Anatomy 3: Anatomy of Spinal Nerves Flashcards
What type of receptors exist in all body wall structures for somatic general sensory spinal nerves. List some examples
Sensation specific receptors
Pain, touch, temperature, proprioception, vibration
What type of fibres do somatic motor axons on spinal nerves synapse onto on the body wall?
Skeletal muscle
What type of fibres do sympathetic axons on spinal nerves synapse onto?
Smooth muscle
What fibres does the spinal cord segmental synapse between for spinal reflexes?
Somatic sensory and somatic motor axons
Describe the types of general sensory somatic symptoms that the body wall percieves
Pain (neuralgia) Pins and needles (paraesthesia) Numbness (anaesthesia) Sensitivity (hyperanaesthesia) Hot or cold Loss of coordination/ balance/ clumsiness (ataxia)
Describe the types of somatic motor symptoms that the body wall percieves
Muscle stiffness, tightness or spasm (cramp)
Muscle flappiness or looseness (hypotonia)
Muscular weakness (reduced power)
Loss of coordination/ balance/ clumsiness (ataxia)
What are the neural components of the body wall?
Somatic general sensory fibres
Somatic motor fibres
Sympathetic fibres (motor to organs)
Spinal reflexes
What is used to test sensory function of spinal nerves?
Dermatomes
What is used to test motor function of spinal nerves?
Myotomes
In what situation, would we test both motor and sensory function of spinal nerves?
Spinal reflexes
What area of the brain is common for CVA?
Internal capsule
Identify the dermatomal locations of the cervical roots in the upper limb
C1: SN has no sensory axons
C2: Back of scalp and Adams apple (area that looks like a helmet with a strap tied below the chin)
C4: Clavicle and shoulder tip (neck lace)
C3: Back of neck and jugular notch (area between C2 and 4)
C5: ‘Badge patch’ (anterior chest and continues to wrist) WE DIVE TO T1 (most of arm)
C6: Thumb (+ index finger, if you join together they make 6) and lateral posterior arm
C7: Index and middle finger (continuation) and middle posterior forearm
C8: Ring and little finger (continuation) and medial posterior forearm
Identify the dermatomal locations of the thoracic roots in the upper limb and trunk
Entire area makes the letter T T1: Medial forearm (limbs are topmost ) T2: Medial arm and sternal angle T4: Male nipple ('boob') T8: Xiphoid process T10: Umbilicus (bell butTEN) T12: Pubic symphysis
Identify the dermatomal locations of the lumbar roots in the pelvis and lower limb
Supplies legs and loin
L1: Groin ‘hands in pockets’ (1nguinaL area)
L2: Anterior thigh
L3: Anterior thigh
L4: KNEE (to medial malleolus) (down on L4s) )
L5: Dorsum of foot (middle part of sole is triangle like an inverted V (roman for 5) and big toe (biggest number = biggest toe)
Identify the dermatomal locations of the sacral roots in the lower limb
Concentric fashion (out to in)
S1: Heel (POSTERIOR LEG) and last two toes (smallest no. = smallest toe)
S2: Posterior knee (lateral leg and foot inc. little toe) (FREE INC, GENITAL AREA)
(BULLSEYE OF ANUS)
S3: Buttock (FREE INC. GENITAL AREA)
S4: Perineum
S5: Perianal skin (anus)
What is the sensory area supplied by the posterior ramii, allowing us to test these ramii?
Supply a strip of skin centrally down back and posterior neck (C2 - C8 spinal nerves)
How would we test the sensory component of the anterior ramii?
Forms plexuses - cervical, brachial, lumbar, sacral which can be tested
Which spinal cord levels do not contribute to anterior ramii?
T2 - T12
Which nerves are formed from the bifurcation of L1?
Ilioinguinal and iliohypogastric
Which nerves are formed from the anterior ramii of T2 - T11?
Intercostal nerves
Which nerve is formed from the anterior ramii of T12?
Subcostal nerve
What is the difference between a spinal nerve and a named nerve?
Spinal nerves are axons originating from one spinal cord level e.g. L5 spinal nerve, whereas named nerve are axons originating from 1 or more spinal cord levels supplying an area e.g. musculocutaneous nerve (C5, 6, 7)
Identify the plexus and list the nerve roots giving rise to the named nerve cutaneous innervation of the neck
CERVICAL PLEXUS
Anterior ramii of C1, 2, 3, 4
Identify the specific sensory nerves and roots which form the named nerve cutaneous innervation of the neck
CERVICAL PLEXUS
LITTLE GOATS TRED SOFTLY:
Starting from -
11 o’clock: Lesser occipital nerve (C2) - posterior to external ear
1 o’clock: Great auricular nerve (C2, 3) - angle of mandible and external ear
3 o’clock: Trasverse cervical nerve (C2, 3) - anterior neck
6 o’clock: Supraclavicular (C3, 4) - clavicle, shoulder pain