Clinically relevant anatomy of spinal nerves Flashcards
What is contained within the anterior horn of the spinal cord?
Motor cell bodies
Somatic general sensory symptoms
Neuralgia Paraesthesia Anaesthesia Hyperaesthesia Thermal Ataxia
Somatic motor symptoms
Muscle stiffness, tightness or spasm
Reduced tone or hypotonia
Reduced power
Ataxia
Common upper limb and trunk dermatomes
C2 - back of scalp and adams apple C3 - back of neck and jugular notch C4 - clavicle and shoulder tip C5 - regimental badge area C6 - thumb C7 - middle finger C8 - little finger T1 - middle forearm T2 - medial arm and sternal angle T4 - nipple T10- umbilicus T12 - pubic symphysis
Common lower limb dermatomes
L1 - groin L2 - anterior thigh L3 - anterior knee L4 - medial malleolus L5 - dorsum of foot S1 - heel S2 - posterior knee S3 - buttock S4 - perineum S5 - perianal skin
What does dermatomal testing allow you to check the integrity of?
Dorsal rootlets
Dorsal roots
Spinal nerve
What does a dermatomal and myotomal indicate a problem with?
Spinal nerve
Do posterior rami form plexuses?
No - anterior rami
Do T2-T12 form a plexus?
No - they form the intercostal nerves to supply the anterolateral trunk wall and the subcostal nerve
Cervical plexus
Little, Goats, Tread, Softly Lesser occipital nerve Greater auricular nerve Transverse cervical nerve Supraclavicular nerve
Where does the lesser occipital nerve supply?
Skin posterior to the external ear
Where does the great auricular nerve supply?
Skin over angle of mandible and external ear
Where does the transverse cervical nerve supply?
Skin over anterior neck
Where does the supraclavicular nerve supply?
Skin over the clavicle and shoulder tip
What is the nerve point of the neck?
Where sensory nerves of the cervical plexus converge to pass from superficial to deep fascia
Found at the midpoint of the posterior border of the SCM
Which nerve supplies the anatomical snuff box?
Cutaneous branch of the radial nerve
Which anterior rami will refer pain from the myocardium?
T1 and T2
Somatosensory part of brain?
Postcentral gyrus in the parietal lobe
Which ascending track is for pain?
Spinothalamic
What does the cervical plexus of C1-4 supply?
Neck postural and strap muscles
Diaphragm
What does the brachial plexus of C5-T1 supply?
Muscles of upper limb
Extrinsic back muscles
What do the T2-L3 motor axons supply?
Postural back muscles via posterior rami
Intercostal muscles via anterior rami
Anterolateral abdominal wall muscles
What does the lumbosacral plexus of L1-S4 supply?
Muscles of lower limb
Perianal skeletal muscles
What is the C5 myotome?
Shoulder abduction via deltoid muscle
What is the C6 myotome?
Elbow flexion via biceps brachii
What is the C7 myotome?
Elbow extension via triceps brachii
What is the C8 myotome?
Finger flexion via flexion digitorum superficialis
What is the T1 myotome?
Finger abduction via dorsal interossei
What is the L3 myotome?
Knee extension via quadriceps femoris
What is the L2 myotome?
Hip flexion via psoas major and iliacus
What is the L4 myotome?
Ankle dorsiflexion via tibialis anterior
What is the L5 myotome?
Great toe extension via extensor hallucis longus
What is the S1 myotome?
Ankle plantarflexion via gastrocnemius
What is the S2 myotome?
Knee flexion via biceps femoris
What does an upper motor neurone lesion result in?
Spasticity
What does a lower motor neurone lesion result in?
Flaccidity
How can spinal reflexes be tested?
C5,6 = biceps brachii C6 = brachioradialis C7 = triceps brachii L3 = knee jerk S1 = ankle jerk
