When you get a bruise can you injure skin or muscle tissue?

Yes...but. Most bruises reflect extravasated of blood in the surface of the skin. Very common in pts. >65 y/o, females, pts. On anticoagulants ( warfarin, aspirin, plavix, (clopidogrel) aggrenox, Pradaxa ), pts with low platelets (petechiae). Bruises depending on the location, number, color are of value in forensic medicine to help victims from physical abuse death or alive where obviously subcutaneous tissue is injured.
Yes. Bruising is bleeding under the skin and can be all the way to your bone (bone bruise). A deep bruise in muscle (a hematoma) can rarely transform to bone (hetrotopic ossification) which may require surgery. All bruises are injuries, some so minor you may not notice them, others can be limb or even life threatening. A bruised brain for example can be a consussion if mild or lethal if major.