Neurologic Exam
Cranial Nerves and Examination Methods
|
Cranial Nerve |
Nerve |
Exam |
|---|---|---|
|
I |
Olfactory |
Test sense of smell |
|
II |
Optic |
Perform funduscopic exam, visual acuity, visual fields, pupillary response |
|
III |
Oculomotor |
Assess medial, superior, and inferior recti muscles, inferior oblique, and levator palpebra superioris muscles; cover/uncover test (Figure 22-1) |
|
IV |
Trochlear |
Assess superior oblique muscle, cover/uncover test (Figure 22-1) |
|
V |
Trigeminal |
Assess muscles of mastication, sensation to face and anterior scalp, corneal reflex |
|
VI |
Abducens |
Assess lateral rectus muscle, cover uncover test (Figure 22-1) |
|
VII |
Facial |
Assess facial muscles, taste (anterior 2/3 of tongue), parasympathetics to lacrimal and salivary gland |
|
VIII |
Auditory |
Test hearing to finger rub, vestibular function |
|
IX |
Glossopharyngeal |
Test gag and palate elevation |
|
X |
Vagus |
Test gag and palate elevation |
|
XI |
Spinal accessory |
Assess strength of trapezius and sternocleidomastoid |
|
XII |
Hypoglossal |
Assess tongue bulk and atrophy, symmetry |
- 4+: Hyperreflexia with clonus
- 3+: Hyperreflexia with spread across joint
- 2+: Normal
- 1+: Hyporeflexia
- 0: No movement
- Muscle bulk and tone
- Assess pronator drift for subtle weakness
- Muscle strength:
- 5/5: Full strength
- 4/5: Full ROM against light resistance
- 3/5: Full ROM against gravity only
- 2/5: Full ROM in horizontal plane (gravity eliminated)
- 1/5: Trace (“flicker”) of movement
- 0/5: No movement
- Cerebellum and basal ganglia testing
- Finger to nose, heel to shin, rapid alternating movements
- Assess for head tilt or tremor, fluidity of movement
- Assess for abnormal movements
- Assess gait in the forward and backward directions; heel, toe and tandem gait
- Romberg test : Assess patient standing with feet together and eyes closed; if patient steps to the side or falls → positive test result (may indicate a disturbance in vestibular apparatus or proprioception)
- Test in all extremities (Figure 22-2)
- Pin prick, temperature sensation (spinothalamic tract in anterior spinal cord)
- Vibration, proprioception (posterior columns in posterior spinal cord)
- Assess for sensory level on the trunk if concern for spinal cord lesion
|
Maneuver |
Description |
Significance |
|---|---|---|
|
Babinski sign |
Upgoing plantar response |
Localizes to corticospinal tract |
|
Hoffman sign |
Flicking of patient’s second or third finger causes contraction of the ipsilateral thumb |
Localizes to corticospinal tract at or above cervical spinal cord |
|
Abdominal reflex |
Stroke abdomen toward umbilicus; lack of brisk contraction of abdominal muscles toward stroke is a ⊕ test |
Localizes to the corticospinal tract at or above thoracic spinal cord |
|
Cremasteric reflex |
Stroke inner thigh caudal to rostral, resulting in contraction of cremasteric muscle |
Localizes to the corticospinal tract at or above lumbar spinal cord |
|
Primitive reflexes
|
Percuss forehead, and eye blink does not extinguish Percuss lips in the midline, and lips pucker Stroke thenar eminence of hand, and mentalis muscle moves |
Suggest frontal lobe damage (except in neonates or infants) |
eFigure 22-2
Cutaneous innervation (anterior and posterior views). (Reproduced with permission from Simon RP, Greenberg DA, Aminoff MJ: Clinical Neurology, 7th ed. Available at http://www.accessmedicine.com.easyaccess2.lib.cuhk.edu.hk.
New York: McGraw-Hill. Copyright © The McGraw-Hill Companies. All rights reserved.)
Normal Infant Reflexes that Appear at Birth
|
Reflex |
Description |
Disappearance |
|---|---|---|
|
Moro (startle) |
Lift head 30 degrees and allow to fall to neutral Positive: Arm extension and abduction → arm adduction |
1–3 mo |
|
Palmar grasp |
Flexion of hand when object placed against palm |
4 mo |
|
Root |
Stroking cheek causes mouth to turn toward stimulus |
3–4 mo |
|
Tonic neck |
Head is turned to side while the child is supine. Positive: Ipsilateral arm/leg extension, contralateral arm and leg flexion (“fencing posture”); normal infant tries to break reflex |
5–6 mo |
|
Babinski |
Stroke lateral border of sole from heel to great toe Positive: Great toe dorsiflexion, fanning of other toes |
1–2 yr |
Clinical Discrimination of Upper and Lower Motor Neuron Lesions
|
UMN Lesion |
LMN Lesion |
|---|---|
|
Hyperreflexia (± Hoffman, Babinski signs) |
Hyporeflexia |
|
Hypertonia |
Hypotonia |
|
Spasticity |
Flaccidity |
|
Normal muscle bulk |
± Muscle atrophy |
|
No fasciculations |
Fasciculations |
Actions of the Principal Muscles and Their Nerve Root Supply
|
Action tested |
Roots* |
Nerves |
Muscles |
|---|---|---|---|
|
Brachial | |||
|
Adduction of extended arm |
C5, C6 |
Brachial plexus |
Pectoralis major |
|
Initiation of abduction of arm |
C5, C6 |
Brachial plexus |
Supraspinatus |
|
Abduction and elevation of arm up to 90° |
C5, C6 |
Axillary nerve |
Deltoid |
|
Flexion of supinated forearm |
C5, C6 |
Musculocutaneous |
Biceps, brachialis |
|
Extension of forearm |
C6, C7, C8 |
Radial |
Triceps |
|
Extension (radial) of wrist |
C6 |
Radial |
Extensor carpi radialis longus |
|
Adduction of flexed arm |
C6, C7, C8 |
Brachial plexus |
Latissimus dorsi |
|
Supination of forearm |
C6, C7 |
Posterior interosseous |
Supinator |
|
Extension of proximal phalanges |
C7, C8 |
Posterior interosseous |
Extensor digitorum |
|
Extension of wrist (ulnar side) |
C7, C8 |
Posterior interosseous |
Extensor carpi ulnaris |
|
Pronation of forearm |
C6, C7 |
Median nerve |
Pronator teres |
|
Radial flexion of wrist |
C6, C7 |
Median nerve |
Flexor carpi radialis |
|
Opposition of thumb against fifth finger |
C8, T1 |
Median nerve |
Opponens pollicis |
|
Abduction and adduction of fingers |
C8, T1 |
Ulnar |
Interossei |
|
Crural | |||
|
Hip flexion from semiflexed position |
L1, L2, L3 |
Femoral |
Iliopsoas |
|
Hip flexion from externally rotated position |
L2, L3 |
Femoral |
Sartorius |
|
Extension of knee |
L2, L3, L4 |
Femoral |
Quadriceps femoris |
|
Adduction of thigh |
L2, L3, L4 |
Obturator |
Adductor longus, magnus, brevis |
|
Abduction and internal rotation of thigh |
L4, L5, S1 |
Superior gluteal |
Gluteus medius |
|
Extension of thigh |
L5, S1, S2 |
Inferior gluteal |
Gluteus maximus |
|
Flexion of knee |
L5, S1, S2 |
Sciatic |
Biceps femoris, semitendinosus, semimembranosus |
|
Dorsiflexion of foot (medial) |
L4, L5 |
Peroneal (deep) |
Anterior tibial |
|
Dorsiflexion of great toe |
L5, S1 |
Peroneal (deep) |
Extensor hallucis longus |
|
Eversion of foot |
L5, S1 |
Peroneal (superficial) |
Peroneus longus and brevis |
|
Plantar flexion of foot |
S1, S2 |
Tibial |
Gastrocnemius, soleus |
|
Inversion of foot |
L4, L5 |
Tibial |
Tibialis posterior |
|
Contraction of anal sphincter |
S2, S3, S4 |
Pudendal |
Perineal muscles |
Neuroimaging Basics
|
Modality |
Best For Examining |
Advantages |
Disadvantages |
|---|---|---|---|
|
US |
Ventricles and gross brain structure of neonates with open fontanelles TCD for sickle cell disease |
Can be done at bedside Quick No radiation Relatively inexpensive |
Poor resolution |
|
CT |
Intracranial blood or calcifications Cranial bone integrity |
Quick Able to be used if implantable device is present and MRI is contraindicated Relatively inexpensive |
Poorly defines soft tissues Poor visualization of posterior fossa Radiation exposure |
|
CTA |
Intracranial arterial system |
Quick Inexpensive |
Radiation exposure May cause renal injury from contrast Possible iodine allergy |
|
MRI |
Brain parenchyma |
Best definition of soft tissues Better resolution of structures Best for evaluating posterior fossa No radiation |
Requires time to obtain images Slight risk of irreversible renal scarring (primarily in those with preexisting renal disease) May require sedation More expensive than CT |
|
MRA |
Intracranial arterial system, carotids, basilar arterial system Vascular malformations |
No contrast necessary No radiation |
Requires more time to obtain images More expensive than CT |
|
MRV |
Intracranial venous system (eg, r/o sinous venous thrombosis) Vascular malformations |
No radiation |
Requires more time to obtain images More expensive than CT |
|
MRS |
Suspected metabolic d/o Evaluation of neonatal HIE Noninvasive biochemical tumor typing (via assessment of molecular composition and biochemical changes in brain tissue) |
No radiation |
Requires specialized neuroradiologist interpretation |
CT Signal Density
MRI Signal Intensity
|
Fat |
CSF |
Gray Matter |
White Matter |
Bone |
Blood | |
|---|---|---|---|---|---|---|
|
T1 |
Very bright |
Dark |
Intermediate |
Bright |
Very dark |
See below; depends on chronicity |
|
T2 |
Dark |
Very bright |
Intermediate |
Dark |
Very dark |
Common MRI Sequences and Potential Applications
|
T1 |
T2 |
Flair |
DWI |
ADC |
GRE/FFE |
SWI |
|---|---|---|---|---|---|---|
|
Structure and anatomy (gray matter is darker, white matter is brighter) |
Pathology (white matter is darker, gray matter is brighter) |
Pathology (pathology causing any parenchymal edema is bright) |
Acute ischemia (ischemia is bright within 30 min) |
Acute ischemia (ADC is dark where DWI is bright if true ischemia is present and not artifact) |
Blood (blood is dark) |
Microhemorrhages (blood is dark) |
Evaluation of Intracranial Hemorrhage Using MRI
|
Acute (6 h–day 3) |
Early Subacute (day 3–day 7) |
Late Subacute (1 wk–1 mo) |
Chronic (months–years) | |
|---|---|---|---|---|
|
T1 |
Isodense or dark |
Bright |
Bright |
Dark |
|
T2 |
Very dark |
Dark |
Bright |
Dark |
Abnormal Skull Shape and Craniosynostosis
Types of Craniosynostosis
|
Suture |
Cranial Abnormality |
Features |
Frequency (%) |
|---|---|---|---|
|
Sagittal |
Scaphocephaly |
AP elongation, reduced biparietal distance |
40–60 |
|
Unilateral coronal |
Anterior plagiocephaly |
Recession of the forehead, elevation of the ipsilateral eye |
20–30 |
|
Bilateral coronal |
Brachycephaly |
“Tower-like,” pointed head; reduced overall size; flattened forehead |
10 |
|
Metopic |
Trigonocephaly |
Pointed frontal bone, hypotelorism |
5–10 |
|
Lambdoid |
Posterior plagiocephaly |
Flattening of the occipital area, prominence of the contralateral frontal area |
1–3 |
- Premature fusion of sutures may:
- Alter skull growth. If there is synostosis of all sutures, brain growth may be altered.
- Growth is arrested perpendicular to the suture.
- Compensatory growth increases parallel to the suture.
- Occurs in one or more sutures (sagittal most often affected).
- Alter skull growth. If there is synostosis of all sutures, brain growth may be altered.
- Craniosynostosis is most commonly nonsyndromic but may be associated with certain genetic syndromes (eg, abnormalities of FGFR genes, including Apert, Crouzon, Pfeiffer, Jackson Weiss, and Muenke syndromes).
Chiari Malformations
|
Anatomy |
Common Associations |
Possible Presentations |
Treatment | |
|---|---|---|---|---|
|
Chiari I |
Tonsils extend >5 mm below the foramen magnum |
Syrinx |
Headache, Respiratory difficulties |
May require decompression |
|
Chiari II |
Low-lying torcula Downward vermian displacement Small posterior fossa Beaked tectum Cervicomedullary kink Large massa intermedia |
Myelomeningocele Syringohydromyelia Hydrocephalus |
Increasing FOC Tethered cord syndrome |
May require decompression CSF shunting |
|
Chiari III |
Chiari II plus cervical cephalocele |
Cephalocele Microcephaly |
Cephalocele Respiratory deterioration Lower cranial nerve dysfunction |
Surgical repair and shunting |
|
Chiari IV |
Severe cerebellar hypoplasia |
Respiratory suppression |
None |
Full access? Get Clinical Tree
