Organisation of nerves in thorax Flashcards
Where do somatic nerves innervate?
Skin and skeletal muscles
Where do autonomic/visceral nerves innervate?
Organs, smooth muscle
What are the functions of somatic spinal nerves?
Motor - skeletal muscle only
Sensory to body wall NOT viscera
What do segmental nerves combine to?
Plexi - supply specialised areas
What type of innervation enters the posterior dorsal horn?
Sensory
What type of innervation leaves the ventral horn?
Motor - to muscles
What is the difference between the posterior root and ramus?
Root: Sensory nerves
Ramus: Post. has sensory and motor nerves and Ant. has all others (skin/muscle)
What is a dermatome?
Area of skin which is supplied by a single spinal nerve on one side/from a single spinal cord
What is a myotome?
Part of skeletal muscle supplied by a single spinal nerve on one side/ from single spinal cord level
What are spinal levels?
The levels on innervation which the spinal nerves innervate
What spinal levels innervate the arm?
C5-8 and T1
Why is T1 spinal level relevant?
Cardiac referred pain
Why is T3 spinal level relevant?
3rd and 4th intercostal space
Why is T4 spinal level relavant?
Nipple line, 4-5th interspace
Why T6 spinal level relevant?
Xiphoid process
Why is T10 spinal level relevant?
Navel
Why is T12 spinal level relevant?
Pubis
Where do IC nerves originate?
Only from spinal cord - so can be spinal or segmental - anterior 1ry rami
Where are IC nerves present in the thorax?
Under the ridge of the ribs, between the innermost and internal layers
How many IC nerves do we have?
11 pairs and 1 subcostal
What kind of innervation do the IC muscles carry?
Both motor and sensory
Where does the lateral cutaneous branch of IC nerves supply?
The anterior and posterior IC spaces, supplies skin
Where does the anterior cutaneous branch of IC nerves supply?
The lateral and medial IC spaces, including skin outside of chest wall
What nerves supply the IC muscles?
The IC nerves from the anterior ramus
At which level does the IVC cross the diaphragm?
T8
What does the phrenic nerve motor fibres supply?
Skeletal muscle of the diaphragm
Where are the phrenic nerves derived from?
Anterior Rami of C3-5
What kind of nerves are the phrenics?
Somatic so no autonomical function or visceral distribution
What do the sensory fibres of the phrenic supply?
Central diaphragm, pleural covering, mediastinal pleura and pericardium (peritoneum on inf surface of diaphragm)
Where do sympathetic nerves have cell bodies?
Thoraco-lumbar cord
How do the symp nerves reach their destination?
Travel with vessels
Where do the autonomic motor nerves innervate?
Cardiac muscle, smooth muscle and glands