ANATOMY Thorax – Nerves

Thorax – Nerves

  1. Phrenic nerve p125 instant anatomy, p188 Lasts

a. Strives to reach midline at all levels F

b. Medial relations identical F - completely different (R related to venous structures, L related to
arterial structures

c. Only supplies own side of diaphragm T

d. Arises from C6 F - C3,4,5 (mainly C4)

e. Both give off recurrent laryngeal nerve F - No from Vagus

  1. Which one of the following statements concerning a typical intercostal nerve is INCORRECT – Pg 100new moore

a. it is a mixed spinal nerve T

b. it passes in the neurovascular plane between the internal
intercostal and innermost intercostal muscles T

c. is collateral branch has no cutaneous distribution F – Wrong it does
d. in its course around the body wall the nerve lies below

the vein and the artery T

e. the main nerve itself has an anterior terminal branch T - it has an anterior cutaneous branch

Thorax – Muscles

  1. In the chest wall p176 Lasts for intercostals space p93, 97 NM

a. the neurovascular bundle lies between the external and
internal intercostals F - it lies between the internal intercostals and the transversus

b. the transversus muscle lies between the internal and
external intercostals F - it goes ext interc, int interc and innermost inercostal muscles

c. the intercostal artery lies between the nerve and vein T - VAN from sup to inf

d. the intercostal artery is more superficial than the vein F

e. runs nerve vein artery F - Nerve inferior, then artery, then vein superiorly

f. b) runs above rib F - below

g. c) runs under inferior border T

ANATOMY Thorax – Circulation

  1. Regarding the right coronary artery p156NM

a. course through the left auricle and infundibulum F - this is the LCA. The RCA goes between the R aortic sinus and
pulm trunk.

RCA gives arises from the R aortic sinus of the ascending aorta and passes to the R side of
the pulm trunk running in the coronary groove.
The L goes between the L auricle and the pulmonary trunk.

b. supplies 60% of AV nodes F - Says 80% in Moore (via posterior IV artery)

c. usually has a posterior interventricular branch T - the artery which gives off the Post interventricular branch is the
dominant branch. This occurs from the R in 67% of people

d. supplies 30% of SA nodes F - Says 60% in Moores

e. 50% of AV nodes are supplied by the RCA F - 80%

f. 50% of SA nodes are supplied by the RCA F - 60%

g. arises from posterior sinus F - from R sinus

h. wrong course Course is to R of pulmonary trunk, running in coronary groove

  1. Coronary arteries p156 NM, 196 Lasts

a. The right arises from the posterior coronary sinus F - R aortic sinus

b. There are arteriolar anastomoses between the
terminations of the left and right coronary arteries T - They are considered end-arteries although
collaterals do occur…

c. The left supplies the conducting system in the
majority of patients F - RCA suppliesSA in 60%, AV in 80%

d. right arises from the posterior coronary sinus F - from the R coronary sinus

e. left supplies the conducting system in most patients F - Not best answer: It supplies the IVS but the
AV node is 80% and SA node
is 60% of time by RCA (via the anterior

f. right supplies the posterior descending branch in
most patients T

g. there are no arteriolar anastomoses between left and right F

  1. Regarding Internal Mammary artery p178 Lasts (Ie the internal thoracic artery)

a. Descends straight down 1cm medial to border off sternum F - 1cm lateral to border of sternum

b. Branch of 2nd part of subclavian artery F - 1st part

c. Gives off two intercostal branches F - Gives off two anterior intercostals at EACH
intercostals space then
at the costal margin gives off superior epigastric
and musculophrenic

d. Runs with companion vein which drains into brachiocephalic T - x2 venae commitantes accompany it and
drain into brachiocephalic vein.

Summary: Internal intercostals comes of the first branch of the subclavian artery
and descends 1cm lateral to the sterna border. It gives of two anterior
intercostals arteries at each intercostals space and splits into the superior
epigastric and musculophrenic arteries at the costal margin. It runs with x2
venae comitantes which drain into the brachiocephalic vein

  1. Which one of the following statements concerning the relations of the arch of the aorta

a. the ascending aorta arches backwards to reach the body
of the fourth thoracic vertebra T - as per paragraph below

b. the arch is crossed on its left side by the phrenic
and vagus nerves T - picture, difficult to tell but left side looks like phrenic and
vagus are close to aortic arch.

c. the left recurrent laryngeal nerve passes upwards on
the left side of the arch of the aorta F - Pg 150 loops around subclavian on right; on left runs
around arch of aorta and ascends in tracheo-
oesophageal groove – so runs upward on right side of
d. ends by becoming the thoracic aorta posterior to the
2nd left sternocostal joint T

e. the trachea lies on the right side of the arch of the aorta T

The arch of the aorta, the curved continuation of the ascending aorta begins
posterior to the 2nd right sternocostal joint and the level of the sternal angle and
arches superoposteriorly and to the left. The arch of the aorta ascends anterior
to the right pulmonary artery and the bifurcation of the trachea to reach it’s apex
at the left side of the trachea and oesophagus, as it passes over the root of the
left lung. The arch descends of the left side of the body of T4 vertebrae.