Head and Neck - The Bony Skull and Scalp Flashcards
What is the most common joint between most bones in the skull?
Fibrous suture joint
How is the skull divided?
Into 3 parts
What are the 3 parts of the skull?
Neurocranium, viscera- cranium (facial skull) and mandible
What are the 3 parts of a skull bone?
Periosteum, compact cortical bone, cancellous dipole (spongy bone)
What are the 8 bones of the cranium?
1 frontal, sphenoid, ethmoid, occipital
2 parietal, temporal
Name the 4 sutures of the skull.
Sagittal, coronal, lambdoid, squamous
Where is the sagittal suture between?
2 parietal bones
Where is the coronal suture between?
Parietal bones and frontal bone
Where is the lambdoid suture between?
Parietal bones and occipital bone
Where is the squamous suture between?
Parietal bone and temporal bone
What do the bones of the facial skeleton give attachment to?
Muscles of tongue, mastication and pharynx
What are the 14 facial bones?
2 nasal, lacrimal, inferior nasal concha, maxilla, palatine, zygomatic
1 vomer, mandible
What are the bony prominences of the skull?
Occipital protuberance, mastoid process, zygomatic arch, styloid process, occipital condyles
What is the occipital protuberance?
Bump at the back of the head and is part of the occipital bone
What bone is the mastoid process part of?
Temporal bone
What is the zygomatic arch?
Cheek bone and is part of the zygomatic process of the temporal bone and the temporal process of the zygomatic bone
What bone is the styloid process part of?
Temporal bone
What is the occipital condyles?
Where head sits on atlas and is part of the occipital bone
What are the 3 fosse of the cranial cavity?
anterior, middle and posterior cranial fossae
What are the parts of the sphenoid bone?
The body, lesser/greater wings, lateral and medial pterygoid plates
On the floor of the skull looking from the inferior aspect, what can be seen?
Occipital condyles, mastoid and styloid processes, pterygoid plates of sphenoid bone, palatine bone
What is the foramen magnum?
Largest foramen in the posterior cranial fossa
What 2 structures pass through the foramen magnum?
Spina cord and R&L vertebral arteries
What is the role of air spaces?
Decrease the weight of the skull
What are the 3 bones that play a role in hearing?
Hammer/malleus
Anvil/incus
Stirrup/stapes
Where can the external auditory canal be seen?
On the outside without having to look inside the ear
Where does the petrous part of the temporal bone lie?
Immediately inside the canal on the floor of the skull
What is found within the petrous part of the temporal bone?
Ear ossicles
Where does the scalp extend from and to?
Anteriorly: superciliary arches/supraorbital arches
Posteriorly: superior nuchal lines
Laterally: superior temporal bone
What are the superior nuchal lines?
(Slightly) part of the occipital bone
What 2 bones form the zygomatic arch?
Anteriorly: temporal process of zygomatic bone
Posteriorly: zygomatic process of temporal bone
What type of joint is present between these 2 bones at the zygomatic arch?
Oblique suture/fibrous joint
What are the 5 layers of the scalp?
S: skin C: connective tissue A: aponeurosis of the occipitofrontal muscle (epicranial aponeurosis) L: loose connective tissue P: periosteum
What makes up the pericranium?
Periosteum, compact cortical bone, cancellous diploe
What is the epicranial aponeurosis? (2 points to be made)
3rd layer of the scalp
Connects frontal and occipital bellies of occipitofrontalis muscle
What is the action of the occipitofrontalis muscle?
It is a muscle of facial expression
On contraction of the anterior belly it raises the eyebrows
What cranial nerve supplies the anterior part of the scalp (anterior to the auricle of the external ear)?
Trigeminal Nerve (Cr N V)
What are the 3 branches of the trigeminal nerve?
Ophthalamic (V1), Maxillary (V2) and Mandibular (V3)
What do the fibres of the ophthalmic nerve carry?
Purely sensory
What do the fibres of the maxillary nerve carry?
Purely sensory
What do the fibres in the mandibular nerve carry?
Sensory and motor
What cranial spinal nerves supply the posterior half of the scalp (posterior to the auricle of the ear)?
Cutaneous branches of the anterior and posterior rami of the cervical spinal nerves C2 and C3
What structure forms from the ventral rami of C5 to T1?
Brachial plexus
What do the ventral roots of the spinal nerve carry?
Motor fibres
What do the dorsal roots of the spinal nerve carry?
Sensory fibres
What do the ventral and dorsal rami of the spinal nerves carry?
Both sensory and motor fibres
Do they spinal nerves carry any parasympathetic fibres?
No
What fibres could a cranial nerve carry?
Sensory, motor or parasympathetic fibres
Cranial nerves can carry a combination of these
How do sympathetic fibres reach these regions supplied by cranial nerves?
Post-ganglionic fibres form the sympathetic chain from a plexus and hitch a ride with blood vessels
What is general sensory?
Ordinary sensations: touch, temperature, pain etc
What is special sensory?
Vision, hearing, taste
In which layer of the scalp are blood vessels present?
2nd layer: connective tissue layer
What are the branches of the external carotid artery that supply the scalp?
Superficial temporal artery, posterior auricular artery, occipital artery
What are the branches of the internal carotid artery that supply the scalp?
Supratrochlear artery, supra-orbital artery (both branches from ophthalmic artery which is the first branch of ICA)
Where can the pulse of the superficial temporal artery be felt?
In front of the tragus of the ear
What veins drain the scalp?
Supraorbital, supratrochelar, facial, submental, anterior jugular, internal jugular, subclavian, external jugular, posterior auricular, superficial temporal
Do the veins that drain the scalp anastomose with each other?
Yes
What veins, apart from the veins that anastomose with each other, do the veins that drain the scalp anastomose with?
Diploic veins in the skull bones
Through what veins is the blood drained to the venous sinuses of the brain?
Diploic veins and emissary veins
What can emissary veins do?
Emissary veins can spread infection intracranially
What is dipole?
Spongy cancellous bone separating the inner and outer layers of the cortical bone of the skull
What potential grave complication could arise from scalp infections due to the presence of emissary veins?
Meningitis
What is the lymphatic drainage of the scalp?
There is no lymph nodes in the scalp. Lymph drains away from scalp into lymph nodes of the head and neck
