Scalp & Cranial Cavity

Question 1

what does the scalp consist of?

Answer 1

skin & subcutaneous tissue

Question 2

where is the scalp located?

Answer 2

• from the superior nuchal line of the occipital bone to the supraorbital margins of the frontal bone
• laterally extends over the temporal fascia to the zygomatic arch

Question 3

what is the face?

Answer 3

the anterior aspect of the head from forehead to chin & from one ear to another

Question 4

why is the face an important anatomical structure?

Answer 4

plays an important role in communication by making expressions through the facial muscles

Question 5

what does individuality of the face arise from?

Answer 5

primarily from anatomical variation in the shape & relative prominence of the features of underlying cranium

Question 6

what does the SCALP mnemonic stand for?

Answer 6

Skin
Connective tissue
epicranial Aponeurosis
Loose connective tissue
Pericranium

Question 7

what is the dense connective tissue layer in the scalp?

Answer 7

subcutaneous layer rich in neurovascular structures
- richly vascularised
- cutaneous nerves

Question 8

If a scalp wound compromised the epicranial aponeurosis, what would occur?

Answer 8

gaping wound that require sutures to close

Question 9

what is the function of the loose connective tissue in the scalp?

Answer 9

separates scalp properly from underlying pericranium and calvaria
- allows free movement of outer layers over underlying calvaria

Question 10

what is the pericranium?

Answer 10

external periosteal layer

Question 11

what can be found in the skin of the scalp?

Answer 11

• hair follicles
• sweat glands
• sebaceous glands

Question 12

where is the skin of the scalp the thickest?

Answer 12

over the occipital bone

Question 13

What is located in the epicranial aponeurosis? what is its function?

Answer 13

tendon & muscle of occipitofrontalis
- this layer PREVENTS superficial wounds from gaping open

Question 14

what is an important clinical implication of infection reaching the loose connective tissue of the scalp?

Answer 14

loose connective tissue contains spaces susceptible to distension with fluid or infection spread
- fluid/infection may spread to eyelids or root of nose because the frontal belly of the occipitofrontalis inserts into skin & subcutaneous tissue (and NOT into bone)

Question 15

how can scalp infections spread to the intracranial structures?

Answer 15

via emissary veins

Question 16

what are the cervical nerves that supply cutaneous/sensory innervation to the scalp?

Answer 16

• lesser occipital nerve (C2)
• greater occipital nerve (C2)
• great auricular nerve (C2 & C3)
• third occipital nerve (C3)

Question 17

What is considered the “danger area” of the scalp?

Answer 17

Loose connective tissue
- contains emissary veins (valveless veins that connect the extracranial veins of scalp to intracranial dural venous sinuses)
- potential pathway for spread of infection

Question 18

What are the trigeminal nerves that supply the scalp?

Answer 18

• supratrochlear nerve
• supraorbital nerve
• zygomaticotemporal nerve
• auriculotemporal nerve

Question 19

what is the skin over the mandible innervated by?

Answer 19

the cervical plexus with the great auricular nerve

Question 20

what arteries supply the scalp?

Answer 20

anterior scalp = internal carotid artery
lateral & posterior scalp = external carotid artery

Question 21

where does lymphatic drainage in the posterior of the scalp take place?

Answer 21

mastoid and occipital nodes drain to deep cervical nodes

Question 22

where does anterior lymphatic drainage of the scalp occur?

Answer 22

pre-auricular and parotid nodes

Question 23

what lobe of the brain sits in the anterior cranial fossa?

Answer 23

frontal lobe

Question 24

what is the shallowest part of the cranial base?

Answer 24

anterior cranial fossa

Question 25

what bones make up the middle cranial fossa?

Answer 25

sphenoid and temporal bones

Question 26

what lies in the hypophyseal fossa?

Answer 26

the pituitary gland

Question 27

what bones make up the posterior cranial fossa?

Answer 27

sphenoid, occipital & temporal bones

Question 28

what is a buttress?

Answer 28

a thicker portion of cranial bone that transmits forces around weaker regions of the cranium

Question 29

where can the frontonasal buttress be found?

Answer 29

from the region of the canine teeth between the nasal and the orbital cavities to the central frontal bone

Question 30

what is the function of the occipital buttress?

Answer 30

transmits forces received lateral to the foramen magnum from the vertebral column

Question 31

what is the function of cranial meninges?

Answer 31

membranous layers that help in protection of the brain (and spinal cord)

Question 32

what are the different layers of cranial meninges?

Answer 32

- dura mater - arachnoid mater - subarachnoid space - pia mater

Question 33

what are the layers of the dura mater?

Answer 33

- periosteal layer (attached to bone) - meningeal layer (in contact with arachnoid mater)

Question 34

what lines the dura mater?

Answer 34

the arachnoid mater

Question 35

what is the subarachnoid space?

Answer 35

a fluid filled space that contain cerebrospinal fluid and blood vessels

Question 36

what is the difference between the pia mater & the arachnoid mater?

Answer 36

- pia mater enters the sulci of the brain - arachnoid mater does not

Question 37

what is the function of the dura mater folds?

Answer 37

limits the movement of the brain within the cavity

Question 38

what are examples of dura mater folds?

Answer 38

- falx cerebri - tentorium cerebelli - falx cerebelli - diafragma sellae

Question 39

what is the blood supply of the dura mater?

Answer 39

supplied by meningeal arteries that are in the periosteal layer - anterior meningeal arteries - middle & accessory meningeal arteries - posterior meningeal arteries