leg, shin
脛 centers on the lower leg, specifically the shin area between the knee and ankle.
脛 combines the flesh radical ⺼ with 巠, which likely contributes the sound. The character specifically refers to the shin or lower leg.
The flesh radical ⺼ on the left points to a body part, and the right side 巠 looks like a vertical line with cross-strokes, like the straight shin bone. Together they form 脛, the shin.
For ケイ, imagine a shin guard shaped like the letter K: K -> ケイ, protecting the straight shin bone.
shin; shank; lower leg
tibia; shinbone
calf
anterior tibial muscle; musculus tibialis anterior
shin; front of lower leg
tibialis posterior muscle
hairy legs
thin leg
to have a guilty conscience
to depend on someone else's (financial) support (usu. one's parents'); to gnaw on (someone's) shin
leggings; gaiters
tibia (of an insect)
tibial artery
relying on one's own resources; being entirely on one's own