Musculoskeletal system Flashcards
Label the image with joint names
Describe a fibrous joint?
- No joint cavity
- Held together by fibrous tissue
- Have little or no movement
Describe suture joints?
Fibrous joint composed of a thin layer of dense fibrous connective tissue that unites bones of the skull.
Irregular interlocking edges of sutures give them added strength and decrease their chance of fractures.
Some are present during childhood and are replaced by bone in the adult. (synostosis) – a joint in which there is complete fusion of bone across the suture line.
Describe gomphoses joints?
Type of fibrous joint in which a cone shaped peg fits into a socket.
The substance between the two is the periodontal ligament.
Describe syndesmoses joints?
•There is considerably more fibrous connective tissue than there is in a suture.
As a result the fit between the bones is not quite as tight.
The fibrous connective tissue forms an interosseous membrane or ligament that permits some degree of flexibility and movement.
E.g distal articulation between the tibia and fibula.
Describe a cartilaginous joint?
- No joint cavity
- Held together within cartilage
Describe a cartilaginous symphyses joint?
•e.g. pubic symphysis (holding the pubic bones together)
Connecting material is a broad, flat disc of fibrocartilage.
Also found in intervertebral discs between bodies of the vertebrae, (the outer portion of an intervertebral disc is fibrocartilagenous material) – annulus fibrosis.
Describe a cartilaginous synchondroses joint?
•e.g. joint between the first rib and the sternum
The connecting material is hyaline cartilage.
Most common type is epiphyseal plate – connects epiphysis and diaphysis of a growing bone.
The hyaline cartilage is eventually replaced by bone or fibrocartilage when growth occurs
Outline a condyloid (ellipsoid) joint?
E.g. Metacarpophalyngeal joints.
An an ovoid articular surface articulates with an elliptical cavity.
This permits movement in two planes.
Thus movements = flexion, extension, abduction, adduction and circumduction.
Label the types of joint
What is a synovial joint?
The bones forming the joint have a synovial cavity and are united by the dense irregular connective tissue of an articular capsule, and often by accessory ligaments.
What is a saddle joint?
Give an example
Possible movements
First carpo-metacarpal joint.
Articular surface of the bone is saddle shaped and the articular surface of the other bone is shaped like the legs of a rider sitting in the saddle.
Movements are side to side and back and forth.
What is a ball and socket joint?
Give an example
Possible movements
Hip
Ball like surface of one bone fitted into a cup like depression of another bone.
E.g also shoulder.
Movement in three planes – rotation, flexion-extension and abduction and adduction.
What is a gliding joint?
Give an example
Possible movement
Patellofemoral
Articulating surfaces of bones are usually flat.
Only side to side and back and forth movements are permitted.
Ligaments etc restrict other movements such as rotating.
What is a hinge joint?
Give an example
Possible movement
Knee
Convex surface of one bone fits into the concave surface of another. – movement tends to be in a single plane.
Usually flexion and extension.
What is a pivot joint?
Give an example
Possible movement
Rotational movement eg median atlanto-axial joint, and radioulnar joints (pronation/supination,)
The rounded or pointed surface of one bone articulates with a ring formed partly by another bone and partly by a ligament
A pivot joint is uniaxial because it allows rotation only around its own longitudinal axis.
What structures are involved in a synovial joint?
Joint cavity
- Contains synovial fluid
Articular cartilage
- Remnant of hyaline model
Joint capsule
- Synovial membrane (inner)
- Fibrous membrane (outer)
Additional structures
- Accessory ligaments
- Articular discs
- Bursae
What are the 2 layers of the articular capsule?
- Synovial membrane (inner)
- Fibrous membrane (outer)
Outline the fibrous membrane of the articular capsule?
Dense irregular connective tissue- flexibility of fibrous capsule permits movement at the joint, and its great tensile strength prevents dislocation.
Fibres of fibrous capsules are arranged in parallel bundles – highly adapted to resist recurrent strain (LIGAMENTS) – strength of ligaments is one of principle factors in holding bone to bone.
Outline the synovial membrane of the articular capsule?
Areolar connective tissue with elastic fibres and a variable amount of adipose tissue.
Secrete synovial fluid.
What does synovial fluid do?
What is it made of?
Lubricates and reduces friction in a joint
Supplies nutrients to and removes metabolic wastes from the chondrocytes of the articular cartilage.
Contains phagocytic cells – remove microbes and debris resulting from wear and tear in the joint.
Synovial fluid – hyaluronic acid and an interstitial fluid formed from blood plasma.
With increased movement it becomes less viscous.
What is the function of articular discs (menisci) in synovial joints?
Allow two bones of different shapes to fit tightly, and maintain stability of joint and direct flow of synovial fluid to areas of most friction.
What is the function of bursae in synovial joints?
Eleviate friction e.g in shoulder joint – cushion the movement of one part of the body over another.
Label this image
What modality is it?
MRI
What are the properties of hyaline cartilage?
What colour is it?
What’s it made of?
Where’s it found?
What is it’s function?
- Can withstand high levels of physical stress
- Low friction
- Avascular
Bluish white and shiny ground substance with collagen fibres – contains numerous chondrocytes, most abundant of cartilage.
Seen at ends of long bones ant. ends of ribs, nose, parts of larynx, trachea, bronchi, bronchial tubes, and embryonic skeleton.
•Provides smooth surfaces for movement at joints, flexibility, and support.
Label this image
What modality?
MRI
What are ligaments?
What popular ligament is commonly ruptured by footballers?
How?
- Fibres that attach bone to bone
- Can be extra- or intra- capsular
- Cruciate ligaments are inter-capsular and stabilise the joint
- Commonly ruptured due to excessive lateral movement (common footballing, skiing and squash injury)
Label this image
Describe the position of the suprapatellar bursa?
Situated between the distal femur and the suprapatellar tendon
Describe the position of the repatellar bursa?
Situated between the anterior surface of the patella and the skin
Describe the position of the intrapatellar bursa?
Situated below the patella, between the proximal tibia and the patellar ligament
Label this image
What modality?
MRI
Outline what a skeletal muscle is?
- Attached to bone (via tendons)
- Voluntary muscle
- Produce movements by exerting force on tendons, which in turn pull on bones or other structures such as skin.
What are tendons and ligaments?
- Dense connective tissue
- Mainly collagen
- Tension : one direction only
- Strong and pliable
- Attaches muscle to periosteum of the bone. Tendons are enclosed by tubes of fibrous connective tissue (tendon sheaths) – tendon sheaths reduce friction as tendons slide back and forth.
How much do tendons stretch?
•Tendons do not stretch at all (otherwise muscles could not exert a pulling force on bone)
How much do ligaments stretch?
•Ligaments do stretch a little to accommodate movement of a joint.
Remember that the fibres of fibrous capsules are arranged in parallel bundles – highly adapted to resist recurrent strain.
Strength of ligaments is one of principle factors in holding bone to bone.
What is collagen?
(long answer)
Structure?
Where is it found?
White connective tissue fibre,
The most numerous fibre present in ordinary connective tissue
Elongated, straight or slightly curved fibres which gives tensile strength to the tissue
- Very tough and resistant to a pulling force yet allow some flexibility in the tissue because they are not taut.
Fibres often occur in bundles made up of many tiny fibrils lying parallel to one another.
Collagen fibres are found in most types of connective tissue especially bone, cartilage, tendons and ligaments.
Label this image
What is it showing?
Rotator cuff muscles
Label this image to point out what it is showing
Label this image
Which image is normal?
The body of the vertebrae vertically don’t line up as well
What do fat pads on a lateral elbow x-ray show?
Fat is normally present in joint capsule of elbow, but typically hidden in the concavity of the olecranon and coronoid fossae, (i.e.not usually visible).
But injuries that cause intra-articular haemorrhage may force the fat out of the fossa, producing triangular radioluscent shadows anteriorly & posteriorly (usually radial head fracture in adults).
What does this image show?
What is it?
Lipohaemarthrosis
A lipohaemarthrosis refers to a joint fluid accumulation that is composed of both blood and fat (lipo- fat, haem- blood, throsis- joint)
