Future mouth. Facial structures begin to develop around here at weeks 4-8
covered on the outside by ectoderm and on the inside by endoderm, separates the foregut from the amniotic cavity. The membrane will rupture around the end of the 4th week (26 days) allowing the amniotic fluid to pass into the pharynx
Single/unpaired. Surrounds ventrolateral part of forebrain. Has a fronal and nasal part (if the name didn't give it away…). Frontal portion forms the forehead. Nasal portion forms upper part of stomedium and nose.
Dual/paired. Produced by the neural crest cells that migrate from the neural fold into the maxillary prominence. Form the lateral boundary of the stomodeum. Move medially to meet the paired prominence from the other side. Give rise to maxillary/palatine shelves.
Produced by migration of the neural crest. Forms the caudal boundary of the primitive mouth (stomedium). Gives rise to the mandible and the lower lip
Nasal sac/pit, give rise to olfactory epithelium
a fissure or opening—a gap. It is the non-fusion of the body's natural structures that form before birth. Feeding is distorted because suction cannot be generated
First Pharyngeal Arch
First pharyngeal arch developed in fetal life. Between stomodeum and first pharyngeal groove. Eventually evelops into: Muscles of mastication Mylohyoid m Anteior belly of digastric Tensor tympani Tensor veli palatini. Trigeminal nerve is the nerve of the first arch
Second Pharyngeal Arch
Eventually develops into muscles of facial expression, Stylohyoid, Posterior belly of digastric, Hyoid bone. Facial nerve is the nerve of the second arch
Trigeminal! Branches into Opthalmic, Maxillary, and Mandibular for innervation of superficial face
Opthalmic Division of CNV
Sensory of innervation of the forehead
branch of opthalamic division of CNV, sensory to lateral forehead and upper eyelid
Branch of opthalamic division of CNV, sensory to medial forehead and upper eyelid
Branch of opthalamic division of CNV, Sensory to medial part of the eye and root of nose
Maxillary division of CNV
Sensory to the skin between the lower eyelid and the upper lip and the skin over the zygomatic bone and nose
Branch of maxillary division of CNV, comes from below eyeball. Sensory to skin of the lower eyelid, cheek, lateral nose and upper lip, Sensory to skin over the anterior part of temporal fossa.
Mandibular Division of CNV
Sensory to the skin over the mandible. Splits to mental nerve, buccal nerve, and auriculotemporal nerve.
Branch of mandibular division of CNV. Sensory over the skin of chin and lower lip
Buccal Nerve (Long Buccal)
Branch of mandibular division of CNV. Sensory to the skin and the oral mucosa of the cheek
Branch of mandibular division of CNV. Sensory to the scalp anterior to the ear and posterior part of the temporal fossa
Great auricular nerve
Branch of cervical plexus. Sensory to skin inferior to ear and over parotid gland.
AKA tic douloureux. Disorder of sensory root of CNV. Sudden sharp pain in face, 15-20 minutes. Maxillary nerve usually involved. Cause unknown
Muscles of Facial Expression
Lie in the superficial fascia Attached partly to the skin. Enable us to move the skin of the face and change our facial expressions. Do not move bones of the face. All muscles of the facial expression are innervated by the facial nerve. There is no distinct deep fascia on the face. Facial lacerations gape widely. Muscles are arranged around the natural openings of the face and act as sphincters.
Sphincter muscle of the orbit. Has an orbital portion and palpebral portion. Produces crows feet – wrinkling of the skin lateral to the orbit.
Orbicularis Oculi Orbital
Concious eye closure
Orbicularis Oculi Palpebral
Unconcious eyelid movement
Depressor Anguli Oris
Trangular muscle. Depresses corners of mouth.
Extend from the zygomatic bone to the lateral corner of the mouth. act to raise the corner of the mouth and the upper lip (Smiling!) Same fxn as minor, different attachment
Extend from the zygomatic bone near orbicularis oculi to the lateral corner of the mouth. act to raise the corner of the mouth and the upper lip (Smiling!) Same fxn as major different attachment
Levator labii superioris
Descends from the infraorbital margin to the upper lip. Acts to raise the upper lip
Levator anguli oris
Extends from the maxilla (below the infraorbital foramen) to the corner of the mouth. Raises the corner of the mouth
Depressor Labii Inferioris
Attached inferiorly to the mandible and superiorly blends with the orbicularis oris muscle. Depresses the lower lip
Attached to the alveolar processes of the mandible and maxilla and the pterygomandibular raphe. Aids in mastication (but is not a muscle of mastication. Keeps cheek taut so you don't bite it! Used in whistling.
Sphincter muscle of the mouth/oral cavity. Encircles the mouth and forms a prominence of the upper and lower lips. When contractly, mouth is closed. Comprssed tips against lips, holds food during mastication.
Lies in superficial fascia. Blends with skin above mandible. Depresses mandible and stops neck from wrinkling/folding.
Muscles of Scalp
Occipitalis and frontalis (Often considered one muscle: occipitofrontalis, connected by epicranial aponeurosis). The two bellies of the muscle are interconnected by a tendinous sheath known as the epicranial aponeurosis No bony attachments Produces a surprised look when contracted
Motor Innervation of Superficial Face Muscles
Facial Nerve (CNVII), exits parotid and gives off 5 branches: To Zanzibar By Motor Car. Temporal, Zygomatic, Buccal, Marginal Mandibular, Cervical
proceeds superiorly slightly anterior to the ear
courses towards the corner of the eye
motor to the muscles over the cheek area
proceeds inferomedially across the mandible
courses below the mandible to supply the platysma
Damage to CNVII or its branches producing paralysis in some or all of the muscles it innervates
Usually the 4th branch of the external carotid. crosses the mandible (slightly anterior to the angle) and then follows a sinuous course across the face to the medial angle of the eye. Compression of facial artery - done at the mandible but does not stop bleeding completely because of anastomosis with the facial artery on the other side of the face. Branches to inferior labial, superior labial, and angular arteries.
Inferior labial artery
Branches from facial artery. Supplies blood to lower lip
Superior labial artery
Branches from facial artery. Supplies blood to upper lip
Terminal part of facial artery. Medial corner of eye.
Superficial Temporal Artery
One of the terminal Branches of the External Carotid Artery. Branches into 3 to supply face and scalp: transverse facial, parietal, and frontal
Transverse Facial Artery
Branch of superficial temporal artery. Follows parotid duct transversely across the face
Branch of superficial temporal artery. Supplies lateral part of scalp
Branch of superficial temporal artery. Supplies anterior part of scalp.
Begins as angular vein at root of nose. No valves, so reflux of infection in danger area (triangle around nose) is a signifcant risk. Makes connections with the cavernous sinus and the pterygoid plexus of vein