Shoulder and Elbow Flashcards
What is the pectoral girdle
The clavicle and the scapula
What bone is contained in the arm
The humerus
What bones are contained in the forearm
Radius and ulna
What is the conoid tubercule
A ridge on the clavicle where a ligament attaches
Two articular surfaces of the clavicle
Sternoclavicular joint (medial)
Acromioclavicular joint (Lateral)
Which epicondyle of the humerus projects out more (and hence can be used for identification in an x-ray)
Medial
What shape is the sternoclavicular joint
Saddle
What is the only joint that attaches the upper limb to the axial skeleton
Sternoclavicular joint
What type of joint is the acromioclavicular joint
Synovial plane joint (with fibrocartilaginous articular disc
What type of joint is the glenohumeral joint
Synovial multiaxial (ball and socket) joint
What type of joint is the elbow joint
Synovial complex hinge joint
What type of joint is the proximal radioulnar joint
Synovial unixial pivot joint
(Between radial head and radial notch of ulna)
Function of annular ligament
Holds proximal radioulnar joint in place
What type of joint is the distal radioulnar joint
Synovial, uniaxial pivot joint
(between ulnar head and ulnar notch of radius)
(articular disc between)
what connects the radius and ulna all the way down the bones
interosseous membrane
what happens in pronation of the forearm
ulna stays in place
radius “radiates” around the ulna to cross over it
what is the brachial
the arm
what is the brachial plexus
intricate nerve network of the arm
what are the spinal roots for the brachial plexus
C5 - T1
the sections of brachial plexus
- Roots (formed by anterior rami)
- trunks
- divisions
- cords
- terminal branches (peripheral nerves)
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What nerves supply the musculocutaneous nerve
C5-C7
What nerves supply the median nerve
C5 - T1
What nerves supply the Axillary nerve
C5 and C6
What nerves supply the Radial nerve
C5-T1
What nerves supply the Ulnar nerve
C8 - T1
what does the antebrachial fascia cover
The entire forearm both anteriorly and posteriorly
what does the brachial fascia cover
the entire arm (upper arm)
what are the three functions of fascia
Increases surface area of attachment for muscle = greater efficacy
group of muscles can work together for one action
limits space = limits inflammation and infection
what muscles are contained in the anterior compartment of the arm
(Flexor compartment)
- biceps brachii
- coracobrachialis
- brachialis
what nerve supplies the flexor compartment of the arm and forearm
musculocutaneous
what muscles are contained in the posterior compartment of the arm
(Extensor compartment)
- triceps brachii
- anconeus
what nerve supplies the extensor compartment of arm
radial
what nerve supplies the extensor compartment of the forearm
radial
what nerve mainly supplies the flexor compartment of the forearm
median
what are the exceptions to “the median nerve supplies the flexor compartment of the forearm”
The ulnar nerve supplies
- the flexor carpi ulnaris muscle
- HALF of the flexor digitorum profundus muscle
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What nerve supplies the hand
Ulnar nerve
(except thumb muscles and two lateral lumbricals)
what nerve supplies the deltoid and the teres minor
axillary nerve
what are the posterior axioappendicular muscles of the pectoral girdle
superficial - trapezius and latissimus dorsi
deep - levator scapulae and rhomboid major/minor
general origins and insertions of trapezius
from midline between skull and T12 to acromion, spine of scapula and lateral clavicle
nerve supply of trapezius
spinal accessory nerve (CNXI)
function of trapezius
elevation, depression, rotation and retraction of scapula
general origins and insertions of latissimus dorsi
midline from T7, iliac crest and scapula to intertubercular groove
nerve supply of the latissimus dorsi
thoracodorsal nerve (C6-C8)
functions of latissimus dorsi
extension, adduction and medial rotation of the humerus
what nerve supplies the levator scapulae and rhomboids
dorsal scapular nerve (C4-C5)
function of levator scapulae and rhomboids
retraction and elevation of scapula
general origin and insertions of rhomboids and levator scapulae
medial border of scapula to cervical and thoracic vertebrae
origin of rhomboid major
inferior to scapular spine
insertion of rhomboid minor
spine of scapula
origin of levator scapulae
superior angle (superior to) scapular spine
general origins and insertion of pectoralis major
clavicle and sternum to intertubercular groove
which nerves supply the pectoralis major
medial and lateral pectoral nerves (C5-T11)
two heads of pectoralis major
clavicular head and sternocostal head
functions of pectoralis major at the GH joint
adduction, medial rotation, flexion (clavicular head) and extension (sternocostal head)
functions of pectoralis major at the scapulothoracic joint
draws scapula anteroinferiorly
general origin and insertions of the pectoralis minor
coracoid process to the costal cartilages of ribs 3-5
what nerve supplies the pectoralis minor
medial pectoral nerve (C8-T1)
function of pectoralis minor at the scapulothoracic joint
draws scapula anteroinferiorly
general origin and insertions of serratus anterior
medial border of scapula to ribs 1-9
which nerve supplies the serratus anterior
long thoracic nerve (C5-C7)
functions of the serratus anterior
protraction and rotation of the scapula
general origin and insertion of subclavius
clavicle to first rib
which nerve supplies the subclavius
nerve to subclavius (C5-C6) ??
function of subclavius
anchors and depresses clavicle
general origins and insertion of deltoid muscle
lateral clavicle, acromion and spine of scapula to deltoid tuberosity of humerus
which nerve supplies the deltoid muscle
axillary nerve (C5-6)
function of the clavicular region of the deltoid muscle
flexions and medial rotation of the arm
what is the function of the acromial region of the deltoid muscle
abduction of the arm
what is the function of the scapular spine region of the deltoid muscle
extension and lateral rotation of the arm
general origin and insertion of the teres major
inferior lateral border of scapula to intertubercular groove
which nerve supplies the teres major
lower subscapular nerve (C5-C6)
what is the function of the teres major
medial rotation and extension of the arm
what makes up the rotator cuff
supraspinatus, infraspinatus, subscapularis and teres minor muscles
where do the three posterior muscles of the rotator cuff insert
the greater tubercle of the humerus
(the anterior muscle attaches to the lesser tubercle)
what is the collective action of the rotator cuff
holds the humeral head in the glenoid cavity during all movements of the GH joint
which nerve supplies the supraspinatus and infraspinatus muscles of the rotator cuff
suprascapular nerve (C4-C6)
which nerve supplies the subscapularis muscle of the rotator cuff
subscapular nerve (C5-C7)
which nerve supplies the teres minor muscle of the rotator cuff
axillary nerve (C5-C6)
function of the supraspinatus muscle
abduction of the arm to 15 degrees
function of the infraspinatus and teres minor muscles
lateral rotation of the arm
function of the subscapularis muscle
medial rotation of the arm
origin of long head of biceps brachii
supraglenoid tubercle
origin of short head of biceps brachii
coracoid process
attachments of biceps brachii
radial tuberosity and antebrachial fascia via bicipital aponeurosis
functions of biceps brachii
flexion and supination of forearm
weak extension of arm
origin and insertion of coracobrachialis
coracoid process to humerus midshaft
function of coracobrachialis
flex and adduct arm
origin and insertion of brachialis
anterior humerus to coronoid process of ulna
function of brachialis
strong arm flexor
what are the three anterior arm muscles
biceps brachii, coracobrachialis, brachialis
what are the two posterior arm muscles
triceps brachii, anconeus
origin of long head of triceps brachii
infraglenoid tubercle
origin of lateral head of triceps brachii
posterior humerus, superior to radial groove
origin of medial head of triceps brachii
posterior humerus, inferior to radial groove
insertion of triceps brachii
olecranon process of ulna
function of triceps brachii
extension of forearm
origin and insertion of anconeus
lateral epicondyle of humerus to lateral olecranon process
function of anconeus
extension of forearm, stabilises elbow
which nerve roots are involved in flexion of the elbow
C5, C6
which nerve roots are involved in extension of the elbow
C6, C7
how many muscles do each of the layers of the anteriorforearm have
superficial - 4
intermediate - 1
deep - 3
what is the common origin of the 4 superficial muscles of the anterior forearm
medial epicondyle
what are the four muscles of the superficial layer of the anterior forearm
pronator teres
flexor carpi radialis
palmaris longis
flexor carpi ulnaris
which of the flexor carpi muscles is involved in abduction of the hand
flexor carpi radialis
(FC Ulnaris = adduction)
which muscle is contained in the intermediate layer of the anterior forearm
flexor digitorum superficialis
how many tendons does the FDS have
4 tendons; 1 to each middle phalanx of digits 2-5
what are the three muscles of the deep layer of the anterior forearm
flexor digitorum profundus
flexor pollicis longus
pronator quadratus
how many tendons does the FDP have
4 tendons; 1 to each distal phalanx of digits 2-5
what is the common origin of the muscles of the posterior forearm
lateral epicondyle
what are the five muscles of the superficial posterior forearm
brachioradialis
extensor carpi radialis longus
extensor carpi radialis brevis
extensor digitorum
extensor digiti minimi
function of the brachioradialis
flexor of mid-pronated forearm
(think about having a drink)
function of the extensor carpi radialis longus
extension of the wrist and abduction of the hand
function of the extensor carpi radialis brevis
extension of the wrist and abduction of the hand
what are the five muscles of the deep posterior forearm
supinator
extensor indicis
abductor pollicis longus
extensor pollicis longus
extensor pollicis brevis
What is gastrulation
A process of cell division and migration resulting in the formation of the three germ layers
what are the distinct regions of the mesoderm (medial to lateral)
notochord
paraxial mesoderm
intermediate mesoderm
lateral plate mesoderm
extraembryonic mesoderm
what regions of the embryo have no mesoderm
oropharyngeal membrane and cloacal membrane
(form the mouth and anus and so no muscle formed)
between which days of development are the paraxial, intermediate and lateral plate formed
days 17-21
what forms the paraxial mesoderm
cells moving bilaterally and cranially from the primitive streak
where dies the paraxial mesoderm lie
adjacent to notochord and neural tube
what does the paraxial mesoderm form
the somites in the embryo
what does the intermediate mesoderm form
the genitourinary system
what is the name of the cavity that splits the lateral plate mesoderm
intraembryonic coelom
what are the two layers of the lp mesoderm
somatic or parietal layer
splanchnic or visceral layer
examples of smooth muscle that come from ectoderm instead of mesoderm
pupil, mammary, and sweat glands
what forms skeletal muscle (mesoderm)
the paraxial mesoderm
describe somitogenesis
paraxial mesoderm gets organised into somites
form alongside the developing neural tube in a craniocaudal sequence over time (from day 20)
3 pairs of somites form every day until the end of week five
what genes control somitogenesis
FGF family, Wnt, Notch
describe the clock and wave mechanism
somites form in a head to tail fashion via overlapping gradients.
Clock gene expression = notch
Once cells at right “time” they express notch, allowing them to react to the wave.
Wave of FGF8 is washing up the somites
It will only have an effect on the somites if the mesoderm is at the right “time”: and expressing notch
How many pairs of somites are present at the end of the 5th week
42-44 pairs, these go on to form the axial skeleton
what is a somite
a block of paraxial mesoderm that give rise to the axial skeleton
what is the process of somite differentiation referred to as
epithelisation
what becomes the sclerotome
cells in the ventral and medial area of the somite undergo an epithelial-mesenchymal transition
what becomes the dermomyotome
cells in the dorsal half of the somite
what does the dermomyotome split to form
the dermatome - dermis of the back
myotome - muscles
what is a myoblast
a muscle cell precursor which undergo cell division under the influence of growth factors
What forms primary myotubes
myoblasts aligned into chains and fuse, cell membranes disappear - multinucleated myotubes - primary myotubes
what mediates the differentiation of myoblasts into myotubes
myogenin
function of MYOD and MYF5
transcription factors that activate muslce-specific genes.
they enable the differentiation of myogenic precursor cells in the dermomyotome into myoblasts
what molecular regulation of somite differentiation occurs in both the neural tube and the lateral plate mesoderm
WNT proteins (activating) and BMP (inhibitory) combine to activate MYOD in the dermomyotome - creating a group of muscle cells precursors which express MYF5
what molecular regulation of somite differentiation occurs in the notochord
‘sonic hedgehog’ and ‘noggin’ factors induce sclerotome formation
what happens if you take away both MYF5 and MYOD (experimentally in mice)
loss of function mutation results in a complete lack of skeletal muscle formation
from which type of mesoderm does cardiac muscle originate
splanchnic lateral plate
what are the 2 directions of embryonic folding
lateral folding: driven by the somites
cephalocaudal folding: driven by the CNS
what is the function of the amniotic membrane
protection of developing embryo and fetus
what is the function of the notochord
important signalling structure during development of mesoderm and nervous system.
triggers development of CNS
what does the sclerotome form
ribs and vertebrae
what does the dermatome form
dermis and some muscles
what does the myotome form
skeletal muscles
what is appositional growth
growth on the surface
increase in width of bone - seen during development and in fractures. Chondroblasts deposit collagen matrix on cartilage beneath the periosteum and add bone
what is interstitial growth
increase in length. Result of the growth plate of cartilage model producing bone during childhood up until puberty
what is endochondral ossification
cartilage model is laid down as a precursor to bone
what is intramembranous ossification
cartilage not involved. Condensation of mesenchyme straight to bone
what is mesenchyme
connective tissue formed from mesoderm. Highly migratory and essentially a stem cell population of the MSK system
what is a myotome (in embryology)
part of the somite that forms the muscles
what are osteoclasts derived from
blood monocytes/macrophages
what are osteoblasts derived from
osteoprogenitor cells
what type of mesoderm fuses to close the body wall of the embryo during folding
somatic lateral plate mesoderm
what is the ECM composed of
50% water
proteins
glycoproteins
proteoglycans
glycosaminoglycans (GAG)
describe the structure and function of collagen
30% of protein mass - major component of connective tissue
Gly-X-Y repeat
triple helical structure
tensile forces
what signifies collagen maturation
addition of sugar molecules
what are two examples of enzymes that cleave off propeptides
C-proteinase (Bmp1) - tolloid family
n-proteinase (ADAMTS family members)
what is the collagen turn-over half life
approx 120 years in the human body
in what rhythm is collagen produced
circadian - synthesised at night, secreted during the day
describe osteogenesis imperfecta
brittle bone disease
autosomal recessive and dominant forms
collagen type 1 related (major fibrillar collagen)
COL1A1 and COL1A2 heterotrimeric protomer
what is a heterotrimeric protomer
macromolecule made up of three subunits - alpha, beta and gamma
what is classical OI
autosomal dominant
COL1A1 or COL1A2 mutation
describe type 1 OI
less severe, no symptoms at birth
early onset osteoporosis, few fractures
reduced collagen levels
difference between normal and mild OI collagen levels
normal:
8 x proalpha1 + 4 x proalpha2 = 4 procollagen
mild OI:
4 x proalpha1 + 4 x proalpha2 = 2 procollagen
DUE TO MUTATIONS
describe recessive OI-HSP 47
recessive OI = no collagen mutation but instead a mutation in HSP47 which leads to delyaed collagen secretion from cells
describe the onset of severe OI
80% glycine missense mutations (Dominant negative)
effect on modification due to delay in folding
secretion of mutant chains
disruption of the gly-X-Y sequence slows the rate of folding resulting in over modification of the chains N-terminal to the disruption
what is opsonisation
The process by which opsonins are used to tag foreign pathogens for phagocytosis.
What mediates cell adhesion
Integrin
What mediates cell rolling
Selectins
What is cell rolling upregulated by
Interleukin 1 and TNF
What stimulates cell adhesion
interleukin 1 and TNF
What stimulates cell migration
Chemokines act on leukocytes to stimulate migration across endothelium
Outline the steps of phagocytosis
- opsonization
- engulfment using pseudopodia
- formation of phagosomes
- fusion with lysosomes containing enzymes to form phagolysosomes
- material destroyed and removed from cell by pinocytosis
Describe serous fluid
usually a transudate, found in pleural, pericardial, peritoneal spaces
Compare exudate vs transudate
Exudate fluid has HIGH protein and HIGH cellular content
Transudate fluid has LOW protein and LOW cellular content
describe Fibrinous exudate
fluid rich in fibrin, an exudate due to high protein content, often on serosal surface, meninges
describe suppurative exudate
pus forming, an exudate rich in neutrophil polymorphs
describe haemorrhagic exudate
severe vascular injury or depletion of coagulatory factors
describe pseudomembranous exudate
surface exudate on mucosal/epithelial sites
What is the function of exudate
allows delivery of nutrients, dilution of toxins, entry of antibodies and stimulates the immune response
describe the kinin system
activated by coagulation factor XII
bradykinin alters vascular permeability and mediates pain
beneficial effects of acute inflammation
- dilution of toxins by oedema fluid
- increased entry of antibodies and drug transport
- fibrin traps microorganisms
- delivery of nutrients
- stimulation of immune response
detrimental effects of acute inflammation
- digestion of normal tissues
- swelling
- inappropriate response (eg type 1 hypersensitivity)
what defines inflammation as chronic
- it is persistent and lacks resolution when the inflamed tissue is unable to overcome the effects of the injurious agent.
- it persists for weeks, months, or years with ongoing tissue damage
- it is characterised by infiltrates of lymphocytes, plasma cells, and macrophages.
what do Th1 cells activate
Il-2
INF y
TNF b
Il-3
What do Th2 cells activate
IL-4
IL-5
IL-6
IL-9
IL-10
IL-13
What differentiates between a macrophage and a monocyte
Macrophages reside in tissues
Monocytes are circulating
What is the function of a macrophage/monocyte
Involve chemotaxis
Synthesise TNF, IL-1, IL-6
Phagocytosis
Antigen presenting cells that link between innate and adaptive immune response
List the 6 activated macrophage products involved in tissue destruction
Toxic oxygen metabolites
Proteases
Neutrophil chemotactic factors
Coagulation factors
Arachidonic acid metabolites
Nitric oxide
List the 4 activated macrophage products involved in fibrosis
Growth factors (PDGF, FGF)
Fibrogenic cytokines (TGF beta)
Angiogenesis factors
Remodelling collagenases
what is a granuloma
Granulomas comprise groups of activated macrophages with a modified appearance (epithelioid macrophages) and giant cells (formed from fused epithelioid macrophages)
What are some examples of causes of chronic granulomatous inflammation
infectious agents such as tuberculosis, leprosy, toxoplasmosis
foreign material such as talc
crohn’s disease
sarcoidosis
response to tumour such as hodgin lymphoma
what are epithelioid macrophages
modified macrophages arranged in small nodules or clusters
they have a mainly secretory role rather than phagocytosis
multinucleated giant cells form where material is difficult to digest
what cells are involved in granulomatous inflammation
epithelioid macrophages, lymphocytes CD4 and CD8
describe how granulomatous inflammation can be delayed type hypersensitivity
T cell mediated immune reaction.
the antigen is presented to CD4+ T cells which in turn takes time to produce IFN gamma and other cytokines resulting in macrophage activation.
three processes in wound healing
inflammation
proliferation
maturation
what is healing by primary intention
healing of a simple wound such as an incised wound, where the edges are closely opposed
what is healing by secondary intention
healing of a wound with a larger surface defect in which the edges cannot be closely opposed or one that is dirty or infected
phases of (muscle?) healing
formation of blood clot
formulation of granulation tissue
cell proliferation and collagen deposition
scar formation
wound contraction
connective tissue remodelling
recovery of tensile strength
describe the inflammatory phase of fracture healing
- haematoma forms at the site of fracture
- prostaglandins recruit neutrophil polymorphs, macrophages, lymphocytes and fibroblasts to the site of injury
- granulation tissue, ingrowth of vessels, migration of mesenchymal cells occurs
- nutrients and oxygen are supplied by the exposed bone and muscle
describe the repair phase in fracture healing
- fibroblasts lay down stroma to support ingrowing vessels
- collagen matrix is laid down
- osteoid is secreted and mineralised leading to soft callus formation
- callus ossifies after 4-6 weeks by forming bridge of woven bone between fracture fragments
describe the remodelling phase of fracture healing
- occurs slowly over months and years
- returns bone to its original shape, structure and mechanical strength
- facilitated by mechanical stress
local factors influencing wound healing
- type, size and location of wound
- movement within wound
- infection
- presence of foreign,necrotic material
- irradiation
- poor blood supply
systemic factors influencing wound healing
- age
- nutrition
- systemic disease
- drugs
- smoking
