The scalp A. Is attached by occipitalis muscle to the skull B. Is attached by the frontalis muscle to the skull C. Receives sensory innervation from the dorsal rami of first 3 cervical nerves D. Is supplied, in part, by the ophthalmic artery E. Drains directly to the subcutaneous lymph nodes at the base of the skull
**Core Concept**
The scalp is a complex structure consisting of multiple layers, including the skin, subcutaneous tissue, galea aponeurotica, and pericranium. Understanding its attachments, innervation, and vascular supply is crucial for various medical and surgical procedures.
**Why the Correct Answer is Right**
The scalp is indeed attached to the skull by the occipitalis muscle, which is one of the three muscles of the scalp (occipitalis, frontalis, and auricularis). The occipitalis muscle originates from the occipital bone and inserts into the galea aponeurotica, which in turn attaches to the skull. The frontalis muscle, on the other hand, is attached to the galea aponeurotica and the skin of the forehead, but not directly to the skull. The scalp receives sensory innervation from the trigeminal nerve (cranial nerve V), specifically from the ophthalmic and maxillary divisions, not the dorsal rami of the cervical nerves. The ophthalmic artery, a branch of the internal carotid artery, provides blood supply to the scalp, including the forehead and the anterior part of the scalp. The scalp drains lymphatic fluid into the subcutaneous lymph nodes at the base of the skull, including the occipital and anterior cervical lymph nodes.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the frontalis muscle is attached to the galea aponeurotica and the skin of the forehead, not directly to the skull.
**Option B:** This option is incorrect because the frontalis muscle is not attached to the skull, but rather to the galea aponeurotica and the skin of the forehead.
**Option C:** This option is incorrect because the scalp receives sensory innervation from the trigeminal nerve (cranial nerve V), not the dorsal rami of the cervical nerves.
**Option D:** This option is incorrect because the scalp receives blood supply from the ophthalmic artery, but also from other arteries including the superficial temporal artery and the occipital artery.
**Clinical Pearl / High-Yield Fact**
The scalp is a unique structure that requires careful consideration during surgical procedures, such as craniotomies and scalp reductions. Understanding its anatomy and blood supply is crucial for preventing complications and ensuring optimal outcomes.
**✓ Correct Answer: A. A = True, B = False, C = True, D = True, E = True**