Bone, Anaesthetics, Fracture and Soft tissue injury

Question 1

what is hydroxyapatite?

Answer 1

crystals of the mineralised matrix of bone- Ca10(PO4)6(OH)2

Question 2

what is the metaphysis?

Answer 2

growth plate between the diaphysis and epiphysis

Question 3

what are the layers of lamellar bone?

Answer 3

there is an outer layer of cortical (compact) bone and an inner layer of trabecular (spongy) bone

Question 4

what is the endosteum?

Answer 4

an inner lining which forms the boundary to the central medullary cavity

Question 5

what is woven bone?

Answer 5

newly calcified, immature bone which has an irregular arrangement of collagen fibres. forms during development and healing

Question 6

what is the structure of lamellar bone?

Answer 6

there are structures called osteons which are layers of lamellae (layers of collagen fibres) surrounding a central Haversian canal with osteocytes trapped within lacunae. canaliculi form connections between lacunae

Question 7

how are the lamellae organised?

Answer 7

each lamellae has collagen fibres arranged at 90 degrees to the adjacent lamellae. this organisation gives strength to the bone

Question 8

what is the function of trabecular bone?

Answer 8

keeps the bones light whilst maintaining structural integrity

Question 9

what is the mechanism of action of local anaesthetics?

Answer 9

they block initiation and propagation of action potentials by blocking Na channels thus preventing the voltage dependant increase in Na

Question 10

why would you co-administer adrenaline with a local anaesthetic?

Answer 10

vasoconstrictor- reduces blood flow to the area so the local anaesthetic isn’t cleared as quickly so it is more effective

Question 11

what are the major side effects of local anaesthetics?

Answer 11

allergy, redness of skin
CNS stimulant/depressant effects- restlessness, tremor, respiratory depression
myocardial depression
vasodilation- BP drop

Question 12

what is the clinical use of propafol and thiopental sodium?

Answer 12

both IV anaesthetics
propafol- used for induction/maintenece of anaesthesia in adults/ children (not neonates)
thiopental sodium- bibiturate used for induction of anaesthesia only

Question 13

what is isoflurane?

Answer 13

widely used volatile liquid anaesthetic- inhalation

Question 14

how can ultrasound be used in musculoskeletal disease?

Answer 14

ultrasound can be used to help diagnose:
tendon tears/tendonitis 
muscle tears, masses or fluid collection 
inflammation or fluid within joints 
nerve entrapments

Question 15

what is the approach used to treat fracture?

Answer 15

identify mechanism of injury- if high energy- ABCDE
wound care- cleaning
pain management- immobilisation, analgesia
imaging
fracture care- reduction and immobilisation (plaster, splint) or surgical fixation

Question 16

what are the symptoms of fracture?

Answer 16

pain 
deformity 
bone crepitus 
abnormal mobility 
associated soft tissue injury 
neuromuscular compromise

Question 17

how are fractures classified?

Answer 17

growth plate involvement- skeletally mature/immature
location- which bone, proximal/distal, inter-articular, diaphysis, epiphysis
extent- complete/incomplete
orientation- transverse/ oblique/ spiral
displacement- non-displaced/ displaced
fragmentation- comminuted (multiple pieces)/ segmental (fracture in two places)
soft tissue- open/closed
pathological- due to pre-exisiting pathology

Question 18

what are the complications of fracture?

Answer 18

neuromuscular injuries
compartment syndrome 
infection- open fracture/ surgery 
long- term- stiffeness, arthritis, growth disturbance 
DVT/PE

Question 19

what are the types of soft tissue injury?

Answer 19

penetrating- incised wound, laceration
blunt- bust laceration, crush, de-gloving, avulsion, amputation
burns- superficial/full thickness
tendon injury- division, rupture, avulsion
nerve injury- division, traction, compression

Question 20

what patterns of motor and sensory loss occur with femoral nerve injury?

Answer 20

sensory- anterior thigh, medial leg (via saphenous nerve)

motor- knee extension

Question 21

what patterns of motor and sensory loss occur with sciatic nerve injury?

Answer 21

sensory- lateral leg via branches

motor- hip extension/knee flexion

Question 22

what patterns of motor and sensory loss occur with tibial nerve injury?

Answer 22

sensory- sole of foot

motor- plantar flexion, toe flexion

Question 23

what patterns of motor and sensory loss occur with superficial peroneal nerve injury?

Answer 23

sensory- lateral side of lower 2/3 of leg, dorsum of foot (except 1st web space)
motor- ankle eversion

Question 24

what patterns of motor and sensory loss occur with deep peroneal nerve injury?

Answer 24

sensory- 1st web space

motor- ankle dorsiflexion (foot drop), toe extension

Question 25

what patterns of motor and sensory loss occur with sural nerve injury?

Answer 25

sensory- posterolateral leg