Thorax Cardiovascular Flashcards
Surface projection of sternum
Description:
• Flat bone with three parts: manubrium, body, and xiphoid process
• Characteristic features include jugular notch and sternal angle (angle of Louis)
• Articulates with upper seven costal cartilages and clavicles
Also known as:
• Sternum also known as the “breastbone”
Comment:
• Provides attachment for pectoralis major muscle
Cephalic v.
Cephalic v.
Drainage:
• Skin and subcutaneous structures of lateral and dorsal hand, forearm, and arm
Course:
• Ascends from dorsum of hand to anterolateral forearm and arm
• Passes into deltopectoral triangle
Pectoralis major m.
Action: • Adduction of arm • Medial rotation of arm • Clavicular head: flexion of arm • Sternocostal head: extension of arm (from flexed position)
Innervation:
• Lateral pectoral nerve (C5-7)
• Medial pectoral nerve (C8-T1)
Pectoralis minor m.
Action:
• Stabilizes scapula (holds it against thoracic wall)
• Protraction (abduction) of scapula (assists serratus anterior)
• Lateral rotation of scapula (e.g., depresses the acromion)
Innervation:
• Medial and lateral pectoral nerves
Comment:
• Pectoralis major and minor muscles also known as “pecs”
• Pectoralis minor active during forced inspiration
Sternum
Description:
• Flat bone with three parts: manubrium, body, and xiphoid process
• Characteristic features include jugular notch and sternal angle (angle of Louis)
• Articulates with costal cartilages of true ribs (1-7), combined costal cartilages of false ribs (8-10), and clavicles
Also known as:
• “Breastbone”
Comment:
• Floating ribs (ribs 11-12): not attached to sternum
• Provides for attachment of sternocleidomastoid, pectoralis major, sternohyoid, and sternothyroid muscles
Costal cartilages
Description:
• Attaches rib to sternum
• True ribs (ribs 1-7): attached directly to sternum by costal cartilages
• False ribs (ribs 8-10): attach indirectly to sternum via a shared costal cartilage
• Costal margin created by costal cartilages of ribs 7-10
Internal thoracic a.
Course:
• Descends adjacent to sternum within thoracic cavity
Distribution: • Intercostal spaces • Breast • Pericardium • Diaphragm • Anterior abdominal wall
Branches: • Anterior intercostal • Pericardiacophrenic • Superior epigastric • Musculophrenic
Also known as:
• Internal mammary artery
Internal thoracic v.
Drainage: • Anterior thoracic wall, including breast • Anterior abdominal wall • Diaphragm • Pericardium
Tributaries: • Musculophrenic • Superior epigastric • Pericardiacophrenic • Anterior intercostal
Course:
• Ascends posterior to costal cartilages, just lateral to sternum
Also known as:
• Internal mammary vein
Comment:
• Formed by union of superior epigastric and musculophrenic veins
Thyroid gland
Description:
• Bilobed endocrine gland
• Normally composed of left and right lateral lobes connected across midline by isthmus of gland
Function:
• Follicular cells: synthesize and secrete thyroid hormones T3 (triiodothyronine) and T4 (thyroxine)
• Parafollicular cells: synthesize and secrete calcitonin
Comment:
• Lobes lie lateral to trachea and larynx
• Enlarged thyroid gland known as a goiter, typically due to insufficient dietary iodine
Parietal pleura
Description:
• Thin, serous membrane
• Lines pulmonary cavity
• Fused to internal walls of thoracic cavity and lateral surface of mediastinum
• Continuous with visceral pleura at root of lung
• Regions include mediastinal, cervical, diaphragmatic, and costal
Comment:
• Pleural cavity created by narrow space between parietal and visceral layers of pleura
• Thorax has three subdivisions: mediastinum and right and left pulmonary cavities
• Costal and peripheral diaphragmatic pleura innervated by intercostal nerves
Right lung
Description:
• Three lobes: upper (or superior), middle, and lower (or inferior), separated by two fissures - oblique and horizontal
• Medial surface has hilum with airway and pulmonary vessels
• Surface of lung covered with visceral pleura
Function:
• Primary organ of respiration
Visceral pleura
Description:
• Thin, serous membrane
• Fused to surface of lung
• Continuous with parietal pleura at root of lung
• Separated from parietal pleura by pleural cavity
Comment:
• Thoracic cavity divided into midline mediastinum and right and left pulmonary cavities
Phrenic nerve
Contributions:
• Ventral rami of C3-5 spinal nerves
Motor:
• Diaphragm
General sensation:
• Parietal layer of pleura and peritoneum over central diaphragm
• Mediastinal pleura
• Parietal pericardium
Comment:
• Supplies all motor innervation to diaphragm (hint: remember C3, 4, 5 “keeps the diaphragm alive”)
Thymus Gland
Description:
• Large, bilobed gland in children
• Atrophies during adolescence
• Remnant in adults consists primarily of fibrous and adipose tissue
Function:
• Secretes thymopoietin and thymosins that stimulate and promote differentiation, growth and maturation of T-lymphocytes
• Site for maturation and differentiation of T-lymphocytes (primarily in young individuals)
Fibrous pericardium
Description: • Forms fibrous sac enclosing heart • External to serous pericardium • Fused to diaphragm • In contact with parietal (mediastinal) pleura
Left lung
Description:
• Two lobes: upper (or superior) and lower (or inferior), separated by oblique fissure
• Medial surface has hilum with airway and pulmonary vessels
• Surface of lung covered with visceral pleura
Function:
• Primary organ of respiration
Axillary v.
Drainage:
• Pectoral, shoulder, and scapular regions
Course:
• Passes through axilla with axillary artery surrounded by cords and branches of brachial plexus
Termination:
• Continues as subclavian vein at lateral border of rib 1
Comment:
• Single, large, deep vein that accompanies axillary artery
• Axillary vein formed by continuation of basilic vein, with contribution of paired brachial veins
Right brachiocephalic v.
Drainage:
• Head and neck (right side)
• Upper limb (right)
Tributaries:
• Internal jugular
• Subclavian
Course:
• Descends vertically from junction of internal jugular and subclavian veins
• Posterior to right sternoclavicular junction
• Does not cross midline
Also known as:
• Right innominate vein (Latin: innominatus = nameless)
Comment:
• Lacks valves
Superior vena cava
Drainage: • Head • Upper limbs • Posterior thoracic walls • Mediastinal structures
Tributaries:
• Formed by union of right and left brachiocephalic veins
• Arch of azygos vein
Course:
• Descends in mediastinum from level of right 1st costal cartilage
Termination:
• Right atrium
Pulmonary a.
Course:
• Left: laterally, inferior to arch of aorta and anterior to left main bronchus
• Right: laterally, posterior to ascending aorta and superior vena cava
• Through root and hilum of respective lungs
Distribution:
• Lung
Branches:
• Lobar arteries to lung lobes
Comment:
• Conveys oxygen-poor blood to lung
Right auricle
Description:
• Small, conical, pouch-like extension of right atrium
• Thin, rough wall (pectinate muscles)
Right atrium
Description:
• One of four heart chambers
• Thin, smooth, posterior wall
• Thin, rough anterior wall (pectinate muscles)
• Receives superior and inferior venae cavae and coronary sinus
• Internal features include interatrial septum, fossa ovalis, and crista terminalis
Comment:
• Forms right surface of heart
• Separated from right ventricle by atrioventricular (tricuspid) valve
Ascending aorta
Origin:
• Left ventricle (aortic vestibule)
Distribution:
• Heart (via coronary arteries)
Branches:
• Right and left coronary arteries
• Continues as arch of aorta
Comment:
• Has aortic valve at origin
• Large arteries do not by themselves supply structures, but do so through their branches
Arch of aorta
Course:
• Arches diagonally and posteriorly to the left
Distribution:
• Head, including brain
• Neck
• Upper extremities
Branches: • Brachiocephalic trunk • Left common carotid • Left subclavian • Continues as descending (thoracic) aorta
Comment:
• Ligamentum arteriosum attached to concave surface of arch
• Large arteries do not by themselves supply structures, but do so through their branches
Left brachiocephalic v.
Drainage:
• Head and neck (left side)
• Upper limb (left)
Course:
• Descends obliquely to the right from junction of internal jugular and subclavian veins
• Posterior to manubrium
• Crosses midline
Termination:
• Superior vena cava
Also known as:
• Left innominate vein (Latin: innominatus = nameless)
Comment:
• Lacks valves
Subclavian v.
Drainage:
• Upper limb
• Superficial back and neck
Course:
• Begins at lateral border of rib 1
• Arches over rib 1 to enter thoracic cavity
Termination:
• Joins internal jugular vein posterior to sternum to form brachiocephalic vein
Comment:
• Lies anterior to anterior scalene muscle
• Access point to large veins for insertion of electrical leads for heart pacemaker or tubes to administer chemotherapeutic agents to cancer patients
Pulmonary trunk
Origin:
• Right ventricle
Course:
• Ascends within pericardium
• Initially anterior to ascending aorta and then to its left and slightly posterior
Distribution:
• Lungs
Branches:
• Right pulmonary artery
• Left pulmonary artery
Comment:
• Conveys oxygen-poor blood from right ventricle of heart
• Has pulmonary (semilunar) valve at its origin
• Large arteries do not by themselves supply structures, but do so through their branches
Internal jugular v.
Drainage:
• Cranial cavity, including brain
• Face
• Neck
Course:
• Formed in jugular foramen of skull
• Descends through neck in carotid sheath
• Enters thorax
Termination:
• Posterior to sternum unites with subclavian vein to form brachiocephalic vein
Comment:
• Enclosed in carotid sheath
Left recurrent laryngeal n.
Contributions:
• Branch of vagus nerve (CN X) in thorax
Motor:
• Intrinsic laryngeal muscles, except cricothyroid
Sensory:
• Mucous membranes of trachea and larynx (inferior to vocal fold)
Comment:
• In thorax, left recurrent laryngeal nerve loops inferior to arch of aorta
• In thorax, right recurrent laryngeal nerve loops inferior to right subclavian artery
• Recurrent laryngeal nerves ascend in neck to larynx
• Terminal part (within larynx) is termed inferior laryngeal nerve
Ligamentum arteriosum
Ligamentum arteriosum
Origin:
• Left pulmonary artery
Course:
• Ascends to attach to arch of aorta on its concave surface
Comment:
• A fibrous cord
• Remnant of ductus arteriosus in fetus
• Ductus arteriosus shunts blood in fetus from pulmonary artery to aorta, thereby bypassing lungs
Right ventricle
Location:
• Heart
Description:
• One of four heart chambers
• Rough, muscular walls (trabeculae carneae)
• Muscle wall thicker than either atrium, and thinner than left ventricle
• Internal features include papillary muscles, chordae tendineae, interventricular septum, and conus arteriosus
Comment:
• Separated from right atrium by atrioventricular (tricuspid) valve
• Separated from pulmonary trunk by pulmonary valve
• Responsible for pumping oxygen-poor blood to lungs
Heart
Description:
• Conical, muscular organ with four chambers: two atria and two ventricles
Function:
• Pumps blood to body
• Modified cardiac muscle cells in right atrium secrete the hormone atriopeptin (atrial natriuretic peptide) in response to distension (stretching) of the atrial wall
• Atriopeptin reduces blood volume by causing water loss and sodium excretion into urine (with less blood volume, blood pressure is reduced)
Left Ventricle
Description:
• One of four heart chambers
• Thick, muscular walls
• Internal features include papillary muscles, chordae tendineae, trabeculae carneae, interventricular septum, and aortic vestibule
Comment:
• Separated from left atrium by left atrioventricular (bicuspid or mitral) valve
• Separated from aorta by aortic valve
• Walls twice as thick as right ventricle
• Forms apex of heart
• Responsible for pumping oxygen-rich blood to body (except lungs)
Apex of Heart
Location:
• Heart (inferolateral point)
Description:
• Blunt tip of left ventricle
Comment:
• Surface projection at left 5th intercostal space in mid-clavicular line
Left common carotid a.
Course:
• Exits thorax and ascends in neck
Branches:
• Internal and external carotid arteries (at level of C4 vertebra)
Comment:
• Has no branches before terminal branches
• Enclosed in carotid sheath
• Carotid sheath is a fascial sleeve which contains common and internal carotid arteries, internal jugular vein, vagus nerve (CN X), and lymphatic channels
• Large arteries do not by themselves supply structures, but do so through their branches
Left main bronchus
Description:
• Formed at bifurcation of trachea
• Longer, more narrow, and less vertical than right main bronchus
• Component of root and hilum of left lung
Comment:
• Foreign bodies that enter trachea tend to pass to right main bronchus
Right main bronchus
Description:
• Formed at bifurcation of trachea
• Shorter, wider, and more vertical than left main bronchus
• Component of root and hilum of right lung
Also known as:
• Right primary bronchus
Comment:
• Foreign bodies that enter trachea tend to pass to right main bronchus
Pulmonary vv.
Drainage:
• Lungs
Course:
• Two veins pass through root of each lung (i.e., four pulmonary veins in total) and directly into left atrium
Comment:
• Pulmonary veins carry oxygen-rich blood
Parietal layer of serous pericardium
Description:
• Thin, serous membrane fused to inner surface of fibrous pericardium
• Outer limit of pericardial cavity
• Continuous with visceral layer of serous pericardium
Comment:
• Pericardial cavity created by narrow space between parietal and visceral layers of serous pericardium
Inferior vena cava
Drainage:
• Everything inferior to diaphragm, except posterior abdominal wall, which drains into azygos system
Course:
• Ascends from level of L4 vertebral body, through diaphragm, to heart
Termination:
• Right atrium of heart
Comment:
• Largest vein of body
