HEAD AND NECK I Flashcards
What is the zygomatic arch?
The cheekbone, formed by the zygomatic process of the temporal bone and the temporal process of the zygomatic bone
What are the rami of the mandible?
The vertical parts on either side of the jawbone. Flat quadrilateral bones marked by oblique ridges. Their outer surface is an attachment for the masseter muscle
What is the coronoid process?
A thin, triangular eminence of the mandible which is flattened from side-to-side and varies in shape and size. Its anterior border is convex and is continuous below with the anterior border of the ramus
What is the condyle of the mandible?
The head of the mandible, which presents an articular surface for articulation with the articular disk of the temporomandibular joint. It is convex in the AP aspect, and from side to side
What is the external auditory meatus
The passageway that leads from the outside of the head to the tympanic membrane, or eardrum membrane, of each ear. It conducts soundwaves to the tympanic membrane. It is a partly cartilaginous and partly bony canal of diameter 6mm and length 25mm
What does the tympanic membrane separate?
The external ear from the middle ear
What’s the infratemporal fossa?
A complex area located at the base of the skull, deep to the masseter. It is closely associated with both the temporal and pterygopalatine fossae and acts as a conduit for neurovascular structures entering and leaving the cranial cavity
What is the lateral pterygoid plate of the sphenoid bone?
The lateral pterygoid plate is a broad, thin and everted and forms the lateral part of a process from the inferior part of the sphenoid bone. It’s an origin for the lateral pterygoid muscle
What is the medial pterygoid plate of the sphenoid bone?
A horse-shoe shaped process that arises from the underside of the sphenoid bone. It’s narrower and longer than the lateral pterygoid plate and has a hook-like process, the pterygoid hamulus, around which the tensor veli palatini glides
What is the carotid canal?
A passage within the petrous temporal bone that transmits the internal carotid artery and sympathetic plexus. Its inferior opening is called the carotid foramen and is situated anteriorly to the jugular foramen and medially to the carotid plate
What does the carotid canal open into?
The middle cranial fossa, superior to the foramen lacerum
What is the styloid process of the temporal bone?
A slender, pointed part that projects anteroinferiorly from the inferior surface of the petrous temporal bone. It serves as an anchor for several muscles of the tongue and larynx
What is the stylomastoid foramen?
A rounded opening on the inferior surface of the petrous temporal bone, between the base of the styloid and mastoid processes. It transmits the facial nerve
What divides the jugular foramen into 2 parts and what are these parts?
A fibrous or bony septum called the jugular spine separates the jugular foramen into the smaller pars nervosa and the larger pars vascularis
What does the pars nervosa of the jugular foramen contain?
The inferior petrosal sinus and the glossopharyngeal nerve
What does the pars vascularis of the jugular foramen contain?
The jugular bulb (a venous expansion), the vagus nerve and the accessory nerve
What is the occipital condyle?
A round protuberance of the occipital bone
What is the pterygopalatine fossa?
A bilateral, conical depression extending deep from the infratemporal fossa to the nasal cavity via the sphenopalatine foramen
What is the calvaria?
The top part of the skull, which includes the superior portions of the frontal, occipital and parietal bones
What is a fontanelle?
An anatomical feature of the infant human skull comprising any of the soft membranous sutures between cranial bones that make up the calvaria of a foetus or infant
What is craniosynostosis?
A birth defect where 1 or more sutures of the skull close too early, which can limit or slow the growth of the baby’s brain. The baby’s head will stop growing in the affected area(s), leading to abnormal shaping of the head
What is sagittal synostosis?
The baby’s head grows long and narrow (scaphocephaly)
What is coronal synostosis?
The baby may have a flattened forehead on the side of the skull that closed early (anterior plagiocephaly)
What is bicoronal synostosis?
The baby’s head will grow broad and short (brachycephaly)
What happens in lambdoid synostosis?
The baby’s head may be flattened on the back side (posterior plagiocephaly)
What is the mental foramen?
One of the 2 foramina on the anterior surface of the mandible. It transmits the terminal branches of the inferior alveolar nerve and vessels (the mental artery)
What is the auriculotemporal nerve?
A sensory branch of the posterior division of the mandibular nerve (V3) that runs with the superficial temporal artery an vein, and provides sensory innervation to various regions on the side of the head
What is the maxillary artery?
The largest terminal branch of the external carotid artery that arises at the back of the neck of the mandible. It supplies deep structures of the face, such as the mandible, maxilla, teeth, muscles of mastication, palate, nose and part of the cranial dura mater
What is the mandibular nerve?
The third branch of the trigeminal nerve. It has a sensory role in the head, and also has motor function. V3 exits the cranium through foramen ovale. It courses through the infratemporal fossa
Describe the masseter and its points of origin and insertion
A strong, thick rectangular muscle that originates from the zygomatic arch and extends down to the mandibular angle. It has a superficial part and a deep part
What’s the function of the masseter?
Elevation and protrusion of the mandible, as well as supporting the articular capsule of the temporomandibular joint
What innervates the masseter?
The masseteric nerve of the mandibule nerve
What’s the blood supply to the masseter?
The masseteric artery
What are the 4 muscle of mastication?
Masseter, temporalis muscle, the lateral pterygoid muscle and the medial pterygoid muscle
Describe temporalis
Temporalis is a flat, broad, fan-shaped muscle that lays within the temporal fossa, superior to the zygomatic arch, so it covers much of the temporal bone
Origin and insertion of temporalis
Origin- the temporal fossa
Insertion- the apex and medial surface of the coronoid process of the mandible
Innervation of temporalis
Deep temporal branches of the mandibular nerve
Actions of temporalis
Elevates the mandible and retracts the mandible
What covers temporalis?
A dense layer of deep temporal fascia
Describe the lateral pterygoid muscle and its origin and insertion
Origin- the underside of the greater wing of the sphenoid and the lateral aspect of the lateral pterygoid plate
Insertion- the anterior condylar process, the capsule of the temporomandibular joint and the front edge of the articular disc.
Its fibres run posterolaterally
Innervation of the lateral pterygoid muscle
Lateral pterygoid nerve of the mandibular nerve
Describe the actions of the lateral pterygoid on bilateral and unilateral contraction
Bilateral contraction causes protrusion and depression of the mandible and stabilisation of the condylar head during closure.
Unilateral contraction allows medial movement of the mandible
Describe the medial pterygoid muscle and its origin and insertion
Origin- deep head from the lateral pterygoid plate; superficial head from the tuberosity of the maxilla
Insertion- the medial surface of the ramus and angle of the mandible
Fibres run posteroinferolaterally
Innervation of the medial pterygoid muscle
Innervated by the medial pterygoid nerve of the mandibular nerve
Describe actions of the medial pterygoid muscle on bilateral and unilateral contraction
Bilateral contraction causes elevation and protrusion of the mandible
Unilateral contraction causes medial rotation of the mandible
What does orbicularis oculi surrouns?
The palpebral aperture
What are the parts of orbicularis oculi?
A thin palpebral part and a more substantial orbital part
Origin and insertion of orbicularis oculi
Origin- medially from the medial palpebral ligament and the bone above and below it
Insertion- lateral to the palpebral aperture
Action of orbicularis oculi
Contraction of the palpebral part closes the eye gently, while contraction of the whole muscle screws up the eyes by closing the eyelids tightly
What do the superficial fibres of orbicularis oris encircle?
The oral commissure
Origin and insertion of orbicularis oris
Origin- the medial aspects of the maxilla and mandible
No insertion
Action of orbicularis oris
Close the oral commissure and press the lips together
What fills the deep hollow between the buccinator and masseter?
The buccal fat pad
What 2 muscles are used t smile?
Zygomaticus major (pulls on orbicularis oris superoposteriorly) Risorius (pulls on orbicularis oris posteriorly
Describe platysma
It lies partly in the face, but mainly in the neck. It lies within the subcutaneous fascia of the neck. Most of its fibres insert along the border of the mandible, but its more posterior fibres insert into orbicularis oris
What is the action of platysma?
Pulls the corners of the mouth inferoposteriorly
