Neurology Flashcards
Femoral nerve anatomy
The femoral nerve (L2, 3, 4) is formed within psoas major and emerges from its lateral border to lie between psoas and iliacus in the iliac fossa.
It reaches the thigh beneath the inguinal ligament lying lateral to the femoral artery in the femoral triangle.
Its posterior division becomes the saphenous nerve as it enters the adductor canal.
The sciatic nerve divides into tibial and common peroneal nerves.
The lateral femoral cutaneous nerve supplies the skin over the lateral thigh.
Surface anatomy: C4 T4/5 T8 T10 T12
The carotid artery bifurcates at C4.
The manubriosternsal joint (angle of Louis) lies at the level of the T4/5 intervertebral disk.
The caval opening in the diaphragm lies at T8.
The oesoghageal opening of the diaphragm lies at T10.
The aortic opening is at T12.
Foramen magnum
The foramen magnum transmits the
Medulla Meninges Vertebral arteries Anterior and posterior spinal arteries Spinal accessory nerves Sympathetic plexus.
Brown-Sequard syndrome
Brown-Sequard syndrome is characterised by loss of ipsilateral motor function and contralateral loss of pain and temperature sensation.
It usually occurs following a penetrating injury.
It has the best prognosis of the incomplete spinal cord syndromes.
An elderly patient with a previous history of spinal canal stenosis sustains an extension injury of the cervical spine.
The upper limbs are more affected than the lower limbs and perianal sensation is preserved.
Type of injury?
Central cord syndrome usually occurs in patients over the age of 50 years as a result of extension injuries.
Upper limbs are more affected than lower limbs with both motor and sensory loss.
The prognosis is fair.
68-year-old man has recently had a carotid endarterectomy under deep cervical plexus block.
Picture shows small left pupil and ptosis
Cerebrovascular embolus Horner's syndrome Myocardial infarction Recurrent laryngeal nerve palsy Subarachnoid haemorrhage
Carotid endarterectomy may be performed under local anaesthesia using a deep cervical plexus block of C2, C3 and C4. Complications may occur related to anaesthesia or the surgery.
Cerebrovascular events such as embolisation or, less commonly, subarachnoid haemorrhage, may occur as well as post-operative myocardial infarction. Central nervous system (CNS) or systemic toxicity from the local anaesthetic may also occur. Local nerve effects such as recurrent laryngeal nerve (hoarse voice) and phrenic nerve block may occur due to the anaesthetic.
This man has a small left pupil and ptosis on the left which is consistent with Horner’s syndrome. This could be due to the anaesthesia or the surgery itself.
BRACHIAL PLEXUS INJURIES:
A 38-year-old man presents with a small area of anaesthesia over the lateral aspect of upper arm following subcoracoid dislocation of the shoulder.
The axillary (circumflex) nerve is often damaged in anterior dislocation of the shoulder. There is consequent paralysis of the deltoid muscle, with a small area of anaesthesia at the lateral aspect of the upper arm.
BRACHIAL PLEXUS INJURIES:
A 54-year-old lady presents with a wrist drop and mild sensory loss over the lateral side of the back of the hand following a fall. She complains of pain over the mid-shaft of humerus
Radial nerve injury is commonly associated with the fracture of the mid shaft of the humerus, where the radial nerve lies in the spiral grove. Such injuries cause wrist drop (paralysis of the extensor muscles of the wrist, finger and thumb), and also paralysis of the brachioradialis and the supinator muscles. There is sensory loss over the dorsal aspect of the root of the thumb.
BRACHIAL PLEXUS INJURIES:
A 67-year-old lady presents to the Emergency department with a prominent (standing out) vertebral border and the inferior angle of the scapula. She recently underwent mastectomy for breast cancer.
Long thoracic nerve (nerve of Bell), comprising C5, 6, 7 nerve roots, supplies the serratus anterior muscle. This nerve may be injured following injuries to the brachial plexus or could be damaged during surgeries to the chest wall, breast or the axillary region. Paralysis of the serratus anterior muscle causes winging of the scapula
A 45-year-old male presents with discomfort in the fingers of his left hand. On examination the ring and little fingers of his left hand are flexed and unable to extend completely. He is able to make a fist with the hand. Palpation reveals thickened nodules on the medial half of the palm.
Duputyrens contracture
A 55-year-old female presents with a two month history of pins and needles in the fingers of the right hand, particularly at night. On examination, there is some loss of the sensation over the palmar aspect of the lateral three fingers.
Median nerve compression
Classical carpal tunnel syndrome is described with paraesthesiae, typically at night with the patient getting out of bed and shaking the hands. It is caused by entrapment within the carpal tunnel and is associated with:
pregnancy obesity manual work acromegaly hypothyroidism rheumatoid arthritis.
A 37-year-old male, who has a 15 year history of type 1 diabetes, presents with a two day history of weakness of the left hand. On examination he is unable to extend his wrist or fingers of the left hand but there is no sensory loss. Right hand is normal.
Radial nerve palsy results in wrist drop with weakness of extension of the wrist and extension of the fingers. There may be associated loss of sensation over the back of the hand. It may be caused, as in this case, by mononeuritis multiplex associated with diabetes, but is usually caused by compression in the axilla (crutch or Saturday night palsy) or humeral shaft fracture.
A 20-year-old female presents with pain in her right hand particularly when writing. On examination she has a firm subcutaneous tender nodule on the dorsal aspect of the right wrist.
Ganglion
A ganglion is a protrusion of the synovial membrane of the wrist joint. Usually these are painless but can become painful with repetitive use. The condition may resolve but occasionally surgery is required.
A 40-year-old male complains of pain in the middle two fingers of his right hand whilst playing golf. On examination there is tenderness and swelling of the distal interphalangeal joints of the right ring and middle fingers.
Heberdens’ node
Heberden’s nodes are located on the distal interphalangeal joints and usually due to osteoarthritis/degenerative changes. Inflammation may occur giving rise to the pain.
Bouchard’s nodes are located on the proximal interphalangeal joint.
A 45-year-old female presents with a month history of pain and tenderness over the right wrist particularly when gripping her tennis racquet. On examination there is pain on pinching the thumb and forefinger together and pain on palpation over the radial aspect of the wrist
DeQuervain’s tenosynovitis implies inflammation of the tendons of two specific muscles on the thumb side of the hand - the abductor pollicis longus (APL) and the extensor pollicis brevis (EPB). The condition is 10 times more common in women, more often arises in the dominant hand, and usually occurs between the ages of 35 and 55. Rest and analgesics are the most appropriate treatment.
Visual field defects
Parietal lobe tumour
A Bitemporal hemianopia B Central scotoma C Cortical blindness D Enlarged blind spot E Homonymous hemianopia F Inferior homonymous quadrantanopia G Superior homonymous quadrantanopia H Tunnel vision I Uniocular blindness
Inferior homonymous quadrantanopia
A parietal lobe tumour is associated with disturbed sensation including localisation of touch and disturbed two point discrimination. The typical associated visual field defect is a lower homonymous quadrantanopia and it affects the upper fibres of the optic radiation. This is the classical lesion and tumours of the temporal lobe tend to produce superior homomomous quadrantanopia. However,very large tumours can produce homonymous hemianopia.
Visual field defects
Bilateral occipital infarction
A Bitemporal hemianopia B Central scotoma C Cortical blindness D Enlarged blind spot E Homonymous hemianopia F Inferior homonymous quadrantanopia G Superior homonymous quadrantanopia H Tunnel vision I Uniocular blindness
Cortical blindness
Bilateral occipital infarction results in cortical blindness where the brain is unable to process the light signals it receives from the retina and optic nerves.
Visual field defects
central retinal artery occlusion
A Bitemporal hemianopia B Central scotoma C Cortical blindness D Enlarged blind spot E Homonymous hemianopia F Inferior homonymous quadrantanopia G Superior homonymous quadrantanopia H Tunnel vision I Uniocular blindness
Uniocular blindness
A central retinal artery occlusion would typically result in sudden uniocular blindness. Causes of central retinal artery occlusion include emboli (carotid stenosis, AF) and giant cell arteritis.
A 12-year-old boy who is wheelchair bound with a meningomyelocele, has long term urinary incontinence which occurs both day and night. Urine culture is sterile.
A Antibiotics B Bladder neck surgery C Desmopressin D Incontinence pants E Intermittent self catherisation F Star chart
The 12-year-old with meningomyelocele has an autonomic bladder and so would benefit from intermittent self catherisation.
A 6-year-old boy presents as his mother is concerned that he has began to wet the bed on a few occasions over the last month after being dry for the previous three months. Otherwise he is a healthy lad.
A Antibiotics B Bladder neck surgery C Desmopressin D Incontinence pants E Intermittent self catherisation F Star chart
It is not unusual for children under the age of 6 to wet their beds now and again, even after having been toilet trained for a number of years. In fact, some children - boys especially - will continue to have the occasional wet bed even beyond their sixth year.
Although desmopressin is an appropriate treatment for nocturnal enuresis as this young child has, this child should respond to appropriate psychological training and the mother should be reassured. Using nappies for this lad would be negative re-inforcement for bed wetting and should be avoided. Using a star chart should be an encouragement
A 45-year-old man who is treated with gentamicin for abdominal infection presents with deafness. He has had peak and trough gentamicin concentrations measured which have been within the recommended therapeutic range. On examination, tuning fork tests and audiometry suggests a global decrease in hearing acuity.
A Acoustic neuroma B Acute otitis media C Barotrauma D Ototoxicity E Petrous temporal bone fracture F Wax impaction
Deafness could result when there is impediment to conduction of sound waves from exterior to the brain or conductive - lesions could be in the auditory canal, middle ear or sensory neural - lesions of inner ear (cochlear) and acoustic nerve.
Clinical examination includes tuning fork tests which assess air conduction (AC) and bone conduction (BC) in the individual compared to that of the examiner (presuming his hearing is normal).
The common tests used are Rhinne’s test and Weber’s test.
Rhinne’s test has two components - first where the AC of the examiner and the patient are compared. The second part helps differentiate conductive deafness and sensory neural deafness. In normal individuals, the AC > BC. But, in conductive deafness, BC > AC.
If a person is found to be deaf by Rhinne’s 1 and has a normal AC BC relation, he has sensory neural deafness.
Weber’s test compares BC on both sides and lateralises to the normal side.
Gentamicin is well recognised to be ototoxic and is particularly toxic to the cochlear. Although, ensuring adequate therapeutic concentrations may minimise this side effect ototoxicity may still occur even with concentrations maintained in the therapeutic range.
A 55-year-old man with poor physical hygiene presents with sudden onset severe left earache and deafness after taking a shower. He says he tried to clean his ears but it only worsened the pain. It is very difficult to get views of his eardrums.
A Acoustic neuroma B Acute otitis media C Barotrauma D Ototoxicity E Petrous temporal bone fracture F Wax impaction
Hearing reduction after a shower is not uncommon with water in the auditory canal and may exacerbate hearing decline associated with wax. However, discomfort and hearing loss may be compounded by trying to displace the water through stuffing objects into the auditory canal.
Reflexes
Biceps
A L1 B L3, L4 C S1, S2 D C5, C6 E C7, C8 F C8, T1 G S3, S4
C5/6
The biceps jerk is elicited by supporting the patient’s forearm on yours, this produces relaxation, as well as partially flexing the patient’s arm. You can feel as well as see the normal response, which is contraction of the biceps muscle and flexion of the forearm.
Reflexes
Knee
A L1 B L3, L4 C S1, S2 D C5, C6 E C7, C8 F C8, T1 G S3, S4
L3/4
The knee jerk is elicited by letting the patient’s leg dangle over the side of the bed (N.B. the legs should not be in contact). This flexes the knee and stretches the tendon. Strike the tendon directly just below the patella. Extension of the lower leg is the expected response. Placing the left hand on the thigh will confirm contraction of the quadriceps.
