Upper limb Neurology Flashcards
How many segments of the spinal cord are there?
31
What is a dermatome?
A dermatome is an area of skin in which sensory nerves derive from a single spinal nerve root.
The surface of the skin is divided into specific areas called dermatomes are derived from the cells of a somite.
Where is C5 dermatome test?
arm over lateral deltoid region
Where is C6 dermatome test?
dorsal web of hand (top of thumb)
Where is C7 dermatome test?
palmar surface of middle finger
Where is C8 dermatome test?
Little finger, medial side of hand and forearm
- (edge of hypothenar)
Where is T1 dermatome test?
medial arm and axilla
What is a myotome?
A myotome is the group of muscles that a single spinal nerve innervates. In vertebrate embryonic development, a myotome is the part of a somite that develops into the muscles.
What is the clinical significance of a dermatome?
Useful help localize neurologic levels, particularly in radiculopathy.
Effacement or encroachment of a spinal nerve may or may not exhibit symptoms within a dermatomal area covered by the compressed nerve roots in addition to potential weakness, or deep tendon reflex loss.
How do you perform C5 myotome test?
C5/C6 (Axillary Nerve):
Deltoid
Arm outstretched at 90 degrees. Dr stands behind patient pushing form downward on the arm and pt tries to resist
How do you perform C6 myotome test?
C5/C6 (Musculocutaneous Nerve):
Biceps Brachii
Pt flexes arm with thumb out to the side / supinated.
dr puts arm on same shoulder
dr pulls force down whilst pt tries to resist
C5/C6/C7 (Radial Nerve):
Brachioradialis
exactly the same as bicep but pt’s arm is not supinated and thumb is positioned upwards
dr pulls force down whilst pt tries to resist
C6/C7 (Radial Nerve):
Wrist Extensors
dr support patient under forearm
other hand on pt hand and try to bring the wrist into flexion (down) whilst pt resists
How do you perform C7 myotome test?
C6/C7/C8 (Radial Nerve):
Triceps Brachii
Pt flexes arm with thumb out to the side / supinated.
dr puts arm on same shoulder
dr pushes force up whilst pt tries to resist
C6/C7/C8 (Median & Ulnar Nerve):
Wrist Flexors
pts arm is palm up
dr supports arm forearm
other hand on pt hand and try to bring the wrist into extension whilst pt resists
How do you perform C8 myotome test?
C8/T1 (Median & Ulnar Nerve):
Finger Flexors
pt has hands supine
dr puts hands over pt’s finger pads and pulls them towards dr whilst pt resists.
How do you perform T1 myotome test?
C8/T1 (Deep branch of Ulnar Nerve):
Finger ABductors
pt has hands prone and fingers spread
dr tried to ADDuct hands and pt resists
C8/T1 (Deep branch of Ulnar Nerve):
Finger ADDuctors
Pt has fingers adducted tightly and dr tries to separate fingers
What areas do you perform arm reflex tests?
C5 - Bicep tendon - thumb over base of bicep and use reflex hammer over thumb
C6 - brachioradialis muscle belly or tendon further along the forearm
C7 - olecranon - support pt’s arm so fully relaxed
C8 - fingers in figure 8 (finger flex myotome position) - tab dr fingers to feel reflex
How do you perform a C5 Reflex tendon test?
C5 - Bicep tendon - thumb over base of bicep and use reflex hammer over thumb
How do you perform a C6 Reflex tendon test?
C6 - brachioradialis muscle belly or tendon further along the forearm - ensure you support the patients arm - can use thumb to test the reflex hammer on
How do you perform a C7 Reflex tendon test?
C7 - olecranon - support pt’s arm so fully relaxed - area just above olecranon should result in reflex like ricky Gervais
How do you perform a C8 Reflex tendon test?
C8 - fingers in figure 8 (finger flex myotome position) - tab dr fingers to feel reflex
What is Hyporeflexia?
Hyporeflexia is an absent or diminished response to testing. It usually indicates a disease/disorder that involves one or more of the components of the two-neuron reflex arc itself.
What is Hyperreflexia?
Hyperreflexia refers to hyperactive or repeating (clonic) reflexes. These usually indicate an interruption of corticospinal and other descending pathways that influence the reflex arc due to a suprasegmental (lesion above the level of the spinal reflex pathways).
Peripheral neuropathy is also a common cause of absent reflexes. The causes include?
Diabetes
Alcoholism,
Vitamin deficiencies B12, Folic acid
Chronic kidney disease
Gulian Barre
RA, SLE
How do you grade tendon reflex tests?
0 = no response; always abnormal
1+ = a slight but definitely present response; may or may not be normal
2+ = a brisk response; normal
3+ = a very brisk response; may or may not be normal
4+ = a tap elicits a repeating reflex (clonus); always abnormal
Whether the 1 + and 3 + responses are normal depends on what they were previously, that is, the patient’s reflex history; what the other reflexes are; and analysis of associated findings such as muscle tone, muscle strength, or other evidence of disease. Asymmetry of reflexes suggests abnormality.
How do you test the median nerve?
Pt supine
Dr in fencer stance
Arm on pts shoulder – to depress shoulder
Pt rests arm on dr knee – 90 degree
Wrist extension with 2 and 3 digit on thumb
Externally rotate arm 90 degree
Supinate and extend elbow
(walk like an Egyptian)
