Innervation of the Thoracic Cage and Viscera Flashcards
costochondritis caused by what virus
cosackie B virus
intercostal muscle internal and external
External and internal intercostals muscles are perpendicular so perform different roles. External hands in pockets. External with inspiration. Internal ( out and down facing) inspiration
The posterior and anterior roots and rootlets are the only sites where the motor and sensory fibres of a spinal nerve are segregated. The nerve roots could selectively be sectioned for the relief of intractable pain or spastic paralysis.
rhizotomy
12 pairs of thoracic spinal nerves but 11 intercostal nerves.
how is this possible
The anterior rami of T1 – T11 form the intercostal nerves within the intercostal spaces.
The anterior ramus of T12, runs inferior to the 12th rib as the subcostal nerve.
Each intercostal nerve enters an intercostal space between the parietal pleura and the internal (posterior) intercostal membrane.
Each spinal nerve receives communicating branches (rami communicantes) from the sympathetic trunk.
which nerves supply nothing else but the confined space within there own intercostal space
3-6th intercostal nerves - they initially run between the parietal pleura and internal intercostal membrane within the intercostal space then later run round from tbetween internal intercostal and innermost intercostal muscles and terminate as the anterior cutaneous branch
what branches are there of a typical intercostal nerve
collateral branches to supply intercostal muscles and parietal pleura
lateral cutaneous to supply skin of lateral thoracic and abdominal walls
ant cutaneous skin on ant thorax and abdomen
muscular branches to supply intercostal and serratus muscles
atypical intercostal nerves
Run past the thoracic wall and partially or completely supply other organs.
The 1st(brachial plexus- large branch , the inf becomes the intercostal- occasional lateral branches to supply axilla) 2nd(intercostal gives rise to intercostobrachial nerve supplying skin and subcutaneous of the floor of axilla and upper inner surface of the arm) 7th to 11th(nerve firbres have acess to the anterior abdominal wall) ......so you anterior abdominal wall is not supplied by lumbar nerve roots but by the thoracic intercostal nerves)they cross the costal margin to give this innervation intercostal nerves. Become the thoracic-abdomianl nerves of ant abdominal wall
arterial supply of thoracic wall derived from where
3
The thoracic aorta, via the posterior intercostal and subcostal arteries.
The Subclavian artery, via the internal thoracic (internal mammary) and supreme intercostal arteries.
The axillary artery, via the superior and lateral thoracic arteries.
each intercostal space supplied by 3 arteries a large posterior intercostal from thoracic aorta and a small pair of ant intercostal arteries from the internal thoracic artery - nerves accomy and lie superior in costal grooves
at inferior margin of the ribs, costal groove consists of what
Vein, Artery, Nerve (VAN)
so when inserting go to rib at the bottom and then go 1/3 of way up
Above the level of the sternal angle, the cutaneous innervation of the anterior thoracic wall is derived from
supraclavicular nerves (C3 and C4).
Dermatomes C5 – T1 are mainly in the upper limbs and are not significantly represented on the body wall.
Referred to pain organ causing pain – cannot localise it makes you feel pain in the strip of skin it innervates too
e.g. if you have an organ supplied by t1 where will you feel this pain
feel it in your arm as a cervical nerve root may supply that
cromare artery disease to medial Side of the arm
In coronary artery disease, pain is referred along the intercostobranchial nerve (lateral cutaneous branch of the second intercostal nerve) to the medial side of the arm.
The 7th – 11th intercostal nerves supply dermatomes, and muscles of the anterior abdominal wall and parietal peritoneum.
This implies that disease in the thoracic wall may relay as pain in a dermatome that extends across the costal margin into the anterior abdominal wall.
For example, a pulmonary thromboembolism or a pneumonia with pleurisy involving the costal parietal pleura could give rise to abdominal pain and tenderness and rigidity of the abdominal musculature as referred
when would you use an intercostal nerve block
Repair of lacerations of the thoracic and abdominal walls
Relief of pain in rib fracture.
To allow pain-free respiratory movements.
Thoracostomy (chest) tube insertion.
Sympathetic supply:
‘Fight, Flight or Fright’
Increases rate and strength of cardiac contraction, dilates coronary arteries
Thoracolumbar outflow (T1-L2) to sympathetic chain
Cardiac branches T1-5
Parasympathetic supply: Decreases rate and strength of cardiac contraction, constricts coronary arteries Craniosacral outflow ( CN III, VII, IX & X and S2,3,4) Main contributor to thorax = Vagus (X)
innervation of the heart sympathetic and parasympathetic
what happens to the coronary arteries
Sympathetic supply
From sympathetic chain, T1-5
Increases rate and strength of cardiac contraction, dilates coronary arteries
Parasympathetic supply
From Vagus
Decreases rate and strength of cardiac contraction, constricts coronary arteries
Together form Cardiac Plexus
referred pain from the heart goes to where
Referred pain:
Spinal segments innervating heart (T1-5 ) coincide with dermatomes innervating upper chest wall and inner arm, therefore felt as left chest/arm pain
