Head, Neck, and Spine Anatomy

Comprehensive vocabulary flashcards covering head layers, skull bones, sutures, fontanelles, foramina, muscles of facial expression and mastication, neck anatomy, vertebrae, and the temporomandibular joint.

Scalp

The envelope covering the bones of the head, extending from the superior nuchal line to the supraorbital margins, composed of five anatomical layers.

Sebaceous Glands

Glands located in the skin layer of the scalp that secretes sebum or natural oil to lubricate the scalp.

Epicranial Aponeurosis

A thin, tendon-like structure connecting the occipitalis and frontalis muscles to form the occipitofrontalis.

Emissary Veins

Small valveless veins in the loose areolar connective tissue layer that connect extracranial scalp veins with intracranial dural venous sinuses.

Pericranium

The deepest and innermost layer of the scalp and outermost layer of skull bone that separates the scalp from the skull and supplies nutrients.

Axial Skeleton

The division of the skeleton containing $80$ bones, including the skull, hyoid bone, auditory/ear ossicles, and vertebral column.

Appendicular Skeleton

The division of the skeleton containing $126$ bones, including the hip/pelvic girdle and shoulder girdle.

Parietal Bones

Paired cranial bones that form the side and roof of the cranial cavity, containing internal surface depressions for dura mater blood vessels.

Temporal Bones

Paired cranial bones forming the inferior lateral aspects of the cranial cavity and parts of the cranial base.

Frontal Bone

An unpaired cranial bone forming the anterior and superior portions of the skull, separated in infancy by the temporary frontal suture.

Occipital Bone

An unpaired cranial bone forming the posterior and inferior portions of the skull, containing the foramen magnum and occipital condyles that articulate with C1.

Ethmoid Bone

A light, spongy unpaired cranial bone located between the orbits, containing the cribriform plate, nasal conchae, and crista galli.

Sphenoid Bone

A wedge-shaped, unpaired cranial bone acting as the keystone of the cranial floor, housing the pituitary gland in the sella turcica.

Nasal Bones

Paired flat, small rectangular facial bones that form the bridge of the nose and protect the upper entry to the nasal cavity.

Inferior Nasal Conchae

Paired facial bones forming part of the inferior lateral wall of the nasal cavity that project into the cavity and assist with the sense of smell.

Lacrimal Bones

The smallest facial bones, shaped like fingernails, containing a fossa that houses the lacrimal sac for gathering tears.

Palatine Bones

Paired facial bones forming the posterior portion of the hard palate, part of the floor, and posterolateral wall of the nasal cavity.

Zygomatic Bones

Paired cheek bones that form the cheek prominences and parts of the lateral walls and floor of each orbit.

Vomer

An unpaired triangular facial bone that forms part of the nasal septum separating the right and left nasal conchae.

Maxilla

Paired upper jaw bones forming most of the hard palate and articulating with every facial bone except the mandible.

Mandible

The largest, strongest, and only movable facial bone, forming the lower jaw used for chewing.

Ear Ossicles

Three pairs of small auditory bones located in the ear: malleus (hammer), incus (anvil), and stapes (stirrup).

Cranial Sutures

Synarthrodial (immovable) joints that connect the bones of the skull.

Anterior Fontanelle

A diamond-shaped soft spot (Bregma) measuring about $3 \times 2\,\text{cm}$ at the junction of the sagittal and frontal sutures that ossifies at $18-24\,\text{months}$.

Posterior Fontanelle

A triangular or Y-shaped soft spot (Lambda) located at the junction of the sagittal and lambdoid sutures that closes at $9-12\,\text{months}$.

Nasion

An anatomical landmark defined as the depression found at the upper root of the nose.

Pterion

The thinnest, most vulnerable portion of the lateral skull formed by meeting sutures, overlying the middle meningeal artery.

Inion

The external occipital protuberance forming a small eminence at the posterior skull used for head circumference measurement.

Glabella

The skin located between the superciliary ridges, used as the landmark for tapping in the glabellar tap reflex (Myerson's sign).

Occipitofrontalis

A muscle of facial expression whose frontal belly raises the eyebrows and wrinkles the forehead in surprise.

Corrugator Supercilii

A facial muscle that approximates the eyebrows medially to produce a frowning expression.

Procerus

A facial muscle that wrinkles the nose, expressing disgust or distaste.

Zygomaticus Major

A facial muscle that pulls the corners of the mouth laterally and superiorly to produce a smile.

Mentalis

A facial muscle that protrudes the lower lip, expressing pouting or doubt.

Orbicularis Oris

A sphincter-like muscle surrounding the mouth that closes the lips, as used in kissing.

Risorius

A facial muscle that pulls the corners of the lips laterally during a grimace.

Buccinator

A facial muscle that puffs out the cheeks and aids in blowing, whistling, and sucking.

Platysma

A superficial neck and lower face muscle that depresses the angle of the mouth.

Levator Palpebrae Superioris

The principal muscle responsible for $80\%$ of eye opening, innervated by CN III.

Orbicularis Oculi

The muscle surrounding the eye responsible for blinking, winking, and closing the eyelids, innervated by CN VII.

Atlas

The first cervical vertebra (C1), characterized by lacking both a vertebral body and a spinous process.

Axis

The second cervical vertebra (C2), characterized by the presence of the odontoid process.

Hyoid Bone

A U-shaped neck bone with no bony articulations that supports the tongue and provides attachments for neck and pharynx muscles.

Anterior Triangle of the Neck

A cervical region bounded superiorly by the mandible, anteriorly by the anterior neckline, and inferiorly by the anterior border of the SCM.

Posterior Triangle of the Neck

A cervical region bounded anteriorly by the posterior border of the SCM, posteriorly by the trapezius, and inferiorly by the clavicle.

Sternocleidomastoid

A neck muscle producing cervical flexion bilaterally, and ipsilateral lateral flexion with contralateral rotation unilaterally.

Torticollis

A condition presenting with a twisted neck and tight SCM muscle, stretched using opposite movements of rotation and lateral flexion.

Thoracic Outlet Syndrome

A condition associated with tight scalene muscles resulting in a decreased or absent radial pulse during Adson's test.

Temporomandibular Joint

The only synovial joint in the head, classified as a ginglymo-arthrodial joint between the temporal bone and mandibular condyle.

OPP of TMJ

The open-packed position of the TMJ, where the mouth is slightly open, lips are together, and teeth are not in contact.

CPP of TMJ

The close-packed position of the TMJ, characterized by teeth being tightly clenched.

Temporalis

A muscle of mastication innervated by CN V3 that elevates and retrudes the mandible.

Masseter

A muscle of mastication innervated by CN V3 that elevates and protrudes the mandible.

Medial Pterygoid

A muscle of mastication innervated by CN V3 that elevates, protrudes, and produces lateral deviation of the mandible.

Lateral Pterygoid

A muscle of mastication innervated by CN V3 that depresses (opens) and protrudes the mandible.

Deciduous Teeth

Primary or milk teeth consisting of $20$ total teeth: $8$ incisors, $4$ canines, and $8$ molars.

Permanent Teeth

Adult teeth consisting of $32$ total teeth: $8$ incisors, $4$ canines, $8$ premolars, and $12$ molars.

Maximal Intercuspation

The position of jaw occlusion where maxillary and mandibular teeth achieve greatest intercuspal contact, representing the CPP.