Introcution To Anatomy Flashcards
Classification of joints
Joint -
The two general categories -
Joints are sites where two skeletal elements come together
General categories:
Skeletal - elements separated by a cavity eg synovial joints
No cavity - components are held together by connective tissue eg solid joints
Synovial joint -
Solid joint -
Synovial - connections between skeletal components where elements are separated by narrow articular cavity.
Solid - connections between skeletal elements. Adjacent surfaces are linked by fibrous connective tissue/by cartilage. Restricted movement.
Characteristics of a synovial joint -
Cartilage layer ( usually hyaline ) covers articulating surfaces. Therefore bony surfaces do not normally make direct contact. On radiograph, wide gap will appear between adjacent bones.
Presence of joint capsule consists of inner synovial membrane and outer fibrous membrane.
It is common, but NOT universal that articular discs, fat pads and tendons may be present.
Shapes and movements of synovial joints:
Plane (flat) -
Hinge -
Pivot -
Plane - sliding/gliding movements. Bone moves across surface of another
Hinge - allow movement around one axis that passes transversely through the joint. Permit flexion and extension.
Pivot - movement around one axis that passes longitudinally along bone shaft
Shapes and movements of synovial joints:
Bicondylar -
Condylar -
Saddle -
Ball and socket -
Bicondylar - movement is one axis with limited rotation and 2nd axis formed by two convex condyles eg knee joint
Condylar - (ellipsiod) movement around two axis that are right angles to each other. Eg wrist joint
Saddle joint - movement around two axes that are at right angles to each other, articular surfaces saddle shaped. Eg thumb joint
Ball and socket - movement around multiple axis eg hip
Solid joint:
Fibrous joints include:
Sutures -
Gomphases -
Syndesmoses -
Sutures - only in skull where adjacent bones are linked by thin layer of connective tissue. Sutures ligament
Gomphases - only between teeth and adjacent bone. Horst collagen tissue fibres run between root of tooth and bony socket.
Syndesmoses - (most common) two adjacent bones linked by a ligament. Eg radius and ulna.
Solid joint;
Cartilaginous joints include:
Synchondroses -
Symphases -
Synchondroses - two ossification centres in a developing bone retina separated by a layer of cartilage. Joints allow bone growth and eventually will become completely ossified ( hardens )
Symphases - two separate bones are interconnected by cartilage. Most of these are in midline. Include pubic symphasis and intervertebral discs.
Types of movement at a joint
Physiological -
Accessory -
Physiological - voluntary sweeping movement of one body segment. Often change of angle between two bones eg flexion,extension,abduction,abduction
Accessory - involuntary small gliding adjustments between joint surfaces to facilitate smooth and full movement. Eg spin,roll,glide,slide
Factors limiting movement:
Tension in ligaments
Tension in antagonist muscle
Approximation of soft tissue or bony parts
Closed pack positions - joint surfaces approach full congruence (best fit). Joint said to be in ‘close pack’. Joint structures tensioned.
Muscle intro:
The three types -
Three types of fibres -
Cardiac smooth and skeletal (skeletal is 1/3 of body weight)
Slow oxidative - type I
Fast oxidative - type IIa
Fast glycolytic - type IIb
Functions of skeletal muscles:
Produce movement and locomotion
Stabilise joints and limit movement
Produce body heat
Maintain posture
Store carbs - glycogen
Protect and support viscera
Give body contour
Muscle roles
Agonist/prime mover -
Antagonist -
Agonist - responsible for movement
Antagonist - movement opposing that of agonist
Muscle roles
Fixator -
Synergist -
Fixator - steadies the base. Stabilises proximal attachment of the agonist
Synergist - improves quality and control by preventing unwanted movement in the adjacent joints.
Muscle work
Isometric contraction -
Isotonic contraction and the two types -
Isometric - increase in tension, no length change. Therefore no movement produced
Isotonic - increase in tension which changes muscle length so movement is produced
Concentric - muscle shortens
Eccentric - muscle lengthens
What does muscle insufficiency relate to?
Types:
Active insufficiency -
Passive insufficiency -
Only relates to muscles that pass over more than one joint eg hamstring
Active - muscle, passes over two joints can not actively shorten sufficiently enough to produce full range of movement at both joints (agonist)
Passive - muscle, passes over two joints can’t be passively lengthened enough to allow full range of movement at both joints (antagonist)
