Session 1

Question 0

What is the Axial skeleton and Appendicular skeleton?

Answer 0

The divisions of the skeleton:

Axial skeleton forms the longitudinal axis of the body (protection and support; skull - brain, vertebral column - cord, rib cage - heart and lungs)

Appendicular Skeleton is made up of the upper and lower extremities including the pectoral girdle and the pelvic girdle that attach the extremities to the axial skeleton (mobility)

Question 1

Describe the skeleton and list its mechanical and physiological functions:

Answer 1

Sturdy, flexible framework

• Support
• Protect
• Shape
• Movement (skeleton provides anchoring points for muscles and act as levers for joints)
• Haemopoiesis (red marrow)
• Mineral storage (bone matrix: calcium and phosphate)
• Lipid storage (yellow marrow)

Question 2

What are the bone shapes and give an example for each

Answer 2

Long bone e.g. Femur

Short bone e.g. Calcaneus

Flat bone e.g. Parietal bone (of the skull)

Sesamoid bone e.g. Patella (kneecap)

Irregular bone e.g. Sphenoid bone (of the skull)

Question 3

What can irregular bones be?

Answer 3

Pneumatic - sinuses/mastoids (bones have air spaces within them making them lighter than solid bone and are only found in the skull)

Accessory - rare, secondary ossification centre develop separately to the main bone (‘extra bone’)

Question 4

Give the structure of a long bone

Answer 4

*Apophysis: bony outgrowth

Question 5

Define Facet, Sinus, Meatus, Fissure and Notch (bone anatomy terms)

Answer 5

Facet: flattened surface for joint/muscle attachment

Sinus: hollow space

Meatus: tunnel or canal

Fissure: cleft/narrow slit

Notch: a large groove

Question 6

What is a joint?

Answer 6

The articulation between 2 or more bones (anywhere where 2 bones join)

Question 7

How are joints classified?

Answer 7

Classified structurally according to the tissues that lie between the bones and therefore:

Fibrous

Cartilaginous

Synovial

Question 8

Describe Fibrous joints

Answer 8

Sutures (tight union between bones of the skull)

Syndesmoses (between distal fibula and tibia - interosseous membrane)

Gomphosis (teeth - gums)

Question 9

Describe Cartilaginous Joints

Answer 9

Synchondroses, Primary Cartilaginous: connecting medium is hyaline e.g. hyaline cartilage epiphyseal growth plate in long bones

Symphyses, Secondary Cartilaginous: a fibrocartilaginous fusion -disc of fibrocartilage in the joint cavity - pubic symphysis, intervertebral joint

Question 10

Describe Synovial Joints (Diarthrosis)

Answer 10

Articular capsule (synovium/synovial membrane)

Synovial fluid

Articular cartilage - hyaline

NB: not all joints allow movement but the synovial joints all for the greatest range of movements and have structural features that permit this movement to occur freely.

Question 11

Demonstrate Joint Movements: Flexion and Extension, Abduction and Adduction, Internal and External Rotation, Circumduction

Answer 11

(NB: joint between the scaphoid and hamate is a gliding joint a ‘rotate and twist’)

See Lecture 1.1 and 1.2 if unsure!

Question 12

What are the types of Synovial Joint?

Answer 12

Hinge

Saddle

Plane

Pivot

Condyloid

Ball and socket

Question 13

Describe a Hinge joint

Answer 13

Permits flexion and extension only (e.g. Elbow)

Question 14

Describe a Saddle joint

Answer 14

Concave and convex joint surfaces eg. 1st metacarpophalangeal joint

Question 15

Describe a Plane joint

Answer 15

Permits gliding or sliding movements (e.g. Acromioclavicular joint)

Question 16

Describe a Pivot Joint

Answer 16

Allows rotation; a round bony process fits into a bony ligamentous socket (e.g. atlantaxial joint and proximal radio-ulnar joint)

Question 17

Describe a Condyloid joint

Answer 17

Permit flexion and extension, adduction, abduction and circumduction (e.g. metacarpophalangeal joint)

Question 18

Describe a ball and socket joint

Answer 18

Permits movement in several axes; a rounded head fits into a concavity (shoulder and hip joints)

Question 19

What does the stability of the joints depend on?

Answer 19

Size, shape and arrangement of the articular surfaces

Ligaments

Muscles/muscle tone around the joint

• Ligaments and bursae (fluid filled sacs) commonly found in association with joints are prone to damage.

Ligaments (by excessive stretching, tearing and even rupture) due to joint injuries and the bursae may become inflamed due to excessive friction between the two structures that move relative to each other.

Question 20

Describe the Subclavius

Answer 20

Lies almost horizontally when the arm is in the anatomical position.

Located inferior to the clavicle and affords some protection to the subclavian vessels and the superior trunk of the brachial plexus if the clavicle fractures.

Subclavius anchors and depresses the clavicle and stabilizes it during movements of the upper limb.

It also helps resist the tendency for the clavicle to dislocate at the sternoclavicular joint e.g. When pulling hard during a tug-of-war game.

Nerve innervation: nerve to Subclavius (C5, C6)

Question 21

What is Poland Syndrome?

Answer 21

Both the Pectoralis major and minor are absent; breast hypoplasia and absence of two to four rib segments are also seen

Question 22

What happens when the long thoracic nerve is injured?

Answer 22

Serratus anterior is paralysed.

The medial border of the scapula moves laterally and posteriorly away from the thoracic wall - winged scapula.

The upper limb may not be able to be abducted above the horizontal position because the Serratus anterior is unable to rotate the Glenoid cavity superiorly to allow complete abduction of the limb.

Question 23

Describe how a joint may be functionally classified

Answer 23

A joint may be:

• immovable (synarthrosis)
• slightly movable (amphiarthrosis)
• freely movable (diarthrosis)

Question 24

How may a deficiency of Vitamin A affect bone?

Answer 24

May cause an imbalance in the ratio of osteoblasts and osteoclasts, thereby slowing the growth rate.

Question 25

How do bisphosphonates and calcitonin provide therapy to those with osteoporosis?

Answer 25

• They both inhibit osteoclast activity.
• Calcitonin can also stimulate osteoblast activity and favours calcium uptake into bone

Question 26

What is Paget’s Disease?

Answer 26

Progressive bone disease in which a pattern of excessive bone destruction is followed by bone formation contributing to thickening of bones.

This deformity usually involves the skull, pelvis and lower extremities and occurs affter the age of 40 and is typical in the 60s