portal vein
- SMV + splenic vein
1. Describe the parts of the stomach and its relationships
- Cardiac part/cardia: posterior to 7th left costal cartilage, 2-4 cm from midline at level of T11
- Fundus: related to left dome of diaphragm, contains air, lies posterior to 5th rib in the midclavicular plan
- Body: pyloric antrum and pyloric canal which is continuous with pylorus
- Pylorus: sphincter
1. when supine → level of 9th costal cartilage at level of L1; 1.25 cm right of midline
2. when erect → location varies, L2-L4
7. Describe the parts of the duodenum and its relationships
\
1. Superior part
- anterior to first part = liver and gallbladder
- posterior to first part = bile duct and portal vein
2. Descending part
- lies anterior to renal vessels
3. Horizontal
- Lies anterior to the IVC, aorta, right ureter, right gonadal artery
4. Ascending
- Suspensory ligament of Treitz (musculus suspensorius duodeni): extends from upper aspect of the
8. Define the surface anatomy of the small intestine along with its structures (3 subdivisions) and function
- Duodenum: C- shaped organ which receives openings of pancreatic bile ducts, measures approx. 25 cm, extends from pylorus on the right side → wraps around head/neck of pancreas → terminates left side of duodenojujunal junction; four parts (superior, descending, horizontal, ascending*)
- *suspensory ligament of treitz
- Jejunum: part of the midgut, proximal 2/5 of small intestine
- Ileum: part of midgut, distal 3/5 of small intestine, enters ascending colon at ileocecal junction
- J&I → suspended from posterior abdominal wall via mesentery
9. Describe the origin and ending of the small intestine and its location in relation to the other body organs/landmarks
- Duodenum: starts on @ pylorus (CC 9, L1, 1.25 cm R of midline);
- 1: liver and gallbladder anterior to 1st part of duodenum; bile duct and portal vein are posterior to it
- 2nd part lies anterior to renal vessels
- 3rd part lies anterior to IVC, aorta, right ureter, right gonadal artery
- 4th part: suspensory ligament attaches here and to the diaphragm + tissue around celiac trunk
- Jejunum
- suspended from posterior abdominal wall by mesentery
- Ileum
- enter ascending colon at level of ileocecal junction
10. Describe the wall structure of the small intestine
- Jejunum: few large loops, tall/large/closely packed plicae, deep red in color 2/2 greater vasculature long vasa recta
- Ileum: lots of short loops, pale pink in color, short vasa recta, sparse plicae, lots of lymphoid tissue
11. Explain the characteristics of the three different regions of the small intestine
- Duodenum: 4 parts → superior, descending, horizontal, ascending
- Jejunum: proximal 2/5 of small intestine
- Ileum: distal 3/5
12. Describe superior mesenteric artery syndrome
- Narrowing of the SMA angle w/ aorta → compresses third part of duodenum
- Normal range: 38-65 degrees