MSK Flashcards
What are the primary and secondary risk factors for osteoporosis?
Primary:
-ageing
-gonadal insufficiency
Secondary:
-nutrition- scurvy, malnutrition, malabsorption
-malignancy- leukaemia, myeloma
-endocrine- hyperparathyroid, thyrotoxicosis, cushing’s
-drugs- corticosteroids, alcohol, heaprin
-systemic disease- TB, RA, chronic liver disease (esp PBC)
Most common bacteria that causes osteomyelitis
Staph aureus
Most common organism to cause osteomyelitis in:
-sickle cell anaemia patients
-IVDU
-HIV/ AIDS
-immunosuppressed/ long term IV meds/nutrition
-Salmonella (also septic arthritis)
-Pseudomonas
-Bartonella
-Fungal osteomyelitis
Commonest site for ostemyelitis?
Long bones (upper/ lower limbs)
Commonest site for osteomyelitis in dialysis patients
Thoracic spine + ribs
Commonest site for osteomyelitis in IVDU patients
Medial/ lateral clavicle
Risk factors for osteomyelitis
Recent trauma/ surgery
systemic dieases- DM/ sickle cell
poor vascular supply
peripheral neuropathy
IVDU
What is the reverse popeye sign indicative of?
Distal biceps brachii tendon rupture
Risk factors for biceps brachii tendenopathy
-steroids
-smoking
-flouroquinolone abx
-CKD
With rupture of the biceps brachii tendon which forearm action would be the weakest
Elbow supination
What are the potential spaces between the neck fascia
Retropharyngeal space
Visceral space
Describe the potential spaces between the neck fascia
Retropharyngeal- between the pretracheal (visceral) and prevertebral fascia
-extends from skull base -> posterior mediastinum
Visceral- space within visceral pre-tracheal fascia
-extends from hyoid –> superior mediastinum
What types of injuries are likely to be missed in a FAST scan
Retroperitoneal injuries
(eg: renal laceration)
Commonest organism to cause septic arthritis in young sexually active adults
N Gonorrhea
Describe the Trendenlenburgs position and physiological effects
Head down-legs up
Improves blood pressure
Increases venous return
reduces intra-cranial pressure
Describe the Reverse- Trendenlenburgs position and physiological effects
Head up-legs down
Reduces blood pressure
Reduced venous return
Reduced cerebral perfusion
Fractures of which bones are most likely to indicate high energy trauma and severe hidden soft tissue injuries?
Sternum
Scapula
1st rib
[extremely hard to brake- have great vessels and cardiopulmonary apparatus underneath]
Describe the flexor tendon injury zones
https://orthofixar.com/wp-content/uploads/flexor-tendon-zones-2.webp
What nerve supplies all muscles in the extensor compartment of the forearm
Radial nerve
How many muscles are there in the superficial extensor compartment
7:
-Brachioradialis
-Extensor carpi radialis longus
-brevis
-Extensor digitorum
-Extensor digiti minimi
-Extensor carpi ulnaris
-Anconeus
What are the muscles of the deep extensor compartment of the forearm
-Supinator
-Abductor pollicis longus
-Extensor pollicis longus
-brevis
-Extensor indicis
(only to thumb + index finger)
Patient presents with new confusion, shortness of breath, tachycardia, pyrexia, oliguria and a petechial rash following a RTA with a femoral fracture the day before.
Whats the Dx?
Fat embolism syndrome
Risk factors for Fat embolism syndrome
Long bone fractures
IM nailing
What structures are damaged in O’Donoghue’s triad/ unhappy triad
-ACL
-MCL
-medial meniscus
What was later found to be contradictory to the unhappy triad?
LCL tears are more likely to accompany ACL ruptures than MCL tears
When are Abx indicated in orthopaedic surgery
-All joint replacements
-All prosthetic/FB implantations
Clinical characteristics of osteogenesis imperfectica
B-blue sclera
D-dentogenesis imperfectica (stained teeth)
S- sensorineural hearing loss
M- multiple fractures
What is the difference in having hypertension w/ bradycardia vs hypotension w/ bradycardia?
HYPER +brady = raised ICP (cushings triad)
HYPO + brady (in absence of hypovolaemia) = cervical cord injury (loss of sympathetic drive)
Clinical findings suggestive of cervical cord injury
-pain above but not below clavicle
-flaccid areflexia
-can flex but not extend at elbows
-hypotension + bradycardia
-diaphragmatic breathing
-priapism
Why does cervical cord injury lead to diaphramatic breathing
No innervation of intercostal muscles when there is a spinal cord injury above T1 hence only the diaphragm is available for breathing
Commonest salter harris type fracture?
Salter harris type 2
Least common SH fracture
Salter harris type 5 then type 1
Describe a Jefferson fracture
Blow out/ burst fracture of the ATLAS (anterior and posterior parts separate)
Best diagnosed on CT (not open mouth xr view)
Describe a hangman’s fracture
Bilateral fracture of the pars interarticularis of the AXIS
MOI of jefferson and hangman’s fractures
Jeffersons = axial loading
Hangmans = hyperextension of neck
How would you identify a cervical vertebra
-large triangular vertebral foramen
-short transverse processes w/ foramina
-short bifid spinous process
-no/ v-small vertebral bodies
What pass’s through the transverse foramina of cervical vertebrae
Vertebral arteries
What section of vertebrae increase in size the further down the spine you go
Lumbar
Describe thoracic vertebrae
-Large vertebral bodies
-long transverse and spinous processes
-circular vertebral foramen
-have costal and 2 demi facets each (articulate with ribs)
Where are the lamina and pedicles on the vertebrae
Lamina= connects the transverse and spinous processes
Pedicle= just next to the vertebral bodies, connect it to the rest of the vertebral arch
Name the spinal ligaments from anterior to posterior
-Anterior spinal ligament
-Posterior
-ligamentum flavum
-interspinal ligament
-supraspinal ligament
Superiorly in the cervical spine, what does the supraspinous ligament continue as
Nuchal ligament
Describe the classification of odontoid peg fractures
ADERSON & D’ALONZO classification:
Type1 = odontoid tip # (due to disruption of alar ligament)
Type 2= base of odontoid peg # (high non-union rate/ AVN as vascular supply disrupted)
Type 3 = # extends into body of axis (C2)
What are the ligaments present between C1 & C2
2 alar ligament
1 apical ligament
1 transverse ligament
Describe the sequence of changes to bone in osteomyelitis
-transient bacteriaemia
-focus of acute inflammation at the metaphysis of long bones
-necrosis of bone and formation of sequestrum
-formation of new subperiosteal bone that forms a shell over the dead bone
-pus may drain into:
nearby joint OR through sinus out onto skin surface
T/F: Children are more affected by septic arthritis than adults
True
Risk factors for septic arthritis
-steroid injections
-diabetes
-RA
-immunosuppression
Which organisms cause septic arthritis in:
-normal patients
-IVDU
-children
-discitis
-prosthetic joints
-staph aureus
-gram -ve organisms
-H. influenzae
-brucella abortus
-staph epidermidis
What are the steps in bone healing following a fracture
Fracture = damage to bone + periosteal blood vessels
-Haematoma forms
-macrophages, polymorphs and fibroblasts arrive at haematoma
-fibrosis, angiogenesis and formation of an organised clot (end of week 1)
-osteoblasts lay down woven bone to form callus
-woven bone remodelled into lamellar bone (according to stress orientation)
Commons sites for AVN
-NOF
-anatomical neck of humerus
-scaphoid
-talus
