Spinal Nerves (Sensory) Flashcards
Briefly, what does a spinal nerve pair supply?
Everything in one segment of the body
Where does somatic sensory supply from a spinal nerve pair act?
On sensation specific receptors in all body wall structures
Where do each of the following motor modalities from a spinal nerve synapse a) somatic motor? b) sympathetic?
a) All body wall skeletal muscle fibres b) All body wall glands and smooth muscle fibres
Describe a spinal reflex?
Spinal cord segmental synapses between somatic sensory and motor axons
Name the 3 areas of the CNS where somatosensory pathology can originate from?
Ascending spinal cord tracts (DCML/spinothalamic), internal capsule or primary somatosensory cortex
Dermatomal testing allows you to assess the integrity of what structures? Are these structures sensory or motor or both?
Dorsal rootlets (sensory), dorsal root (sensory), spinal nerve (sensory and motor)
Describe where each of the following dermatomes supplies: a) C2? b) C3? c) C4?
C2 = back of scalp and adam’s apple / C3 = back of neck and jugular notch / C4 = clavicle and shoulder tip
Describe where each of the following dermatomes supplies: a) C5? b) C6? c) C7? d) C8?
C5 = badge patch / C6 = thumb / C7 = middle finger / C8 = little finger
Describe where each of the following dermatomes supplies: a) T1? b) T2?
T1 = medial forearm / T2 = medial arm and sternal angle
Describe where each of the following dermatomes supplies: a) T4? b) T10? c) T12?
T4 = male nipple / T10 = umbilicus / T12 = pubic symphysis
Describe where each of the following dermatomes supplies: a) L1? b) L2? c) L3? d) L4? e) L5?
L1 = groin (hands in pockets) / L2 = anterior thigh / L3 = anterior knee / L4 = medial malleolus / L5 = dorsum of foot
Describe where each of the following dermatomes supplies: a) S1? b) S2? c) S3? d) S4? e) S5?
S1 = heel / S2 = posterior knee / S3 = buttock / S4 = perineum / S5 = perianal skin
What does the sensory component of the posterior rami supply?
A strip of skin down the centre of the posterior neck and back
The area of the back which is supplied by the T2 posterior rami is found just above which structure? The area of the back which is supplied by the L3 posterior rami is found just above which structure?
Spine of the scapulae / Iliac crests
Anterior rami combine to form what? Which are the only anterior rami for which this is not the case?
Plexuses / T2-T12
What nerves are responsible for sensory supply to the upper anterolateral trunk wall?
Intercostal nerves
What forms intercostal nerves?
Anterior rami of T2-T11
What nerves are responsible for sensory supply to the lower anterolateral trunk wall?
Ilioinguinal and iliohypogastric nerves
What forms the ilioinguinal and iliohypogastric nerves?
The bifurcation of the anterior ramus of L1 spinal nerve
What nerve is responsible for supplying the T12 dermatome of the anterolateral trunk wall?
Subcostal nerve
What forms the subcostal nerve?
T12 anterior ramus
What is the main difference between a spinal nerve and a named nerve?
Spinal nerves contain axons originating from only one spinal cord level. Named nerves contain axons originating from one or more spinal cord levels supplying a particular area.
Describe briefly the cutaneous innervation of the neck a) posteriorly? b) anteriorly?
a) posterior rami of C2-C8 b) cervical plexus formed of anterior rami C1-C4
Where does the lesser occipital nerve (C2) supply?
The skin posterior to the ear
Where does the great auricular nerve (C2, C3) supply?
The skin over the angle of the mandible and some of the external ear
Where does the transverse cervical nerve (C2, C3) supply?
The skin over the anterior neck
Where do the supraclavicular nerves (C3, C4) supply?
The skin over the clavicles and shoulder tips
What NERVES (not roots) make up the cervical plexus?
Lesser occipital nerves, great auricular nerve, transverse cervical nerve, supraclavicular nerves
What nerve and nerve roots are responsible for referred pain from the diaphragm?
Supraclavicular nerves (C3, 4)
What is the nerve point of the neck?
The area where all of the sensory nerves of the cervical plexus converge and pass from superficial to deep fascia
Where is the nerve point of the neck found?
The midpoint of the posterior border of SCM
Which nerve roots are responsible for referred pain from the myocardium?
T1 and T2 anterior rami
The anatomical snuffbox is supplied by cutaneous branches of which nerve?
Radial nerve
