Axillary Nerve
C5-C6
Fractured neck of humerus; anterior dislocation
Presents: Flattened deltoid, loss of arm abduction at shoulder, loss of sensation over deltoid muscle and lateral arm
Musculocutaneous
C5-C7
Upper trunk compression
Presents: loss of forearm flexion and supination, loss of sensation over lateral forearm
Radial nerve
C5-T1
Midshaft fracture of humerus, compression of axilla, due to crutches or sleeping with arm over chair
Presents: Wrist drop, loss of elbow, wrist and finger extension
Decreased griop strength
Loss of sensation over posterior arm/forearm and dorsal hand
Median nerve
C8-T1
Fracture of medial epicondyle, fractured hook of hamate, from fall on outstretched hand
Ulner claw on digit extension
Radial deviation of wrist upon flexion
Loss of wrist flexion, flexion of medial fingers, abduction and adduction of fingers, actions of 2 lumbrical muscles
Loss of sensation over medial 1.5 fingers
Recurrent medial nerve
C5-T1
Superficial laceration of palm
Presents: Ape hand
loss of thenar muscle group, opposition, abduction, and flexion of thumb
Illiohypogastric
T12-L1
Sensory - suprapubic region
Motor - transversus abdominis and internal oblique
Injury: Abdominal injury
Presents: Burning or tingling pain in surgical incision site radiating to inguinal and suprapubic region
Genitofemoral nerve
L1-L2
Sensory: Scrotum/labia majora, medial thigh
Motor: Cremaster
Injury: Laproscopic surgery
Presents: Decreased anterior thigh sensation beneath inguinal ligament and absent cremaster reflex
Lateral Femoral Cutaneous
L2-L3
Sensory: anterior and lateral thigh
Injury: Tight clothing, obesity, pregnancy
Presents: Decreased anterior and lateral thigh sensation
Obturator nerve
L2-L4
Sensory: medial thigh
Motor: Obturater externus, adductor longus, adducter brevis, gracilis, pectineus, adductor magnus
Injury: Pelvic surgery
Presentation: decreased thign sensation medially and decreassed adduction
Femoral nerve
L2-L4
Sensory: anterior thigh, medial leg
Motor: quadriceps, iliopsoas, pectineus, sartorius
Injury: Pelvic fracture
Presentation: Decreased thigh flexion and lex extension
Sciatic nerve
L4-S3
Sensory: posterior thigh
Motor: Semitendinous, semimembranosus, biceps femoris, adductor magnus
Injury: Herniated disc
Presentation: Splits into common peroneal and tibialnerves
Common peroneal nerve
L4-S2
Sensory: Dorsum of foot
Motor: Biceps femoris, tibialis anterior, extensor muscles of foot
Injury: Trauma or compression of lateral aspect of leg, fibular neck fracture
Presents: PED = Peroneal everts and dorsiflexes; if injured, foot droPED
Loss o sensation on dorsum of foot
Tibial nerve
L4-S3
Sensory: sole of foot
Motor: Triceps surae, plantaris, popliteus, flexor muscles of foot
Injury: Knee trauma, baker cyst, tarsal tunnel syndrome
Presentation: TIP tibial inverts and plantarflexes; if injured, cant stand on TIPtoes
Superior gluteal nerve
L4-S1
Motor: gluteus medius, gluteus minimus, tensor fascia latae
Injury: Iatrogenic injury during intramuscular injection to upper medial gluteal region
Presentation: Pelvis tilts
Inferior gluteal
L5-S2
Motor: Gluteus maximus
Injury: Posterior hip dislocation
Presents: difficulty climbing stairs, rising from seated position
Pudendal
S2-S4
Sensory: Perineum
Motor: External urethral and anal sphincters
Injury: Stretch ninjury during childbirth
Presents: decreased perineal sensation and genital area sensation. Can cause fecal incontinence
Can be blockd with local anesthtic using ischial spine as landmark
Oculomotor nerve motor function
All eye muscles except Lateral rectus, superior oblique
Eye muscle innervation
Lateral rectus: VI
Superior oblique: IV
Cranial nerve IV damage
Eyes move upward, particularly with contralateral gaze
CN VI damage
Medially directed eye that cannot abduct
Cranial nerves in the carvernous sinus?
3,4,5(1), 5(2), 6
Jaw jerk reflex
V3 sensory - muscle spindle from masseter to V3 motor - masseter
Corneal reflex
V1 opthalamic (nasociliary branch) to VII temporal branch: orbicularis oculi
Lacrimation reflex
V1 (loss of reflex does not preclude emotional tears) to VII
Glossopharyngeal nerve
Taste and sensation from posterior 1/3 of tongue, lacrimation, salivation, monitoring carotid body and sinus chemo- and baroreceptors, and elevation of pharynx/larynx
Facial nerve
Facial movement, taste from anterior 2/3 of tongue, lacrimation, salivation (submandibular and sublingual glands), eyelid closing (orbicularis oculi), auditory volume modulation
Vagus
Taste from supraglottic region, swallowing, soft palate elevation, midline uvula, talking, cough reflex, parasympathetics to thoracoabdominal viscera, monitoring aortic arch chemo and baroreceptors
Hydrocephalus
Increased CSF volume leading to ventricular dilation and increased ICP
Communicating hydrocephalus
Decreased absorption by arachnoid granulations leading to increased ICP, papilledema and herniation
Normal pressure hydrocephalus
“Wet, wobbly, and wacky”
Urinary incontinence, ataxia, and cognitive dysfunction
Affects elderly; idiopathic; CSF pressure elevated only episodically; does not result in increased subarachnoid space volume
Noncommunicating hydrocephalus
Blockage of CSF circulation within ventricular system - blockage of aqueduct of Sylvius; colloid cyst blocking foramen of Monro; tumor
Ex vacuo ventriculomegaly
Appearance of increased CSF on imaging, but is actually due to decreased brain tissue and neuronal atrophy. ICP is normal, triad is not seen