After arriving in New Jersey, US, for a one-year cultural exchange program, I noticed that many local people love Chinese culture. I felt like sharing our culture with them. As one of the 13th-generation disciples of Chen-style tai chi, I set up a tai chi club for local primary students. My tai chi program lasted for 10 weeks, with classes taking place every Tuesday.

    I have been in several cultural exchange programs before, but I haven't really worked with little kids. It was a little intimidating for me at first. Kids are extremely noisy and active. It was challenging enough just to take control of the class. In the beginning, we could only go over a few gestures during each class, as I spent most of my time working on class discipline (纪律).

    However, as the class went on, we grew more and more familiar with each other. Slowly, I found the fun and sense of achievement that lies under the kids' nervousness and tiredness. Watching the kids learn tai chi under my instruction was exciting. Nothing made me happier than seeing their smiles after learning a new gesture. With each punch, kick and stretch, I could sense their progress and their interest in learning. They asked me many questions about tai chi.

    This experience also improved my leadership. I realized that it was important to unite the whole class and encourage kids to help one another when they meet difficulties. I will try my best to spread tai chi culture here.

如图所示为根尖结构模式图．请根据要求回答下列相关问题：

同学们课间经常打闹，有一次小明不小心将健康强壮的甲同学推到，使该同学的后脑撞击在了课桌角上，甲同学当时出现心跳，呼吸停止，尽管实施急救措施，但不幸的是，该同学永远地离开了人世，因此请同学们一定要注意玩闹时的安全，避免类似的悲剧再次发生．请问甲同学主要谁伤到了脑的哪个部位？（    ）

骨组织的营养物质供应主要依靠骨膜中的血管．（判断对错）