MSK- PART A Flashcards
Skeletal system definition?
all of the bones and cartilage of the body that collectively provide the supporting framework for the muscles and organs
what does the musculoskeletal system consist of?
- bones of the skeleton
- joints
- skeletal (voluntary) muscles that move the body
Articulating surface?
The part of the bone that enters into the formation of a joint
Articulation?
joint between two or more bones
Bony sinus?
A hollow cavity within a bone
border?
ridge of bone seperating 2 surfaces
condyle?
smooth rounded projection of bone that forms part of a joint
facet?
small, generally flat, articulating surface
fissure or cleft?
narrow slit
foramen?
hole in a structure
fossa?
hollow or depression
meatus?
tube shaped cavity within a bone
septum?
partition separating 2 cavitites
How many bones are a baby born with? how many bones does an adult have?
babies: 300
adult: 206
Functions of bones? (6)
- framework of body
- attachment to muscles and tendons
- movement
- protecting the organs
- haemopoiesis (production of blood cells in red bone marrow)
- mineral storage
what is the function of calcium phosphate?
the mineral reservoir within bone is essential for maintenance of blood calcium levels, which must be tightly controlled
5 types of bones?
- long
- short
- irregular
- flat
- sesamoid
long bones?
- shaft and 2 extremities
- longer than wide
examples: femur, tibia, fibula
Short, irregular, flat and sesamoid bones characteristics?
- no shafts or extremities
- diverse in shape and size
short bone example?
carpals (wrist)
example of irregular bone?
vertebrae and some skull bones
example of flat bones? (3)
- sternum
- ribs
- most skull bones
example of sesamoid bone?
- patella (knee cap)
Feet account for what fraction of the human’s body? how many bones are in the feet?
- 1/4 of all bones in body
- 52 bones
what are bone markings?
- rough surfaces, raised protuberances and ridges that give attachment to muscle tendons and ligaments
- bone tissue is continually being remodelled and replaced when damaged
bones of the skeleton are divided into what 2 groups?
- axial skeleton
2. appendicular skeleton
Axial skeleton consists of? (4)
- skull
- vertebral column
- ribs
- sternum
central body core of the body
appendicular skeleton consists of?
- shoulder girdle with upper limbs
- pelvic girdle with lower lims
what is a joint?
site at which any 2 or more bones articulate or come together
2 functions of joints?
- allow flexibility and movement
- allow attachment between bones
what are Fibrous joints?
- movement?
- linked with tough, fibrous material
- often permits no movement
example of fibrous joints?
joints between the skull bones, sutures, are completely immovable
what are Cartilaginous joints formed by? are the moveable?
- a pad of fibrocartilage, a tough material that acts as a shock absorber
- may be immovable, as in the cartilaginous epiphyseal plates
or - limited degree of movement, as between the vertebrae, which are separated by the intervertebral discs
What are Synovial joints? Do they allow movement?
- presence of a space or capsule between the articulating bones
- capsule is lubricated with a small amount of fluid
- permit a range of movement
what are Articular or hyaline cartilage? what do they provide? function?
- parts of the bones which are in contact are always covered with hyaline cartilage
- provides a smooth articular surface, reduces friction
- strong enough to absorb compression forces and bear the weight of the body
What is Capsule or capsular ligament? function?
- joint is surrounded and enclosed by a sleeve of fibrous tissue which holds the bones together
- loose to allow freedom of movement but strong enough to protect it from injury
what is Synovial membrane? function?
- epithelial layer lines the capsule and covers all non-weight-bearing surfaces inside the joint
- secretes synovial fluid
what is Synovial fluid?
thick sticky fluid, of egg-white consistency, which fills the synovial cavity
synovial fluid function? (5)
- nourishes the structures within the joint cavity
- contains phagocytes, which remove microbes and cellular debris
- acts as a lubricant
- maintains joint stability
- prevents the ends of the bones from being separated, as does a little water between two glass surfaces.
what is a bursa? function?
- Little sacs of synovial fluid orbursaeare present in some joints, e.g. the knee
- act as cushions to prevent friction between a bone and a ligament or tendon, or skin where a bone in a joint is near the surface
what is synovial bursa? how much fluid does it generally contain?
- normally potential spaces that are collapsed and not often visualized
- generally contain up to 4mm of fluid - more if inflamed or infected
what is circumduction?
movement of a limb or digit so that it describes the shape of a cone
types of synovial joints are classified according to?
- range of movement possible or shape of the articulating parts of the bones involved
what are ball and socket joints? what movement do they allow for? examples?
- head of one bone is ball-shaped and articulates with a cup-shaped socket of another
- joint allows for a wide range of movement, including flexion, extension, adduction, abduction, rotation and circumduction
Examples : shoulder and hip.
What is a hinge joint? movement? examples?
- articulating ends of the bones form an arrangement like a hinge on a door
- movement restricted to flexion and extension
Examples: elbow ,knee, ankle and the joints between the phalanges of the fingers and toes (interphalangeal joints).
Gliding joints? movement? examples?
- articular surfaces are flat or very slightly curved and glide over one another
- amount of movement possible is very restricted; this group of joints is the least movable of all the synovial joints
Examples : the joints between the carpal bones in the wrist, the tarsal bones in the foot, and between the processes of the spinal vertebrae (note that the joints between the vertebral bodies are the cartilaginous discs)
what are pivot joints? movement? examples?
- allow a bone or a limb to rotate
- One bone fits into a hoop-shaped ligament that holds it close to another bone and allows it to rotate in the ring thus formed
- example: the head rotates on the pivot joint formed by the dens of the axis held within the ring formed by the transverse ligament and the odontoid process of the atlas
condyloid joints? movement? example?
- sits within a cup-shaped depression on the other bone
- permit flecion, extension, abduction, adduction, circumduction
example: the joint between the condylar process of the mandible and the temporal bone, and the joints between the metacarpal and phalangeal bones of the hand, and between the metatarsal and phalangeal bones of the foot
What is the saddle joint? movement? example?
- articulating bones fit together like a man sitting on a saddle
- movement simular to condylid joint but with additional flexability
example: base of thumb, between trapezium of the wrist and 1st metacarpal bone
3 types of muscle?
- skeletal
- cardiac
- smooth
what is skeletal muscle? how are they attached? characteristics?
- voluntary muscle
- attached to the bone via tendons
- used to move the skeleton
- striped or striated
what is the action of skeletal muscles?
- move a body part, the muscle or its tendon must stretch across at least one joint
- when it contracts, the muscle then pulls one bone toward another
when the elbow is bent during flexion of the forearm what is the main mover?
- biceps brachii
- when it contracts its shortening pulls on the radius, moving the forearm up toward the upper arm and bending the elbow
skeletal muscle cell contracts in response to?
stimulation from a nerve fibre
when individual muscle cells in a muscle shorten what occurs?
they pull on the connective tissue framework running through the whole muscle, and the muscle develops a degree of tension (tone)
what is isotonic contraction?
(iso = same; tonic = tension):
- power generated by the muscle is used to lift the manageable weight, and tension in the muscle remains constant
- muscle shortening
what is isometric contraction?
(iso = same; metric = length):
- muscles would be unable to shorten, and the power generated increases the muscle tension instead
Antagonistic pairs? example?
- many muscles/muscle groups of the body are arranged so that their actions oppose one another
Example: bending the elbow, when the main flexors on the front of the upper arm contract, the muscles at the back of the upper arm must simultaneously relax to prevent injury
originof a muscle?
proximal attachment; this is generally the bone that remains still when the muscle contracts, giving it an anchor to pull against
insertion of muscle?
distal attachment site, generally on the bone that is moved when the muscle contracts
what is anisotropy?
- common artifact seen in musculoskeletal ultrasound
- occurs when the ultrasound beam encounters a structure at a non-perpendicular angle
- artifact results with a loss of echogenicity in structure
- manipulate the heel-toe and fore-aft angulation of the probe to avoid this artifact
- see anisotropy more commonly in tendons and ligaments, but it also occurs in muscle and nerves to a lesser extent
Tendons sono?
fibrillar pattern of parallel hyperechoic lines in the longitudinal plane
and a hyperechoic round-to-ovoid shape in the transverse plane
Bursae on U/S?
- in a normal joint, the bursa is a thin, black/anechoic line which is less than 2mm thick
- bursa fills with fluid when irritated or infected, will distend and enlarge, with inflammatory debris expressed as internal brightness echoes
Normal peripheral nerves on U/S?
- Normal peripheral nerves typically appear as echogenic fascicular structures
and tend to be slightly less echogenic than tendons or ligaments
where are nerves located?
are visible running along fascial planes, paired with blood vessels, and sometimes within muscles
nerver SAG vs. TRV?
- Longitudinally, appear as hyperechoic fibrillar cords
- viewed in transverse orientation, the nerve fascicles give a “honeycomb” appearance and are less densely fibrillar than tendons
ligaments on U/S?
- have an appearance similar to tendons
- are static stabilizers connecting bone to bone
- can be differentiated from tendons by noting their more compact fibrillar, hyperechoic pattern
Fibrocartilage and Articular Cartilage on U/S?
thin hypoechoic rim paralleling the echogenic articular cortical surface
represents hyaline cartilage
