Joints (Articulations)Definition: Site at which two or more bones come together

Some joints have no movement

some only slight movement

some are freely moveable

Fibrous (Fixed) Joints

In these joints, the bones

are in very close contact

and are separated only

by a thin layer of fibrous

connective tissue

• An example of this type of joint is the sutures in the skull between skull bones

Cartilaginous (slightly moveable) joints

These joints are

characterized by

bones that are

connected by

hyaline cartilage

(fibro cartilage)

Example: The joints between the vertebral bodies

Synovial (freely moveable) joints

(Diarthrosis joint)

Most joints are freely

movable

Considerable

movement

is permitted at all

synovial joints

Types of movement

Movements which can occur are:

Flexion - Extension

Abduction - Adduction

Rotation - Circumduction

Pronation - Supination

Inversion - Eversion

Flexion and Extension

Flexion at the elbow joint

Extension at the elbow joint

Abduction and Adduction

Abduction at the hip joint Adduction at

the hip joint

Rotation and Cicumduction

Rotation at the atlas – axis joint

Circumduction at the shoulder joint

Types of Synovial joint

Synovial joints are subdivided according to the movements possible

They are subdivided into:

Ball and Socket

Condyloid

Saddle

Pivot

Hinge

Gliding

Ball and Socket joints

The ball-shaped end of one bone fits into a cup-shaped socket on the other bone allowing the widest range of motion including rotation.

Examples include the shoulder and hip

Condyloid joints

Oval shaped condyle fits into elliptical cavity of another allowing angular motion but not rotation.

This occurs between the metacarpals (bones in the palm of the hand) and phalanges (fingers) and between the metatarsals (foot bones excluding heel) and phalanges (toes).

Saddle joints

This type of joint occurs when the touching surfaces of two bones have both concave and convex regions, the shapes of the two bones complement one another and allow a wide range of movementThe only saddle joint in the body is in the thumb

Pivot joints

Rounded or conical

surfaces of bone fit

into a ring of bone or

tendon allowing

rotation

An example is the

joint between the

axis and atlas in the neck

Hinge jointsA convex projection A convex projection on one bone fits into on one bone fits into a concave depression a concave depression in another permitting in another permitting only only flexion and flexion and extensionextension

Examples of hinge joints Examples of hinge joints = = elbow and knee jointselbow and knee joints

Gliding joints

Flat or slightly flat

surfaces move against

each other allowing

sliding or twisting

without any circular

movement

This happens in the carpals in the wrist and the tarsals in the ankle.

Characteristics of a synovial joint

Articular or Hyaline CartilageStrong enough to support the weight of the body

Provides smooth surface for articulation

Capsular LigamentSleeve of fibrous tissue which joins the bones together,

therefore provides joint stability

Sufficiently loose to allow movement

Synovial membrane

This is composed of secretory epithelial cells that secrete a thick, sticky fluid which:

a) acts as a lubricant

b) provides nutrients

c) helps maintain joint stability

(prevents the ends of bone separating)

(Little sacs of synovial fluid – bursae -

are found in some joints, act as cushions)

Extra capsular structures

Ligaments

help stabilise the joint

Muscles

enable movement

Nerves

enable movement

Case Study 1• Callum is four years old. He has just fallen from

the slide in the park and has banged his head. He is developing a bit of a lump on his forehead (there is no skin injury) and he has started crying. His mother is also really upset and wants to take him to A & E.

• What advice would you give his mother?

• What sort of bone is the skull?

• What is the function of the skull bone?

Case Study 2• Stephen is 21 years old and has been trying to

get fit and improve his health. He has started playing rugby and has injured his ankle in a match. He finished the game but now is limping and his ankle is looking very bruised and swollen.

• What advice would you give Stephen?

• What is the collective name for the bones in the ankle?

• What sort of bones are these?

• What injuries are common in the ankle?

Case Study 3Melanie has been diagnosed with schizophrenia

and has been taking antipsychotic medication for a few years. Unfortunately, she has put on five stone in weight during this time. The CPN calculates her BMI as 31.6 (5ft 6ins and 14stone).

How might this excess weight affect Melanie’s joints?

Which joints are more likely to be affected?What advice would you give her?

Case Study 5Mrs Evans (who is 65 years of age) has Non

Insulin Dependent Diabetes Mellitus (NIDDM). She is quite concerned about her risk of osteoporosis (her mother had the condition and fractured her hip, twice).

Is she at risk?

What nutrients and hormones are required for bone health?

What advice would you give to Mrs Evans?