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
- 5/5: Full strength
- 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
- Finger to nose, heel to shin, rapid alternating 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
- Pin prick, temperature sensation (spinothalamic tract in anterior spinal cord)
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.)
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 |
UMN Lesion | LMN Lesion |
|---|---|
Hyperreflexia (± Hoffman, Babinski signs) | Hyporeflexia |
Hypertonia | Hypotonia |
Spasticity | Flaccidity |
Normal muscle bulk | ± Muscle atrophy |
No fasciculations | Fasciculations |
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 |
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 |
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 |
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) |
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 |
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.
- Growth is arrested perpendicular 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).
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 |
