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Cranium is made up of
Neurocranium and Viscerocranium
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Neurocranium
- Bony case surrounding the brain and its coverings (calvaria and cranial base)
- - temporal, parietal, frontal, ethmoid, sphenoid, occipital
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Viscerocranium
- Bones of the face associated with the pharyngeal arches
- - maxilla, inferior nasal concha, zygomatic, palatine, nasal, lacrimal, ethmoid, vomer
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Mandible
- Articulates with temporal bone at temporomandibular joint
- - Processes: alveloar (houses teeth), coronoid (muscle insertion), condylar (supports mandibular condyle)
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Bones of the orbit
Frontal, maxilla, zygomatic, sphenoid, ethmoid, lacrimal, palatine
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Apertures within the orbit
Superior orbital fissure, inferior orbital fissure, optic foramen, opening of nasolacrimal canal
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Piriform aperture
- External opening of nasal cavities
- - Nasal bone (superiorly)
- - Maxilla (everywhere else)
- - Septum- vomer (inferiorly), perpendicular plate of ethmoid (superiorly)
- - Nasal conchae- curved bony plates on wall to increase surface area for mucosa; superior (ethmoid), middle (ethmoid), inferior (separate)
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Temporal fossa
depression on side of braincase that accommodates the temporalis muscle
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Temporal lines
Ridges of muscle attachment for temporalis muscle and temporal fascia
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Zygomatic arch
- Arch of bone made up of the zygomatic process of the temporal bone and the temporal process of the zygomatic bone
- - attachment for masseter muscle and temporal fascia
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Anterior cranial fossa
- Supports frontal lobes and olfactory bulbs, forms root of orbit
- - back edge is sphenoidal crest
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Middle cranial fossa
- Supports temporal bones laterally
- - medial part is called sella turcica, surrounded by anterior and posterior clinoid processes, pit at center (hyposphyseal fossa) supports pituitary gland
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Posterior cranial fossa
- Supports cerebellum, pons, and medulla oblongata
- - Starts at petrous ridge
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Sagittal suture
- On midline
- - Premature closure results in a long and narrow skull- scaphocephaly
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Coronal suture
- In frontal plane
- - Premature closure results in short skull- brachycephaly
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Lamboid suture
- curves laterally and ventrally from posterior end of sagittal suture
- - between occipital and parital bones
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Squamosal suture
Between temporal and parietal bone
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Metopic suture
on midline, between left and right frontal bone
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Pterion
- Region on side of cranium where parietal, frontal, sphenoid, and temporal bones meet
- - vulnerable to injury becasue middle meningeal artery runs inside the cranium here
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Bregma
Where coronal suture meets sagittal suture- anterior fontanelle
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Lambda
Where lambdoid suture meets sagittal suture- posterior fontanelle
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Glabella
Area between the eyebrows- vertical creases
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Eyelids
- Superior and inferior palpebrae
- - slit- palpebral fissure
- - angles- medial and lateral canthi
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Nasal cartilages
septal, lateral, alar
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Red zone of lips
vermillion
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Philtrum
groove running from nasal septum to upper lip
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Orbilularis oculi
- Orbital group
- - orbital- peripheral portion arising from orbital margin and medial palpebral ligament
- - palpebral- from medial palpebral ligament through both lids to insert on lateral palpebral raphe
- - lacrimal- courses posterior to lacrimal sac, aids in tear collection
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Levator labii superioris alaeque nasi
- Nasal group
- - from maxilla to side of nose and insert on skin of upper lip
- - elevates upper lip and dilates the nostril
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Levator labii superioris
- Oral group
- - arises from maxilla at inferior margin of orbit, deep to obicularis oculi and courses inferiorly to insert on the lateral half of the upper lip
- - elevates the upper lip
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Zygomaticus minor
- Oral group
- - arises from zygomatic bone in front of zygomaticus major and passes obliquely downward to insert on lateral part of upper lip
- - elevates upper lip
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Zygomaticus major
- Oral group
- - arises from zygomatic bone and passes obliquely downward to insert at corner of mouth
- - pulls mouth upward and outward, as in smiling and laughing
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Levator anguli oris
- Oral group
- - arises from maxilla and passes downward and laterally to insert on the corner of the mouth
- - lies deep to levator labii superioris
- - elevates the corner of the mouth
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Risorius
- Oral group
- - arises from the parotid fascia and buccal skin and inserts onto the corner of the mouth
- - widens the mouth
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Depressor anguli oris
- Oral group
- - arises from mandible and fibers pass upwards to insert on angle of mouth
- - triangular in shape- fibers converge on mouth
- - depresses the corner of the mouth- grief
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Depressor labii inferioris
- Oral group
- - arises from mandible and the fibers pass upward and medially to insert on the lower lip
- - medial fibers cross
- - depresses lower lip and draws it laterally
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Mentalis
- Oral group
- - arises from incisive fossa of the mandible and inserts into skin of the chin
- - rasies and protrudes the lower lip
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Orbicularis oris
- Oral group
- - formed by interlacing fibers of other muscles as well as buccinator
- - also from intrinsic fibers within the substance of the lips
- - fibers encircle the oral orifice
- - closure, pursing, and protrusion of the lips
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Buccinator
- Oral group
- - arises from pterygomandibular raphe but also from maxilla and mandible and its fibers pass forward to insert onto mouth
- - forms substance of cheek
- - aids in mastication, whistling, and blowing
- - pierced by parotid duct
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Auricular muscles
around ears, rudimentary
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Platysma
- arises from the superficial fascia of skin of thorax and courses upward through the neck to insert onto lower part of face
- - wrinkles skin of neck and face, also active in sudden, deep inspiration
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Occipitofrontalis
- occipitalis- arises from acciptal bone and inserts into the epicranial aponeurosis
- --pulls scalp posteriorily and wrinkles posterior scalp
- frontalis- arises from epicranial aponeurosis and inserts into skin over forehead
- --wrinkles skin over forehead
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Facial nerve
- emerges from stylomastiod foramen, pierces the parotid gland and emerges as 5 branches which supply the facial muscles
- - bell's palsy
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Trigeminal nerve
- cutaneous supply of face
- - ophthalmic division
- - maxillary division
- - mandibular division
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CN V1
- sensory to forehead, upper eyelid, and much of nose
- - supraorbital- emerges through supraorbital foramen (forehead and upper lid)
- - supratrochlear- emerges from upper medial angle of eye (medial eye and forehead)
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CN V2
- sensory to lower eyelid, prominence of cheek, ala of nose, part of temple, and upper lip
- - infraorbital- emerges though infraorbital foramen
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CN V3
- sensory to skin over mandible, lower lip, fleshy part of cheek, part of auricle, part of temple
- - motor branches to mucles of mastication
- - mental- emerges via mental foramen (mandible, lower lip)
- - buccal- emerges exteral to buccinator (cheek skin and mucus membrane)
- - auriculotemporal- course with superficial temporal vessels (face and scalp in temporal region)
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