Week 5 Flashcards
1
Q
Approximately how big are lymph nodes?
A
<0.5cm in length
2
Q
In which position is it best to feel for a patient’s lymph nodes in the head/neck?
A
Standing behind the patient using both hands to lightly palpate
3
Q
How can the areas draining to the upper and lower lymph nodes of the head/neck be distinguished?
A
Imaginary line from the medial aspect of the eye to the angle of the mandible
4
Q
Why might the occipital lymph nodes become enlarged?
A
Head lice infection
5
Q
What is the location of the submental lymph nodes and what areas do they drain?
A
Under the chin
Tip of the tongue, anterior floor of the mouth, lower lip, incisors
6
Q
What is the location of the submandibular lymph nodes and what areas do they drain?
A
Medial side of mandible, close to submandibular gland
Most of the mouth, nasal cavity, maxillary sinus, skin of the face
7
Q
What is the location of the parotid/pre-auricular lymph nodes and what areas do they drain?
A
Surface of parotid gland, in front of the ear
Upper face, forehead, scalp
8
Q
What is the location of the posterior auricular lymph nodes and what areas do they drain?
A
Behind the ear
Scalp behind the ear
9
Q
What is the location of the occipital lymph nodes and what areas do they drain?
A
Upper neck
Posterior scalp
10
Q
What is the location of the deep cervical lymph nodes and what areas do they drain?
A
In line with internal jugular vein in the neck
Other nodes, thyroid gland, larynx, posterior tongue, pharynx, inner ear
11
Q
What is the location of the superficial cervical lymph nodes and what areas do they drain?
A
Posterior triangle
Local skin
12
Q
What is the location of the jugulo-digastric lymph nodes and what areas do they drain?
A
Where digastric muscle crosses internal jugular vein
Palatine tonsil
13
Q
What is the location of the jugulo-omohyoid lymph nodes and what areas do they drain?
A
Where omohyoid muscle crosses internal jugular vein
Lingual tonsil
14
Q
What is the location of the supraclavicular lymph nodes and what areas do they drain?
A
Posterior triangle, above clavicle
Lower neck, chest/thorax/upper abdomen (oesophagus and stomach)
15
Q
What is the lymphatic drainage of the tongue?
A
Front - submental nodes
Back - deep cervical nodes
16
Q
What is the lymphatic drainage of the maxillary sinus?
A
Submandibular nodes
17
Q
What is the lymphatic drainage of the pharynx and larynx?
A
Deep cervical nodes
18
Q
What is the lymphatic drainage of the palatine tonsil?
A
Jugulo-digastric node
19
Q
What is the lymphatic drainage of the lingual tonsil?
A
Jugulo-omohyoid node
20
Q
What are the features, attachments and function of the digastric muscle?
A
2 bellies with central tendon
Attached to hyoid bone via fascia and posterior belly to mastoid process
Lifts hyoid bone, opens the mouth
21
Q
What are the features, attachments and function of the omohyoid muscle?
A
2 bellies with central tendon
Attached to clavicle via fascia and posterior bell to scapula
22
Q
What infections affect the lymphatic system itself?
A
Glandular fever
Lymphoma
23
Q
Which cartilage in the neck is the only complete ring?
A
Cricoid cartilage
24
Q
What type of cartilage are thyroid, cricoid and arytenoid cartilage?
A
Hyaline cartilage
25
What parts of the body are elastic cartilage?
Pinna of the ear
| Epiglottis
26
What is the vocal fold and where does it extend to?
Fold in the mucosa inside the larynx which contains elastic fibres at its core
Arises from arytenoid cartilage and spans towards thyroid cartilage at the laryngeal prominence
27
Where do thyroid and cricoid cartilage meet?
At the inferior horn of the thyroid cartilage - cricothyroid joint
28
What type of joint is the cricothyroid joint?
Synovial
29
What is the cricothyroid muscle and what is its function?
Small muscle from side of the cricoid cartilage to the thyroid cartilage
Contracts to pull thyroid cartilage slightly upwards towards cricoid cartilage with simultaneous rotation at the cricothyroid joint which causes laryngeal prominence to tilt forwards slightly, tensing the vocal cords to increase the pitch of the voice by increasing the frequency
30
Where is the cricothyroid ligament/membrane found?
Between thyroid cartilage and cricoid cartilage anteriorly (thicker at the front)
31
How is an emergency airway placed?
Needle inserted between cricoid cartilage and thyroid cartilage, through cricothyroid ligament
32
How is a planned/elective airway placed?
Horizontal incision along skin tension lines, push aside strap muscles, find isthmus of thyroid gland, clamp/divide/tie off gland, incision between 2nd/3rd/4th tracheal ring for ventilation tube
33
When placing an elective airway, why do surgeons avoid the 1st tracheal ring?
Risk of scar tissue and stricture formation
34
What important structure lies over the 2nd-4th tracheal rings?
Isthmus of the thyroid gland
35
What shape is the cricoid cartilage?
Signet ring - narrow at the front, wider at the back
36
How can aspiration of vomit be prevented clinically?
Pressing on cricoid (transcricoid pressure) closes lower pharynx to prevent vomit coming up
37
Which muscle attaches the back of the tongue to the hyoid bone?
Hypoglossus muscle
38
Which muscle attaches the side of the tongue to the mandible?
Genioglossus muscle
39
Which muscle attaches the top of the tongue to the styloid process?
Styloglossus muscle
40
Which nerve innervates all extrinsic muscles of the tongue (except palatoglossus)?
Hypoglossal nerve
41
Which nerve innervated the palatoglossus muscle?
Vagus nerve
42
Which extrinsic tongue muscle does the vagus nerve innervate?
Palatoglossus
43
Where might fish bones become lodged in the neck?
Piriform fossa
| Vallecula
44
What is the glottis?
Part of the airway between the vocal folds
45
Where is the sinus/ventricle of the larynx and what is its function?
Between vocal and vestigial folds
| Provides mucus lubrication for vocal folds
46
What is the anatomical basis of a cough?
Irritation of larynx mucosa → vagal afferents → deep breath in, glottis closes, diaphragm relaxes, abdominal and pelvic floor muscles contract → vocal folds move apart → dislodgement of irritant
47
At what vertebral level is the cricoid cartilage?
C6
48
What is the function of the mylohyoid muscle?
Supports structures in the floor of the mouth and separates it from the submandibular region
49
What 2 factors prevent food from entering the larynx?
Epiglottis sphincter mechanism
| Larynx moves up and forwards to meet epiglottis
50
Where does the parotid gland open in the mouth?
Next to the 2nd upper molar
51
Where does the submandibular gland open in the mouth?
Floor, under the front of the tongue
52
Where does the sublingual gland open in the mouth?
Floor
53
What are the intrinsic tongue muscles responsible for?
Changing the shape of the tongue
54
What are the extrinsic muscles of the tongue responsible for?
Tongue movement
55
What nerve provides sensation to the larynx?
Vagus nerve (recurrent laryngeal, internal and external branches of superior laryngeal)
56
At which vertebral level does the trachea bifurcate?
T4
57
Where would a muscle graft for the tongue be taken from?
Unattached - wrist (palmaris longus) or thigh
| Attached - pectoralis or platysma
58
What is the function of a tracheostomy cuff?
Keeps the ventilation tube open and prevents blood/secretions entering the airway and air from escaping
59
What is the normal function of the tongue?
Move and taste food
| Make and direct sound
60
What epithelium is present on the tongue?
Non-keratinised stratified squamous epithelium
61
What is the optic disc?
Optic nerve head - point of exit for ganglion cell axons leaving the eye; blind spot; no rods or cones overlying
62
What is the macula?
Functional central area of retina; 20/20 and best colour vision
63
What is the fovea?
Central part of macula (500 microns)
64
What cell type is found in the macula?
Cone photoreceptors
65
What is the blood supply of the macula?
None - dependent on choroid for O2 and metabolic support
66
What are the 2 types of age-related macular degeneration?
Exudative (wet)
| Atrophic (dry)
67
What is the pathology in exudative age-related macular degeneration?
New blood vessels growing under retina from choroid; rapid, distorted vision
68
What is the pathology in atrophic age-related macular degeneration?
Atrophy of outer retina; slow, blurring
69
What is metamorphopsia?
Distorted vision
70
How is visual acuity recorded? Give examples
As the distance chart is read/distance at which it should be read
E.g. 6/6 - normal (reads at 6 metres what should be seen at 6)
6/12 - reads at 6 metres what should be seen at 12
71
How is visual acuity <6/60 tested?
Count fingers, hand motions, light perception
72
How do fundus fluorescein angiograms work?
Inject fluorescein intravenously; fluorescein bound to albumin (remains within normal capillaries because of blood-retinal barrier); use blue flash and yellow filter to see details of retinal circulation
73
What is optical coherence tomography and what images can be taken using it?
Low-powered laser interferometry
| Generates detailed cross-sectional image of retina
74
How does AMD lead to blindness?
Blood vessels and scar tissue grow under retina → leaking vessels cause retinal oedema → block transport of O2 and nutrients from choroid → eventual scarring causes destruction of photoreceptors
75
How is AMD initiated?
Photoreceptors continue to produce photosensitive pigment throughout life → ends of photoreceptor cells decay and are removed by retinal pigment epithelium → end products accumulate, causing drusen
76
What are drusen?
Yellow deposits under the retina made up of lipids
77
What are the major risk factors for AMD?
```
Smoking
Age (>70)
Diet
Family history
Genetics
```
78
How is diet implicated in AMD?
High doses of vitamin A and C and zinc may be protective
79
What genetic components are implicated in AMD?
Polymorphisms in complement factor H gene strongly linked (7.4x increased risk)
Complement genes (CFB, CF1, C2 and C3)
Lipids (genes for HDL and LDL)
Extracellular matrix (collagen and matrix metalloproteinase)
80
What is the normal function of complement factor H?
Regulates inflammation, prevents complement-mediated attack on own cells
81
What pathological changes are seen in AMD?
```
Thickening and elevation of macula
Retinal distortion
Intraretinal haemorrhage
Intraretinal fluid
Subretinal haemorrhage
Choroidal neovascularisation
```
82
What treatments are available for AMD?
Anti-VEGF drugs – ranibizumab, bevacizumab, aflibercept
83
What is VEGF?
Vascular endothelial growth factor
| Up-regulation of VEGF promotes growth of new vessels
84
How are anti-VEGF drugs administered?
Given locally via intra-vitreal injections, sterile procedure, needs clean room, repeated monthly for three doses (then as required)
85
What is the IVAN trial and what were its findings?
Comparison of ranibizumab (expensive, monthly) and bevacizumab (cheap, as required) - no major difference in efficacy at 12 months
86
Why is ranibizumab used instead of bevacizumab despite it being more expensive and inconvenient?
Bevacizumab is not licensed
87
What are the major causes of blindness/visual impairment?
```
Cataract
Glaucoma
AMD
Corneal scarring
Diabetic retinopathy
```
88
What is the psychosocial impact of blindness/visual impairment?
Economic (unable to work, increased care, health risks)
Loss of independence (domestic, shopping, finance, navigation)
Communication (hearing impairment, non-verbal, social interaction, TV/film/media)
Social/psychological (increased isolation, anxiety, depression)
89
What can peripheral neuropathy lead to?
Selective proprioceptive loss
90
What is the consequence of selective large fibre sensory neuronopathy?
No sensory feed-back from muscle, skin or joint from below the neck
91
What is proprioception?
Signals contributing to conscious and subconscious mechanisms of motor control
92
What is position sense?
Conscious awareness of the relative positions of our body parts in space
93
What is kinaesthesia?
Sense of movement, speed of movement, direction of movement (heaviness or sense of effort)
94
What receptors provide important proprioceptive signals?
Joint receptors
Cutaneous receptors
Golgi tendon organ receptors
Muscle spindle receptors
95
What joint receptors are slowly adapting?
Type I - Ruffini endings
Type III - Golgi endings
Type IV - free nerve endings
96
What joint receptors are rapidly adapting?
Type II - Panciniform endings
97
What sensory endings do muscle spindles have and what do they respond to?
Primary and secondary
Both respond to stretch of the muscle and signal changes in length
Primary ending also has high dynamic sensitivity and responds to changing length and tapping/vibrating
98
What do primary endings of muscle spindles respond to?
Muscle stretch
| Changing length, tapping, vibrating
99
What muscle efferent (motor) axons are there?
α - skeletomotor
| γ - fusimotor
100
What muscle afferent (sensory) axons are there?
Ia - muscle spindle (primary)
Ib - tendon organ
II - muscle spindle (secondary)
III - pressure/pain receptors
101
What cutaneous afferent axons are there?
II - touch, temperature
| III - pain, temperature
102
What is the maximum conduction velocity of sensory axons in humans?
87 m/s
103
What is Hursh's conversion factor?
Condution velocity in m/sec
----------------------------------
total fibre diameter in μm
104
What is the relation between fibre diameter and conduction velocity for large myelinated fibres?
6
105
What is the relation between fibre diameter and conduction velocity for small myelinated fibres?
4.5
106
What constitutes the total diameter of a fibre?
Diameter of axon plus myelin sheath
107
What descending pathway is activated in transcranial magnetic stimulation?
Corticospinal
108
What principle is used by transcranial magnetic stimulation?
Electromagnetic induction
109
Briefly outline the process of TMS
Magnetic stimuli applied to motor cortex → activation of descending motor pathway (corticospinal tract) → magnetic field produced within cortex which leads to current flow (electromagnetic induction) → APs produced in pyramidal neurons with long axons to spinal cord → connect directly/indirectly with motoneurons → twitch contractions are elicited in skeletal muscles
110
How is TMS being researched for therapeutic use?
Repetitive rhythmic TMS (rTMS) for depression and stroke
111
What are platinum grid array electrodes used for?
Seizure monitoring and brain mapping on subdural cortical surfaces in conscious patients
112
What happens to proprioception when the tendon is vibrated?
Impaired
113
What is a muscle twitch?
Brief contraction
114
How can muscle contraction be controlled?
Adjustment of number of motor axons firing at any one time - recruitment
Varying frequency of action potentials in motor axons - summation
115
At what stimulation interval is intracellular calcium able to revert to baseline levels, maintaining separate muscle twitches?
200ms
116
At what stimulation interval is intracellular calcium unable to revert to baseline levels, causing a stronger contraction due to summation?
200-75ms
117
At what stimulation interval is intracellular calcium unable to revert to baseline levels and relaxation prevented, causing tetany?
<75ms
118
What muscles are responsible for movement of the thumb towards the fingers?
Adductor pollicus
| Flexor muscles of thumb
119
What muscles are responsible for bending of the wrist?
Flexor carpi radialis and ulnaris
120
What muscles are responsible for movement of all fingers and pulling of thumb towards index finger? What nerve innervates these?
Intrinsic hand muscles
| Ulnar nerve
121
Fell asleep with hand over the back of a chair. Numbness in the back of the hand and weakness of the wrist. Wrist drop. Weakness of wrist and finger extension. Sensory loss over the radial aspect of the posterior surface of the hand and the posterior surface of the forearm. What is the diagnosis?
Saturday night palsy
122
What nerve is affected in Saturday night palsy and how?
Radial
| Nerve becomes compressed in radial groove/spiral groove of humerus
123
What nerves can be injured by compression?
Sciatic nerve - disc prolapse
| Median nerve - carpal tunnel syndrome
