Thorax 1 - Chest wall (neurovascular & muscles) Flashcards
what artery supplies the first 6 anterior intercostal spaces? what artery does it arise from?
internal thoracic artery - arises as branches directly from the subclavian artery
which artery supplies the 7th to 9th anterior intercostal spaces? what artery does it arise from?
musculophrenic artery - one of the terminal branches of the internal thoracic artery
from which artery do the posterior intercostal arteries in the 1st and 2nd intercostal spaces arise?
supreme thoracic artery - arises directly form the costocervical trunk (which is from the subclavian artery)
the 3rd to 11th posterior intercostal spaces are supplied by branches directly from WHICH artery?
(thoracic) aorta
what artery supplies the 12th posterior intercostal space? where does it arise from?
subcostal artery - from thoracic aorta
which artery supplies the first six anterior intercostal spaces?
A) Musculophrenic artery
B) Internal thoracic artery
C) Subcostal artery
D) Supreme thoracic artery
B: internal thoracic artery
from which artery do the posterior intercostal arteries in the 3rd to 11th intercostal spaces arise?
A) Subclavian artery
B) Thoracic aorta
C) Internal thoracic artery
D) Costocervical trunk
B: thoracic aorta
the artery supplying the 12th posterior intercostal space is a branch of which artery?
A) Internal thoracic artery
B) Subclavian artery
C) Thoracic aorta
D) Axillary artery
C: thoracic aorta
which artery supplies the 8th anterior intercostal space?
A) Musculophrenic artery
B) Internal thoracic artery
C) Thoracic aorta
D) Subcostal artery
A: musculophrenic artery
TRUE/FALSE: the supreme thoracic artery supplies the 3rd to 11th posterior intercostal spaces
FALSE - supplies the 1st and 2nd posterior intercostal spaces
into which vein do the anterior intercostal veins drain?
internal thoracic vein
the posterior intercostal veins primarily drain into which venous system?
azygos/hemiazygos venous system
at which vertebral level does the azygos vein drain into the superior vena cava?
T4
the accessory hemiazygos vein crosses the midline at which vertebral level to drain into the azygos vein?
T8
the hemiazygos vein crosses the midline at which vertebral level to drain into the azygos vein?
T9
TRUE/FALSE: the anterior intercostal veins drain directly into the internal thoracic vein
TRUE
TRUE/FALSE: the posterior intercostal veins drain into both the azygos and hemiazygos systems
TRUE
which of the following veins drain the anterior intercostal spaces?
A) Internal thoracic vein
B) Azygos vein
C) Hemiazygos vein
D) Lateral thoracic vein
A: internal thoracic vein
at which vertebral level does the accessory hemiazygos vein cross the midline?
A) T8
B) T9
C) T4
D) T6
A: T8
the posterior intercostal veins in the 3rd to 11th spaces drain into which venous system?
A) Subclavian vein
B) Azygos system
C) Internal thoracic vein
D) Lateral thoracic vein
B: azygos system
describe the arterial supply to the anterior intercostal spaces
first 1-6 intercostal spaces supplied by the internal thoracic artery - arises directly form subclavian artery
7-9th intercostal spaces supplied by musculophrenic artery - a terminal branch of the internal thoracic artery
describe the arterial supply to the posterior intercostal spaces
1st & 2nd intercostal spaces supplied by supreme thoracic artery - branches directly from the costocervical trunk, a branch of the subclavian
3rd-11th intercostal spaces supplied directly by branches of the thoracic aorta
12th intercostal space supplied by subcostal artery - branch of the thoracic aorta
what artery runs parallel to the internal thoracic vein?
internal thoracic artery
describe the venous return from the anterior intercostal veins
anterior intercostal veins drain into the internal thoracic vein
describe the venous system associated with the posterior intercostal veins & key vertebral landmarks
posterior intercostal veins drain into the azygos/ hemiazygos system
at T9 - hemiazygos vein crosses the midline & drains into the azygos vein
at T8 - accessory hemiazygos vein crosses midline & drains into azygos
at T4 - azygos vein drains into superior vena cava
does the azygos vein drain into the superior or inferior vena cava? at what vertebral level?
superior vena cava - at T4
what do the anterior rami of thoracic spinal nerves T1-T11 form?
intercostal nerves
what structure does the the subcostal nerve (T12) travel inferior to?
the 12th rib
which of the following is NOT supplied by the posterior rami of thoracic spinal nerves?
A) Intercostal muscles
B) Deep back muscles
C) Joints of the spine
D) Skin of the back around the vertebral column
A: intercostal muscles - supplied by anterior rami of T1-11
the anterior rami of T1-T11 thoracic nerves supply which structures?
intercostal muscles & thoracic skin (via cutaneous branches)
TRUE/FALSE: the posterior rami of T1-11 supply the intercostal muscles
FALSE - intercostal muscles supplied by anterior rami of T1-11
what do the posterior rami of thoracic spinal nerves supply?
vertebrae & joints of the spine
deep back muscles
skin of the back around the vertebral column
the subcostal nerve corresponds to which thoracic spinal nerve?
A) T11
B) T12
C) T10
D) T9
B: T12
which part of the thoracic spinal nerve system forms the intercostal nerves?
A) Posterior rami (T1-12)
B) Anterior rami (T1-11)
C) Subcostal nerve (T12)
D) Anterior rami (T1-12)
B: anterior rami (T1-11)
the posterior rami of thoracic spinal nerves primarily supply which of the following?
A) intercostal muscles & thoracic skin
B) skin of the chest wall & deep back muscles
C) joints, spine, deep back muscles, and skin of the back
D) joints of the spine, deep back muscles & thoracic skin via cutaneous branches
C: joints, spine, deep back muscles, and skin of the back
describe the innervation of the intercostal spaces by the anterior & posterior rami
anterior rami of T1-11 form intercostal nerves & T12 forms the subcostal nerve - supply the intercostal muscles & thoracic skin via cutaneous branches
posterior rami supply the spine, joints, deep back muscle & skin of the back near the vertebral column
sensory loss around the nipple indicates a problem with which potential nerve/ vertebral level?
T4 & associated thoracic spinal nerves
what thoracic-level dermatome is associated with the umbilicus?
T10
origin and insertion of the pectoralis major?
origin - has two heads:
- clavicular head = medial 1/2 of the clavicle
- sternocostal head = first 6 costal cartilages & sternum
insertion - greater tubercle of humerus
actions of the pec major? (3)
adduction of arm
medial rotation of arm
extension of flexed arm
innervation to the pectoralis major? what do they originate from?
medial & lateral pectoral nerves - from medial & lateral cords of the brachial plexus
origin & insertion of the pectoralis minor?
origin - 3rd to 5th ribs
insertion - coracoid process of scapula
innervation to pectoralis minor?
medial pectoral nerve
actions of the pectoralis minor? (3)
stabilises scapula against thoracic wall
protraction of scapula
depression of scapula
origin & insertion of subclavius?
origin - junction of 1st rib & 1st costal cartilage
insertion - inferior surface of middle clavicle
innervation to subclavius? what trunk of the brachial plexus does this nerve arise from?
nerve to subclavius - arises from superior trunk
actions of the subclavius? (3)
- stabilises clavicle at sternoclavicular joint
- depresses clavicle
- protects adjacent neurovascular bundle of subclavian vessels & brachial plexus during fractures
origin and insertion of serratus anterior?
origin - anterior surface of ribs 1-9
insertion - medial border of scapula (anterior surface)
innervation to serratus anterior?
long thoracic nerve
actions of serratus anterior?
protracts scapula & keeps it against thoracic wall
upward rotation of scapula during arm elevation
what clinical condition results from damage to the long thoracic nerve?
winging of the scapula - medial border of the scapula protrudes outward
how does winging of the scapula present clinically when a patient pushes against a wall?
scapula doesn’t stay against the thoracic wall - instead protrudes outward
in what situations might damage to the long thoracic nerve occur, leading to winging of the scapula?
breast surgery, trauma, nerve compression
what muscle is affected in winging of the scapula due to long thoracic nerve damage? what role does this structure play in normal scapular movement?
serratus anterior muscle - innervated by long thoracic nerve, involved in stabilising the scapula against the thoracic wall
damage to nerve leads to outward protrusion of the scapula = winging
what artery starts dividing into its branches once it passes the pectoralis minor?
axillary artery (screw the lawyer, save a patient)
