Label B corresponds to which structure surrounding each fascicle?

Label B corresponds to which structure surrounding each fascicle?

• A. Perineurium
• B. Epineurium
• C. Nodes of Ranvier
• D. Clefts of Schmidt-Lanterman

Answer: (A)

The main idea is recognizing how connective tissue wraps organize a peripheral nerve. Each fascicle—a bundle of nerve fibers—is enclosed by a protective, layered sheath called the perineurium. This perineurial sheath defines the boundaries of the fascicle and helps create a controlled microenvironment for the fibers inside. The outermost covering of the whole nerve is the epineurium, which binds multiple fascicles together. Inside a fascicle, individual axons are wrapped by their own endoneurial sheath. The other options aren’t about enclosing a fascicle: nodes of Ranvier are gaps in myelin along an axon, and Schmidt-Lanterman clefts are channels within the myelin. So the sheath surrounding each fascicle is the perineurium.

The main idea is recognizing how connective tissue wraps organize a peripheral nerve. Each fascicle—a bundle of nerve fibers—is enclosed by a protective, layered sheath called the perineurium. This perineurial sheath defines the boundaries of the fascicle and helps create a controlled microenvironment for the fibers inside. The outermost covering of the whole nerve is the epineurium, which binds multiple fascicles together. Inside a fascicle, individual axons are wrapped by their own endoneurial sheath. The other options aren’t about enclosing a fascicle: nodes of Ranvier are gaps in myelin along an axon, and Schmidt-Lanterman clefts are channels within the myelin. So the sheath surrounding each fascicle is the perineurium.