Unit 2: The Thorax Flashcards
what are the muscles of the posterior thorax?
- splenius muscles
- trapezius
- latissimus dorsi
- rhomboids
- levator scapulae
- serratus posterior
- erector spinae
- multifidus
what are the regions of the splenius muscles?
- capitis
- cervicis
what are the OIAIs of the splenius capitis?
- origin: nuchal ligament, spinous processes of C7-T3
- insertion: mastoid process (temporal bone), lateral third of superior nuchal line
- action: bilaterally - extends the neck; unilaterally - rotates and laterally flexes the neck
- innervation: posterior/dorsal rami C2-C3
what are the OIAIs of the splenius cervicis?
- origin: spinous processes of T3-T6
- insertion: transverse processes of C1-C2
- action: bilaterally - extends the neck; unilaterally - rotates and laterally flexes the neck
- innervation: posterior/dorsal rami C4-T1
what are the relative location of the splenius muscles?
capitis is superficial and superior to cervicis
what are the regions of the trapezius?
- superior (descending) part
- middle (transverse) part
- inferior (ascending) part
where is the trapezius and what is it innervated by?
- most superficial muscle
- spinal accessory nerve (CN XI)
what are the OIAs of the superior trapezius?
- origin: superior nuchal line, external occipital protuberance
- insertion: lateral third of the clavicle
- action: elevate and retract the scapula
what are the OIAs of the middle trapezius?
- origin: spinous processes of T1-T4
- insertion: spine and acromion of scapula
- action: retract scapula
what are the OIAs of the inferior trapezius?
- origin: spinous processes of T5-T12
- insertion: spine of the scapula
- action: depresses and retracts scapula
what are the regions of the latissimus dorsi?
- vertebral part
- iliacal part
- costal part
- scapular part
what is the origin of the vertebral part of the latissimus dorsi?
spinous processes T7-T12 and the thoracolumbar fascia
what is the origin of the iliacal part of the latissimus dorsi?
iliac crest
what is the origin of the costal part of the latissimus dorsi?
body of ribs 9-12
what is the origin of the scapular part of the latissimus dorsi?
inferior angle of the scapula
what are the IAIs of the latissimus dorsi?
- insertion: medial side of the floor of the intertubercular (bicipital) groove of the humerus
- action: adducts and medial rotates the arm at the glenohumeral joint (GHJ); extends humerus at the GHJ; elevates the trunk (pull up) and moves the truck anteriorly (cross-country skiiing)
- thoracodorsal nerve of the brachial plexus (C6-C8)
what are the OIAIs of the rhomboid major?
- origin: spinous processes T2-T5
- insertion: medial border of the scapula, inferior to the spine
- action: retract and elevate the medial border of the scapula
- innervation: dorsal scapular nerve (C4-C5)
what are the OIAIs of the rhomboid minor?
- origin: spinous processes C6-C7
- insertion: medial border of the scapula, superior to the spine
- action: retract and elevate the medial border of the scapula
- innervation: dorsal scapular nerve (C4-C5)
where are the splenius muscles relative to the rhomboids?
deep
what are the OIAIs of the levator scapula?
- origin: transverse processes C1-C4
- insertion: medial border of the scapula, superior to the spine
- action: elevates medial border of the scapula; if scapula is fixed, flexes the neck laterally
- innervation: dorsal scapular nerve (C4-C5)
where is the levator scapula relative to the splenius muscles?
deep
what are the regions of the serratus posterior and where do they lie relative to surrounding muscles?
- superior; lies deep to rhomboids and levator scapula and superficial to splenius muscles
- inferior; deep to latissimus dorsi
what are the OIAIs of the serratus posterior superior?
- origin: spinous processes C7-T3
- insertion: upper border of ribs 2-5
- action: elevates ribs (contributes to inhalation)
- innervation: intercostal nerves
what are the OIAIs of the serratus posterior inferior?
- origin: spinous processes T11-L2
- insertion: inferior border of ribs 9-12
- action: depresses ribs (contributes to exhalation
- innervation: intercostal nerves
what are the regions of the erector spinae (intermediate muscles) and their collective action?
- spinalis (medial)
- longissimus (middle)
- iliocostalis (lateral)
- action: extends and laterally flexes spine
what are the OIIs of the spinalis?
- origin: spinous process T11-L2
- insertion: spinous process T1-T8
- innervation: posterior/dorsal ramus
what are the OIIs of the longissimus?
- origin: thoracolumbar fascia, sacrum, and transverse processes of lumbar vertebrae
- insertion: transverse processes of cervical and thoracic vertebrae + lower ribs 3-12
- innervation: posterior/dorsal ramus
what are the OIIs of the iliocostalis?
- origin: iliac crest, sacrum, and the erector spinae aponeurosis
- insertion: angle of the ribs and the transverse processes of C4-C6
- innervation: posterior/dorsal ramus
what are the OIAIs of the multifidis?
- origin: sacrum and transverse processes
- insertion: spinous processes 2-3 vertebrae above
- action: extends and laterally flexes the spine; active in rotation and proprioceptive feedback
- innervation: posterior/dorsal ramus
where is the multifidis relative to the erector spinae?
deep
what is the triangle of auscultation?
thin layer of muscle lying between the skin and the inferior lobe of the lung
what is the clinical purpose of the triangle of auscultation?
makes respiratory sounds easily heard through a stethoscope
what makes up the lateral border of the triangle of ausculation?
medial border of the scapula
what makes up the inferior border of the triangle of auscultation?
latissimus dorsi
what makes up the superiomedial border of the triangle of auscultation?
inferior trapezius
what are the regions of the pectoralis major?
- clavicular part
- sternocostal part
what are the OIAIs of the clavicular part of the pectoralis major?
- origin: medial half of the clavicle
- insertion: lateral part of the intertubercular (bicipital) groove of the humerus
- action: flexes arm at GHJ
- innervation: lateral pectoral nerve of the brachial plexus
what are the OIAIs of the sternocostal part of the pectoralis major?
- origin: sternum and costal cartilages of rib 2-7 + aponeurosis of the external oblique
- insertion: lateral part of the intertubercular (bicipital) groove of the humerus
- action: extends arm at the GHJ
- innervation: medial pectoral nerve of the brachial plexus
what is the collective movement of the pectoralis major?
medial rotation and adduction of the arm at the GHJ
what are the OIAIs of the pectoralis minor?
- origin: body of ribs 3-5
- insertion: coracoid process of scapula
- action: depresses and protracts the scapula (against thoracic cage)
- innervation: lateral and medial pectoral nerve
what are the order of muscles of the anterior thorax from superficial to deep?
- pec major
- pec minor
- serratus anterior
what are the muscles of the anterior thorax?
- pectoralis major
- pectoralis minor
- serratus anterior
- subclavius
what are the OIAIs of the serratus anterior?
- origin: body of ribs 1-9
- insertion: medial border of scapula
- action: laterally rotates the scapula (in abduction of the upper limb); stabilizes the scapula (boxer muscle)
- innervation: long thoracic nerve of the brachial plexus
what are the OIAIs of the subclavius?
- origin: junction of 1st rib and costal cartilage
- insertion: middle third of clavicle
- action: anchors and depresses clavicle
- innervation: C5 and C6 (nerve to subclavius)
where are the subclavian vessels?
run over the first rib; vein anterior to artery
when do the subclavian vessels become the axillary vessels?
lateral border of 1st rib
what are the distribution of vertebrae?
- 7 cervical
- 12 thoracic
- 5 lumbar
- 5 sacral
- 4 coccygeal
what are the atypical vertebrae of the cervical vertebrae?
- C1 (atlas)
- C2 (axis)
- C7 (vertebra prominens)
why is C1 (atlas) atypical?
- lacks a spinous process and a body
- compromised of anterior and posterior arches
- non-bifid
- supports the skull
what parts of the vertebrae do not have intervertebral discs?
- between C1 and C2
- between sacral and coccygeal vertebrae (fused)
what kind of joint is the atlanto-occipital joint and what is it formed by?
- superior articular facets of C1 and occipital condyles
- synovial joint
what movement does the atlanto-occipital joint facilitate?
flexion and extension of the head (ex. nodding head)
why is C2 (axis) atypical?
has a superiorly-pointing odontoid process (dens)
what forms the atlanto-axial joint and what kind of joint is it?
- between C1 and C2 (dens is held into the facet of the atlas)
- synovial joint
what ligament holds the dens into the facet of the atlas?
transverse ligament of the atlas
what movement does the atlanto-axial joint facilitate?
rotation of the head (ex. shaking head no)
what makes C7 (vertebra prominens) atypical?
long, palpable, non-bifid spinous process
where do variations in vertebrae most commonly occur?
between adjacent groups
what is sacralization?
a lumber vertebra becoming a sacral vertebra
what is lumbarization?
a sacral vertebra becoming a lumbar vertebra
what forms the vertebral canal and what does it enclose?
- articulations between the vertebral foramina
- spinal cord
what are the landmarks of C1?
- anterior arch
- anterior tubercle
- posterior arch
- posterior tubercle
- transverse process
- transverse foramen
- superior articular facet
- inferior articular facet
what are the landmarks of C2?
- body
- dens (odontoid process)
- spinous process
- transverse process
- transverse foramen
- superior articular facet
- inferior articular facet
what are the distinct features of the cervical vertebrae?
- small, saddle-shaped vertebral bodies
- large and triangular vertebral foramina
- transverse foramina
- superior articular facets pointing supero-posteriorly
- inferior articular facets pointing infero-posteriorly
- short, bifid spinous processes
what goes through the transverse foramina of the cervical vertebrae?
vertebral arteries and veins
what vertebrae permit the most movement?
cervical is the most mobile and specialized for movement
what are the distinct features of the thoracic vertebrae?
- costal facets (demi-facets) located superiorly and inferiorly on each side of body
- costal facet of the transverse process
- long, sloping spinous process that overlies lower vertebra
- smaller circular vertebral foramen
- nearly vertical superior (posterior-pointing) and inferior (anterior-pointing) articular facets (limited movement)
what are the lumbar vertebrae specialized for?
support
what are the distinct features of the lumbar vertebrae?
- large vertebral bodies for extra support
- sagittally oriented articular facets for flexion, extension, and lateral flexion of spine
what is the curvature of each portion of the vertebrae?
- cervical: concave posteriorly
- thoracic: concave anteriorly
- lumbar: concave posteriorly
- sacrum: concave anteriorly
what are intervertebral discs?
- fibrocartilaginous discs that act to absorb shock and support the weight of rostral segments
- provide cushioning
- allow slight movement
how many intervertebral discs are in the human body?
23
what are the 2 major components of intervertebral discs?
- nucleus pulposes
- annulus fibrosus
what is the nucleus pulposes of an intervertebral disc?
gelatinous (jelly-like) filling of the disc
what is the annulus fibrosus of an intervertebral disc?
ring of fibrocartilage which encircles the intervertebral disc
what is a herniated disc?
structural failure of the annulus leading to bulging of the nucleus pulposes
what is the most common injury associated with herniated discs?
compression of spinal nerve
what is the most common cause associated with spinal cord injury?
fracture of vertebrae, spill of disc contents
what are the distinctive features of the sacrum?
- ala
- sacral promontory
- auricular surface
- superior articular facet
- anterior sacral foramina
- posterior sacral foramina
- sacral canal
- sacral hiatus
what forms the pelvic spine?
sacrum and coccyx
what forms the sacroiliac joint?
sacrum and hip bones (os coxae)
what is the function of the sacrum?
provides stability and strength in the pelvic region
what is the function of the sacral canal?
- caudal continuation of the spinal canal
- permits passage of the cauda equina
what is the cauda equina?
bundle of spinal nerve roots that stem caudally from the end of the spinal cord (L1-L2)
what is the clinical importance of the sacral hiatus?
caudal epidural injections
what are true ribs?
- attach directly to the sternum via their own costal cartilage
- ribs 1-7
what are false ribs?
- attach indirectly to the sternum via the cartilage of the rib above
- ribs 8-10
what are floating ribs?
- do not attach to the sternum
- ribs 11-12
what are the distinctive features of the first rib?
- groove for subclavian vein
- groove for subclavian artery
- scalene tubercle (anterior scalene insertion)
- only 1 articular facet (connected to T1 only)
what are the distinctive features of the second rib?
serratus anterior tuberosity
how does a rib articulate with the vertebral column?
- inferior facet articulates with the numerically corresponding vertebra’s superior facet
- superior facet articulates with inferior facet of the numerically superior vertebra
- tubercle articulates with numerically corresponding transverse facet
how is the male sacrum shaped compared to the female sacrum?
longer and narrower
what is the function of the costal groove of a rib?
provides protection and yields passage of the intercostal nerve, vein, and artery
what are the features of the floating ribs?
short and have no neck or tubercle
what are the distinctive features of the sternum?
- manubrium
- suprasternal/jugular notch (T2-T3)
- clavicular notch
- costal notches
- body
- xiphoid process (T10)
what forms the sternal angle?
junction between body and manubrium
- T4-T5
what forms the sternoclavicular joint?
sternal end of clavicle + clavicular notches
where does the xiphoid process lie approximately and what is its function?
- T10
- attachment point for diaphragm
what forms the xiphisternal joint?
body + xiphoid process (T9)
what is the pericardium?
connective tissue sac that encompasses the heart and proximal portions of the great vessels
what are the portions of the pericardium, from superficial to deep?
- fibrous pericardium (continuous with central tendon of diaphragm)
- serous pericardium
- cardiac muscle
what composes the serous pericardium, from superficial to deep?
- parietal pericardium
- visceral pericardium
what is pericarditis and its possible deficits?
inflammation of serous pericardium
- reduced capacity for smooth heart movement
what is the thymus?
site of T cell maturation, covers the atria
what are the great vessels?
aorta, superior and inferior vena cava, and the pulmonary arteries and veins
what is the hilum and where is it located?
- the point of attachment and entry of pulmonary arteries and veins + primary bronchi
- located on medial surface of both lungs
what are the structures of the right lung?
- superior lobe
- middle lobe
- inferior lobe
- horizontal fissure
- oblique fissure
- hilum
- base
- apex
- costal surface
- posterior (vertebral) border
- anterior border
- inferior border
what is the mediastinum?
houses the heart, trachea, esophagus, and great vessels
what divides the superior and inferior mediastinum?
- T4
- transverse thoracic plane
- sternal angle
what is in the superior mediastinum?
- thymus
- portions of the great vessels
- nerves
- trachea
- esophagus
what is in the inferior mediastinum?
- heart
- pericardium
what is the trachea?
airpipe; terminates at the carina and bifurcates into left and right primary bronchi
what is the esophagus and where is it located?
food pipe; posterior and slightly left of the trachea, posterior to the hilum of the left lung
what are differences in the left and right lung?
- right lung has 3 lobes (left lung only has 2 w/ oblique fissure separating them)
- left lung has cardiac notch (and lingua)
what separates the superior lobe and middle lobe of the right lung?
horizontal fissure
what separates the middle lobe and inferior lobe of the right lung?
oblique fissure
what is the diaphragm?
domed muscle that separates thoracic and abdominal cavities
what is the action of the diaphragm?
increases the volume of the thoracic cavity and inflates the lungs (flattens during inhalation)
where do the fibres of the diaphragm converge/insert?
central tendon
what is the diaphragm innervated by?
each hemidiaphragm innervated by a phrenic nerve (C3-C5, bilateral innervation)
what happens if the phrenic nerve is damaged?
paradoxical movement: during inhalation, diaphragm will move superiorly on injured side while undamaged side moves inferiorly
where is the caval hiatus/opening located relative to the other openings?
- T8
- superior and anterior
where is the esophageal hiatus located relative to the other openings?
- T10
- inferior and posterior to caval hiatus
- superior and anterior to aortic hiatus
where is the aortic hiatus located relative to the other openings?
- T12
- inferior and posterior
what is the larynx?
general area superior to trachea; innervated by laryngeal nerve (branch of vagus nerve)
what are auricles/atrial appendages?
flap-like extensions of atria with unknown functions
what is the clinical relevance of the left atrial appendage?
major site of thrombus (clot) formation in patients with non-valvar atrial fibrillation
what separates the atria?
interatrial septum
what separates the ventricles?
interventricular septum
what separates the right atria and ventricle?
right AV (tricuspid) valve
- 3 leaflets
what separates the left atria and ventricle?
left AV (bicuspid/mitral) valve
- 3 leaflets
what separates the right ventricle and the pulmonary trunk?
pulmonary semilunar valve
what separates the left ventricle and aorta?
aortic semilunar valve
what are the function of papillary muscles?
control the leaflets of the AV valves, located in the ventricular walls
- initiate contraction prior to ventricular systole (contraction closes valves)
what are the chordae tendinae?
connects leaflets of AV valves and papillary muscles
what lines the ventricular walls?
trabeculae carnae
what lines the atrial walls?
pectinate muscles
what are the most proximal branches of the aorta?
coronary arteries, running on either side of the pulmonary trunk
what does the right coronary artery branch into?
- posterior interventricular artery (lies in posterior interventricular groove)
- marginal artery
what does the right coronary artery supply?
most of the right side of the heart
what does the left coronary artery supply?
left heart, part of the right ventricle, and most of the conducting system of the heart
what does the left coronary artery branch into?
- circumflex artery (lies in coronary (AV) sulcus)
- anterior interventricular artery (lies in anterior interventricular groove)
what do the coronary veins drain into?
coronary sinus (lies in coronary sulcus)
what are the coronary veins?
- great cardiac vein (lies in anterior interventricular groove)
- middle cardiac vein (lies in the posterior interventricular groove)
what composes the thoracic cage and what is its function?
ribs, sternum, thoracic vertebrae (strong, domed shape)
- encloses the organs of the thoracic cavity and moves to facilitate ventilation
how are intercostal spaces named?
for superior rib
what is the general offset of the vertebral bodies and spinous processes?
spinous processes generally lower
why is the xiphoid process vulnerable to fracture and dislocation?
CPR
what is the midclavicular line?
line that descends inferiorly form the midpoint of the clavicle
what is the axillary line?
demarcates the axillary fossa (armpit)
what is the anterior axillary line?
lateral border of pec major
what is the posterior axillary line?
lateral border of latissimus dorsi
what is the scapular line?
pass through inferior angle of the scapula
what is a supernumerary nipple?
additional nipple commonly located on midclavicular line
where is breast tissue relative to pec major?
superficial
where is a subglandular breast implant placed?
anterior to pec major and pec minor
- recapsulates original anatomy
where is a submuscular breast implant placed?
between pec major and pec minor
- more common
where is the jugular notch relative to the origin of the internal jugular veins?
slightly caudal and medial
what kind of joint is the 1st sternocostal joint?
synarthrosis and a synchondrosis (permits least amount of movement)
- hyaline cartilage directly united with sternum
what kind of joints are the 2nd-7th sternocostal joints and the sternoclavicular joint?
synovial plane joints (relatively mobile)
what kind of joints are the manubriosternal joint and xiphisternal joint?
symphyses (ossify in adulthood)
how many joints permit rotation of the head and what is the pivot point?
- 3 joints
- dens
what is the hangman’s fracture?
dens fracture - occurs due to hyperextension of neck causes by being hung
what is the function of the auricular surface of the sacrum?
articulates with ilium of hip bone to form the sacroiliac joint
what is the costotransverse joint?
joint between facet of transverse process of vertebra and tubercle facet of rib
what is the costovertebral/costocorporeal joint?
joint between head of rib and superior + inferior articular facets of vertebrae
what kind of joints are the costovertebral joints?
synovial
- vulnerable to injury (sprain), causing pain and immobility
what shape is the articular surface of the tubercle of ribs 1-6?
convex
what movement is permitted at ribs 1-6?
rotation permitting elevation and depression of the sternal end of the ribs in the sagittal plane (pump-handle movement)
what does “pump-handle movement” mean?
upper portion of the rib cage expands anteriorly
what shape is the articular surface of the tubercle of ribs 7-10?
flat
what movement is permitted at ribs 7-10
gliding permitting elevation and depression of the lateral ribs in the transverse plane (bucket-handle movement)
what movement facilitates forced expiration?
combination of anterior and lateral expansion of the rib cage (pump-handle + bucket-handle)
what is flail chest?
extreme case of rib fracture
- flail segment moves paradoxically in respiration
where are the most common herniated discs?
L4-L5 and L5-S1
- bearing the most load
what is the pattern of the spinal nerves?
- C1-C7 above vertebra, C8 onwards below vertebra
how do the ventral (anterior) rami travel from the spinal nerve?
transversely
what innervates the deep muscles of the back?
posterior (dorsal) ramus
where does the spinal cord end?
L1-L2
what does the cervical dermatome sense?
head, neck, upper limb
what does the thoracic dermatome sense?
anterior and posterior thorax
what does the lumbar dermatome sense?
anterior lower limb + lateral portions of posterior lower limb + medial portions of feet
what does the sacral dermatome sense?
genitals + medial portions of posterior lower limb + lateral portions of feet
what does spinal cord injury result in?
causes loss of sensory and motor function from that point below
what does spinal nerve injury result in?
causes loss of sensory and motor function in a single dermatome/myotome
C2 myotome
back of head + superior neck
C3 myotome
inferior neck
C4 myotome
clavicle area
C5 myotome
elbow flexors
C6 myotome
wrist extensors
C7 myotome
elbow extensors
C8 myotome
finger flexors
T1 myotome
finger abductors
L2 myotome
hip flexors
L3 myotome
knee extensors
L4 myotome
ankle dorsiflexors
L5 myotome
long toe extensors
S1 myotome
ankle plantar flexors
where does the phrenic nerve originate?
anterior (ventral) rami of C3-C5
what are the bony articulations (synovial joints) of the shoulder complex?
sternoclavicular joint, acromioclavicular joint, and glenohumeral joint
what is the physiological coupling that couples the scapula to the thoracic cage?
scapula-thoracic joint
what muscles are involved in elevation of the scapula?
- upper trapezius
- levator scapula
what muscles are involved in depression of the scapula?
- serratus anterior
- pectoralis minor
what muscles are involved in retraction of the scapula?
- trapezius
- rhomboids
what muscles are involved in protraction of the scapula?
- serratus anterior
- pectoralis minor
what is the origin of the diaphragm?
- lumbar vertebrae
- ribs 7-12
- xiphoid process
how are the intercostal spaces named?
for rib above
where do intercostal nerves originate?
ventral (anterior) rami
what composes the intercostal space?
intercostal muscles, veins, arteries, and nerves
what is the order of vessels/nerves in the intercostal space, rostral to caudal, in the costal groove of a rib?
VAN
- veins
- arteries
- nerves
how do the intercostal veins drain into the IVC?
azygos vein
where are the VANs located?
costal groove of a rib, sandwiched between innermost intercostals and internal intercostals
how are the external intercostals organized?
originate on inferior border of rib, insert on superior border immediately below
what muscles are used during inspiration?
- external intercostals
- intercartilaginous portions of internal intercostals
- both act to enlarge rib cage
what are the actions of the external intercostals and the intercartilaginous portions of the internal intercostals?
pulls inferior rib to superior rib, enlarging rib cage
what muscles are used during forced exhalation?
internal intercostal muscles (excluding intercarilaginous portions)
how are the internal intercostals organized?
originate on superior border of rib, insert on inferior border of rib immediately above
what is the action of the internal intercostals?
pulls superior rib to inferior rib, shrinking rib cage
what do the pulmonary cavities consist of?
lungs, bronchial tree, pleural membrane, and pulmonary vessels
what creates the pleural cavity?
visceral and parietal pleura
what is a pneumothorax?
collapsed lung
- pressure in the pleural cavity exceeds pressure in the lung, causing visceral pleura to shrink (loses continuity with parietal pleura)
- treated by evacuating air in pleura to re-inflate lung
what is a hemothorax?
blood in the pleural cavity
what is a hydrothorax?
fluid in the pleural cavity
what is a thoracentesis?
insertion of a chest tube through intercostal space
- used to remove air, pus, blood, fluid from intrapleural space (pleural cavity)
what are recesses?
space between the lungs and the parietal pleura present in normal, quiet breathing
- shrink during forceful breathing
how many lobar (secondary) bronchi does each lung have?
lobar bronchi supply the lobes of the lung, so:
- right lung has 3 lobar bronchi
- left lung has 2 lobar bronchi
what is a bronchoscopy?
passage of a camera into the proximal tracheobronchial tree
- diagnostic and used to remove things
how does the mediastinum shift with posture?
- supine: aortic arch superior to transverse thoracic plane
- standing: aortic arch transected by transverse thoracic plane
