Anatomy Flashcards
(176 cards)
1
Q
Sensory innervation to the hip joint and capsule ?
A
Arises from lumbar and sacral plexus
Superior-anterior capsule
- Femoral nerve (L2-4)
- Obturator nerve (L2-4)
Posterio-inferior capsule (L4-S3)
Overlying skin supplied predominantly by nerves from lumbar plexus
Lateral cutaneous nerve of the thigh (L2-3)
Iliohypogastric nerve (L1)
Superior cluneal nerves (L1-3)
2
Q
What are the borders of the fascia iliaca compartment?
A
Potential space
Anteior fascia iliaca (fascia covering iliacus muscle and psoas major)
Posterior = iliacus/psoas major
Lies posterior to femoral vessels
3
Q
What nerves are blocked by fascia iliaca compartment block?
A
- Femoral nerve
- Lateral femoral cutaneous nerve of thigh
- Obturator nerve
4
Q
Where is foramen magnum found? Name 4 structures that pass through it?
A
Found posterior cranial fossa; basilar part of occipital bone
4 structures
- Tip of odontoid process
- Ligaments (apical, tectorial ligaments)
Neurovascular
- Lower end of medulla (+meninges)
- Cerebellar tonsils (variant)
- Spinal roots of CN11 (within subarach space)
- Vertebral arteries
- Anterior and posterior spinal arteries (within subarach space)
5
Q
Name 3 types of brain herniation
A
- Subfalcine (cingulate)
- Uncal (transtentorial)
- Tonsilar (cerebellar)
6
Q
What ocular features are false-localising signs in brain injury and why?
A
Cerebellar herniation causes
CN3 palsy - compressed on margin of tentorium by herniation of uncus
CN 6 - long intracranial course compressed by oedema
7
Q
What awake surgical procedures are permitted by use of an axillary block ?
A
Shoulders below the elbow - forearm/wrist/hand
8
Q
Structure for approaching a nerve block question
A
Consent
Stop before you block - confirm side + site
“SLIMRAG”
Sterility
Light source/US
IV access
Monitoring (AAGBI minimum standards)
9
Q
Vascular supply to the nose?
A
Supplied by the carotid artery
Anterior/posterior ethmoid arteries
- branch of opthalmic, originates from internal carotid
Sphenopalatine and greater palatine
- branch of maxillary, originates from external carotid
Superior labial and lateral nasal arteries
- branch of facial, originates from external carotid
Anastamose under nasal mucosa to form plexuses e.g. Little’s area
10
Q
Innervation of the nose?
A
External skin
- Opthalmic V1 division of trigeminal via anterior ethmoid and external nasal branches of nasocilliary nerve
- Maxillary V2 divisions of trigeminal nerve via nasal branches of infraorbital nerve
Internal mucosa
- Mainly V2 via sphenopalatine ganglion
- Septum has innervation from V1 via anterior ethmoid
Special sensory via CN1 through cribiform plate
11
Q
Anatomy of upper motor neurone pathway?
A
UMN
- Leave primary motor cortex (posterior frontal lobe)
- Decussate in the medulla
- Descend in contralateral corticospinal tract
- Synapse in anterior horn of spinal cord with LMN
12
Q
Features of left MCA occlusion?
A
Right hemisensory loss
Right ataxia
Speech impairment
Right homonymous hemianopia
13
Q
6 complications of interscalene block?
A
- Horner’s syndrome
- Epidural/subarachnoid injection
- Phrenic nerve block
- Recurrent laryngeal nerve block
- Intravascular injection
- Pneumothorax
14
Q
Armitage formula for caudal blocks
A
All with 0.25% bupivicaine
Sacro-lumbar block = 0.5ml/kg
Upper abdominal block = 1ml/kg
Mid-thoracic block = 1.2ml/kg
15
Q
Sensory branches of cervical plexus
A
“Lets Go To Sleep”
Lesser cervical
Greater auricular
Transverse cervicalis
Supraclavicular
Ansa cervicalis C1,2,3
Lesser occipital C2
Transverse cervicalis C2,3
Greater auricular C2,3
Supraclavicular C3,4
Phrenic C3, 4, 5
16
Q
Blood supply to bronchi
A
Supplied by bronchial circulation
2 bronchial arteries to left lung arise from descending thoracic aorta
1 bronchial artery supplying right lung arising from thoracic aorta, left bronchial artery or intercostal artery
Bronchial veins
Pulmonary veins (85%) and Bronchial veins (15%)
Right sided into azygos vein, left sided into hemiazygos vein
17
Q
What is the arterial blood supply of the spinal cord?
A
Anterior cord supplied by SINGLE ANTERIOR spinal artery
- Formed by 2 union vertebral arteries at foramen mag
- Supplies anterior 2/3 of spinal cord
Posterior cord supplied by 2 POSTERIOR spinal arteries
- Derived from posterior inferior cerebellar arteries
- Lie on posterolateral surface of cord
- Supply posterior 1/3
ASA and PSAs form PIAL arterial plexus
Segmental (radicular) feed into this system arising from vertebral, cervical, aortic, pelvic arteries
Most important is artery of Adamkiewicz
18
Q
What is the importance of the Artery of Adamkiewicz
A
Arises from thoracolumbar part of aorta, usually enters at L1
Thoracic cord anterior portion is most vulnerable, better supply to cervical and lumbosacral cord
Importance is that spinal cord ischaemia may result from interruption to this artery e.g. during aortic cross clamping, aortic dissection or trauma
19
Q
What is the venous supply of spinal cord?
A
Tortuous plexus
3 anterior spinal veins
3 posterior spinal veins
Form anastamosing network
Anterior and Posterior INTERnal vertebral venous plexuses
Drain into
Dural venous sinuses
Posterior EXTERNAL vertebral venous plexus (anterior aspect of ligamentum flavum)
Anterior EXTERNAL vertebral venous plexus
20
Q
Clinical relevance of spinal venous drainage
A
External vertebral venous plexus drains into intercostal, azygos, hemiazygos
Lumbar region drained by BATSON plexus, valveless network connected to pelvic organs.
Relavance:
Pregnancy gravid uterus obstructs IVC flow
Increased pressure in BATSON plexus = higher risk of venous cannulation during epi insertion. Also reduced epidural space therefore smaller volumes
Cancer of pelvic organs may metastasise to lumbar spine e.g. prostate cancer and lumbar spine mets
21
Q
What is anterior spinal artery syndrome
A
Disruption of arterial supply to anterior cord results in:
- Complete motor loss, areflexia, decrease tone below lesion
- Loss of pain/temperature at and below lesion
- Interruption of sympathetic outflow (hypotension)
PRESERVATION of proprioception and vibration sense (intact dorsal columns)
22
Q
General approach to regional blocks
A
Full anaesthetic history and examination
Informed consent of the patient
Trained assistant
Full monitoring as per AAGBI guidelines
Ultrasound machine
IV access
‘Stop before you block’
23
Q
How would you perform - Axillary Plexus Block
A
GENERAL APPROACH BITS
Positioned supine position with
Aseptic technique
Ultrasound probe positioned with short axis to arm distal to pec major insertion
Aim is to achieve LA spread around median, ulnar, radial nerve around axillary artery
In addition target musculocutaneous nerve situated between biceps and coracobrachialis
Total volume 20-25mls 0.25% bupivicaine (around 5mls per nerve)
24
Q
Tell me about the blood supply of the liver
A
Dual blood supply
25% of CO
1200-1400mls/min
Contains 10-15% of total blood volume, acts as powerful reservoir
Hepatic Artery
- High pressure/resistance
- Branch of coeliac trunk (branch of AA)
- Carries Oxy blood
- 20-30% blood supply
- 40-50% of oxygen supply
Portal Vein
- Low pressure/resistance
- Union of SMV and Splenic Vein
- Carries NUTRIENT RICH and OXYGEN POOR blood
- 70-80% of blood supply
- 50-60% of oxygen supply
Deoxygenated detoxified blood exits via hepatic veins to join IVC
25
Draw a diagram demonstrating difference between Clasic Lobule
Portal Lobule and Hepatic Acinus
26
What factors affect hepatic blood flow?
Myogenic autoregulation
- Hepatic arterial system
Metabolic/chemical control
- CO2, O2 and pH changes
Neural control
- Adrenaline, Angiotensin II and Vasopressin constrictors of arterial and venous system
Hepatic arterial buffer response (HABR)
- Phenomenon where decrease in portal venous blood flow increases hepatic arterial blood flow and vice versa
27
General preparation points for nerve blocks
Consented
Positioning optimise and ergonomics of screen
IV access and monitoring
Trained assistant
Resus equipment available
ANTT: Skin prep chlorhexidine 2%, drape, gloves
"Prep, Stop, Block"
28
Benefits of a good analgesic strategy for major surgery
Additional implications for outcomes beyond analgesia
- Reduced respiratory complications
- Improved return of bowel function
- Early mobilisation
- Reduced opioid related side effects
29
Nerve block options for major abdominal surgery
Spinal perioperatively with intrathecal morphine
Epidural analgesia
Rectus sheath block/catheter
TAP block/catheter
Quadratus lumborum block/catheter
Transversalis fascia block/catheter
30
RECTUS SHEATH BLOCK/CATHETER
Indications:
Positioning:
Volume:
Side effects
Complications:
Sonoanatomy:
RECTUS SHEATH BLOCK/CATHETER
Indications: Unilateral or bilateral midline blocks e.g. laparotomy midline. Ideal for upper/midline abdo. Good somatic coverage
Positioning: Supine
Volume: 10-20mls per side
Side effects: Rectus weakness
Complications: Vessel puncture, intra-abdominal viscus puncture, LAST, catheter migration
Sonoanatomy:
- Probe transversely placed superior or inferior to umbilicus
- Identify linea alba and move probe laterally to identify linea semilunaris, Ext oblique/Int oblique/TA and recus sheath
- IN OR OUT of plane
- Target plane is between rectus muscle and posterior rectus sheath on lateral side of muscle (where nerves pierce to form cutaneous anterior coverage)
31
What is the innervation of the anterior abdominal wall
Arises from T6-L1 nerves
Travel in plane between internal oblique and transversalis abdominus muscles
Lateral cutaneous branches
Anterior cuteneous branches penetrate through rectus abdominus and travel superficially
32
TAP BLOCKS
Indications:
Positioning:
Volume:
Side effects
Complications:
Sonoanatomy:
TAP BLOCKS
Indications: Unilateral block involving entire abdominal wall (Lateral + Midline structures) reliably from T10-L1 but can cover upper abdomen if subcostal blocks performed
Positioning: Supine
Volume: 20-30mls/side
Side effects: Abdominal wall muscle weakness, spread to quadriceps causing weakness
Complications: Vessel puncture, intra-abdominal viscus puncture, LAST, catheter migration
Sonoanatomy:
Place probe in transverse orientation on anterior abdominal wall and identify rectus.
Slide laterally identifying linear semilunaris and then 3 abdominal wall muscles.
Midaxillary line - aim between I. Oblique and Transversus abdominus
33
QUADRATUS LUMBORUM BLOCK
Indications:
Positioning:
Volume:
Side effects
Complications:
Sonoanatomy:
QUADRATUS LUMBORUM BLOCK
Indications: Unilateral abdominal wall analgesia (entire of abdomen) including some visceral analgesia from T7-L1 spread and hip analgesia
Positioning: Supine or lateral (for anterior QLB)
Volume: 15-30mls/side
Side effects: Abdominal wall muscle weakness
Complications: Renal or visceral puncture, haematoma from vascular puncture, LAST, leg weakness
Sonoanatomy: Lateral, probe placed transversely. Aim is lateral corner of quadratus muscle aiming to spread LA around quadratus
34
ESP block
Indications:
Positioning:
Volume:
Side effects
Complications:
Sonoanatomy:
ESP block:
Spreads via paravertebral space
Indications: Unilateral chest wall/abdominal/lumbar analgesia.
Rib fractures. Thoracotomy/breast surgery. Colorectal, urological, obstetric
Positioning: Sat up. Lateral. Prone
Volume: 20-30mls
Side effects: ESP weakness
Complications: Pneumothorax, LAST, sympathetic blockade, epidural spread
Sonoanatomy:
Can be performed at multiple levels.
T5 - chest wall
T10 - abdominal
L3 - lumbar
35
What is a neuron
A neuron is an electrically excitable cell that communicates with other cells through synapses
36
Serratus Anterior block
Indications:
Positioning:
Volume:
Side effects
Complications:
Sonoanatomy:
Serratus Anterior block
Indications: Analgesia to axilla, anterolateral chest wall and skin on upper medial arm (intercostobrachial)
Positioning: Supine with arm abducted to 90degrees
Volume: 20mls
Side effects: Weakness of Lat dorsi and S. Ant
Complications: Vessel puncture, nerve injury, pneumothorax
Sonoanatomy:
Place probe transversely in mid axillary line 5th rib laterally
Slide probe posteriorly to visualise Lat Dorsi arising superior to S. Ant.
Target plane is between Lat D and S. Ant targeting lateral cutaneous branches of intercostal nerve
37
Motor branches of cervical plexus
"MAP"
Motor branches (to sternocleidomastoid, levator scapulae)
Ansa cervicalis
Phrenic nerve
38
What is the cervical plexus
The cervical plexus is a conglomeration of cervical nerves formed by the anterior (ventral) rami of spinal nerves C1-C4 (a.k.a. 1st-4th cervical nerves).
39
What is the boundaries of the anterior abdominal wall
Extends from costal margin superiorly to inguinal ligament and pelvic bone inferiorly
Laterally contains
- 3 muscle layers (ext oblique, internal oblique, transversus abdominus)
Medially contains
- Paired rectus muscles. Enclosed by rectus sheath seperated by linea alba
40
What is the sensation to the foot?
5 nerves - 4 from sciatic, 1 from femoral
4 sciatic
1. Tibial nerve (sole of foot)
2. Superficial peroneal (dorsum of foot)
3. Deep peroneal (between 1st and 2nd metatarsal)
4. Sural (lateral aspect)
1 femoral
- Saphenous nerve (medial aspect of foot)
41
Indications and contraindications for ankle block
Indications
- Anaesthesia or analgesia for foot surgery e.g. bunionectomy, forefoot arthroplasty, osteotomy
- Analgesia for fractures/soft tissue injury
Contraindications
- Patient refusal
- Local anaesthetic allergy
- Local infection
- Burns/oedema/scarring in area of block
42
Foot block. Tibial nerve
Anatomy -
Block conduct -
Foot block. Tibial nerve
Anatomy -
*Located at medial malleolus, mid point between achilles and posterior aspect of medial malleolus or just behind posterior tibial artery
Block conduct -
*Insert needle 45 degrees towards tibia, contact bone, withdraw, aspirate, 5mls
43
Foot block. Saphenous/Superficial Peroneal/Sural nerves. How to
Nerves are all superficial therefore can be blocked in 180 degree arc
Saphenous passes anterior to medial malleolus, just posterior to saphenous vein
Superficial peroneal passes subcutaneously on anterolateral ankle
Sural passes subcutaneously postero-superiorly to lateral malleolus
Saphenous = insert anteriorly from posterior aspect of medial malleolus
Superficial peroneal = anterior to lateral malleolus insert 1cm towards anterior aspect of ankle
Sural = half way between superior lateral malleolus and achilles, aim towards lateral malleolus
44
Deep peroneal nerve injection?
Lateral to extensor hallucis tendor
Insert in groove lateral to tendon 2-3cm distal to intermalleolar line, contact bone and withdraw
45
Specific treatment with lipid emulsion?
IV bolus injection of intralipid 20%
- 1.5ml/kg over 1 min (around 100mls for 70kg patient)
Start IV infusion
- 15ml/kg/hr (around 1000ml/hr for 70kg patient)
Max 2 repeat boluses at 5 min intervals if adequate circulation not restored
Double infusion to 30ml/kg/hr if inadequate circulation not restored
46
What is the autonomic innervation of the heart
Sympathetic - from upper thoracic sympathetic trunk
Parasympathetic - via vagus nerve
47
Sympathetic innervation of heart in detail
Pre-ganglionic
- Leave lateral horn of cord
- Travel to form paravertebral ganglia through white rami communicantes
SYNAPSE WITH POSTGANGLIONIC USING NICOTINIC RECEP (ach)
Post ganglionic
- Leave ganglia via grey rami communicantes
- Travel within cardiac nerves to the cardiac plexus, then synapse with heart
- B1 adrenergic, noradrenaline
48
Effect of increased sympathetic cardiac activity
Positive chronotropy
- Increased gradient to threshold potential in SA node
cAMP mediated
Positive inotropy
- Cardiac myoscytes increases Ca++ influx in plateau phase
- Inc. force of contraction
Protein kinase A mediated
Shorter action potential duration
- Increased opening of delayed rectifier K+ channels during phase 3, shortening repolarisation time
Increased rate of transmission through AV node
49
Parasympathetic innervation of heart
Pre-ganglionic
- Right and left vagus
- Exits via jugular foramen
- Travel through carotid sheath
- Right descends anterior to subclavian
- Left descends between CC and subclav
Thorax
- Right vagus --> cardiac plexus --> SA node
- Left vagus ---> cardiac plexus AV node
NICOTINIC RECEPTOR, acetylcholine
Post ganglionic
-ve chronotropy
iGPCr dec Na+ influx, reduced gradient of pacemaker potential, dec HR
dec conduction velocity
50
Name the cardiac afferents
Atrial/Ventr/Pulmonary stretch receptors
- RIght and left vagal afferents
Cardiac sensory A-fibres and C-fibres
Dorsal horn of spinal cord synapse on same tract in dorsal horn as somatic afferents from left arm and shoulder
51
3 diagnostic criteria for death
Somatic criteria e.g. head fallen off
Circulatory criteria e.g. cardiopulm arrest
Neurological criteria e.g. devastating brain injury in apnoeic coma
52
What is death
The permanent loss of capacity for consciousness and permanent loss of ability to breathe
53
4 conditions needed as preconditions for brain stem death testing
1. Aetiology of sufficient magnitude to cause permanent cessation of brainstem function
2. Assessment period sufficient to exclude recovery potential
3. Exclusion of reversible factors
4. Both eyes and ears examinable
54
What must NOT be present
Temp <36
Na <125 or >160
BSL <3 or >20
K <2
Mg <0.5 or >3.0
Phos <0.5 or >3.0
No drugs e.g. opioids or muscle relax
Normal cardiac/resp parameters
No acute endocrine pathology
55
Reflex arc for CN II
Sensor = optic nerve CN2
Response = parasympathetic
56
Reflex arc for CN V, VII
Corneal
Sensor = V1
Response = VII
Facial pain
Sensor = V1
Response = VII
Caloric testing
Sensor = VIII
Response III, IV, VI
57
CN IX and X reflex arc
Gag reflex =
IX to nucleus solitarius
Response = X from nucleus ambiguus
Cough
Sensory = X
Response = phrenic and intercostal
58
How to perform apnoea test
Ventilate with 100% O2 for 10mins
Disconnect from ventilator
O2 sats maintained by tracheal catheter
CO2 rises 0.4-0.8kPa/min
Start >5.3kPA
End >8.0kPA and pH <7.3 and rise >2.7
Observe 5 mins
59
Who performs brain stem death testing
2 doctors
Both registered 5 years
1 is a consultant
No conflict of interest
2 sets of tests
60
What is the caudal space
Most distal portion of epidural space
Located within sacral canal
Accessed through sacral hiatus
Commonly used to provide analgesia in paediatric urology + lower limb ortho
61
Contents of caudal space
Dural sac at S2
Venous plexus
Coccygeal nerve
Sacral nerves
Fat
62
What are the landmarks for caudal
Sacral hiatus
Access is through sacrococcygeal membrane
- Lies between sacral cornua
- Equilateral triangle between 2 posterior superior iliac spines and sacral hiatus
63
What is the technique for caudal
Explanation Consented
Trained assistant
Positioning optimise - knees to chest
IV access and monitoring
Resus equipment available
ANTT: Skin prep chlorhexidine 2%, drape, gloves
"Prep, Stop, Block"
ANTT
Needle through skin slightly cranial
When entered may feel a click
Aim cranially and advance into canal
-ve aspiration
Inject, check not subcutaneous
64
Complications of caudal blockade
Intravascular injection
Intrathecal injection
Infection
Failure
Hypotension
Urinary retention
Motor block
Insertion into rectum
65
CSF factoids:
Appearance:
Total volume:
Consitutients:
Produced:
Absorbed:
Appearance: Clear (in health)
Total volume: 150mls
Consitutients: Similar to plasma but higher Cl (122-128), No red cells, minimal WCC and mostly lymphs
Produced: Choroid plexus in lateral ventricles, 3rd and 4th ventricle at 500ml/day
Absorbed: Arachnoid villi of saggital and sigmoid dural sinuses and spinal arachnoid villi
66
Describe the flow of CSF
Produced in lateral ventricles, 3rd ventricle and 4th ventricle
Monro - Sylvius - Lushka/Magendie
Moves through 2 foramina of monro into 3rd ventricle
From 3rd ventricle through aqueduct of sylvius to 4th ventricle
4th ventricle through 2 foramina of Lushka and midline foramen of Magendie
67
What are the functions of CSF
1. Buoyancy - reduces effective weight of brain
2. Cushioning, absorbs acceleration/decellaration forces
3. Buffering changes in ICP
4. Constant ionic environment
5. Control of respiration, CO2 diffuses to CSF, central chemoreceptors
6. Glymphatic system
68
Explain low pressure headache
Low CSF pressure <5mmHg
Brain sags
Tension on dura (headache)/veins (subdural)/CN (palsies)
69
What is the coeliac plexus the junction for
3 autonomic neurons
Greater splanchnic - sympathetic from T5-9
Lesser splanchnic - sympathetic from T10-11
Least splanchnic - sympathetic from T12
70
What does coeliac plexus supply
Foregut and midgut abdominal organs - pancreas/stomach/liver/GB/spleen/duodenum/ascending + transverse colon
71
Relations of coeliac plexus block
Posterior right - vena cava
Posterior left - aorta
Anterior - pancreas
Lateral - kidneys
72
What are the indications for coeliac plexus block
Cancer pain involving
- Pancreas
- Biliary tree
- Retroperitoneal organs
Chronic pain of upper abdominal organs mainly chronic pancreatitis
73
How do you perform a coeliac plexus block
Consent/contraindications
"MAIDE"
Monitoring
Assistant
IV access
Drugs - emergency + intralipid
Equipment including needles, ultrasound
Posterior approach patient prone
CT or fluroscopic guidance
Insert 5-10cm from midline of spinous process of L1
Aim 45 deg towards midline
Pass under 12th rib
Confirm position with contrast
20ml of 50% alcohol or 6% phenol OR local anaesthetic if non-cancer pain
74
Complications of coeliac plexus block
Common = diarrhoea or postural hypotension
Intravascular injection
Retroperitoneal haemorrhage
Injury to kidney or spleen
Local anaesthetic toxicity
Pneumothorax
Sexual dysfunction
Rare = damage to artery of adamkievicz causing paraplegia
75
Indications for stellate ganglion block
Pain syndromes
- Refractory angina, phatom limb pain, post-herpetic neuralgia
Vascular insufficiency
- Raynaud's, scleroderma, frostbite
76
What is the anatomy of the stellate ganglion
The stellate ganglion is a sympathetic ganglion situated on either side of the root of the neck. It is formed on each side of the neck by the fusion of the inferior cervical ganglion with the first, and occasionally second, thoracic ganglion
Anatomical relations:
Anterior - skin, subcut tissue, sternocleidomastoid
Posterior - anterior scalene muscle, brachial plexus, first rib, transverse of C7
Inferior - apex of lung
Medial - vertebral body of C7, oesophagus, thoracic duct, preverterbal fascia
77
How to perform stellate ganglion block
Consent/contraindications
"MAIDEP"
Monitoring
Assistant
IV access
Drugs - emergency + intralipid + local
Equipment including needles, ultrasound
PREP, stop, block
Technique:
Patient positioned supine with head extended and turned to opposite side
Needle insertion between trachea and carotid sheath (level of C6 vertebral transverse process)
Retract sternocleidomastoid and carotid sheath
Contact tubercle then redirect medially and inferiorly to body of C6
Check with fluoroscopy
Aspirate and inject 10ml of 0.25% bupivicaine
Onset of horner's indicates block
78
Complications of stellate ganglion block
Horner's syndrome
Damage to structures
Inadvertant spread of L.A
79
What structures does a Tuohy needle pass through in midline
Skin
Subcutaneous tissue
Supraspinous ligament
Interspinous ligament
Ligamentum flavum
Epidural space
80
Borders of epidural space:
Superior -
Inferior -
Lateral -
Anterior -
Posterior -
Borders of epidural space:
Superior - Foramen magnum
Inferior - Saccrococcygeal membrane
Lateral - Pedicles and intervertebral foramina
Anterior - Posterior longitudinal ligament vertebral bodies and discs
Posterior - Ligamentum flavum
81
Contents of epidural space
Dural sac and spinal nerves
Blood vessels, specifically batson venous plexus
Connective tissue
Fat
82
Thoracic epidural landmarks
C7 is most prominent c spine process
T3 spine of scapula
T7 is inferior angle of scapula
L1 is rib margin
83
Where do you insert Thoracic epidural to get best analgesia
Depends on incision.
If incision is xiphi to pubis T6 to T12
Insert at 1 space higher than middermatome for incision
E.g. T7
84
What are the nerves of the lumbosacral plexus
Iliohypogastric
Ilioinguinal
Genitofemoral
Lateral femoral cutaneous nerve
Obturator Nerve
Femoral nerve
85
Tell me about the lumbosacral plexus
Network of nerves deriving from anterior rami of spinal nerves L1-S4
Lumbar plexus
L1-L4 with minor from T12
Sacral plexus
L4-S1
Pudendal plexus
S2-S4
86
Tell me about the obturator nerve
Derived from L2, L3, L4
Sensory and motor
Motor
- Muscles of medial compartment (obturator externus, adductor longus, adductor brevis, adductor magnus, gracilis)
Sensory
- Skin on medial thigh
87
Tell me about the femoral nerve
Derived from L2, L3, L4
Sensory and motor
Motor
- Muscles of anterior thigh (iliacus, pectineus, sartorius, quads femoris)
Sensory
- Femur and medial malleolus
- Skin of anterior thigh and medial lower leg (saphenous)
88
Tell me about the sciatic nerve
Derived from L4, L5, S1, S2, S3
Sensory and motor
Divides into common peroneal nerve and tibial nerve
Motor
- Posterior thigh (hamstrings)
- Plantarflexors (tibial) and dorsiflexors (common peroneal)
Sensory
- Lateral lower leg (common peroneal)
- Lateral foot (sural)
- Anterior foot (superficial and deep peroneal)
- Sole of foot (tibial)
89
What is the adductor canal bordered by:
Vastus medialus
Adductor magnus
Sartorius
90
What does the adductor canal contain:
Femoral artery
Femoral vein
Nerve to vastus medialis
Saphenous nerve
91
Indication
Multimodal for knee surgery
Foot/ankle surgery in combination with sciatic nerve block
92
What is lumbar plexux block indicated for
THR, TKR, ACL repair
93
Key features of lumbar plexus block
Landmark block with nerve stimulator
Pt. lateral decubitus
Insert needle perpendicular to skin 4cm lateral to midline at iliac crest
Advance until quad twitch
25-30mls
Risks
- Failure
- LA tox
- Epidural spread
- Retroperitoneal haematoma
94
What is lumbar plexopathy
Rare condition - neuronal damage to nerve plexus
Diabetic amyotrophy
Tumour compression
Trauma
Mx. = surgical, steroids, nsaids, gabapentin
95
What is the border of the femoral triangle
Roof - fascia lata
Lateral - sartorius
Medial - adductor longus
Superior - inguinal ligament
Floor - illiopsoas, adductor longus, pectineus
96
Purpose of PENG block
Block articular branches of femoral and obturator nerves - found in fascial layer between psoas tendor and ileum
Less motor blockade then FIB and Fem NB
97
What is the position of the larynx
C3-C6 vertebral level
Root of tongue to cricoid cartilage
98
What is the relations of the larynx
Anterior - skin/thyroid
Posterior - pharynx + oesophagus
Lateral - carotid sheath + thyroid
99
What are the cartilages of the larynx
9
3 unpaired - epiglottis, thyroid, cricoid
6 paire - arytenoid, cuneiform, corniculate
100
Arterial supply of larynx
Superior larnyngeal arteries from external carotid
Inferior laryngral arteries from thyrocervical trunk
Venous = superior and inferior laryngeal veins
101
Describe the innervation of the larynx
Can be classified as motor and sensory
Motor supply
INTRINSIC
- Intrinsic muscles except cricothyroid = recurrent laryngeal nerve
- Cricothyroid = external branch of superior laryngeal nerve
EXTRINSIC
IX and X CNs - elevators e.g. mylohyoid, stylopharyngeus, palatopharyngeus
Depressors C1, 2, 3
Sensory
Glottis and cords = internal branch of superior laryngeal
Subglottic = recurrent laryngeal
102
Describe different types of neuron
Motor
Sensory
Interneuron
Unipolar - single axon from cell body
e.g. cochlear
Bipolar - cell body between dendrites and axon
e.g. retina and olfactory
Pseudounipolar cell - cell body half way down
- e.g most sensory
Pyramidal - single axon, lots of dendrites
e.g. cerebral cortex and hippocampus
103
Describe the relations of the mediastinum
Anterior - sternum
Lateral - lungs and pleura
Posterior - thoracic spinal column
104
Describe the contents of the mediastinum
Heart
Major blood vessels - aortic arch, pulmonary arteries and veins, SVC, descending aorta
Thymus
Oesophagus
Thoracic duct
Trachea
Lymph nodes
105
What is within the superior mediastinum and what are its borders
Formed by imaginary line between T4 posteriorly and sternum anteriorly
Contains:
- Aortic arch
- Thymus
- SVC
106
What structures lie along the transverse thoracic plane
Carina
Left recurrent laryngeal nerve, where it loops underneath the aortic arch adjactnt to ligamentum arteriosum
107
What are the 3 regions of the inferior mediastrinum
Anterior mediastinum (in front of pericardium)
Middle mediastinum (contains the pericardium)
Posterior mediatstinum (behind the pericardium)
108
Anterior mediastinum (in front of pericardium) ?contents
Thymus, aortic arch, SVC (same as superior)
109
Middle mediastinum (contains the pericardium) ?contents
Heart, carina and bronchi, phrenic nerve
110
Posterior mediatstinum (behind the pericardium)
Descending aorta, oesophagus, vagus nerve, sympathetic chain, thoracic duct, azygos vein
111
7 differentials of mediastinal mass
Thymoma
Thyroid goitre with retrosternal extension
Lymphoma
Sarcoidosis
TB
Oesophageal ca
Thoracic aortic aneurysm
112
What are the signs and symptoms of SVC obstruction
Oedema and facial swelling
Tongue and pharyngeal oedema
Headache
Dsypnoea
Dilated neck and chest veins
Pemberton's +ve, ask pt to lift arms, facial swelling and cyanosis and resp distress
113
Signs and symptoms of tracheobronchial compression?
Dyspnoea
Stridor
Orthopnoea
Cough
Unilateral wheeze
Recurrent pneumonia
NB may worsen with +ve pressure ventilation, pts should be kept spont ventilating
Change in position may offload compressed bronchus
Rigid scope may be required, with jet ventilation
114
What is the motor and sensory components of ulnar nerve
115
What is the motor and sensory components of radial nerve
116
What is the motor and sensory components of median nerve
117
What are the 3 ways of classifying nerve injury
Neuropraxia
- Damaged myelin, axons intact
- Recovery weeks-months
Axonotmesis
- Axonal disruption
- Endoneurium and other supporting tissue conserved
Neurotmesis
- Complete distruction of all supporting connective tissue structures
- Surgery may be required
- Poor prognosis
118
What are the vagal nuclei where do they arise
In the medulla
Motor
- Nucleus ambiguus in reticular formation
Sensory
- Nucleus tractus solitatarius
Parasympathetic
- Dorsal nucleus of vagus below floor 4th ventricle
All exit through jugular foramen
119
Describe the anatomy of the tracheobronchial tree
Composed of conducting airways and respiratory airways
23 generations
Conduction
0-15 = Trachea/Main bronchi/Bronchioles
Respiratory
16-23 = Respiratory bronchioles, Alveolar Ducts, Alveolar sacs
120
Tell me about the anatomy of the trachea
10cm long, 2cm wide
From C6 (larynx) to T4-5 (carina)
20-25 C shaped cartilaginous rings which are posteriorly deficient
Relations:
Anterior
*Neck - isthmus of thyroid gland
*Thorax - brachiocephalic artery and vein
Posterior
*Oesophagus + recurrent laryngeal nerve
Laterally
NECK: Lateral lobes of thyroid, inferior thyroid artery, carotid sheath
THORAX:
Left = common carotid and subclavian arteries and aorta
Right = pleura, vagus, azygos
121
Right lung lobes and segments
122
Left lung lobes and segments
123
What are the contents of the paravertebral space
Spinal nerves
White and grey rami communicantes
Sympathetic chain
Intercostal vessels
Fatty tissues
124
Indications for paravertebral block
Unilateral surgical procedures
- Thoracostomy
- Breast surgery
- Cholecystectomy or liver resection
Acute pain
- Rib fractures
- Herpetic neuralgia
Chronic pain
- Neuropathic pain e.g POST herpetic neuralgia
- Refractory angina
125
Advantages of paravertebral over epidural block
Easier to learn
Unilateral so less sympathetic block therefore less hypotension
Less urinary retention
Can be done asleep as less chance of neuro complications
Using local alone avoids sedation
Evidence that it reduces chronic pain
Higher success rate
126
Complications of paravertebral
Epidural spread and associated complications
Horners syndrome in high thoracic
Pneumothorax
Intravascular injection
Infection
Total spinal - V. rare
127
What is the paravertebral space
Wedge shaped space either side of vertebral column
Borders =
Medial = intervetebral foramina, bodies/discs, epidural space
Anterolateral = pleura
Posterior = superior costotransverse
Superior inferior = heads of ribs
128
3 intercostals
External
Internal
Innermost
129
Describe the sensory innervation of the chest wall
Segmental sensory innervation originates from thoracic spinal nerves
- Emerge from intervetebral foramina
- Divide into anterior (ventral) and posterior (dorsal) rami
Posterior supplies muscles and skin of back
Anterior become intercostal nerves, travel with vessels just below rib
130
Describe branches of intercostal nerve
Travels between innermost and internal intercostals
Gives off lateral cutaneous branch (emerging mid axillary)
Gives off anterior branch (emerging near sternum(
131
What is the orbit
Pyramidal cavity comprised of 7 bones
Lateral
- Zygoma
- Sphenoid
Medial
- Ethmoid
- Maxilla
- Lacrimal
- Sphenoid
Inferior
- Maxilla
- Palatine
- Zygoma
Superior
- Frontal
- Sphenoid
Sphenoid is everywhere but the floor
132
5 extraocular muscles supplied by CN III
Levator palpebrae superioris
- Raises upper eyelid
Superior rectus
- Contraction causes globe elevation
Inferior rectus
- Contraction causes globe depression
Medial rectus
- Adduction of globe
Inferior oblique
- Elevates abducts and laterally rotates eye (up and out)
133
What does superior oblique do
Depression and intorsion (down and out)
134
Sensation of the eye
Somatic and Vision
Somatic = V1 of CNIII
Nasociliary
Lacrimal
Vision = CN II
135
What passes in Sup Orbital Fissure
CNIII
CNIV
CNVI
Opthalmic of CNV
Superior opthalmic vein
Sympathetic nerves
136
What passes in Inf Orbital Fissure
Zygomatic of maxillary nerve CN V(2)
Inferior opthalmic vein
137
What passes in Optic Canal
CN II
Opthalmic artery
138
Describe parasympathetic eye innervation
Preganglionic arising in Edinger Westphal nucleus in midbrain
Travel with CNIII
Leave CNIII and synapse with Postganglionic in ciliary ganglion
Innervate sphinctor pupillae and cilliary muscles via short ciliary nerves
**Effect = pupil constriction + accomodation**
139
Describe sympathetic eye innervation
1st order arises in hypothalamus
Descends to T1 spinal cord level
2nd order ascends sympathetic chain
Synapses in superior cervical ganglion
Travels alongside internal carotid
3rd order postganglionic innervates iris dilator and levatoe palpabrae superioris
140
What are the causes of horner's syndrome
Anything that disrupts sympathetic outflow to the head
Triad of
- Puppilary constriction
- Ptosis
- Anhydrosis
Within midbrain/spinal cord
- Syringomyelia, MS
Preganglionic fibres
- Cervical rib, apical lung ca.
Postganglionic fibres
- Cavernous sinus thrombosis
- Carotid artery dissection
- Local anaesthetic
141
What topical agents can be used for eye anaesthesia
Tetracaine 0.5%
Oxybuprocaine 0.4%
142
Anatomy of the oesophagus
25cm long
Fibromuscular tube
Descends within superior then posterior mediastinum
C6 = Originates
T10 = Enters abdomen through oesophageal hiatus in right crus of diaphragm
T11 = Ends. Cardiac orifice of stomach
143
Innervation of oesophagus
Oesophageal plexus with inputs from
Parasympathetic
- Branches of vagus
Sympathetic
- Branches of cervical and thoracic sympathetic chain
144
Blood supply of oesophagus
Cervical - inferior thyroid
Thoracic - oesophageal arteries
Abdomen - left gastric and left inferior phrenic
145
Where does food get stuck in oesophagus
Mnemonic ABCD
Arch of aorta
Bronchi (left main)
Cricoid cartilage
Diaphragmatic hiatus
146
Describe origin of blood supply to upper limb (on left)
Left subclavian originates from aorta
Becomes left axillary artery at lateral border of first rib
Left axillary becomes left brachial at lower margin of teres major
Left brachial divides into radial, ulnar, common interosseous arteries in ACF
147
What is subclavian steal syndrome
Arises due to narrowing in subclavian artery
Retrograde flow from vertebral artery 'steals' from posterior circulation
Symptoms:
- Dizziness/vertigo
- Visual symptoms: transient visual loss, diplopia
- Transient LOC
148
What makes up the thoracic outlet
Posterior T1 vertebrae
Laterally first rib
Anteriorly manubrium
149
What is contained within the thoracic outlet
Trachea
Oesophagus
Thoracic duct
Lung apices
- Left and Right common carotids
- Left subclavian artery
- IJVs
- Subclavian veins
- Brachiocephalic veins
Nerves
- Vagus
- Recurrent laryngeal
- Phrenic nerves
- Sympathetic trunks
150
Why is the first rib important
It's the shortest, flattest, and most curved rib, forming the opening of the thoracic cage with T1 vertebra and manubrium.
Key features include a singular articular surface, a scalene tubercle, and grooves for the subclavian artery and vein
151
What is thoracic outlet syndrome
Compression of nerves, arteries or veins in the thoracic outlet
Usually occurs as vessels and brachial plexus pass between first rib and clavicle
Classified
1. Neurogenic TOS 95% - pain/weakness/parasthesia, on abduction
2. Arterial TOS - pain, pallor, cold arm, loss of radial pulse
3. Venous TOS - pain, swelling, DVT
Causes - congenital e.g. cervical rib (C7), trauma, tumours (pancoast)
152
Tell me about the 5th cranial nerve
The largest cranial nerve
Responsible for facial sensation and innervation of muscles mastication
Located in meckel's cave in middle cranial fossa
153
Describe sensory components of trigeminal nerve
V1 exits skull via superior orbital fissure
- Sensory information from scalp and forehead and nose
V2 exits skull via foramen rotundum
- Sensory information from lower eyelid, cheek, nares, upper lip, upper teeth, gums
V3 exits via foramen ovale
- Carries information from lower lip, lower teeth and gums, chin and jaw, tongue sensation via lingual nerve
Converge on TRIGEMINAL GANGLION - information carried to PONS
154
Describe non sensory components of trigeminal nerve
**Motor**
Originates in pons
Neurons pass directly through Trigem Ganglion without synampsing
Travel with V3 to muscles of mastication
**Autonomic**
Lacrimal glands via V1 and V2
Nasal glands via V2
Submandibular, sublingual, parotid glands via V3
155
3 methods of trigem ablation
| Th
Thermal
Chemical
Mechanical
Perc offered to those not fit for crani
156
How does the mnemonic 1x3x5x7x9x11 apply to the spleen
Dimensions are 1x 3x 5 inches
Weight is 7 ounces
Lies under ribs 9-11
2 types of tissue, red/white pulp
157
Spleen blood supply
Arterial - splenic artery, short gastric arteries
Venous - splenic vein
Lymphatics: efferent lymphatic vessels only
158
How can splenic injuries be classified
Grade 1 - 5
Subcapsular haematoma surface area
5 = shattered spleen
159
What is the splanchnic circulation
Comprises of arterial supple and venous drainage of intraabdominal organs
Arterial originates from
Coeliac trunk
Superior Mesenteric artery
Inferior Mesenteric artery
venous drainage forms portal vein
160
What supplies foregut and what is in it
Liver, spleen, stomach, pancreas, upper duodenum
Coeiliac trunk
161
What supplies midgut and what is in it
lower duodenum, jejunum, ileum, proximal 2/3 colon up to splenic flex
Supplied by SMA
162
What supplies hindgut and what is in it
Distal 1/3 colon, upper rectum
Supplied by IMA
163
How is splanchnic arterial supply controlled
Intrinsic
- Metabolic (H+, K+, adenosine)
- Myogenic
Extrinsic
- Sympathetic
- Parasympathetic
Humoral
- Within/outside the gut (gastrin, vip, prostaglandin, GIP, vasoprssin, angiotensin II, neuropeptide Y)
164
Describe the anatomy of the pharynx
A muscular tube that connects the oral and nasal cavity to the larynx and oesophagus
Functions include air conduction, phonation, swallowing
Nasopharynx - upper part, skull base to soft palate
Oropharynx - middle part, soft pallate to superior border epiglottis
Hypopharynx - lower part, superior border epiglottis to inferior border of cricoid cartilage (C6)
165
What are the 3 layers of the pharyngeal wall
Inner layer
- Squamous epithelium
Middle layer
- Fascial layer
- Extends from occiput to upper oesophageal sphincter
- Prone to perforation from accidental oesophageal intubation
Outer layer
- Muscular layer
- Constrictors
- Elevators
Contraction of these facilitates swallowing
166
Tell me about the pharyngeal constrictors and elevators
Constrictors
- Inferior, middle, superior
- During swallowing these contract propelling food into oesophagus
Elevators
- Stylopharyngeus, salpingopharyngeus, palatopharyngeus
- Shorten and widen pharynx
- Elevate trachea during swallowing
167
Innervation of constrictors / elevators
All constrictors innervated by **Vagus (X)**
All elevators innervated by **Vagus (X)** except stylopharyngeus **Glossopharyngeal (IX)**
168
What are the 2 muscles of the inferior constrictors, why are these clinically relevant
Thyropharyngeus and Cricopharyngeus
Herniation between 2 bellies (weakest point) results in pharyngeal pouch
Pseudodiverticulum of mucosa of inferior constrictors
Regurgitation
Gurgling noise
Halitosis
Chronic cough/aspiration
Choking
Hoarseness
Dysphagia
Weight loss
169
Tell me about the pleura
The pleura are a double layer of serous membranes that line the lungs and thoracic cavity
There are 2 pleura - right and left - corresponding to right and left lung
They consist of 2 layers visceral (covers lungs) and parietal (covers thoracic cavity)
Join at the hilum
Potential space between pleura called pleural space and contains serous fluid
170
What are the anatomical relations of the pleura
**Superior**
- extends 2cm above first rib
**Inferior**
- Diaphragm
**Medial**
- Mediastinum
**Lateral, anterior and posterior**
- Ribs, intercostal muscles, costal cartilages
171
What is the sensory innervation of the pleura
Parietal pleura produces well-localised pain and is sensitive to pressure and temperature
Somatosensory neurones
Phrenic
- C3-5 mediastinal and central diaphragmatic parietal
- T1-T11 intercostal nerves - cervical/costal/peripheral diaphragmatic
Visceral pleural innervated by autonomic by pulmonary plexus and sensitive to stretch
172
What causes transudate and exudate effusions
Transudate
- Alteration of starling forces leads to a net filtration of pleural fluid
Exudate
- Local inflammatory process increases capillary permeability to proteins/cells
173
What is the innervation of the shoulder
Sensory innervation arises from both cervical plexus (C3, 4) and brachial plexus (C5, 6)
Cervical plexus
- Skin above clavicle C3 (via superficial cervical plexus)
- Shoulder tip (C4, via supraclavicular nerve)
Brachial plexus
- Skin overlying deltoid muscle (through upper lateral cutaneous branch of **axillary**)
- Skin overlying medial arm and axilla (**medial cutaneous nerve of arm** and **intercostobrachial nerve**)
- AC joint + glenohumeral joint = upper trunk of BP via **suprascapular nerve**
- Inferior capsule and joint by posterior cord of BP via **axillary nerv*
174
What nerves are blocked with a scalp block
Supraorbital
Supratrochlear
Zygamaticotemporal
Auricotemporal
Greater auricular
Greater occipital
Lesser occipital
175
Where is the retroperitoneal space
Anatomical space behind posterior parietal peritoneum
Can be divided into
Anterior pararenal space
Perirenal space
Posterior pararenal space
Great vessel compartment
176
How can you identify a pleural breach
Rapidly rising ETCo2
Rising airway pressures
Falling O2 sats
