Herbivore Thorax Anatomy

Horses have ______ pairs of ribs

18 (36 total)

Three parts of the sternum:

1.) manubrium

2.) body

3.) xyphoid process

manubrium

most cranial portion of the sternum

xyphoid process

most caudal portion of the sternum; cartilaginous

Withers

topographic landmark between the shoulders that is made up of the spinous processes of T2-T8

Five groups of muscles that make up the thorax:

1.) cutaneous muscles

2.) extrinsic muscles

3.) thoracic wall muscles

4.) epaxial muscles

5.) hypaxial muscles

Two cutaneous muscles of the thorax:

1.) cutaneous trunci

2.) cutaneous omobrachialis

cutaneous trunci

muscle of the trunk directly under the skin

cutaneous omobrachialis

muscle of the shoulder and arm directly under the skin; located cranial to cutaneous trunci

Four extrinsic muscles of the thorax:

1.) pectoral muscles

2.) trapezius

3.) serratus ventralis

4.) latissimus dorsi

The horse has ________ pectoral muscles

four

Four pectoral muscles of the horse

1.) deep pectoral

2.) transverse pectoral

3.) descending pectoral

4.) subclavius

Serratus ventralis function

creates a slang to anchor the thoracic limb to the wall of the thorax

Seven thoracic wall muscles of the thorax:

1.) serratus dorsalis cranialis/caudalis

2.) serratus ventralis

3.) scalenus

4.) external intercostal

5.) internal intercostal

6.) rectus thoracis

7.) transversus thoracis

transversus thoracis

creates the floor of the thoracic cavity

Epaxial muscles of the thorax

dorsal to the transverse processes of the thoracic vertebrae

Three epaxial muscles of the thorax

1.) spinalis system

2.) multifidus system

3.) longissimus

Hypaxial muscles of the thorax

ventral to the transverse processes of the thoracic vertebrae

One hypaxial muscle of the thorax

longus colli

Lateral border of the thoracic cavity

ribs

Ventral border of the thoracic cavity

sternum

Dorsal border of the thoracic cavity

thoracic vertebrae

Cranial border of the thoracic cavity

thoracic inlet

thoracic inlet

opening at the cranial portion of the thoracic cavity where things come into the neck

Caudal border of the thoracic cavity

diaphragm

Diaphragm

separates the thoracic and abdominal cavities

Three passageways going through the diaphragm into abdomen

1.) aortic hiatus

2.) esophageal hiatus

3.) foramen vena cava

aortic hiatus is a passageway for (3):

1.) aorta

2.) right azygous vein

3.) thoracic duct

esophageal hiatus is a passageway for (2):

1.) esophagus

2.) vagal trunks

foramen vena cava is a passageway for:

caudal vena cava

Passageways of the diaphragm from dorsal to ventral:

1.) aortic hiatus

2.) esophageal hiatus

3.) foramen vena cava

Pleura

double layered connective tissue membrane surrounding the lungs and thoracic cavity

Two types of pleura:

1.) visceral/pulmonary pleura

2.) parietal pleura

visceral/pulmonary pleura

pleura that is on an organ (lungs)

parietal pleura

pleura that lines the outside wall of the thoracic cavity

Three types of parietal pleura

1.) mediastinal

2.) costal

3.) diaphragmatic

mediastinal pleura

parietal pleural lining the mediastinum

costal pleura

parietal pleural lining the inner surface of the ribs

diaphragmatic pleura

parietal pleural lining the diaphragm

Pleural cavity

space between the folds of the pleura; contains the lungs

costodiaphragmatic recess

space created where the costal pleura reflects on the diaphragmatic pleura

cupula pleurae

extension of the pleura on the right or left side past the level of the first rib into the neck

Line of pleural reflection

where costal pleura reflects to diaphragmatic pleura

The trachea bifurcates into...

left and right primary bronchi

Primary bronchi

the two passageways that branch off the trachea and lead to the right and left lungs

The trachea bifurcates at the ___-____ intercostal space

4th-6th

Three structures of left lung lobe:

1.) cranial lobe

2.) caudal lobe

3.) cardiac notch

Cardiac notch

concave space on the lung in between the cranial and caudal lobes

The cardiac notch of the left lung is located deep to what ribs?

ribs 3-6

Four structures of the right lung lobe

1.) cranial lobe

2.) caudal lobe

3.) cardiac notch

4.) accessory lobe

The cranial and caudal lobes of the right lung are seen on the ________ view

The accessory lobe of the right lung is seen on the _________ view

lateral

medial

The cardiac notch of the right lung is located deep to what ribs?

ribs 3-4

Basal border of the lung

caudal border of the lung in a normal, relaxed state

Basal border of the lung location

ventral aspect of rib 6

middle aspect of rib 11

dorsal aspect of rib 16

The position of the heart in the horse is ________ than in the dog

different

The equine heart is located in intercostal spaces ____-_____

2-6

The equine heart is more ________ in position relative to the dog

vertical

The long axis of the heart is directed _____________ and toward the _______ of the median plane

caudoventrally; left

Pericardium

connective tissue that covers the heart

The left surface of the heart is called the ___________ surface

auricular

Ten structures seen on the auricular surface of the heart

1.) left auricle

2.) right auricle

3.) right ventricle

4.) left ventricle

5.) conus arteriosus

6.) pulmonary trunk

7.) paraconal inerventricular groove

8.) aorta

9.) ligamentum arteriosum

10.) pulmonary veins

conus arteriosus

coning/funneling of the right ventricle as it forms the pulmonary trunk

pulmonary trunk

carries blood away from the heart to the lungs; deoxygenated!

The pulmonary trunk will split into...

left and right pulmonary arteries

paraconal interventricular groove

groove in between the left and right ventricle on the left side of the heart

Within the paraconal interventricular groove are...

paraconal interventricular vein and artery

Pulmonary veins

bring oxygenated blood from the lungs to the heart

The pulmonary trunk exits the heart from the ___________ _________ and the pulmonary veins enter the heart into the ______________ ___________

right ventricle

left atrium

The aorta exits the heart from the __________ __________

left ventricle

ligamentum arteriosum

ligament between the pulmonary trunk and the aorta

The ligamentum arteriosum is a remnant of...

ductus arteriosus

The right surface of the heart is called the _________ surface

atrial

structures seen on the atrial surface of the heart

1.) left atrium

2.) right atrium

3.) right ventricle

4.) left ventricle

5.) pulmonary veins

6.) cranial vena cava

7.) caudal vena cava

8.) coronary groove

9.) subsinuosal interventricular groove

10.) aorta

11.) brachiocephalic trunk

The cranial vena cava enters the heart from the ____________ _______

The caudal vena cava enters the heart from the ____________ _______

right atrium

right atrium

The cranial vena cava branches into the...

right azygous vein

coronary groove

separation of atria and ventricles on both surfaces of the heart

Within the coronary groove is the...

great cardiac vein

great cardiac vein

returns blood that the heart itself has used to the right atrium

subsinuosal interventricular groove

groove in between the left and right ventricle on the right side of the heart

Within the subsinuosal interventricular groove are...

subsinuosal interventricular groove artery and vein

The subsinuosal interventricular groove lies below the...

coronary sinus

coronary sinus

opening of the great cardiac vein as it returns blood back to the right atrium of the heart

The aorta branches into the....

brachiocephalic trunk

brachiocephalic trunk

principal blood supply coming off the aorta that goes cranially to give off the great vessels of the thoracic cavity

The paraconal interventricular groove is on the _________ surface and contains the _________

The coronary groove is on the __________ surface and contains the ___________

The subsinuosal interventricular groove is on the __________ surface and contains the __________

auricular; paraconal interventricular artery and vein

atrial and auricular; great cardiac vein

atrial; subsinuosal interventricular artery and vein

Two heart septa:

1.) interatrial

2.) interventricular

interatrial septum

separates the left and right atrium

interventricular septum

separates the left and right ventricles

Five structures of the right atrium:

1.) caudal vena cava

2.) cranial vena cava

3.) intravenous tubercule

4.) fossa ovalis

5.) opening of the coronary sinus

intravenous tubercule location

located between the caudal and cranial vena cava

intravenous tubercule function

helps direct venous blood into the right atrium from the vena cava

fossa ovalis

depression in interatrial septum

fossa ovalis is the remnant of what structure in the fetus?

foramen ovale

opening of the coronary sinus

where the great cardiac vein returns venous blood into the right atrium

Three structures located in both ventricles:

1.) chordae tendineae

2.) papillary muscle

3.) trabecula septomarginalis

chordae tendineae

thin bands of fibrous tissue that attach to the AV valve to prevent them from inverting

papillary muscle

muscles that attach the chordae tendineae to the wall of the heart

trabecular septomarginalis

Muscular strand that extends across the lumen of the ventricle from the septal to the parietal wall

The trabecular septomarginalis is aka...

moderator band

The moderator band is always in the ______ ventricle and is variable in the ________ ventricle

right; left