WR1 - Skull & Scalp

Question 1

What type of joint is found between bones in the skull?

Answer 1

Fibrous joints called ‘suture joints’

Question 2

What are the 3 parts of the skull?

Answer 2

Neuro-cranium

Facial skull (viscera-cranium)

Mandibe

Question 3

What are the layers of the skull bone?

Answer 3

Top and bottom are Compact bone

Middle layer is called the ‘Diploe’ ,is Spongey bone and contains red marrow

Question 4

Identify dem bones

Answer 4

yes

Question 5

Identify the sutures

What bones do they join?

Answer 5

Sagittal: Parietal to parietal

Coronal: Frontal to parietal

Lambdoid: Parietal to occipital

Question 6

What type of bones make up the facial skeleton?

Answer 6

Irregular bones

Question 7

What muscles are attached to the bones of the face?

Answer 7

Muscles of the:

tongue

Mastication

pharynx

Question 8

What is this bony prominence?

Answer 8

Occipital protuberance

of the occipital bone

Question 9

Identify this

Answer 9

Mastoid process of temporal bone

Question 10

What is the zygomatic arch and what makes it up?

Answer 10

Zygomatic and temporal bone

Question 11

What are these?

Answer 11

Styloid processes of the temporal bone

serves as an anchor point for several muscles associated with the tongue and larynx

Question 12

What are these?

Answer 12

Occipital condyles of the occipital bone

These articulate with the first vertebra (atlas)

Question 13

What are the three fossae of the skull floor?

Answer 13

Anterior cranial fossa

Middle “ “

Posterior “ “

Question 14

What bone is this?

Answer 14

Sphenoid bone

• This makes up part of the floor of the skull
• The ‘greater wing’ is the part that does this

Question 15

What is the largest foramen in the skull floor?

What passes through it?

Answer 15

Foramen MAGNUM

• Medulla
• Meninges
• R&L Vertebral arteries
• Ant & Post Spinal arteries
• Some other things

Question 16

What are the ‘orbits’ of the skull?

Answer 16

The sockets for the eyeball

Question 17

What are air sinuses/sacks in skull bones?

What is their purpose

Answer 17

Air spaces present within the skull bone. They play a role in decreasing the weight of the skull. AIr sinuses are present in bones around the nasal cavity and open into it

Question 18

What are the ear ossicle bones?

Answer 18

Maleus - hammer

Incus - Anvil

Stapes - stirrup

Question 19

What is the canal in the skull which is used for hearing?

Answer 19

External auditory meatus (external ear canal)

Question 20

Which bone is the external auditory meatus found on?

Answer 20

Temporal bone

Question 21

What are the boundaries of the scalp?

Answer 21

• Anteriorly to eyebrows
• Posteriorly to superior nuchal lines
• Laterally to superior temporal line

Question 22

Where is the superior nuchal line?

Answer 22

Question 23

Superior temporal line?

Answer 23

At the top of temporal fossa (but is still on parietal bone)

Question 24

What type of joint is present between the two bones of the zygomatic arch?

Answer 24

Zygomatic - Temporal

‘Oblique suture’ - Fibrous joint

Question 25

What are the layers of the scalp?

Answer 25

**S**kin **C**onnective tissue (dense) **A**poneurosis (of occipitalfrontal muscle) **L**oose connective tissue\* * Spongelike - *allows free movement of the **scalp proper** (upper 3 layers)* **P**ericranium\* * *Dense layer of connective tissue* \*not easily visible

Question 26

The 3rd layer of the scalp is the aponeurosis. What does it join?

Answer 26

Anterior (frontal) and posterior (occipital) bellies of the occipitofrontalis muscle This is a muscle of facial expression (elevates raises eyebrows)

Question 27

Cutaneous innervation of the scalp comes through two sources. What are these?

Answer 27

_Anterior part_ * The 3 branches of **Trigeminal nerve (CN V)** _Posterior part_ * **Cutaneous branches** of cervical spinal nerves **C3 & C4** * **​**Both ventral & dorsal rami suppy the scalp *(Anterior/posterior to external ear canal)*

Question 28

What structure forms from the ventral rami of C5 to T1 spinal nerves?

Answer 28

Brachial plexus

Question 29

What are the branches of the Trigeminal nerve?

Answer 29

Opthalmic - V₁ Maxillary - V₂ Mandibular - V₃

Question 30

Idenfity these facial dermatomes. (these vary a lot across different diagrams)

Answer 30

Question 31

What is the link with herpes zoster and dermatomes?

Answer 31

Dermatome affected on the skin corresponds to the nerve which supplies it So patient with herpes zoster on left upper facial area = Left opthalmic nerve (V1)

Question 32

In which layer(s) of the sculp are blood vessels contained? What characterises these blood vessels?

Answer 32

Dense connective tissue layer Vessels within this layer are unable to fully constrict so lacerations can cause profuse bleeding

Question 33

What are the 2 main arteries that supply the scalp?

Answer 33

External carotid (posterior) Opthalmic artery (anterior) * Large branch of the internal carotid

Question 34

What are the branches of the External carotid and Opthalmic artery that supply the scalp? Identify them

Answer 34

When it says Indirect branches of Internal carotid - it means via Opthalmic artery These are all **anastamosing branches**

Question 35

What two veins in the neck recieve (most of) the drainage from the scalp?

Answer 35

Internal jugular vein (the big one) External jugular vein

Question 36

Identify the superficial veins that drain skull

Answer 36

Superficial temporal is fed into by **Frontal and parietal tributaries**

Question 37

In addition to anastamosing with each other in the scalp, what other veins do the scalp veins anastamose with?

Answer 37

**Diploic veins** in the skull bones (and through these to the venous sinuses of the brain) through valveless veins called '**Emissary veins'**

Question 38

What is the purpose of emissary veins?

Answer 38

Connect the extracranial venous system with the intracranial venous sinuses. They connect the veins outside the cranium to the venous sinuses inside the cranium (ie providing an alternative route for venous drainage)

Question 39

What potential grave complication could arise from scalp infections due to the presence of emissary veins?

Answer 39

* Rupturing of emissary veins = Subdural haematoma * Also provides route for infection spread (meningitis etc)