It is the dense sclerotic bone surrounding the sequestrum. It has holes for the drainage of pus. Its cavity is lined by infected granulation tissue.
Ref: Ortho Maheshwari – p161

It is a piece of dead bone in chronic osteomyelitis, surrounded by infected granulation tissue, trying to eat away the bone. The outer surface of this bone is smooth due to the erosion by granulation tissue, and the inner surface is rough. Image
Ref: Ortho Maheshwari – p161

A fractured bone has a tension side – which tends to move apart due to the distraction forces applied during the action of muscles. According to the tension band principle, the tension side is fixed by using a wire or a plate. Then the distraction forces tend to compress the bone, helping in healing.
Ref: Maheshwari - Orthopedics , p24,25

Nicolas Andry (1658 – 1742), a French doctor coined the term ‘Orthopedics’. In his book, he gave the illustration of the crooked tree, which was later used in the symbols of many orthopedic societies around the world.
Reference: http://www.diavlos.gr/orto96/ortowww/andry1.htm

Blood supply ofa long bone is via:

Diaphyseal nutrient arteries
Metaphyseal vessels
Epiphyseal vessels
Periosteal vessels

Diaphyseal nutrient arteries : They are usually single (in 90% cases), enter through the middle third of the shaft of bone. The direction of entry is away from the region of the dominant growing epiphysis. For example, in humerus, the dominant growing epiphysis is in the head of humerus. So the direction of entry of the nutrient artery of the humerus is towards the elbow.  Mnemonic to remember the direction of entry of nutrient arteries – TOWARDS THE ELBOW …

Joint is innervated by the articular brances of the nerves which supply the muscles which move the joint (Hilton’s law). The fibrous capsule is the most sensitive part of a joint. 
Pattern of nerve supply to the capsule of the joint:
The area of the capsule stretched during the action of a muscle is supplied by the articular branch of the nerve which supplies its antagonist. For example, the part of the capsule of the hip joint which is stretched during abduction of hip is innervated by the obturator nerve which supplies …

Bone remodelling in response to stress was described by German Anatomist/Surgeon Julius Wolff (1836-1902) in the 19th century. Wolff’s law states that bone in a healthy person or animal will adapt to the loads it is placed under.

Costal cartilage is a type of hyaline cartilage. They are prone to calcification after adolescence. The pattern of calification is different in males and females. It is convex in females and concave in males (yellow arrow).
Calcification of costal cartilage