Fascia and Musculature of the Head and Neck

Comprehensive practice flashcards defining the fascial layers, muscles of facial expression, muscles of mastication, neck musculature, and cervical triangles covered in the Head & Neck anatomy lecture.

Skin of the Scalp

Thin outer layer of the scalp containing hair follicles, sweat glands, and sebaceous glands.

Connective Tissue of the Scalp

Thick, dense, and richly vascular subcutaneous scalp layer containing cutaneous nerves.

Epicranial Aponeurosis

Broad, strong tendon layer of the scalp that serves as an attachment site for muscles.

Loose Areolar Tissue of the Scalp

Sponge-like scalp layer that allows free movement of the overlying three layers and can swell due to injury or infection.

Pericranium

Dense layer of connective tissue that forms the external periosteum of the cranium.

Superficial Cervical Fascia

Layer of fatty subcutaneous tissue surrounding the entire neck, situated between the skin and the investing layer of deep cervical fascia.

Platysma

Broad, thin sheet of muscle in the superficial fascia covering the anterolateral neck that depresses the mandible and tenses the skin of the inferior face and neck; innervated by the facial nerve (CN VII).

Investing Layer of Deep Cervical Fascia

Deep cervical fascia layer that encircles the entire neck deep to superficial fascia, attaching superiorly from the superior nuchal line to the mandible and inferiorly to the manubrium, clavicles, acromions, and spines of the scapula.

Pretracheal Fascia

Deep cervical fascia layer in the anterior neck extending from the hyoid bone to the thorax (where it blends with pericardium), consisting of a muscular part enclosing infrahyoid muscles and a visceral part enclosing the thyroid gland, trachea, esophagus, and pharynx.

Buccopharyngeal Fascia

Thin lamina continuing from the pretracheal visceral layer that surrounds the pharyngeal constrictor muscles.

Prevertebral Fascia

Deep cervical fascia layer surrounding the vertebral column and associated muscles; extends from the cranial base superiorly and blends inferiorly with the endothoracic fascia, communicating with the mediastinum.

Carotid Sheath

Tubular fascial condensation formed by contributions from the investing, pretracheal, and prevertebral layers extending from the cranial base to the root of the neck; encloses the common and internal carotid arteries, internal jugular vein, and vagus nerve (CN X).

Alar Fascia

Thin sheet of deep cervical fascia extending from the cranial base to the root of the neck; attaches at the midline to buccopharyngeal fascia and laterally to the carotid sheath.

Retropharyngeal Space

Interfascial space situated between the buccopharyngeal/pretracheal fascia anteriorly, prevertebral fascia posteriorly, and carotid sheaths laterally.

Frontalis

Muscle of facial expression attaching to the skin of the eyebrows and root of the nose that elevates the eyebrows and wrinkles the forehead; innervated by the facial nerve (CN VII).

Occipitalis

Muscle attaching to the lateral two-thirds of the superior nuchal line that draws the scalp backward and wrinkles the back of the head; innervated by the facial nerve (CN VII).

Levator Labii Superioris

Facial muscle originating from the infraorbital margin and inserting into the skin of the upper lip; functions to elevate the upper lip.

Zygomaticus Major

Facial muscle running from the zygomatic bone to the angle of the mouth; functions to elevate the corner of the mouth.

Depressor Anguli Oris

Facial muscle extending from the anterolateral base of the mandible to the angle of the mouth; functions to depress the corner of the mouth.

Depressor Labii Inferioris

Facial muscle extending from the mandible to the skin of the lower lip; functions to depress the lower lip.

Levator Anguli Oris

Deep facial muscle extending from the maxilla just below the infraorbital foramen to the angle of the mouth; acts as an accessory to zygomaticus major to elevate the corner of the mouth.

Buccinator

Deep facial muscle forming the principal substance of the cheek, attaching to the angle of the mouth, mandible, maxilla, and pterygomandibular raphe; keeps the cheeks taut during mastication and assists in smiling.

Orbicularis Oris

Oral sphincter muscle encircling the mouth and attaching into the lips; functions in articulation and mastication.

Orbicularis Oculi

Circular sphincter muscle of the eye enclosing the orbital margin and eyelids; closes the orbital opening and aids the flow of tears by emptying the lacrimal sac.

Procerus

Nasal muscle extending from the forehead to the skin over the bridge of the nose; depresses the medial angle of the eyebrows.

Nasalis

Muscle of facial expression running from the maxilla to the bridge and alar cartilage of the nose; functions to widen the nasal aperture.

Depressor Septi

Facial muscle extending from the incisive fossa of the maxilla to the nasal septum; depresses and widens the nasal aperture.

Temporalis

Muscle of mastication occupying the temporal fossa and inserting onto the coronoid process of the mandible; elevates, retracts, and produces lateral excursion of the mandible; innervated by CN V3.

Masseter

Strong, thick muscle of mastication running from the zygomatic arch to the lateral ramus and angle of the mandible; elevates and protracts the mandible and clenches teeth; innervated by CN V3.

Medial Pterygoid

Muscle of mastication in the infratemporal fossa extending from the lateral pterygoid plate and maxillary tuberosity to the medial surface of the ramus and angle of the mandible; elevates, protracts, and moves the mandible laterally; innervated by CN V3.

Lateral Pterygoid

Short, horizontal muscle of mastication running from the lateral pterygoid plate and greater wing of the sphenoid to the neck of the mandible and TMJ articular disc; depresses, protracts, and moves the mandible laterally; innervated by CN V3.

Sternocleidomastoid

Neck muscle extending from the mastoid process and lateral half of the superior nuchal line to the manubrium and clavicle; unilaterally rotates the head and bilaterally flexes the neck; innervated by the accessory nerve (CN XI).

Digastric Muscle

Suprahyoid muscle whose two bellies connect via an intermediate tendon anchored to the hyoid bone; depresses the mandible, opens the mouth, and elevates the hyoid; anterior belly innervated by CN V, posterior belly by CN VII.

Mylohyoid

Suprahyoid muscle forming the floor of the oral cavity, extending from the medial surface of the mandible to the hyoid; elevates the hyoid, floor of mouth, and tongue during swallowing and speaking; innervated by CN V.

Geniohyoid

Suprahyoid muscle running from the genio of the mandible to the hyoid bone; elevates the hyoid and shortens the floor of the mouth; innervated by C1 via the hypoglossal nerve (CN XII).

Omohyoid

Two-bellied infrahyoid muscle running between the superior border of the scapula and the hyoid bone via a fascial sling at the clavicle; depresses, retracts, and steadies the hyoid; innervated by the ansa cervicalis.

Sternohyoid

Infrahyoid muscle extending from the manubrium and medial clavicle to the hyoid bone; depresses the hyoid following elevation during swallowing; innervated by the ansa cervicalis.

Sternothyroid

Infrahyoid muscle extending from the manubrium of the sternum to the thyroid cartilage of the larynx; depresses the hyoid and larynx; innervated by the ansa cervicalis.

Thyrohyoid

Infrahyoid muscle extending from the thyroid cartilage to the hyoid bone; depresses the hyoid bone and elevates the larynx; innervated by C1 via the hypoglossal nerve (CN XII).

Anterior Scalene

Prevertebral muscle extending from the transverse processes of C3–C6 to the first rib; flexes the neck and elevates the first rib; innervated by cervical spinal nerves C4–C6.

Middle Scalene

Prevertebral muscle extending from the transverse processes of C2–C7 to the first rib; laterally flexes the neck and elevates the first rib; innervated by anterior rami of cervical spinal nerves.

Posterior Scalene

Prevertebral muscle extending from the transverse processes of C5–C7 to the second rib; laterally flexes the neck and elevates the second rib; innervated by anterior rami of spinal nerves C7–C8.

Longus Capitis

Prevertebral muscle running from the basilar part of the occipital bone to the anterior tubercles of C3–C6 transverse processes; flexes the head; innervated by anterior rami of C1–C3.

Longus Colli

Prevertebral muscle extending between cervical and upper thoracic vertebrae; bilaterally flexes the neck and unilaterally rotates it contralaterally; innervated by anterior rami of C2–C6.

Trapezius

Superficial posterior cervical muscle extending from the superior nuchal line and spine to the clavicle and scapula; elevates, retracts, and rotates the scapula superiorly; innervated by the accessory nerve (CN XI).

Splenius Capitis

Posterior cervical muscle extending from the nuchal ligament and C7–T6 spinous processes to the mastoid process and superior nuchal line; bilaterally extends the head and neck and unilaterally flexes/rotates them to the same side; innervated by posterior rami of cervical spinal nerves.

Splenius Cervicis

Posterior cervical muscle extending from the nuchal ligament and C7–T6 spinous processes to the transverse processes of C1–C4; bilaterally extends the head and neck, and unilaterally flexes/rotates them to the same side; innervated by posterior rami of cervical spinal nerves.

Semispinalis Capitis

Deep posterior cervical muscle extending from C4–T12 transverse processes to the occipital bone; extends the head and neck and rotates them contralaterally; innervated by posterior rami of spinal nerves.

Suboccipital Triangle

Deep anatomical space bounded by rectus capitis posterior major, obliquus capitis superior, and obliquus capitis inferior; contains the vertebral artery and suboccipital nerve (posterior ramus of C1).

Stylohyoid

Muscle extending from the styloid process to the hyoid bone that elevates and retracts the hyoid; innervated by the facial nerve (CN VII).

Styloglossus

Extrinsic tongue muscle extending from the styloid process to the tongue; retracts and curls the tongue; innervated by the hypoglossal nerve (CN XII).

Stylopharyngeus

Muscle extending from the styloid process to the thyroid cartilage and pharyngeal wall; elevates the pharynx; innervated by the glossopharyngeal nerve (CN IX).

Genioglossus

Extrinsic tongue muscle extending from the mental spine of the mandible to the dorsum of the tongue; protrudes and depresses the tongue; innervated by the hypoglossal nerve (CN XII).

Hyoglossus

Extrinsic tongue muscle extending from the hyoid bone to the inferolateral aspect of the tongue; retrudes and depresses the tongue; innervated by the hypoglossal nerve (CN XII).

Submental Triangle

Anterior cervical triangle bounded laterally by the right and left anterior bellies of the digastric muscle and inferiorly by the hyoid body; contains submental lymph nodes and tributaries of the anterior jugular vein.

Submandibular Triangle

Anterior neck triangle bounded by the anterior and posterior bellies of the digastric and the inferior border of the mandible; contains the submandibular gland, lymph nodes, CN XII, mylohyoid nerve, and facial vessels.

Carotid Triangle

Vascular anterior neck triangle bounded by the anterior border of the SCM, superior belly of the omohyoid, and posterior belly of the digastric; contains the common and external carotid arteries, internal jugular vein, vagus nerve (CN X), and CN XII.

Muscular Triangle

Anterior cervical triangle bounded by the anterior border of the SCM, superior belly of the omohyoid, and the midline of the neck; contains infrahyoid muscles, thyroid gland, and parathyroid glands.

Occipital Triangle

Upper division of the posterior cervical triangle containing parts of the external jugular vein, sensory branches of the cervical plexus, accessory nerve (CN XI), brachial plexus, and cervical lymph nodes.

Omoclavicular Triangle

Lower division of the posterior cervical triangle (also termed the subclavian triangle) containing the subclavian artery, subclavian vein, and suprascapular artery.