:L Flashcards
what is the main mineral in the mineralised ECM in bones? [1]
what other subtstance is mostly found in the bone matrix [1]?
what is the main mineral in the mineralised ECM in bones? [1]
calcium phosphate
what other subtstance is mostly found in the bone matrix [1]?
type 1 collagen - 90% of bone
bone classification:
- outside, dense part of bone is called?
- inside, less dense is called?
bone classification:
- outside, dense part of bone is called: compact
- inside, less dense is called: spongy (trabeculae)
when are bones not covered in periosteum?
Osteoprogenitor cells are located where?
where they articulate with other bones
Osteoprogenitor cells are located on the outside of trabecula eg beside adipocytes in periosteum
what is periosteum?
what is inside it?
Fibrous capsule surrounding bone
Carries blood and neural supply
Periosteal blood vessels penetrate the bone from this layer.
Inner periosteum is liner by osteoprogenitor cells.
These may differentiate into osteoblasts and so are important in bone growth, modelling and repair.
what are canaliculi?
Tiny canals in bone to allow for the passage of blood vessels for nutrient supply.
They appear as fine lines
Extend from capillaries to osteocytes and their matrix.
Osteocytes are interconnected by the canaliculi through processes. Communication through gap junctions.
where do you find osteocytes? [1]
characteristic feature of osteocytes [1]
role of osteocytes? [1]
how do u prepare bone to see ^? [1] 2
where do you find osteocytes? [1]
- osteocytes encolosed in bone matrix, trapped in lacunae
characteristic feature of osteocytes [1]
- osteocyte processes
role of osteocytes? [1]
- respond to redeuced mechanical stress by secreting MMPs: osteocytic remodelling
how do u prepare bone to see osteocyte processes? [1]
- visible on ground sections (no stain, just dried)
- not visible with H&E
(see photo)
osteoclasts
location? [1]
characteristics? [1]
derived from? [1]
function? [1]
osteoclasts
characteristics?
large and multinucleated
location
at sites where bone is removed
derived from? [1]
from the fusion of the granulocytes / macrophage progenitor cells
function [1]
responsible for bone resorption in response to long term calcium requirements and changing mechanical stresses.
what are osteoclasts activated by?
how does it cause bone remodelling?
which other cells can activate them?
osteoclasts express a receptor molecule called RANK (receptor activator of nuclear factor). interaction with RANKL ligand molecule expressed on osteoblasts
dissolves bone matrix: pumps protons out to acidify & enzymes = bone remodelling
also activated by t-lymphocytes (can express RANKL) during inflammation
what are the two methods of bone formation? [2]
endochrondral ossification: cartilage model as precursor
intramembranous ossification: no cartilage model
which bones does the radiocarpal joint connect? [3]
what type of joint is it? [1]
which bones does the radiocarpal joint connect? [3]
- scaphoid & lunate to radius (not the ulna!)
what type of joint is it? [1]
- condyloid joint (extension and flexion and ulnar and radial devaitation (side to side)
which direction is extension and flexion of the thumb?
which direction is adductio and abduction of thumb?
what is oppositon of the thumb?
muscles of the superficial layer of forearm:
names? [4]
where do they run from / to?
muscles of the superficial layer of forearm:
- Pronator teres (pronates the arm)
- Flexor carpi radialis (flexes the wrist)
- Palmaris longus (small muscle)
- Flexor carpi ulnaris (flexes the wrist)
(Pass Fail Pass Fail)
muscles of the superficial layer do not extend into the digits so they act to
- **flex the wrist
- pronate the arm**
which is the muscle of intermediate layer of forearm?
where does it run to from the medial epidcondyle?
what movements does it cause? [3]
which is the muscle of intermediate layer of forearm?
- flexor digitorum superficialis
where does it run to from the medial epidcondyle?
- middle phalanx
what movements does it cause?
- *- flexes the wrtist
- flexes the MCP
- flexes the PIP**
what are deep layer muscles of the forarm? [3] where run to ? what movements?
flexor digitorum profundus:
- makes way to fingers and distal phalanx !
- causes flexion of the wrist, MCP, PIP and DIP joints
flexor pollicis longus
- *- forearm to distal phalanx of thumb**
- thumb flexion
pronator quadratus
- between ulnar and radius
- initiates pronation of the forearm
what are deep layer muscles of the forarm? [3] where run to ? what movements?
flexor digitorum profundus:
- makes way to fingers and distal phalanx !
- causes flexion of the wrist, MCP, PIP and DIP joints
flexor pollicis longus
- *- forearm to distal phalanx of thumb**
- thumb flexion
pronator quadratus
- between ulnar and radius
- initiates pronation of the forearm
pronation of the forearm is undertaken by pronator quadratus (deep layer) and pronator teres muscle (superficial layer).
which of these is the main muscle involved in pronation and which assists pronation?
pronator quadratus (deep layer): main
pronator teres muscle (superficial layer): assists
what is the carpal tunnel?
what is the layer at the top called?
which nerve runs through?
- At the base of the palm of the hand, there is a groove/tunnel through which 9 flexor tendons pass.
- Across the top is the flexor retinaculum (thickening of the deep fascia)
- median nerve runs through the carpal tunnel
what are the borders of the anatomical snuffbox? [3]
what are the movements initated by:
a) lumbricals?
b) dorsal interrossei?
c) palmar interrossi?
lumbricals: flex MCP
dorsal interrossei: abduct fingers (DAB)
palmar interrossei adduct the fingers (PAD)
which muscles does the synovial sheath reduce friction of? [2]
flexor digitorum superficialis & flexor digitorum profundus to reduce friction of those tendons rubbing together.
how do paedatric and adult x-rays differ in appearance?
in children, bones are growing via epiphyseal growth plate: lengthens the bone but is made by hyaline cartilage: l_ooks seperated from the main shaft of the bon_e (cane make it look fractured)
which is the only rotator cuff muscle to cause internal rotation? [1]
subscapularis
which rotator cuffs cause external rotation of shoulder? [2]
teres minor
infraspinatous
what should you consider when looking for abnormal x-rays? [5]
In an abnormal x ray you are looking for changes in:
Shape, size and or orientation of the bones and joint surfaces
Breaks in the bone
Extra bone (calcification)
Loss of bone
Foreign objects
which bone is this?
why is this bone clinically significant? [1]
scaphoid
why is this bone clinically significant
- has a retrograde blood supply (comes in at distal end and moves proximally) - means if fracture at proximal end -> can become avascular -> lead to necrosis
ID B, C, E & F?
B: corocoid process
C: glenoid fossa
E: acromion
F: biciptial groove (inbetween the tubercles) for long head of bicep tendon
why is the scaphoid a clinically significant bone? [2]
has a retrograde artery (comes in proximally and comes out distally)
if you get a fracture -> portion becomes avascular and necrotic
which joint permits thumb oppositon in the hand? [1]
carpo-metacarpal
what are the characteristics of power grip?
and subtypes? [3]
- *power grip**
- all fingers flexed around object, thumb curled around to press agaisnt / meet fingers
- all muscles closing hand are active
- wrist extensors are active - stable base
- most primitive (new borns can do)
i) hook or snap
ii) cylindrical grasp
iii) spherical grasp
what are the characteristics of power grip?
and subtypes? [3]
- *power grip**
- all fingers flexed around object, thumb curled around to press agaisnt / meet fingers
- all muscles closing hand are active
- wrist extensors are active - stable base
- most primitive (new borns can do)
i) hook or snap
ii) cylindrical grasp
iii) spherical grasp
what are the two main types of grip? [2]
which is more complex to perfom?
- power grip
- precision grip - more complex
what do patients with radial nerve palsy struggle to be able to do?
why?
what do patients with radial nerve palsy struggle to be able to do?
- power grip
why?
- wrist extensors are active when performing a power grip - causes stabilisation
ulnar nerve lesion would effect which of the following?
- flexor pollicis brevis
- oppenens pollicis
- adductor pollicis
- abductor pollicis brevis
ulnar nerve lesion would effect which of the following?
- flexor pollicis brevis
- oppenens pollicis
- *- adductor pollicis**
- abductor pollicis brevis
what are 4 muscles of thenar emincence? & innervation?
- flexor pollicis brevis - median nerve
- oppenens pollicis - median nerve
- abductor pollicis brevis - median nerve
- adductor pollicis - ulnar nerve
where do you test for sensory innervation for
a) radial nerve
b) median nerve
c) ulnar nerve
where do you test for sensory innervation for
a) radial nerve: between thumb & first thing dorsally
b) median nerve: outside of second finger
c) ulnar nerve: outside of little finger
all of the muscles of the thenar eminance are innervated by the median nerve apart from which muscle? [1]
all of the muscles of the thenar eminance are innervated by the median nerve apart from which muscle? [1]
adductor pollicis
