Musculoskeletal System Flashcards
what is a joint?
place where 2 or more bones make contact (articulation)
explain the 3 types of joints and the classifications of each
fibrous - bones joint by dense fibrous connective tissue (e.g sutures)
cartilaginous - bones joint by cartilage (IVDs)
synovial - bones not directly joined, allows movement - limited by shape of synovial joint (e.g shoulder joint)
what 3 categories can joints be classified into based on their function?
synathrosis - no movement (sutures)
amphiarthrosis - little movement (distal tibiofibular, pubic symphysis)
diarthrosis - free movement (synovial joints)
explain the structure of synovial joints
articular surfaces are lined by articular cartilage, providing protection to joint surface
joint capsule around joint lined by synovial membrane, excreting synovial fluid providing lubricant and friction protection
ligaments outside joint with collagen connecting bone to bone
what are the 3 shapes of synovial joints
uniaxial - one way movement (pivot, hinge, plane) e.g elbow
biaxial - 2 way movement (condyloid, saddle) e.g carpometacarpal
muntiaxial - multi-direction movement (ball & socket) e.g hip
explain how osteoarthritis can occur through joint abnormalities
overusage of joints
damage in articular cartilage at each end of bone surfaces cause wearing down meaning osteophytes can form from bone overgrowths
weight distribution changes
trauma/injury
what are the 3 types of muscle and where are they found?
skeletal (voluntary) - MSK
cardiac (involuntary) - heart
smooth (involuntary) - blood vessels, viscera
what are the functions of the muscular system?
locomotion, stability, posture, protection, respiration (skeletal)
circulation, digestion, urination, vision (smooth/skeletal)
describe skeletal muscle structure
consist of muscle fibres bundles (muscle cells)
muscle fibres grouped into muscle fascicles (grouped, forming one or more heads/bellies)
connected to bone or other structures (using tendons or aponeurosis)
relate muscle function to its structure
movement range depends on fibre length (muscles contract 30% of their length)
muscle strength depends on fibre numbers
describe the 6 classifications of skeletal muscle
flat - parallel fibres with an aponeurosis
pennate - feather-like
fusiform - spindle shaped with round, thick belly and tapered ends
convergent - arise from broad area and converge to form a single tendon
quadrate - four equal sides
circular - surround body opening or orifice
what are the functions of the vertebral column?
support, movement, protection
what features do a typical vertebra have and what is their function?
vertebral body - for weight transfer, IVDs between
vertebral arch - forms vertebral foramen, surrounds and protects spinal cord
what is the pedicle of the vertebra?
the foot of the arch
what is the transverse process in the vertebra?
a muscle/ligament attachment (ribs in thorax)
what is the lamina of the vertebra?
the lateral and posterior part of the arch
what is the spinous process of the vertebra?
a posterior muscle or ligament attachment
what do the superior/inferior articular processes form in the vertebrae?
joint formations
what do the superior/inferior vertebral notches form in the vertebrae?
forms intervertebral foramen (for spinal nerves)
compare the movement levels of each segment in the vertebral column
cervical - most mobile
thoracic - least mobile for extention/flexion/lateral bending
lumbar - least rotation
what are the 2 types of vertebral joints, and what kind of joint are they?
zygapophyseal (facet) joints - synovial/plane joints
symphysis (IVD) joints - secondary cartilaginous joints
what 6 joints does a typical vertebra form?
4 zygapophyseal
2 IVD
what do the IVDs form in the vertebral column?
forms the fibrocartilagenous joints of the vertebral bodies
what are the functions of IVDs?
stability/flexibility
pressure regulation
water-cushion function (shock absorption)
what are the 2 components of IVDs?
annulus fibrosus and nucleus pulposus
describe the structure of the annulus fibrosus
high tensile strength
fibrous sheath on outer surface (with collagen rings)
fibrocartilage inner zone
describe the structure of the nucleus pulposus
gelatinous structure
80-85% water
what can occur in a slipped disc?
prolapse of IVD (hernia)
a tear in the annulus fibrosus can cause the nucleus pulposus to protrude
this can impinge on spinal cord/nerves
where does the atlas articulate?
and what is unusual about the atlas vertebra?
holds weight of skull
it has no body
what is unusual about the axis vertebra?
contains odontoid process (dens) to connect with C1 vertebra
what joints allow us to nod our head ‘yes’ and shake our head ‘no’?
atlanto-occipital - synovial joint from C1 to base of skull (yes)
atlanto-axial - synovial pivot joint from C1-C2 (no)
what is the functions of the ligaments in the MSK?
connects bone to bone
provides joint support
restricts joint movement
where does the anterior longitudinal ligament extend from and attach to?
extends from skull base
attached to anterior surface of sacral vertebral bodies and IVDs
what does the anterior longitudinal ligament do?
prevents hyperextention
where does the posterior longitudinal ligament attach to and line?
attached from C2
attaches to posterior surface sacral vertebral bodies and IVDs
lines posterior surface of vertebral canal
what does the posterior longitudinal ligament do?
weakly resists hyperflexion
where does the supraspinous ligament extend to and connect?
cord like ligament from C7 to sacrum
connects tips of spinous processes
where does the nuchal ligament extend to, attach to and connect to?
strong fibroelastic tissue from skull base to C7
supports head on neck and provides muscle (trapezius) attachment
what ligaments are found inbetween spinous and transverse processes?
interspinous - between spinous
intertransverse - between transverse
where do the ligamenta flava pass through and form?
pass between laminae and form part of vertebral canal
what do the ligamenta flava do?
resist separation of vertebrae during flexion
what are the 4 major curvatures of the spine?
secondary cervical
primary thoracic
secondary lumbar
primary sacral/coccygeal
what are the function of spine curvatures?
accomodate upright posture by aligning the spine with the limbs
what are outward and inward curvatures referred as?
outward - kyphosis
inward - lordosis
Describe tendon structure
Dense, regularly arranged tissue that attaches muscle to bone
High collagen proportion (closely packed)
What are the 3 tendon components?
Tendon, bone insertion and muscle-tendon junction
describe the micro-composition of tendons
cellular (fibroblasts/tenocytes) - 20%
ECM (water, collagen I, elastin) - 80%
name the 3 phases of tendon healing
inflammation
repair
remodelling
describe the inflammation process of tendon healing
inflammatory cells migrate from epitendinous tissues
epitendon defect is filled with granulation tissue, haematoma and tissue debris
matrix proteins laid down for collagen synthesis
describe the repair stage in tendon healing
fibroblast/tenocytes migrate to injury zone and synthesise collagen III, which is laid down in a random orientation
collagen III -> collagen I after ~4 weeks
what is a muscle fascicle?
bundles of muscle cells surrounded by connective tissue
what is a motor unit?
a single motor neurone and all the muscle fibres it innervates
what are the 3 types of motor units?
slow (type 1)
fast fatigue resistant (type 2a)
fast fatiguing (type 2b)
name the 3 differences when moving from motor unit type 1 -> 2a > 2b
larger twitch
faster fatigue
faster rise
what can fatigue mean in muscles?
reduction of force and power, shortened velocity, relaxation rate reduced
describe the possible reasons for peripheral fatigue (within muscle fibres)
failure in excitation-contraction coupling (T-tubule action, Ca release)
failure in force generation at cross-bridges
failure of ATP production by depletion on energy sources
describe the possible reasons for central fatigue in muscles (within nervous system)
loss of excitability in motor complex
failure of nerve transmission into neuromuscular junctions
what is compartment syndrome?
an increase in pressure in a muscle restricting blood flow (iscaemia) and causing pain
what additional components can synovial joints have?
bursae - pockets
labrum - extentions
menisci - cartilage pads
