MSK Session 5 Flashcards
What Re the articulations of the humerus?
Trochlea Capitulum Olecranon fossa Coronoid fossa Radial fossa
What should be considered when examining joints?
Articulations Capsule Ligaments Movements Neurovascular supply Bursae
What in the humerus accommodates proximal ulna movement?
Olecranon fossa
Corona is fossa
What are the articulations of the ulna?
Coronoid process
Trochlear notch
Olecranon process
What are the articulations of the radius?
Head
What is the carrying angle?
Angle made by the forearm and torso
Who has a greater carrying angle?
Women
Which muscles are involved in movement of the elbow joint?
Biceps brachii
Triceps brachii
Brachoradialis
What angle is made at full extension of the elbow joint?
170 degrees
How is pronation/supination achieved?
Head of radius pivots on capitulum of humerus allowing bones to cross in pronation
What is the resting position?
Halfway b/w pronation and supination so that palm faces trunk
What do the capitulum and radial head essentially act together as?
Ball and socket joint
What maintains joint integrity during stretching in the radioulnar joint?
Articular disk which provides an inbuilt recess
What is the sacciform recess?
Specialisation of the synovium which allows capsule twisting at the radioulnar joint
Why is the capsule at the elbow weak anteriorly and posteriorly?
To allow flexion and extension
What strengthens the capsule in the elbow?
Blending of collateral ligaments medially and laterally w/capsule
Which two joints in the forearm share a capsule?
Elbow and proximal radioulnar
What lines the fibrous capsule that encloses the humerus in the elbow?
Synovium
What lies within the coronoid and radial fossae?
Fat pads
What deepens the trochlea notch to stabilise the elbow?
Oblique ulnar collateral ligament
What shape is the posterior ulnar collateral ligament?
Fan
Which ulnar collateral ligament is the strongest?
Anterior
Which ulnar collateral ligament is cord-like, stiff and rigid?
Anterior
Describe the radio-collateral ligament.
Fan-like
Blends w/annular ligament
What is the annular ligament of the radius?
Ligamentous collar arising and inserting into ulna
What is the function of the annular ligament of the radius?
Allow movement but prevent subluxation
What causes students elbow?
Inflammation of the subcutaneous olecranon bursa
Where is the subcutaneous olecranon bursa located?
Overrides the olecranon process
What is the function of the subtendinous olecranon bursa?
Protect from friction from triceps tendon on olecranon process
What causes pain upon flexion and on application of pressure to the area in assembly line workers?
Inflammation of the subtendinous olecranon bursa
How many bursae are there in the elbow joint?
Lots of small ones
How do the nerves travel around the elbow joint?
Radial passes anterior to lateral epicondyle
Ulnar passes posteriorly to medial epicondyle
What does Hilton’s law state?
A BV passing a structure tends to supply it
What provides blood supply to the elbow joint?
Arterial anastomoses formed by collateral arteries and recurrent branches of ulnar, radial and interosseous arteries
Why does occluding one branch in the blood supply to the forearm not cause lots of disruption?
There is built-on redundancy of blood supply
What are the three joints present in the forearm?
Proximal radioulnar
Interosseous membrane
Distal radioulnar
What articulates to form the proximal radioulnar joint?
Head of radius
Radial notch of ulna
Which muscles are used in movement of the radioulnar joints?
Supinator
Biceps brachii
Pronator quadratus
Pronator teres
What type of joint is the interosseous membrane?
Fibrous
In which direction do the fibres of the interosseous membrane run to allow distribution of force from radius to ulna?
Inferio-medially
What articulates in the distal radioulnar joint?
Rounded head of ulna
Ulnar notch on medial radial border
Articular disk
What is special about the articular disk in the distal radioulnar joint?
It is a specialisation of ligaments, not a typical disk
What separates the cavity of the radioulnar joint and the wrist?
Articular disk
What is dislocation?
Complete loss of contact of the joint surfaces
What is subluxation?
Partial dislocation of a joint so that the bone ends are misaligned but are still in contact
What causes pulled elbow?
Upwards force on fully abducted arm causing loss of articulation b/w radial head and capitulum
What subluxation from the annular ligament in pulled elbow?
Radial head
Why is pulled elbow more commonly seen in children?
Ligaments more flexible
Annular ligament has not yet fully adopted funnel-like arrangement
Which joints are involved at the wrist?
Radiocarpal
Distal radius and proximal row of carpal bones except pisiform
What is the radiocarpal joint?
Articulation of distal radius and articular disk w/proximal carpal bones
Is there any ulna involvement at the wrist?
Nope
What are the collateral ligaments of the wrist?
Radial and ulnar
What is the function of the palmar radiocarpal ligament?
Ensures hand follows radius during supination
What is the function of the dorsal radiocarpal ligament?
Ensures hand follows radius during pronation
What limits abduction of the wrist?
Styloid process
What is another term for abduction/adduction of the wrist?
Radial deviation/ulnar deviation
What movements can occur at the wrist joint?
Flexion
Extension
Abduction
Adduction
What happens in a Colles fracture?
Fracture of distal radius causing posterior displacement of distal fragment as force not dispersed to ulna
What is a possible sequelae of scaphoid fracture?
Avascular necrosis due to distal blood supply
Where is tenderness felt in scaphoid fracture?
Over anatomical snuffbox
What holds the vertebral column together?
Ligaments
Why do changes in vertebral column structure cause noticeable changes in height?
It accounts for ~42% of height
What motion describes flexion of the vertebral column?
Bowing
What motion describes extension of the vertebral column?
Leaning backwards
What are the five gross function of the vertebral column?
Provides for the centre of gravity of the body
Attachments for bones
Attachments for trunk muscles
Protection and passage of the spinal cord
Segmental innervation of the body
What line does the spine twist around?
Centre of gravity
How is the weight of the body projected into the lower limbs?
About the vertical line
What is the function of bone attachment in the upper part of the vertebral column?
Bear/support the head
What is the function of bone attachment in the central part of the vertebral column?
Support ribs
Indirectly support UL
What is the function of bone articulation in the lower part of the vertebral column?
Articulates w/hip bones to bear most of body weight
How do trunk muscles determine upright posture?
Attachment to vertebral column and continuous low-level contraction
Other than the vertebral column, where else do trunk muscles attach?
UL
What type of nerves travel from brain to body?
Efferents
What are afferent nerves?
Nerves that pass from the body to the brain
What does the vertebral column allow segmental nerves to do?
Leave or join the cord at specified points to supply their targets
How is the vertebral column arranged in the foetus?
Flexed in a single curvature in a ‘C’ shape
What is a primary curvature of the spine?
Anterior concavity
Where is the primary curvature of the foetal spine retained throughout life?
Thoracic, sacral and coccygeal parts
What causes remodelling of the primary concave curvature?
Limiting of head by cervical spine
At what stage does remodelling of the primary curvature of the foetal spine take place?
~3 months
What is the shape of the spine in the young adult?
4 distinct curves give a figure of ‘S’ shape w/sinusoidal profile
Why are 2 anterior and 2 posterior concavities developed in the young adult spine?
To increase resilience
What is a secondary curvature?
Posterior concavity
What causes the lumbar spine to open up at ~6 months of age?
Crawling and walking
What is a kyphosis?
Abnormally exaggerated anterior concavity of spine
What is a lordoses?
Normal posterior concavity of spine
What starts to disappear in the vertebral column in old age?
Secondary curvatures
What is the overall change in vertebral column arrangement in old age?
Move back to foetal shape with fully continuous primary curvature so that the vertebral column closes up
Why does limiting the head become more difficult in old age?
Secondary curvatures start to disappear
Where are points of weakness in the vertebral column?
C1+2
C7 + T1
L5 + S1
What determines the location of points of weakness in the vertebral column?
Where it meets the centre of gravity
What happens to the vertebrae as you move inferiorly?
They decrease in height
How many discrete vertebrae are there in the spine?
24
What are the two innominate structures formed by fused vertebrae?
Sacrum
Coccyx
How many vertebrae are fused in the sacrum and coccyx to give the total 9 fused vertebrae in the spine?
Sacrum = 5 (+/-1) Coccyx = 4 (+/-1)
What allow synovial joints between arches and adjacent vertebrae in the vertebral arch?
4 articular processes at the junction of lamina and pedicel lined by cartilage
Where are the two transverse processes of the vertebral arch found?
Laterally on each side of midline
Where is the spinous process found on the vertebral arch?
Posteriorly in midline
Where is the lamina of the vertebral arch?
B/w transverse and spin our processes
What reduces the pedicle height to form intervertebral foramen?
2 vertebral notches
What is found at the intervertebral foramina?
Dorsal root ganglia
What is the vertebral body lined with?
Hyaline cartilage
What alternates between C2 to S1?
Vertebral disks and bodies
What is usually the main weight bearer in the vertebral column?
Vertebral body
How does the size of vertebral body change as you move inferiorly?
Increases
What do the discrete vertebrae form between adjacent neural arches to prevent anterior displacement, allow movement and weight bearing?
Facet synovial joints
What reinforces weight bearing on uprighting of the vertebral column?
Ligamentum flavum
What is the intervertebral disc?
Disc of tissue forming secondary cartilaginous joints
What are the intervertebral discs responsible for?
Flexibility of vertebral column
Shock absorbers to dampen impacts to skull
What happens to the size of intervertebral discs moving superior to inferior?
Increase
What feature of the intervertebral discs accounts for secondary curvature of the spine?
Their wedge shape in lumbar and thoracic levels
Describe the wedge shape of lumbar and thoracic level intervertebral discs.
Thickest anteriorly
Thinnest posteriorly
What approximate proportion of the vertebral column is accounted for by the intervertebral discs?
25%
Why do we change in height throughout the day?
High water content of the intervertebral discs changes
Why do we decrease in height with age?
Intervertebral discs shrink
What are the two components of the intervertebral disc?
Nucleus polposus
Annulus fibrosus
What is the nucleus polposus?
Jelly-like water reservoir which has high osmotic pressure
How does the location of the nucleus polposus vary with age?
Centrally located in infant
Posteriorly located in adult
When will the nucleus polposus herniate causing a ‘slipped disc’?
Annulus fibrosis degeneration
What is the difference in effects in posterior and lateral herniation of the nucleus polposus?
Posteriorly = paralysis Laterally = treat w/rest
What is the annulus fibrosus?
Highly complex design made from a series of annular bands w/varying orientations
How do the outer bands of the annulus fibrosus compare to the inner bands?
Outer = collagenous Inner = fibro-cartilaginous
How does the strength of the annulus fibrosis compare to that of the vertebral body?
Stronger irrespective of direction of force
What leads to reactive marginal osteophytosis (bone spurs) in the spine?
Dehydration of the nucleus polposus w/age altering load stresses
What causes osteoarthritis of the facet joints in the spine?
Decreased disc space causing increased stress of joints
What happens to the intervertebral foramen in nucleus polposus degeneration?
Become congested
What happens to segmental nerves in nucleus polposus degeneration?
Become compressed
What does degenerative annular disease lead to?
Marginal osteophytosis at the endplates
What happens to the height of the disc space in degenerative annular disease!
Largely preserved
Where is degenerative annular disease usually seen?
Thoracolumbar spine >50 y.o.
What are examples of degenerative annular disease?
Spondylosis deformens
Senile ankylosis
What is the umbrella term used for both nucleus polposus degradation and degenerative annular disease?
Degenerative disc disease
Clinically, does it matter which type of of degenerative disc disease a patient is suffering from?
Nope
What are the six ligaments of the spine?
Anterior longitudinal Posterior longitudinal Ligamentum flava Supraspinous Interspinous Ligament nuchae
How is the anterior longitudinal ligament arranged?
Flat band that passes from the anterior tubercle of atlas to sacrum
Broadens as it moves inferiorly
Firmly united to periosteum of vertbral bodies
Free over intervertebral discs
What does the anterior longitudinal ligament prevent?
Anterior herniation of intervertebral disc
Is the anterior or posterior longitudinal ligament of the spine stronger?
Anterior
How is the posterior longitudinal ligament arranged?
Back of body of axis to clonal of sacrum
Continued above axis as membrana tectoria
Narrows as it moves inferiorly
Serrated edges
Broadest over IV discs which it is firmly united with
What separates the posterior longitudinal ligament and vertebral bodies?
Emerging basivertebral veins
Why is posterior IV disc herniation more likely?
Freer relationship b/w posterior longitudinal ligament and discs
Why is the ligamentum flavum yellow?
Lots of elastic fibres
What does the ligamentum flava join?
Laminae of adjacent vertebrae
How is the ligamentum flava arranged?
Attached to front of upper lamina and back of lower lamina
What stretches the ligamentum flava?
Spine flexion
What is the supraspinous ligament?
Strong bands of white fibrous tissue that join adjacent tips of spinous processes
How does the supraspinous ligament change in flexion and extension of the spine?
Lax in extension
Taut in flexion
What is the action of the supraspinous ligament in full flexion of the spine?
Effectively prevents erector spinae from extending spine
What do the supraspinous and interspinous ligaments provide?
Support of vertebral column
What is the interspinous ligament?
Relatively weak sheets of fibrous tissue that unite spinous borders along adjacent border
In which region is the interspinous ligament well developed?
Lumbar
What does the interspinous ligament fuse with?
Supraspinous ligament
What does the ligament nuchae attach to?
Occiput
Interspinous ligament
Supraspinous ligament
Spinous processes of all cervical vertebrae
What is the function of the ligament nuchae?
Maintain secondary curvature of spine
Support head
Major attachment of neck and trunk muscles
Which vertebrae are the smallest?
Cervical
What are the features of cervical vertebrae?
Form skeleton of neck
Bifid spinous process
Oval transverse foramen in transverse process
Large vertebral foramen
What is unique about C7 vertebra?
No bifid spinous process
Why might a broken neck be sub-clinical?
Large formaen of vertebrae
What are the characteristics of thoracic vertebrae?
Intermediate in size Increase in size moving inferiorly Facets on sides of body - transverse process Demifactes for articulating w/ribs Vertebral foramen is small and circular
What is the exception to T11+12?
Have costal facets for articulations w/tubercle of ribs instead of facets on transverse process
What are the characteristics of lumbar vertebrae?
Largest
No foramina on transverse process
No costal facets on side of body
Vertebral foramina are triangular and small
What does the atlas (C1) articulate with?
Skull at atlanto-occipital joint
Axis at atlanto-axial joint
Which joint is used in nodding of the head?
Atlanto-occipital
Which joint is used in shaking the head?
Atlanto-axial joint
What are the characteristics of atlas?
Lacks vertebral body Lacks spinous process Widest cervical vertebra Mobile due to no IV disc Neural arch thick to form a powerful lateral mass
What forms the Dens process?
Body of atlas fused w/that of axis
What are the characteristics of axis (C2)?
Strongest cervical vertebra
Rugged lateral mass
Large spinous process
What prevents anterior dislocation of axis?
Dens process
What is hangman’s fracture?
Fracture and dislocation of axis
What injuries is the cervical spine susceptible to?
Whiplash in RTA
Sport injuries in contact sports
What injuries is the lumbar spine susceptible to?
Herniation of L4/L5 or L5/S1 IV discs
Why does rheumatoid arthritis particularly affect the atlanto-axial joint?
Complex arrangement of synovium around transverse ligament of joint
What do side-to-side curvatures of the spine result from?
Unbalanced muscle tone of trunk on L and R sides
What is scoliosis?
Lateral deviation of the spine
