Musculoskeletal Development Flashcards
Does the number of axons innervating a muscle fiber increase or decrease?
- skeletal muscle fiber innervated by many axons but the number decreases to 1 axon
1st year of life, why do the the amount of muscle fibers continue to increase ?
due to division of existing fibers or development of new fibers
What happens to muscle fibers during the years of growth? Why?
yrs of growth, muscle fibers increase in length and cross sectional area by the addition of sarcomeres
muscle fibers increase in size as
a result of blood supply, innervation, nutrition, genetics and exercise (exposure)
Which factors impact fiber types?
Fiber types are dependent upon neuronal input,
genetics, exposure and disease processes
Ossification of the diaphyses of the bone
(body of bone) commences by the end
of the _____ week of gestation and is near complete by birth
8th week of gestation
By _______, the diaphysis (body of the bone) are almost ossified
Birth
The thickness of the diaphysis continues
to grow slowly by adding new bone to the A)________, with spurts of growth @ B)__-__ and C)_______
A) outside surface
B) 4-6 years old
C) puberty
Ossification of the epiphyses of the bone
varies with each bone, but most are ossified by ______.
20 years
The basic structures that will form joints are present by ___-___ weeks of gestation and continues to develop over a long period of time
6-8 weeks
By _______ of gestation acetabulum is deep and
femoral head is well covered
12 weeks
What are some factors that deepen the acetabulum?
Postnatal growth, compression, movement and exposure all increase the depth of the acetabulum
What is a positive adaptation of muscle fibers?
- Our muscles respond to the challenges placed on them
* Increasing environmental exposure, specifically early in development, will influence muscle development
What is negative adaptation of muscle fibers?
Selective atrophy
When might one see selective atrophy of type II muscle fibers?
- children with muscular diseases
- adults with steroid induced atrophy
- spastic muscles of children with CP
- muscles that have been denervated (both atrophy, but more type II)
- malnourished children
When might one see selective atrophy of type I muscle fibers?
- children with hypotonia
* children with congenital myotonic dystrophy
Which is more common, selective atrophy of type I or type II muscle fibers?
Type II
What force length adaptations will occur in muscle secondary to immobilization?
Leads to a shorter muscle, which changes the length
tension curve. The child may now be physiologically strongest in a place in ROM that is inappropriate, or simply not effective
What force length adaptations will occur in muscle secondary to disuse atrophy?
Decreased strength will obviously impact on abilities
Longer tendon & shorter muscle belly
What force length adaptations will occur in muscle secondary to Decreased muscle length?
Arguments for decreased muscle length and increased tendon length in spastic muscles with increased tone
Muscular length changes will have profound
effects on function including:
- posture in sitting, standing
- available ROM and subsequent functional abilities
- gait
- cardiopulmonary
Skeletal adaptations are dependent upon…
Dependent upon genetics, nutrition and mechanical
forces (exposure)
Normal intermittent forces __________ bone growth.
Excessive forces will actually _______ this growth.
Stimulate
Diminish
What do the knees of an infant look like in the frontal plane?
Genu varum
What do the knees of a 20 month old look like in the frontal plane?
Straight
What do the knees of a 2.5 yo look like in the frontal plane?
Genu valgum
What do the knees of a 4-6 year old look like in the frontal plane?
Normal valgum/ straight
The abnormal stresses of spasticity may lead to _______
Degenerative joint disease
Define Dysplasia.
Abnormal development or
growth of tissues, organs, or cells
When would you expect to see hip dysplasia?
CP, MD, downs syndrome or other processes which alter the muscle forces around the hip will predispose a
child to hip dysplasia
According to Buckley et al, which pathologic pediatric population had the most shallow acetabulum?
CP
Femoral anteversion results in a toe___ gait
Toe in
Spasticity will impact
A) antagonist
B) agonist
C) synergist strength
Antagonist
