lie dorsal to the transverse process of the vertebrae

transversospinalis, longissiumus, iliocostalis

function: to extend the vertebral column or to flex it laterally

lie ventral to the transverse processes. usually used in relation to trunk / main body mass

scalenus, serratus dorsalis cranialis and caudalis, external and internal intercostals

muscles of respiration

most medial epaxial muscle system

reaches from the skull to the ilium

in between transversospinalis and iliocostalis

reaches from skull to ilium

most lateral epaxial muscle system

reaches from FIRST RIB to ilium

scalenus, Serratus dorsalis cranialis and caudalis,External and internal intercostal muscles, diaphragm

 fibers run caudoventrally 

  fibers run caudoventrally

O – caudal border of rib

I – cranial border of caudal rib

fibers run cranioventrally

O – cranial border of rib

I – caudal border of cranial rib

attach Dorsally/ laterally at the 3rd and 4th lumbar vertebrae

8th to 13th ribs 

Ventrally  on the caudal sternum

HOLES: 3 -contain the aorta, the esophagus and the vena cava

fibers run cranioventrally

O – thoracolumbar fascia

I – last 3 ribs(caudal portion)

 muscle of expiration!

Cranial: Thoracic inlet – bound by 1st sternebra (manubrium), 1st pair of ribs & costal cartilage, and the 1st thoracic vertebra

Dorsal: Thoracic vertebral bodies

Lateral: Ribs and intercostal muscles

Ventral: Sternebrae

Caudal: Diaphragm

thoracic cavity:

lined by endothoracic fascia which connects the pleura to the thoracic wall and diaphragm. contains thoracic organs.

pleural cavity:

located within the thoracic cavity. There are 2 (1 on either side)

“Space” between the two usually only has a small amount of serous fluid

Reflects on the midline and covers midline structures (thymus, lymph nodes, heart (pericardial mediastinal), nerves, vessels, trachea, esophagus)

paricardial mediastinal pleura 

fibrous pericardium

parietal serous pericardium

right AV orifice (closed by Rt AV valve)

pulmonary truck orifice (closed by pulmonary valve)

aortic orifice (closed by aortic valve)

left AV orifice (closed by L AV valve)

deoxygenated: enter from cranial and caudal vena cavae into the left atrium

(blood from the heart enters at the coronary sinus)

pumped into left ventricle

pumped into pulmonary trunk (artery)

enters lungs and picks up oxygen

oxygenated: enter from pulmonary veins into the left atrium

pumped into left ventricle

pumped into aorta to the rest of the body; coronary arteries supply heart

coronary groove

subsinosal interventricular groove

paraconal interventricular groove

structure that forms the diaphragm by growing inward from the outer walls of the body (in 3 directions)

if it doesn't connect, the animal will have the intestines herniate into the thoracic cavity

thin and watery, acts as lubricant.

different from thick, viscous mucus which collects materials to flush out

(ribs here)

costal parietal pleura

visceral pulmonary pleura outer surface of lung

(lung here)

visceral pulmonary pleura inner surface of lung

pericardial mediastinum

(pericardial cavity here)

parietal serous pericardium

visceral serous pericardium aka epicardium

(heart is here)

be able to visualize path of a penetrating wound from this angle or others and know what it would pass thru if it stops before it hits the heart (lodged in the pericardial cavity)

double folds of pleura just caudal to bronchus/ hilus 

pulmonary pleura reflects medially and becomes adhered to mediastinal pleura

strengthened by interposed enthothoracic fascia

mediastinum of the pleural cavity on the medial caudal lung lobe

if not removed first, it will tear other tissues including lymphatics

lymph in thoracic cavity: chylothorax

Along the horizontal parts of the 8^th and 9^th costal cartilages

Across the 10^th and 11^th costal cartilages at the costochondral junction

Across the middle of the last rib

Passing medially to the second lumbar transverse process

Where diaphragm attaches to the body wall

1.ascending aorta

-     L and R coronary arteries

2.aortic arch

-     brachiocephalic trunk

                                       i.    L and R common carotid

                                     ii.    Right Subclavian

-     Left subclavian

3.descending aorta

trabecula septomarginalis

aka moderator band

from ventricular septum to R ventricle wall

important in synchronizing papillary muscle contraction

LEFT side

pulmonary valve:  3rd intercostal space at costrochondral junction

aortic valve: 4th intercostal space, higher than (dorsal to) other valves

mitral (left AV) valve: 5th intercostal space at costochondral junction

cranial to caudal: spell "PAM"

RIGHT side

right AV valve: 4-5th intercostal space at costochondral junction

• paraconal interventricular branch
• septal branch
• circumflex branch
• subsinuosal interventricular branch

cardiac veins

Middle Cardiac (runs with subsinuosal IV branch)

Great Cardiac (runs with circumflex branch)

Coronary Sinus (same track as great cradiac, diameter changes)

Trabeculaseptomarginalis– conducts Purkinje fibers across lumen of right ventricle

4th rib & caudal come from aorta, first few from costocervical trunk

dorsal and ventral portions merge

IMMEDIATELY caudal to the ribs

dorsal border: aorta

ventral border: internal thoracic artery (comes off subclavian)

damage does not disrupt blood flow to the ribs (important for respiration)

unpaired artery

3 branches:

- left gastric artery (stomach)

- splenic artery (spleen)

- hepatic artery (liver - clean blood)

unpaired artery

supplies gut

unpaired artery

supplies gut

not next to cranial mesenteric : 3 paired arteries in between

phrenicoabdominal trunk (supplies diaphragm, abdominal wall. attaches to adrenal glands - must be moved to take out adrenals)

renal arteries

gonadal arteries (male, testes; female, ovaries)

cranial and caudal mesenteric veins

 left gastric vein

splenic vein

system of two capillary beds for materials to diffuse

hepatic: begins at connection of the cranial and caudal mesenteric veins

also receives input from stomach and spleen

other portal systems:

renal

hypothalmo-pituitary (involved with hormones)

paired:

deep circumflex iliac arteries (dorsocaudal abdominal wall)

external iliac arteries(hind limbs)

internal iliac arteries (pelvic cavity)

unpaired: median sacral artery (tail)

left and right external and internal iliac veins

come together to form left and right common iliac veins

common iliac veins come together to caudal vena cava

recieves blood from hind limbs and pelvis (iliac veins)

receives filtered, deoxgygenated blood from liver (hepatic veins)

enters right atrium of heart

caudal side of diaphragm, down to line of pleural reflection

visualize how the diaphragm sits in a 3D view: it's like a bowl

the bottom of the bowl up to the edges represents the area where the abdominal cavity protrudes into the thoracic cavity

if a wound penetrates from rib 8 - rib 11 (line of pleural reflection) or the parts of the ribs cranial to this (middle of 6-7) and caudal to this ( dorsal part of 12-13) that also overlap, then it will enter both cavities

ribs 1-5 will be only thoracic cavity

Describe and point out the area on the thoracic wall where cardiac puncture should be performed.  Why is this area best for cardiac puncture?

·         Cardiac notch

·         Right side

·         Low

·         4^th-5^th intercostal spaces

·         Where heart will “peak out” between lung lobes

·         Heart will be against thoracic cavity wall

·         If you want to give drugs to heart without hitting lungs

·         The notch is not in the heart itself!