In your body, you have only two types of bone tissue: cortical and cancellous bone. In this lesson, we will learn about the structure and function of cancellous bone, which plays a crucial role in producing blood cells and stem cells and is the primary tissue affected by osteoporosis.
balaclava (plural balaclavas) 1  A warm cap shielding the neck and head, often made out of wool. ( 2 chiefly Canada) A ski mask with holes for the eyes and, sometimes, the nose and mouth, which may be rolled up and worn like a toque or pulled over the face for greater protection.
The first man was white, 6ft, and wore a dark balaclava with lighter stitching around the eye and mouth holes. Women in car snatch terror ordeal He was accosted by a man wearing a balaclava mask and brandishing a knife as he made collections from houses on behalf of a finance company. Police hunt for masked knife attacker The man was wearing a mask or balaclava and the girl managed to fight him off. Mugger tried to rob girl The second man was of stocky build, under 6ft tall, wearing a dark blue fleece, dark trousers, and a balaclava.