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MRCSalah anatomy > Anterior triangle of the neck/abdomen > Flashcards

Anterior triangle of the neck/abdomen Flashcards

1
Q

What are the borders of the anterior triangle of the neck?

A

-Anterior: midline of the neck
-Posterior: anterior border of sternocleidomastoid
-Superior: lower border of the mandible
-roof: external investing fascia
-floor: visceral fascia

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2
Q

What are the subtriangles of the anterior neck triangle?

A

-Submandibular (digastric)
-Muscular (neck strap muscles)
-Carotid triangle (carotid sheath)

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3
Q

Contents of the anterior triangle

A

Digastric triangle (submandibular)
–> Submandibular gland
–> submandibular nodes
–> facial vessels
–> hypoglossal nerve

Muscular triangle
–> strap muscles

Carotid triangle
–> carotid sheath (common carotid, vagus, IJV)
–> ansa cervicalis

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4
Q

What is nerve supply to digastric?

A

–> anterior: mylohyoid
–> posterior: facial nerve

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5
Q
A
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6
Q

Identify strap muscles, 3, 7, 9, 11, 12, 15, 17, 24, 28

A

-Sternohyoid
-Thyrohyoid
-Sternohyoid
-Omohyoid

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7
Q

Nerve supply of strap muscles

A

-All parts by ansa cervicalis C1-C3 except thyrohyoid which is innervated by C1

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8
Q

Action of strap muscles?

A

-Depress the hyoid bone and larynx during swallowing and speaking

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9
Q

1, 11, 16, 18, 19, 21, 37, 43, 54

A
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10
Q

What is the function of spinal accessory nerve?

A

-Trapezius (shrug shoulder)
-Sternocleidomastoid (turns the head to the contralateral side)

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11
Q

What is the surface anatomy of the spinal accessory nerve?

A

-Crosses the posterior triangle of the neck between the point of the junction between the upper 1/3rd and lower 2/3rd of the sternocleidomastoid to the junction between upper 2/3rd and the lower 1/3rd of the trapezius

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12
Q

Identify the great auricular nerve? What is the supply?

A

-Skin over the angle of the mandible
-skin over the parotid gland
-Skin of the lower 1/3rd of the auricleW

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13
Q

What are the boundaries of the posterior triangle of the neck?

A

-Anterior: posterior border of sternocleidomastoid
-Posterior: anterior border of the trapezius
-Base middle 1/3rd of the clavicle
-Apex sternocleidomastoid and the trapezius muscles at the occipital boneWh

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14
Q

What are the contents of the posterior triangle?

A

Nerves
–> accessory nerve
–> phrenic nerve
–> three trunks of the brachial plexus
–> branches of the cervical plexus: supraclavicular nerve, transverse cervical nerve, great auricular nerve, lesser occipital nerve

Vessels
–> external jugular vein
–> subclavian artery (3rd part)

Muscles:
–> inferior belly of omohyoid
–> scalene

Lymph nodes
–> supraclavicular
–> occipital

IJV does not lie within posterior triangle, but the terminal branches of the ext jugular vein do.

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15
Q

Venous stuff

A
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16
Q

What is the origin and insertion of external oblique?

A

Origin:
–> outer surfaces of ribs 5-12

Insertion
–> Iliac crest, pubic tubercle

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17
Q

What is the nerve supply of external oblique?

A

–> ventral rami of lower 6 thoracic nerves (T7-T12)

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18
Q

what is the direction of fibres/action of external oblique

A

Downwards, forwards and medial (hands in pockets)

Actions: Flexion/contralateral rotation of torso

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19
Q

Origin and insertion of internal oblique?

A

O: thoracolumbar fascia, iliac crest, inguinal ligament

I: ribs 10-12

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20
Q

Nerve supply to internal oblique?

A

-Lower 6 thoracic nerves (T7-T12)
-Iliohypogastric, ilioinguinal nerves

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21
Q

Borders of inguinal canal

A

Anterior: External oblique aponeurosis, reinforced laterally by fibres of internal oblique

Posterior: Transversalis fascia

Inferior: inguinal ligament, medially lacunar ligmanet

Superior: arching fibres internal oblique/transversus abdominis

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22
Q

Describe the regions of the anterior abdominal wall

A

Abdomen is divided into 9 regions by 4 lines:
-1st horizontal line: Transpyloric plane (corresponds to 9th costal cartilage/L1 vertebral body)
-Transtubercular planes (joining iliac tubercles, corresponds to lower border L4 body, upper border L5 body)
-Midclavicular planes: 2x vertical lines joining midinguinal points and middle of clavicle

-Right and left hypochondrium
-Epigastric region
-Right and left flank
-Umbilical region
-Left and right iliac fossa
-Pubic region

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23
Q

At what vertebral level does the umbilicus lie?

A

In a flat and muscular abdomen, umbilicus lies at L4 level. This can vary in a pendulous abdomen

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24
Q

At what vertebral level does the transpyloric plane lie?

A

Midway between suprasternal (jugular) notch and pubic symphysis. Usually corresponds to lower border L1

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25
Q

Name some important anatomical structures which frequently lie on the transpyloric plane

A

Right to left:

  1. Upper pole of right kidney
  2. Right and left colic flexures
  3. Fundus of the gallbladder
  4. Head of the pancreas
  5. Pylorus of the stomach
  6. 2nd part of the duodenum
  7. Formation of portal vein by joining of SMV and Splenic vein
  8. DJ flexure
  9. Origin of SMA from aorta
  10. End of spinal cord in adults
    11: hilum of spleen
    12: hilum of left kidney
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26
Q

Name the layers of abdominal wall you would go through when performing an open appendicectomy

A

Skin
Subcutaneous tissue
Camper’s fascia
Scarpa’s fascia
External oblique
Internal oblique
Transversus abdominis
Transversalis fascia
Preperitoneal fat
Parietal peritoneum

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27
Q

Name the two vertical muscles of the anterior abdominal wall

A

The two vertical muscles of the anterior abdominal wall are both contained within the rectus sheath. They are the:
-Rectus abdominis
-Pyramidalis

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28
Q

What are the contents of the rectus sheath?

A

Rectus abdominis
Pyramidalis
Superior and inferior epigastric arteries and veins
Ventral rami of T7-T12 nerve roots
Lymphatics
Fibro-fatty connective tissue

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29
Q

Describe the arterial supply to the anterolateral abdominal wall

A

Internal thoracic
–> superior epigastric artery

External iliac
–> inferior epigastric artery
–> Deep circumflex iliac artery

Femoral artery
–>Superficial circumflex iliac
–> Superficial epigastric

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30
Q

Describe location at which spigelian hernia occurs:

A

-Also known as a lateral ventral hernia
-Herniation through the aponeurotic layer between the rectus abdominis medially and the linea semilunaris laterally
-Linea semilunaris is aponeurotic layer which corresponds with border of rectus abdominis laterally

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31
Q

Name the layers you would go through when performing a midline laparotomy

A

Skin
Subcutaneous tissue
Camper’s fascia
Scarpa’s fascia
Linea alba
Transversalis fascia
Preperitoneal fat
Parietal peritoneum

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32
Q

At what level is there no longer an anterior rectus sheath?

A

Arcuate line:
–> midway between umbilicus and pubic symphysis, although this can be variable
-External olique, rectus abdminis and transversus abdmominis muscle all pass anteriorly below this level

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33
Q

What is the conjoint tendon?

A

Fusion of internal oblique and transversus abdominis tendon

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34
Q

Where is the inferior epigastric artery (surface anatomy)?

A

Inferior epigastric arises from external iliac artery near mid inguinal point, runs superomedially

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35
Q

What are the different positions of the appendix?

A

-Retrocaecal most common
-Then pelvic
-subcaecal
-Pre/post ileal

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36
Q

What is the blood supply to the appendix?

A

Appendicular artery –> ileocolic artery

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37
Q

Are the appendix and caecum retro or intraperitoneal?

A

Intraperitoneal

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38
Q

What is the function of the iliohypogastric nerve and the consequences of its division?

A

-Supplies transversus abdominis and internal oblique
-Skin of suprapubic region

Can be damaged in: appendicectomy, hysterectomy

Consequence is increased likelihood of direct inguinal hernia (weakens posterior wall of inguinal canal

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39
Q

What are the functions of the rectus abdominis muscle?

A

–> flexion of the lumbar spine
–> Stabilises pelvis during walking
–> Depresses ribs: important role in forceful exhaling

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40
Q

Why is the pain in appendicitis migratory?

A

-Appendix is innervated by autonomic nervous supply to mid-gut
-Inflammation in the appendix activates afferent sympathetic fibres, which enter spinal cord at T10 resulting in referred colicky pain to periumbilical area
-Eventially inflammation in appendix will irritate the surrounding parietal peritoneum, which is innervated by the intercostal nerves resulting in constant local pain in RIF

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41
Q

How would you mobilise the ascending colon and why? in open appendicectomy

A

-You would mobilise the colon from lateral to medial due to its attachment to the mesocolon
-The retrocaecal appendix can then be easily visualised
-You would begin in the relatively bloodless plain at the ileocaecal fold

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42
Q

Where do the carotid artery bifurcate?

A

C4-C5 vertebral level (same as the carina)

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43
Q

Where will a foreign body go?

A

-down right main bronchus
-More vertical angle, shorter and wider
-Right main bronchus is more in line with trachea, making more straight line

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44
Q

Where do the carotid sinus and carotid body lie, what is their function?

A

Carotid body
–> at bifurcation
–> chemoreceptor for O2 levels
–> visceral sensation: cartoid sinus branch of glossopharyngeal nerve (9)

Carotid sinus
–> Proximal internal carotid body
–> baroreceptor sensitive to blood pressure
–> visceral sensory: cartoid sinus branch of glossopharyngeal nerve

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45
Q

Describe the course of the ducts of submandibular and parotid ducts

A

Wharton’s duct
–> 5cm in length, emerges anteriorly from gland between mylohyoid, hyoglossus and genioglossus muscles
–> ascends to open on small sublingual papilla at the base of the lingual frenulum bilaterally

Stensen’s duct:
–> arises from anterior surface of gland, traversing masseter muscle
–> pierces buccinator, moving medially
–> opens out into oral cavity near second upper molar

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46
Q

What is the innervation of the parotid gland?

A

Parotid
–> sensory; auriculotemporal nerve (gland). great auricular nerve (fascia)

Parasympathetic: glossopharyngeal innervation from otic ganglion, carried by auriculotemporal nerve

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47
Q

Submandibular gland innervation

A

-parasympathetic: facial nerve via chorda tympani nerve. Travels with lingual nerve, synapses at submandibular ganglion

-Sympathetic: superior cervical ganglion

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48
Q

Why are calculi more common in submandibular gland?

A

-Tortuous length of duct (5cm)
-Ascending secretory pathway
-Nature of salivary secretion (mixed serous and mucous with increased calcium content)

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49
Q

Relationship of nerves to submandibular gland

A

Lingual nerve: begins lateral to gland, then loops beneath the duct

Hypoglossal nerve: deep to the gland

Facial nerve: inferior to the gland

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50
Q

Describe the blood supply and lymphatic drainage of the oesophagus

A

Arterial supply:
–> upper 1/3rd: Inferior thyroid artery (thyrocervical trunk)
–> middle 1/3rd: Branches of descending thoracic aorta
–> lower 1/3rd: Branches from left gastric artery, inferior phrenic artery

Venous drainage
–> Upper 1/3rd: inferior thyroid vein
–> Middle 1/3rd: Azygous vein
–> lower 1/3rd: oesophageal branches left gastric vein

Lymphatic drainage:
–> upper 1/3rd: deep cervical nodes
–> Middle 1/3rd: superior and posterior mediastinal nodes
–> lower 1/3rd: Left gastric nodes and coeliac plexus

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51
Q

What is the arterial supply and venous drainage of thyroid gland?

A

-Superior thyroid artery (external carotid)
-Inferior thyroid artery (thyrocervical trunk)
-Thyroid IMA (brachiocephalic trunk, arch of aorta)

Venous drainage:
–> superior and middle thyroid vein (drain to internal jugular vein)
–> inferior thyroid vein (drains to brachiocephalic vein)

52
Q

What are the boundaries of the posterior triangle?

A

-Posterior: anterior border of trapezius
-Inferior: clavicle
-anterior: posterior border sternocleidomastoid
-Roof: external investing layer of deep cervical fascia
-Floor: prevertebral faica

53
Q

What are the attachments of the omohyoid muscle?

A

-Superior: hyoid bone
-Inferior: scapula
-Two muscle bellies are connected by intermediate tendon, which is anchored to the clavicle by the deep cervical fascia

54
Q

Muscles of the tongue and their innervation:

A

Extrinsic
-> hyoglossus (depression)
-> styloglossus (elevation and retraction)
-> genioglossus (protrusion)
-> palatoglossus (elevation of posterior tongue together with styloglossus)

innervation:
–> all hypoglossal except palatoglossus (vagus nerve)

55
Q

What are the intrinsic muscles of the tongue?

A

-Superior and inferior longitudinal, transverse, vertical

56
Q

branches of subclavian

A

VIT C, D

Vertebral artery
Internal thoracic artery
Thyrocervical trunk
Costcervical trunk
Dorsal scapular artery

57
Q

Explain subclavian steal syndrome

A

Caused by stenosis in subclavian artery proximal to the vertebral artery

During excercise, retrograde flow occurs via ipsilateral vertebral artery to side of stenosis

Causes brainstem ischaemia (symptoms e.g. tinnitus, syncope)

58
Q

How does lymph go from inferior 1/3rd of oeosphagus to venous system?

A

Coeliac lymph nodes –> thoracic duct –> junction of thoracic duct with left subclavian vein or internal jugular vein

59
Q

Function of iliotibial tract in upright position? What is the function of fascia lata?

A

-At hip joint it prevents pelvic tilting: provides lateral stabilisation to hip and extended knee
-At knee: stabilises femur on tibia by counteracting lateral sway movement of the body

Is fascia for gluteus maximus and tensor fascia lata, therefore helps with hip flexion/extension/medial/lateral rotation, abduction

Facia lata: exerts a compressive effect on muscles of thigh when stretched by fascia lata
Aids venous return and centralises muscle mass increasing efficiency of contraction

60
Q

Show musculocutaneous nerve on actor

A

-Originates from lateral cord of brachial plexus
-Descends in lateral upper arm supplying BBC
-Then continues in lateral forearm as lateral cutaneous nerve of forearm

61
Q

What are the origins and insertions of the upwards rotators of the scapula?

A

Trapezius:
-O: External occipital protubrance, nuchal ligament, Spinous process C7-T12
-I: Spine of scapula, acromion, clavicle

Serratus anterior
-O: rib 1-9
-I: ventromedial scapula

62
Q

What muscles originate on asis? What muscles originate on AIIS?

A

-Sartorius
-Tensor fascia lata
-Inguinal ligament

AIIS:
–> Straight head rectus femoris
–> iliofemoral ligament
–> iliacus

63
Q

What is the origin and insertion of psoas major and iliacus?

A

Psoas major
–> vertebral bodies and transverse processes of T12-L5
–> inserts into lesser trochanter

Iliacus
–> originates at iliac fossa and anterior inferior iliac spine
–> inserts into lesser trochanter

64
Q

What are the surface markings of L1 vertebral plane?

A

-Midway between jugular notch and pubic symphysis
-Midway between xiphisternum and umbilicus

65
Q

What is the surface marking of the gallbladder?

A
66
Q

What is the surface marking of the pancreas?

A

L1 in the midline

67
Q

What are the surface markings of the liver?

A

-Superior border runs along nipple line superiorly
-Extends on the left side to the 5th intercostal space midclavicular line
-The inferior border follows the right costal margin

-Runs along the nipple line superiorly
-Right 10th rib inferiorly
-Left 5th intercostal space mid clavicular line

68
Q

What is the safe dose of naloxone?

A

-Give 400mcg initially and await response for 1 minute
-If no response, give further 800mcg
-Continue to uptitrate until adequate resopnse keeping in mind other causes of respiratory depression (maximum 10mg)
-Then commence naloxone infusion at 60% of resuscitative dose as it has a short half life

69
Q

What is the surface marking of the gallbladder?

A

9th costal cartilage, mid clavicular line

70
Q

What is the surface marking of the spleen?

A

-lies behind 9th, 10th and 11th ribs on the left side, hilum is at level of transpyloric plane

71
Q

What is the surface marking of the abdominal aorta?

A

-2 finger breadths above the Transpyloric plane at vertebral level T12
-Down to supracrestal plane (L4)

72
Q

Burns management things i forget

A

Airway
-Airway oedema and intubation

B:
-Ensure adequate ventilation due to tracheal or pulmonary burns causing ineffective gas exchange
-Full thickness chest burns can increase chest expansino

C:
-Central venous line

73
Q

How would you monitor fluid status in burn?

A

-Warmth
-Capillary refill
-Urine output
-Central venous pressure and its response to fluid challenges
-Core temperatures

74
Q

Complications of a burn

A

-Renal failure due to myoglobinuria
-ARDS
-Sepsis
-Electrolyte disturbance (sodium-hypo/hyper, hyperpotassium, hypocalcium)
-Burns shock (losses due to skin loss)
-Constricting circumferential burns
-Coagulopathy (due to DIC/hypothermia)
-Haemolytic leading to haemoglobinuria and anaemia

75
Q

What is the berlin definition of ARDS?

A

Inflammatory syndrome of respiratory failure characterised by hypoxia and reduced lung compliance. Classified accoring to berlin criteria:

-Acute (<7 days)
-Bilateral infiltrates on CXR/CT
-Alveolar oedema of non cardiogenic origin
-PaO2-FiO2 ratio <300mmhg with PEEP/CPAP >5cmh20

76
Q

Describe phases of ARDS pathophysiology

A

Exudative phase
Proliferative phase
Fibrotic phase

77
Q

Describe exudative phase ARDS pathophysiology

A

-Alveolar damage initiated from the initial tissue injury
-Cytokines and inflammatory mediators–> alveolar and endothelial injury.

78
Q

Describe proliferative phase ARDS pathophysiology

A

-Restoration of alveolar-capillary membrane integrity, by the fibroblasts and type-2 pneumocytes
-New surfactant is produced

79
Q

Describe fibrotic phase of ARDS

A

-fibrin deposition leading to ‘scarring’ of the lung tissue.
-can lead to long-term oxygen or even ventilation dependency.

80
Q

What is the management of ARDS?

A

Admit to ITU, give supportive therapy, treat underlying cause

Respiratory support:
—PEEP: 5015 cm H20
–> proning

Steroids

Treat the sepsis if septic

–>Judicious correction of haemodynamic compromise without overloading. Moniotr with CVP
–> if circulatory failure despite adequate hydration (fall in urine or caridac output: consider low dose dopamine as renal arterial dilator, and dobutamine for positive inotropic action

Other supportive care
–> nutritional optimisation
–> dvt prophylaxis
–Gastric ulcer prevention

81
Q

What are the long term sequelae of ARDS?

A

IMpaired gas exchange with refractory hypoxaemia
–> VQ mismatch

Decreased lung compliance
–> stiff, poorly or non-aerated regions of lung

Pulmonary hypertensino

82
Q

How would you classify ARDS causes

A

Direct lung injury
Indirect lung injury

83
Q

ARDS direct lung injury causes

A

-Pneumonia
-Aspiration of gastric contents
-Fat emboli
-Smoke inhalation injury

84
Q

ARDS indirect lung injury causes

A

-Sepsis
-Severe trauma
-Major burns
-Acute pancreatitis
-Multiple blood transfusion

85
Q

What is the treatment of ARDS?

A

Admit to ITU, give supportive therapy and treat underlying cause

Respiratory support:
–>

86
Q

What is a metabolic acidosis

A

Decrease in pH due to metabolic cause

87
Q

What is the anion gap? how is it calculated? What is a normal anion gap?

A

-Difference between cations (+ve-cats are positive) and anions (-ve) in your blood
-(Na+ + K+) - (Cl- + HCO3-)
-Should be 8-16/ around 12

88
Q

What is a high anion gap acidosis? What are the causes?

A

Increase in unmeasured anions: LKTR
Lactate
Ketones
Toxins (salicylates, metformin)
Renal failure (impairment of H+ excretion)

89
Q

What are the causes of normal anion gap metabolic acidosis?

A

-Loss of bicarb, i.e. high bowel output
–> fistulas
–> stomas
–> diarrhoea

Too much Nacl
Renal tubular acidosis (kidneys excrete bicarb)

Bicarb is replaced by chloride which is also a buffer

90
Q

Why is anion gap corrected for albumin? how is this done?

A

the normal AG = 0.2 x [albumin] (g/L) + 1.5 x [phosphate] (mmol/L)

Albumin is major unmeasured anion: changes in albumin levels can significantly change equation

91
Q

Describe patholphysiology of NAGMA vs HAGMA

A

High anion gap metabolic acidosis: bicarb is consumed by unmeasured cation (e.g. h+) as a result of its action as a buffer–> high anion gap

normal anion gap metabolic acidosis: Loss of bicarb is primary pathology, gets replaced by Cl- (also a buffer): therefore is hyperchloraemic metabolic acidosis

92
Q

What are the causes of metabolic alkalosis?

A

-Persistent vomiting (loss of HCL, hypokalaemia, hyponatremia–> kidneys retain sodium at expense of H+ to preserve Na/K+ pumps, worsening alkalosis
-Contraction alkalosis: e.g. due to dehydration: aldosterone causes renal H+ excretion
-Use of loop diuretics and thiazides: loss of sodium and water causes contraction alkalosis
-Primary hyperaldosteronism (conn’s)

93
Q

How is CO2 transported in the blood?

A

-Bicarb (70%)
-Carbaminohaemoglobin (20%)
-Dissolved CO2 (10%)

94
Q

Describe the erythrocyte chloride shift with the equation

A

Describes the movement of chloride into red blood cells which occurs when the buffer effects of deoxygenated haemoglobin increase the intracellular bicarbonate concentration, and the bicarbonate is exported from the RBC in exchange for chloride

95
Q

What is the point in the chloride shift?

A

-Mitigates change in pH which would otherwise occur in peripheral circulation due to metabolic biproducts (mainly CO2)
-Increases CO2 carrying capacity of venous blood
-Chloride changes the shape of haemoglobin to increase oxygen unloading

96
Q

What is the mechanism of the chloride shift?

A

-Chloride moves into erythrocytes, and bicarb moves out, in venous blood

-CO2 diffuses into the red cells
-There it is converted to bicarb by carbonic anhydrase
-Bicarbonate then diffuses out of the cell, and chloride diffuses in
-The reverse takes place in the pulmonary capillaries

97
Q

Examiner will give you an ABG, interpret?
Low pH, raised pCO2, normal bicarb

A

Uncompensated respiratory acidosis

98
Q

What is the cause of the respiratory acidosis?

A

Morphine overdose, depresses the CNS

99
Q

Why is there no metabolic compensation?

A

Renal tubular compensation only occurs over a period of around 48 hours

100
Q

Why is bicarb normal?

A

-The initial response is cellular buffering that occurs over minutes to hours. Cellular buffering elevates plasma bicarb only slightly
-The second step is renal compensation that occurs over 3-5 days. With renal compensation, renal excretion of carbonic acid is increased and bicarb reabsorption is increased

101
Q

What are the types of respiratory failure and what are their causes?

A

Type 1: ventilation/perfusion (V/Q) ismatch: the volume of air flowing in and out of the lungs is not matched with the flow of blood to the lungs
–>pneumonia
–> bronchitis
–> PE
–> pneumothorax

Type 2: caused by inadequate alveolar ventilation: both O2/CO2 are affected. Defined as the buildup of carbon dioxide levels that has been generated by the body but cannot be eliminated
–> increased airways resistance (COPD, asthma, suffocation)
–> reduced breathing effort (drug effects, brain stem lesion)
–> decrease in the area of the lung available for gas exchange (such as in chronic bronchitis)
–> neuromuscular problems
–> deformation (kyposcoliosis

102
Q

What are the response mechanisms to hypercarbia?

A

Elevation in CO2 leads to central acidosis, which stimulates central chemoreceptors and leads to increased respiratory rate in order to blow off extra CO2

103
Q

How does morphine act?

A

-By binding to mu receptors on the respiratory centre causing respiratory depression

104
Q

What are the side effects of naloxone?

A

-Nausea
-Vomiting
-Sweating
-Tachycardia
-Abdominal cramps
-Pulmonary oedema
-Cardiac arrest

105
Q

Scenario: 28 yr old male, leg crushed for a few hours, left unobserved on orthopaedic ward. Bloods: AKI. Urine dip: blood.

What are the complications?

A

-Compartment syndrome
-Rhabdomyolysis

106
Q

What is the clinical picture of compartment syndrome?

A

-Worsening pain: this may be out of proportion to the injury
-Paraesthesia: especially the loss of two point tactile discrimination

Clinical signs
–> tense and swollen compartments
–> sensory loss
–> pain on passive stretching

Loss of regional pulses which is a LATE sign

107
Q

How to diagnose compartment syndrome in a patient with altered sensorium or sensorimotor deficit

A

This can be achieved by:
–> measurement of intercompartmental pressure, tissue pressures of >30mmhg suggest decreased capillary blood flow, which can result in muscle and nerve damage from anoxia
–> blood pressure: the lower the systemic pressure, the lower the compartment pressure that causes compartment syndrome

108
Q

What is a normal compartment pressure?

A

0-15mmhg
If >30, indication for fasciotomy

109
Q

What is the treatment for compartment syndrome?

A

Emergency fasciotomy e.g. in lower leg 4 compartment fasciotomies through 2 incisions as an emergency procedure

110
Q

What will you say to the patient when you consent for fasciotomies?

A

-Explain operation, complications (permanent nerve damage, permanent muscle damage, permanent scarring, loss of affected limb, infection, kidney failure, in rare cases death

111
Q

Why would you get acute renal failure in compartment syndrome?

A

–>Rhabdomyolysis
–>accumulation of myoglobin in renal tubules leads to tubular obstruction
–> formation of obstructive casts with uric acid
–> low blood pressure can lead to renal arteriole vasoconstriction and relative reduced blood flow
–> together these processes lead to ATN

–> nephrotic effect of myoglobulin precipitating in renal tubules
–> decrease extracellular volume –> vasoconstriction
–> renal tubular ischaemia and necrosis
–> myoglobulin, uric acid –> obstructive cast formation

112
Q

What is myoglobin?

A

-O2 binding protein found in muslces

113
Q

What is the definition of rhabdomyolysis?

A

-The release of potentially toxic muscle cell components into the systemic circulation

114
Q

What are the causes of rhabdomyolysis?

A

-Blunt trauma to skeletal muscle e.g. crush injury
-Massive burns
-Hypothermia or hyperthermia
-Ischaemic reperfusion injury e.g. clamp on artery during surgery
-Prolonged immobilisation on hard surface
-Strenuous and prolonged spontaneous excercise e.g. marathon running
-Drugs e.g. statins, fibrates, alchohol

115
Q

What are the biochemical results in rhabdomyolysis?

A

-Increased CK >5 times normal
-Increased lactate, LDH, creatinine
-Electrolyte disturbances:
—> hyperkalaemia (and metabolic acidosis with increased anion gap)
—> hypocalcaemia(myocyte necrosis is associated with calcium influx into cell)
–> hyperphosphataemia
–> hyperuricaemia

-Myoblobinuria suggested by positive dipstick to blood in abscence of haemoglobinuria (red cells on microscopy)

116
Q

What is the managementof rhabdomyolysis

A

-ABC
-> fluid resus: ensure good hydration to support UO >300ml/hr using IV crystalloid until myoglobinuria has ceased
–> diuretics (manittol) may be used
–> alkalinisation of urine: NaHCO3 to prevent renal damage
–> treat electrolyte disturbance (hyperkalaemia
–> monitor ECG, electrolytes,

NaHCO3:
–> tamm horsfall protein precipitates at lower ph, so prevents cast formation

117
Q

What structures pass through the hilum of the lung?

A

-Pulmonary artery and vein (most anteiror)
-Right and left main bronchus (most posterior)
-Bronchial artery and vein
-Lymph nodes
-Autonomic nerves

118
Q

What is the pulmonary ligament?

A

A pleural fold that connects the mediastinal surface of the lung and the pericardium to allow expansion of hilar vessels with increased cardiac output

119
Q
A
120
Q
A

VAD anteiror to posterior: vein, artery, duct

121
Q
A
122
Q

Hilum of lung/hilum of kidney/porta hepatis

A

VAD
-Vein, artery, duct (anterior to posterior)–> renal and lung hilum

RALPH: relation of pulmonary artery to bronchus: right anterior, left posterior and higher

DAVE porta hepatis anterior to posterior:
–> Ducts (left and right hepatic ducts)
–> artery (hepatic artery)
–> Portal vein
–> epiploic foramen of wilmslow

123
Q

What is an intraperitoneal organ?

A

Organ almost entirely covered in visceral peritoneum

124
Q

Name the intraperitoneal organs

A

-Stomach, first and 4th parts of duodenum
-DJ flexure, jejunum, ileum
-liver, spleen, tail of pancreas
-transverse colon, sigmoid colon, upper 1/3rd of rectum

125
Q

What is the difference between a primarily and secondarily retroperitoneal organ?

A

Primarily: developed in retroperitoneum

Secondarily: Initially intraperitoneal, developed suspended by a mesentery. Became retroperitoneal when mesentery fused with peritoneum. Covered on anterior surface only by peritoneum.

126
Q

What are the retroperitoneal organs?

A

Primarily:
-Kidneys
-Adrenal glands
-IVC
-Aorta
-Oesophagus

Secondarily
-2nd and 3rd parts duodenum
-Ascending and descending colon
-Pancreas (exceept tail)
-Middle 1/3rd of rectum

127
Q

Name the infraperitoneal/subperitoneal organs

A

-Lower 1/3rd of the rectum
-Distal ureter
-Urinary bladder

MRCSalah anatomy (15 decks)

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