Head and Neck Anatomy: Skull Bones, Scalp, and Facial Musculature

Vocabulary practice flashcards covering skull osteology (neurocranium and viscerocranium), scalp anatomy and vascular/nerve supply, mimic muscles of the face, and the muscles of mastication.

Neurocranium

The cranial division that encloses and protects the brain, comprising the paired temporal and parietal bones, and the single sphenoid, frontal, occipital, and ethmoid bones.

Viscerocranium

The facial skeleton that forms the framework of the face, consisting of the maxillae, mandible, palatine bones, zygomatic bones, lacrimal bones, nasal bones, vomer, and inferior nasal conchae, along with the hyoid bone and middle ear ossicles.

Parietal Bones

Paired cranial bones that form the upper sides of the skull and articulate with the frontal, sphenoid, temporal, and occipital bones.

Ethmoid Bone

A single midline bone located at the anterior base of the cranium within the ethmoidal notch of the frontal bone, forming part of the roof of the nasal cavity.

Perpendicular Plate of the Ethmoid Bone

The vertical bony plate of the ethmoid bone that forms the upper posterior part of the nasal septum; bounded superiorly by the cribriform plate, inferiorly by the vomer, posteriorly by the sphenoid bone, anterosuperiorly by the frontal and nasal bones, and anteroinferiorly by the septal cartilage of the nose.

Cribriform Plate

The horizontal perforated bony plate of the ethmoid bone situated in the ethmoidal notch of the frontal bone.

Ethmoidal Labyrinth

The paired lateral masses of the ethmoid bone whose outer surfaces form the orbital plate (medial wall of the orbit) and whose inner surfaces form the upper lateral wall of the nasal cavity, giving rise to the superior and middle nasal conchae.

Frontal Bone

A single cranial bone forming the forehead, consisting of three primary divisions: the squamous part, the orbital parts (separated by the ethmoidal notch), and the nasal part.

Sphenoid Bone

A single, butterfly-shaped cranial bone that forms the posterior boundary of the anterior fossa and contributes heavily to the middle cranial fossa; consists of a central body, greater and lesser wings, and pterygoid processes, and contains foramina for nerves and blood vessels.

Lesser Wings of the Sphenoid Bone

Two bony ridges projecting from the anterosuperior aspect of the sphenoid body by two roots that enclose the optic canal, which transmits the optic nerve and ophthalmic artery.

Body of the Sphenoid Bone

The cubical central segment of the sphenoid bone that encloses the paired sphenoidal air sinuses inside.

Temporal Bones

Paired bones situated at the sides and base of the skull, each composed of squama (leaf-like portion), petrous (pyramis), mastoid, and tympanic parts, along with the styloid process.

Occipital Bone

A single cranial bone located at the back and base of the skull, comprising four main portions: the squamous part, two lateral parts, and the basilar part.

Basilar Part of the Occipital Bone

The anterior segment of the occipital bone located anterior to the foramen magnum that articulates with the body of the sphenoid bone.

Foramen Magnum

The great aperture formed at the intersection of the basilar, lateral, and squamous parts of the occipital bone that serves as the conduit connecting the brain (medulla oblongata) to the spinal cord (vertebral canal).

Maxillae

Paired bones uniting to form the entire upper jaw; the largest facial bones apart from the mandible, contributing to the buccal roof, the floor and lateral walls of the nasal cavity, the orbital floor, and containing the maxillary sinuses.

Mandible

The single, largest, strongest, and lowest bone of the face, forming the lower jaw and participating in the temporomandibular joint (TMJ); consists of one central body and two vertical rami.

Palatine Bones

Two "L"-shaped viscerocranial bones positioned posteriorly in the nasal cavity between the maxilla and the pterygoid process of the sphenoid; their horizontal plates form the posterior part of the hard palate.

Zygomatic Bone

Paired facial bones forming the prominence of the cheek, the lateral orbital wall and floor, and completing the zygomatic arch.

Lacrimal Bones

Paired small bones lying anteriorly within the medial orbital walls.

Nasal Bones

Two small bones situated side-by-side between the frontal processes of the maxillae to form the bony bridge of the nose.

Vomer

An unpaired, thin, flat, almost trapezoidal bone forming the posteroinferior part of the bony nasal septum.

Inferior Nasal Conchae

Paired, independent bones formed of curved laminae situated along the inferior aspect of the lateral nasal cavity wall.

Scalp

The specialized soft tissue structure that covers the cranial vault.

Layers of the Scalp

The five structural layers corresponding to the acronym SCALP: Skin, Connective tissue (dense), Aponeurotic layer (Aponeurosis), Loose connective tissue, and Periosteum (Pericranium).

Danger Triangle of the Face

An area of the central face where venous communication through the superior and inferior ophthalmic veins connects to the intracranial cavernous sinus, predisposing to cavernous sinus thrombophlebitis.

Mimic Muscles

Muscles of facial expression located around the nose, eye, mouth, and ear that produce facial expressions reflecting emotions such as anger, surprise, sorrow, and happiness; all receive motor innervation from the facial nerve (CN VII).

Nasalis Muscle

A facial muscle of the nose composed of two parts: the transverse part, which narrows the nostrils, and the alar part, which widens the nostrils.

Orbicularis Oculi Muscle

A sphincter-like muscle encircling the orbit that functions to close the eyelids tightly.

Procerus Muscle

A facial muscle that pulls the medial ends of the eyebrows downward.

Corrugator Supercilii Muscle

A muscle of facial expression located deep to the eyebrow that acts to draw the eyebrows together and downward, producing frowning.

Orbicularis Oris Muscle

The circular oral muscle surrounding the mouth that serves to close the oral aperture.

Buccinator Muscle

A muscle of the cheek known as the blowing muscle, which forms the lateral wall of the oral cavity.

Upper Lip Muscle Group

A collection of mimic muscles that pull the upper lip or mouth corners upward, consisting of levator labii superioris alaeque nasi, levator labii superioris, zygomaticus major, zygomaticus minor, levator anguli oris, and risorius.

Lower Lip Muscle Group

A collection of mimic muscles that depress the lower lip or mouth corners downward, consisting of depressor anguli oris, depressor labii inferioris, and mentalis.

Auricular Muscles

Extrinsic muscles around the ear comprising auricularis superior (elevates the auricle), auricularis anterior (pulls the auricle forward), and auricularis posterior (retracts the auricle backward).

Muscles of Mastication

The four primary chewing muscles that move the mandible—temporalis, masseter, lateral pterygoid, and medial pterygoid—all innervated by branches of the mandibular division of the trigeminal nerve ($V_3$).

Temporalis Muscle

A fan-shaped masticatory muscle originating from the inferior temporal line, temporal fossa, and deep temporal fascia, and inserting into the coronoid process and anterior ramus of the mandible; acts to elevate and retract the mandible.

Masseter Muscle

A powerful masticatory muscle originating from the zygomatic process of the maxilla and zygomatic arch, inserting onto the mandibular ramus, angle, and coronoid process; innervated by the masseteric nerve to elevate the mandible.

Lateral Pterygoid Muscle

A masticatory muscle with two heads: the upper head originates from the infratemporal crest/surface of the sphenoid and inserts into the TMJ articular capsule/disc; the lower head originates from the lateral pterygoid plate and inserts into the pterygoid fovea; functions to depress, protrude the mandible, and open the chin.

Medial Pterygoid Muscle

A masticatory muscle originating from the medial aspect of the lateral pterygoid plate and maxillary tuberosity, and inserting into the pterygoid tuberosity of the mandible; functions to elevate and protrude the mandible, closing the chin.

Vessels of the Scalp

The arterial vasculature supplying the scalp, comprising the supratrochlear, supraorbital, zygomaticotemporal, superficial temporal, posterior auricular, and occipital arteries.

Cutaneous Innervation of the Scalp

Sensory nerve distribution to the scalp provided by branches of the trigeminal nerve ($V_1, V_2, V_3$), dorsal rami of cervical spinal nerves ($C2, C3$), and sensory branches from the cervical plexus.