Muscles Flashcards
Histology, Injuries, Healing, and Assessment
What is the histology of muscle tissue?
It is highly specialized tissue surrounded by basement membrane or external lamina w/contractile, extensibility, elasticity and excitability properties
What are the myofilaments of skeletal muscle
The sarcomere w/thin actin portions and thick myosin portions
- the sarcomeres cause the striations in the mm
What is true of skeletal mm
It is a large, elongated, and multinucleated fibers w/a cellular unit of myofiber and a basement membrane w/collagen, laminin, fibronectin and mm-specific proteoglycan
Which mm fiber types are influenced more by agining
Type II more than type I
What is the effect of aging on mm
There is a decrease in number of mm fibers that may occur secondary to decrease in demand on the body that can be reversed (partially) by exercise
What are the effects of immobilization at the musculotendinous junction
There is an adjustment in the number and length of sarcomeres that occurs w/in 12-24 hours after immobilization
where are the effects of immobilization seen first in a mm
at the musculotendinous junction
What are the effects of immobilization at the mm belly
There is an increase in connective tissue and decrease in tissue extensibility, increase in thickness of endo- and perimysium and the contractile elements are lost before the noncontractile elements
What are some common dysfunctions of mm
- mm spasm
- mm contracture/tightness
- mm imbalances (upper cross syndrome, lower cross syndrome, layer syndrome)
What is the end feel of a mm spasm
The movement has a sudden stop often accompanied by pain
What is an early mm spasm?
It occurs early in the ROM and is associated w/inflammation, seen more in acute conditions
What is a late mm spasm
Occurs at or near the end of the ROM, caused by instability of the joint and irritability of the tissues
What is a mm spasm?
a protective response as the subconscious body tries to protect against further injury
What is spasticity
It is from an UMN lesion providing a resistance to stretch
What is a mm contracture
Adaptive shortening of the mm tendon unit and other soft tissues that cross the joint which results in significant loss of ROM, resistance to passive or active stretch of the joint
How is a mm contracture described
By the location and action of the shortened mm
- ex) hip flexion contracture means they can do flex but not extension
List the types of contractures
- myostatic
- pseudo-myostatic
- arthrogenic or periarticular contracture
- fibrotic contracture and irreversible contracture
What is a myostatic contracture?
The musculotendinous unit has shortened w/o a mm pathology w/dec # sarcomeres that can be resolved w/stretching
What is a pesudo-myostatic contracture
It is limited ROM due to mm hypertonicity associated w/UMN lesion where mm is in constant state of tension, but can be lengthened if the tone is dec
What is an arthrogenic/periarticular contracture
It is an intraarticular pathology that involves adhesions, synovial proliferations, effusion and changes in articular cartilage that restricts arthrokinematics
What is a fibrotic contracture and irreversible contracture
A fibrous change in connective tissue of mm and periarticular structure that is difficult to stretch out, and the longer it occurs, the greater the replacement is with fibrotic contracture, leading to a potential irreversible contracture
Which type of contracture can be treated w/serial casting
fibrotic contracture