Lecture 2: Joints and Muscles Flashcards
What are the 3 factors that affect stability and mobility?
- Shape of the articular surfaces (ex. hip is completely enclosed in hip socket so it is more stable than the shoulder)
- Ligaments (knee is stable bc of multiple ligaments)
- Muscles (involvement in stabilizing joint)
T/F: As stability of a joint increases, mobility also increases
Fale: as stability increases, mobility decreases and vice versa
Joint in which there is not a separation between the bones. Bones are united by dense fibrous tissue or cartilage
- Synarthrodial joints
- Diarthrodial Joints
- Synarthrodial joints
Ex. Suture joints of the skull: no separation b/w bones (dense fibrous tissue)
Ex. Pubic symphysis; unites two bony segments (cartilage)
Joints in which the ends of the bony components are free to move in relation to one another; also known as synovial joint
- Synarthrodial
- Diarthrodial
- Diarthrodial
All diarthrodial joints have 3 features
- a ligamentous capsule that encloses the joint
- the joint capsule forms a joint cavity
- synovial fluid fills the joint cavity
Diarthrodial joints are classified according to __________?
degrees of movement (how many planes of motion there are)
Name the type of joint:
The joint surfaces are irregularly shaped, usually flat or slightly curved; only movement permitted is of gliding nature
Irregular, Gliding, Plane, or Non-axial
ex. carpal bones of hand, tarsal bones of feet
Name the type of joint:
motion of the bony components is allowed in only one of the planes of the body around a single axis
Uniaxial joint
How many degrees of freedom does a uniaxial joint have?
One degree of freedom
A hinge joint and a pivot screw are what type of joints? How many degrees of freedom do they have?
Uniaxial joints with 1 degree of freedom
Hinge joint = humeroulnar joint
Pivot screw = atlantoaxial joint
Name the type of joint:
allows movement in two planes
biaxial joint
How many degrees of freedom does a biaxial joint have?
2 degrees of freedom
Condyloid joints and saddle joints are what type of joints? How many degrees of freedom do they have?
Biaxial with two degrees of freedom
condyloid = wrist joint (radial and ulnar deviation) saddle = carpal metacarpal joint of the thumb
Name the type of joint:
Spherical head of bone fits into cup or saucer-like cavity of the other bone
Triaxial joints
How many degrees of freedom do triaxial joints have?
3 degrees of freedom
T/F: Muscles contribute to stability and mobility
true
Muscles ability to develop tension. Can shorter beyond resting length by pulling from both ends toward center
contractility
ability to muscle respond to stimuli (chemical, electrical, or mechanical)
irritability
ability of muscle to be stretch and recoil or return to normal resting length
elasticity and extensibility
functional unit of the muscle
motor unit
The structure of the motor unit consists of the nerve called ______________, its axon, and all of the muscle fibers it innervates
alpha motor neuron
T/F: structural variations (muscle fiber length, fiber arrangement, and number of muscle fibers) affect not only the overall shape and size of the muscle but also the function of the various muscles
true
T/F: Parallel muscle fiber arrangement provides a large ROM
true
T/F: Penniform (oblique to muscles long axis) muscle fiber arrangement provides great strength and ROM
Fale - it provides great strength but a decreased ROM
Basic structural component of the musculoskeletal system, connects it all together: tendons, ligaments, joint capsules, discs, menisci, muscle sheaths, etc.
Connective Tissue
