Joints

JOINT- A place where two or more bones meet.

1. Fixed or Immoveable JointsThe bones at an immoveable joint cannot move - they overlap or interlock, and are held together by a tough fibre, e.g. the skull.

2. Slightly Moveable JointsThe bones at a slightly moveable joint can only

move a little - they are held together by strong straps called ligaments and are joined by protective

pads known as cartilage, e.g. the ribs.3. Freely Moveable JointsAt a freely moveable joint the bones move

freely.They are also known as synovial joints, andare the largest group of joints found in the

body, e.g. the hips, shoulders and knees.

Types of Joints

There are 3 main types of joint found in the body.

CLASSIFICATION OF JOINT BY STRUCTURE

Fibrous: Have no cavity and are held together by fibrous connective tissue – e.g. the sutures of the skull bones

Cartilaginous: Also have no cavity. There is cartilage between the bones of the joint. May be found between the vertebrae of the spine

Synovial: Has a fluid filled cavity surrounded by an articular capsule. The articulating surfaces are covered in hyaline cartilage – e.g. the hinge joint of the knee

CLASSIFICATION OF JOINT BY MOVEMENT

Fibrous or synarthrosis: Does not allow any movement, which makes more sense when you know where in the body they occur, as they supply protection – e.g. for the brain

Cartilaginous or amphiarthrosis: Allows only limited movement

Synovial or diarthrosis: Is freely moving, as much as the shape of the articulating surface will allow.

JOINT / MOVEMENT TYPES

Joint type Shape of joint Movement range Body place : articulating bones

Ball + socket ball shaped bone fits 3 axes F/E AB/AD R C hip : femur, acetabulum of pelvis into cup shaped socket shoulder : scapula, humerus

Hinge convex and concave 1 axis F/E knee : femur, patella, tibia surfaces fitting together elbow : humerus, radius, ulna

Pivot ring shaped surrounding 1 axis R spine / atlas : odontoid process of axis a cone (turns head from side to side) elbow : proximal ends of radius and ulna

Condyloid modified ball and socket 2 axes F/E AB/AD C knuckle joints of fingers : metacarpals, giving circumduction phalanges

wrist : radius, carpals

Saddle shaped like a saddle 2 axes F/E AB/AD C joint at base of thumb : carpal, giving circumduction metacarpal

Gliding two flat gliding surfaces a little in all directions centre of chest : clavicle, sternum wrist : carpals

ankle : tarsals spine : articulating surfaces of vertebrae

In the picture below the ball and socket joint at the hip allows the player to get height and then the ball and socket joint at the shoulder allows him to SLAM DUNK!!

Hinge joint (the elbow) in use taking a set shot

The knee (HINGE JOINT) is used when flexing (bending) and extending (straightening) the

leg to kick a football

Spin bowling requires a complex movement of the wrist joint – what type of joint?

Bowling underarm involves extension and flexion of the shoulder – what type of joint?

RELATIONSHIP of MUSCULAR SYSTEM to SKELETAL SYSTEM

NAMES OF MAJOR MUSCLE GROUPS

Example : biceps

ORIGIN (static end) : coracoid process / glenoid fossa tubercle of humerus

INSERTION (moving end) : tuberosity of radius

FASCI Aconnective tissue

exam ple : epim ysium

LI GAMEN TSattach bone to boneexam ple : knee jo int

cruciate ligam ents

TEN DON Sattach m uscle to bone

via PER I O ST EUMexam ple : ach illes tendon

PER I OSTEALLAYER S

attach tendons to bone

M USCULARATTACHM ENTS

APON EUR OSI Sa flattened ribbon

shaped tendon

Cartilage, Tendons, Ligaments: What’s the difference?

Cartilage Tendons Ligaments

ToughAttaches bone to muscle

Attaches bone to bone

Flexible Sturdy Elastic

At end of bone Non elastic Stabilise

CushionsSize changes depending on muscle

Made of many fibres

Anchor Strong

Types of Synovial Joints

KEY

Ball & Socket JointHinge Joint

Pivot Joint

Gliding Joint

Saddle Joint

Condyloid Joint

Freely moveable (synovial) joints can be divided into six groups depending upon how they move.

Joints

Synovial Joints

• The articular capsule is a fibrous tissue encasing the joint, forming a capsule

• The synovial membrane acts as a lining to the joint capsule and secretes synovial fluid

• The articular/hyaline cartilage covers the ends of the articulating bones

• Synovial fluid fills the joint capsule nourishes and lubricates the articular cartilage

Joints

Synovial Joints• Ligaments are white fibrous connective

tissues joining bone to bone, making the joint more stable

• Bursa is found where tendons are in contact with bone. It forms a fluid filed sac between the tendon and bone and helps reduce friction

• Articular discs of cartilage act as shock absorbers

• Pads of fat act as buffers to protect the bones form wear and tear

Synovial Joints

Ligament

Cartilage

Ligament

SynovialFluid

Pelvis

SynovialMembrane

Capsule

Femur

Hip Joint

Ball-and-Socket Joint• hip• shoulder

Condyloid Joint• between

metacarpals and phalanges

8-9

Gliding Joint• between carpals• between tarsals

Hinge Joint• elbow• between phalanges

8-10

Pivot Joint• between

proximal ends of radius and ulna

Saddle Joint• between carpal

and metacarpal of thumb

8-11

• ball-and-socket• head of humerus• glenoid cavity of scapula• loose joint capsule• bursae• ligaments prevent displacement• very wide range of movement

8-15

Shoulder Joint

• hinge joint• trochlea of humerus• trochlear notch of ulna• gliding joint

• capitulum of humerus

• head of radius• flexion and extension• many reinforcing ligaments• stable joint

8-17

Elbow Joint

• ball-and-socket joint• head of femur• acetabulum• heavy joint capsule• many reinforcing ligaments• less freedom of movement than shoulder joint

8-19

Hip Joint

• largest joint• most complex• medial and lateral condyles of distal end of femur

• medial and lateral condyles of proximal end of tibia

• femur articulates anteriorly with patella

• modified hinge joint• flexion/extension/little rotation 8-21

Knee Joint

• strengthened by many ligaments and tendons

• menisci separate femur and tibia

• bursae