Lecture 4 (head pt 1)

Question 1

What makes up the scalp proper? List each part

Answer 1

The first 3 layers:
1) Skin
2) Subcutaneous Connective tissue
3) Epicranial Aponeurosis

Question 2

What are the layers of the scalp (NOT scalp proper)

Answer 2

1) Skin
2) Subcutaneous Connective tissue
3) Epicranial Aponeurosis
4) Loose connective tissue
5) Pericranium

Question 3

1) Describe skin of the scalp
2) Describe Subcutaneous Connective tissue of the scalp and its clinical correlation

Answer 3

1) Skin: typical with pilosebaceous units and sweat glands, abundant vascular supply
2) SQ: Thick, dense, richly vascularized with cutaneous nerves
-Embedded in dense connective tissue (limited ability to constrict when injured … bleeds)

Question 4

What is the Epicranial Aponeurosis?

Answer 4

A tendonous sheet of fibrous tissue that covers the calvarium
-Connects the 2 bellies of the occipitofrontalis m. & superior auricular m.
-Continuous with the temporal fascia

Question 5

Describe the jobs of the occipitalis and frontalis

Answer 5

1) Occipitalis muscles: pull scalp posterior
2) Frontalis muscles: wrinkles forehead, raises eyebrows, pulls scalp forward

Question 6

1) Describe the loose connective tissue of the scalp
2) What is unique about this area? What can this cause?
3) What does this unique characteristic allow for?

Answer 6

1) A sponge like layer, potential spaces that may distend with fluid/blood from injury or infection
2) Danger area; there’s no “fire wall”, so infection and bleeding can spread easily throughout this entire layer (ex: hematoma on forehead can migrate and cause a black eye)
-Free movement of the first 3 layers (scalp proper) over the underlying pericranium and skull

Question 7

Why can a black eye result from injury to scalp of the forehead?

Answer 7

Frontal belly of the occipitofrontalis m. inserts into the skin and SQ tissue, not to the bone
-Loose connective tissue of scalp is a sponge-like layer w potential spaces that may distend w fluid/blood from injury or infection

Question 8

1) What stops blood and pus from passing from the forehead to the neck?
2) What stops blood and pus from spreading laterally beyond the zygomatic arches?
2) Explain why loose connective tissue of the scalp is such a dangerous area

Answer 8

1) Occipital belly of occipitofrontalis m. attaches to the occipital bone and mastoid parts to mastoid bone.
2) Epicranial aponeurosis is continuous with the temporal fascia that attaches to the arches.
3) Infection can pass into cranium via emissary veins

Question 9

Why do scalp blood vessels have limited ability to constrict?

Answer 9

They’re embedded in dense connective tissue; scalp wounds bleed a lot

Question 10

1) Describe the pericranium
2) What does it form?

Answer 10

1) Dense layer of connective tissue
2) External layer of the periosteum of skull

Question 11

What can scalp stand for?

Answer 11

1) Skin
2) subcutanous Connective tissue
3) epicranial Aponeurosis
4) Pericranium

Question 12

What are the two structural and functional parts of the cranium? Briefly describe each

Answer 12

1) Neurocranium: cranial vault or “brain bucket” (made up by calvaria + cranial base)
2) Viscerocranium: facial skeleton

Question 13

What are the two parts of the neurocranium?

Answer 13

1) Calvaria (skullcap)
2) Cranial base

Question 14

1) What 5 things does the neurocranium contain?
2) What are its two parts?
3) What bones make it up?

Answer 14

1) Brain, meninges, CSF, proximal CN, vessels
2) Calvaria and cranial base
3) Formed by 8 bones
-4 unpaired: frontal, ethmoid, sphenoid, occipital
-2 paired: temporal and parietal (bilateral)

Question 15

What is the BREGMA?

Answer 15

The intersection of the coronal and sagittal suture lines (soft spot in baby)

Question 16

What is lambda?

Answer 16

The intersection of the sagittal and lambdoid suture lines

Question 17

1) What two things are behind the pterion?
2) What is its clinical significance?

Answer 17

1) Temporal lobe and MMA
2) Can fracture with trauma (and mess with the MMA)

Question 18

What makes up the facial aspect of the cranium (viscerocranium)? List all parts

Answer 18

15 bones:
-Three unpaired midline bones: mandible, ethmoid, vomer
-Six paired or bilateral bones: maxilla, inferior nasal concha (turbinate) zygomatic, palatine, nasal, lacrimal.

Question 19

1) What makes up the orbit?
2) Where are sinuses in relation to the orbits? Why is this clinically relevant?

Answer 19

1) Many thin, fragile bones
2) Medial and inferior to orbits; extension of infections can lead to orbital abscess

Question 20

What are the two primary sources of blood to the brain? List the basic path of each

Answer 20

1) Anterior circulation: Internal carotids > middle and anterior cerebral aa. of circle of Willis.
2) Posterior circulation: Vertebral arteries > basilar artery > circle of Willis

Question 21

What supplies blood to the meninges? (bonus: Describe the basic path)

Answer 21

External carotids
(via maxillary artery through foramen spinosum to middle meningeal artery)

Question 22

What are the two sources of blood supply to the face and viscera of the head? Describe where each goes

Answer 22

1) External carotid: to major branches to face and viscera
2) Internal carotid: to supra orbital/trochlear vessels for frontal region of scalp (mostly brain tho)

Question 23

List the specific path of the artery that supplies the meninges

Answer 23

1) External carotid terminal branch
2) Maxillary artery branch
3) Middle meningeal artery goes through foramen spinosum
4) MMA splits into:
-Anterior branch
-Posterior branch

Question 24

1) Where do the meningeal arteries originate? (reiterate)
2) Where do the cerebral arteries originate?
3) Where do the cerebellar arteries originate?

Answer 24

1) Meningeal arteries: from external carotid aa. via the maxillary artery
2) Cerebral: from the internal carotid and basilar arteries feeding the circle of Willis
3) Cerebellar: from the basilar a. prior to forming the circle of Willis

Question 25

What is the clinical correlation of the meningeal arteries?

Answer 25

-The middle meningeal artery (off the maxillary artery) is in groove of the pterion (the meeting of 3 skull bones)
-Trauma to area/fracture can cause epidural bleed

Question 26

1) Fractures of floor of middle cranial fossa may result in leakage to where?
2) What does this result in?

Answer 26

1) External acoustic meatus
2) CSF otorrhea

Question 27

1) Fractures of floor of anterior cranial fossa may involve what?
2) What may this involvement result in?

Answer 27

1) Cribriform plate of the ethmoid
2) CSF rhinorrhea

Question 28

What may CSF otorrhea and rhinorrhea indicate?

Answer 28

Cranial base fracture and increased risk of meningitis; a clinical sign on exam

Question 29

1) What can cause CSF otorrhea?
2) What can cause CSF rhinorrhea?

Answer 29

1) Fractures of floor of middle cranial fossa (which cause leakage into external acoustic meatus)
2) Fractures of floor of anterior cranial fossa involving the cribriform plate of the ethmoid