Week 1

Question 0

What are the functions of the skeleton?

Answer 0

Maintain body shape
Support and protection of tissues and organs
Movement and storage of calcium triphosphate in bone
Haemopoiesis
Lipid storage

Question 1

Describe endochondral ossification

Answer 1

Primary ossification centre in the diaphysis of hyaline cartilage model. Here, the cartilage calcifies and a nutrient artery penetrates
Secondary ossification centres form at the epiphyses
Epiphyseal growth plates develop
Epiphyses ossify
Growth plates move further apart to lengthen bone
Epiphyseal growth plates are replaced by bone

Question 2

Describe intramembranous ossification

Answer 2

Begins in a highly vascularised connective tissue
Mesenchymal cells differentiate into osteoblasts which are surrounded by collagen fibres and ground substance
Osteoblasts secrete osteoid, which becomes calcified
Osteoblasts become osteoclasts

Question 3

What is osteogenesis imperfecta caused by?

Answer 3

A defect in collagen synthesis by osteoblasts and fibroblasts.

Question 4

Which type of collagen in present in bone, skin and tendons?

Answer 4

Type 1

Question 5

What are features of osteogenesis imperfecta?

Answer 5

Multiple fractures in long bones

Bone deformities due to fracture healing with poor alignment and weak callus

Question 6

How does osteoporosis occur?

Answer 6

Bone density is reduced because osteoclast activity is more than osteoblasts activity
Leads to medullary canals in the centre of the bone becoming enlarged and gaps develop in the lamellae

Question 7

Features of rickets?

Answer 7

Bone is softened due to calcium deficiency - matrix does not calcify
Children have slow growing bones which are often deformed
Epiphyseal plate becomes distorted

Question 8

Features of osteomalacia?

Answer 8

Occurs during bone remodelling
There is deficient calcification of recently formed bone
Bone softening

Question 9

Symptoms of Paget’s disease?

Answer 9

Bone pain
Osteoarthritis
Fractures
Deafness/headaches

Question 10

Pathology of Paget’s disease?

Answer 10

Increased number of osteoclasts, and often over active osteoblasts
An accelerated rate of bone turnover and new bone formation
Bones increase in size and are more brittle so more prone to fracture

Question 11

Which hormones increase calcium plasma concentration?

Answer 11

PTH and calcitrol

Question 12

How does PTH work?

Answer 12

Decreases osteoblasts activity

Question 13

What innervates the pec major and the spinal root values?

Answer 13

Medial and lateral pectoral nerves

Derived from the brachial plexus so C5-T1

Question 14

What is the action of the pec major?

Answer 14

Adducts and medially rotates the humerus
Draws scapula anteriorly and inferiorly

Clavicular head performs flexion of the humerus

Question 15

What is the innervation of the pec minor? Spinal root values?

Answer 15

Medial pectoral nerve

C8, T1

Question 16

Action of the pec minor?

Answer 16

Draws scapula inferiorly and anteriorly against thoracic wall

Question 17

Innervation of the subclavius? Spinal root values?

Answer 17

Nerve to subclavius

C5 and C6

Question 18

Attachments of the subclavius?

Answer 18

Junction of first rib and its costal cartilage

Inferior surface of middle third of clavicle

Question 19

Action of the subclavius?

Answer 19

Anchors and depresses clavicle

Question 20

Innervation of serratus anterior? Spinal root values?

Answer 20

Long thoracic nerve

C5, C6, C7

Question 21

Attachments of the serratus anterior?

Answer 21

1st-8th ribs

Medial border of scapula

Question 22

Action of the serratus anterior?

Answer 22

Rotates the scapula, abducting arm above 90*

Holds scapula against rib cage

Question 23

What is winged scapula?

Answer 23

Injury to long thoracic nerve, paralysing serratus anterior
Medial border of scapula moves laterally and posteriorly away from the thoracic wall
Can be seen when someone leans on their hands against a wall