Head anatomy Flashcards

1
Q

Describe the layers in the diagram below

A

A: Skin
B: Aponeurosis
C: Periosteum
D: Dura
E: Connective tissue
F: Loose areolar tissue
G: skull

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2
Q

Name the layer in which the blood supply lies

A

Connective tissue layer

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3
Q

Describe the arterial supply of the scalp

A

Arterial supply to scalp from anterior midline to posterior midline is:

-Supratrochlear artery (branch of ophthalmic)
–Supraorbital artery (branch of ophthalmic)
-Superficial temporal (external carotid)
-Posterior auricular (external carotid)
-occipital (external carotid)

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4
Q

Describe the venous drainage of the scalp

A

Veins matching names of arteries

Externally collected by:
–> facial
–> retromandibular
–> posterior auricular veins

Intracranially:
–> connect with diploic veins of skull
–> connect with dural venous sinuses via valveless emissary veins

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5
Q

What medical conditions can arise form the superfiical temporal artery?

A

Migraines
Temporal arteriitis

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6
Q

Describe the presentation/investigation/management of temporal arteritis

A

Presentation:

Commonly
–> throbbing headache
–> tenderness when touching scalp

Rarely
–> symptoms of flu
–> jaw claudication
–> pain in neck/upper arms/shoulder
–> problems with eyesight (double vision/blindness/blurry vision)

Investigation
-FBC, U + E, CRP, ESR
-Temporal artery biopsy

Treatment
-Analgesia
-Steroids

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7
Q

Describe presentation/investigation/management of migraine

A

Presentation:
-Headache (unilateral), throbbing in nature
-May be associated with nausea/vomiting/aura
-Can be associated with visual disturbance

Ix
-Clinical diagnosis
-If not settling, exclude temporal arteritis

Mx
-Analgesia
-Preventative medications
-Lifestyle advice: managing precipitating factors

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8
Q

What are the surgical considerations when managing patients with scalp lacerations?

A

-Rich blood supply: profuse bleeding
-Lacerations deep to aponeurosis can gape resulting in difficult skin closure
-Inelastic tissue can make primary closure difficult: may require undermining of adjacent tissues
-

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9
Q

What methods could you use to close simple scalp lacerations?

A

-Likely to require sutures or staples
-Remain in situ for 5-7 days

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10
Q

What type of sutures should be used for closure?

A

-Superficial layer: Non asorbable 3’0 or 4’0
-Deep layer Absorbable 3’0 or 4’0

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11
Q

What is the clinical significance of infections involving the scalp?

A

-Emissary veins have no valves so superfiical scalp infections and also superficial infections of the face can spread intracranially to dural venous sinuses including cavernous sinus

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12
Q

What is the commonest lump to present in the scalp and why?

A

-Large number of sebaceous glands in scalp
-Sebaceous cyst
-Ulcerative or nodulo-ulcerative lesions can be cutaneous malignancies e.g. BCC or SCC

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13
Q

Describe the sensory nerve supply to the face

A

-Trigeminal nerve
–> V1 (sensory)
–> V2 (sensory)
–> V3 (mixed sensory and motor)

Note: Cutaneous sensation to scalp and face anterior to pinna is supplied by trigeminal nerve. Posterior to pinna is supplied by nerve roots C2 and C3 (greater and lesser occipital nerves) and by greater auricular nerve

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14
Q

Name the branches of the ophthalmic division of the trigeminal nerve

A

NFL

Lacrimal
Nasociliary
Frontal

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15
Q

Name the branches of maxillary division of trigeminal nerve

A

Infraorbital
Zygomatic
Superior alveolar
Palatine
Pharyngeal
Superior labial

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16
Q

Name the main divisions of the mandibular division of trigeminal nerve

A

After exiting foramen ovale gives off branches to:
–> medial pterygoid
–> tensor tympani
–> tensor veli palatini

Then divides into (predominantly motor) anterior branch and (predominantly sensory) posterior branch

Anterior division
–> Lateral pterygoid
–> masseteric
–> deep temporal
–> buccal

Posterior division
–> auriculotempral
–> lingual
–> inferior alveolar (also nerve to mylohyoid which supplies mylohyoid and anterior belly of digastric)

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17
Q

Name the sensory branches of the mandibular division of the trigeminal nerve

A

-Buccal
-Auriculotemporal
-Inferior alveolar
-Lingual

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18
Q

Name the branches of the facial nerve within the substance of the parotid gland

A

Temporal
Zygomatic
Buccal
Marginal mandibular
Cervical

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19
Q

What do the branches of facial nerve supply?

A

Temporal
–> frontalis (raises eyebrows)
–> orbicularis oculi (closes eyes)

Zygomatic
–> Orbicularis oculi

Buccal
–> Risorius (smiling)
–> buccinator (mastication)
–> orbicularis oris (pucker and close lips)

Marginal mandibular
–> depressor labii inferioris
–> depressor anguli oris
–> mentalis (allows pouting)

Cervical
–> platysma

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20
Q

What does the marginal mandibular branch of the facial nerve supply? What is the clinical significance of its course?

A

–Depressor anguili oris (frowning, depresses corner of mouth)
-Depressor labii inferioris (depresses lower lip)
-Mentalis (allows pouting)

Nerve runs inferior to the mandible putting it at risk in surgeries such as submandibular gland excision or carotid endarterectomy

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21
Q

Name the structures that attach to the styloid process

A

-Stylohyoid muscle and ligament
-Styloglossus
-Stylopharyngeus
-Stylomandibular ligament

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22
Q

Name the muscles that attach to the mastoid process

A

-Sternocleidomastoid
-Splenius capitis
-Posterior belly of digastric
-longissimus capitis

23
Q

Describe the course of the facial nerve

A

Mixed motor and sensory nerve
–> from nervus intermedius (sensory) and facial nerve nucleus in pons (motor)
–> enters facial canal in petrous temporal bone via internal acoustic meatus
–> Gives off tear, hear, taste branches
–> exits facial canal via stylomastoid foramen
–> gives off 3 more branches (arseholes die slowly)
–> enters parotid between deep and superficial lobes and gives off 5 branches (ten zulus buggered my cat)

24
Q

Name the branches of the facial nerve before it exits the stylomastoid foramen

A

Tear, hear, taste

-Greater petrosal
-Nerve to stapedius
-Chorda tympani

25
Q

Name the extracranial branches of the facial nerve before it enters the parotid gland

A

Arseholes die slowly

-Posterior auricular
-Nerve to posterior belly digastric
-Nerve to stylohyoid

26
Q

Describe the clinical significance of the course of the facial nerve

A

-Branches of facial nerve lie between deep and superficial branches of parotid gland
-Therefore can be injured in superfiical parotidectomy or parotid tumour

27
Q

Identify the following bones on the image (orbit)

A

A: frontal
B: sphenoid
C: zygomatic
D: ethmoid
E: lacrimal
F: maxillary

Many friendly zebras enjoy lazy summer picnic

maxillary
frotnal
zygomatic
ethmoid
lacrimal
sphenoid
palatine

28
Q

Name the openings within the orbit

A

Superor orbital fissure
Inferior orbital fissure
Optic canal
Anterior ethmoid foramen
Posterior ethmoid foramen

29
Q

Name the structures that pass through the superior orbital fissure

A

Oculomotor nerve (superior and inferior division)
Trochlear nerve
V1 and branches (frontal/lacrimal/nasociliary)
Abducens

Superior and inferior ophthalmic vein
Sympathetic nerve fibres

30
Q

Structures passing through Inferior orbital fissure

A

Infraorbital nerve
Infraorbital artery
Infraorbital veins

Inferior ophthalmic vein
Zygomatic nerve

31
Q

Name the structures that pass through the anterior and posterior ethmoid foramina

A

Anterior
–> anterior ethmoid nerve
–> anterior ethmoid vessels

Posterior
–> posterior ethmoid nerve
–> posterior ethmoid vessels

32
Q

Name the structures that pass through the optic canal

A

Optic nerve
Ophthalmic artery
Central retinal artery
Central retinal vein

33
Q

What is the functional loss due to an abducens nerve palsy?

A

Patient is no longer able to abduct eye
Causes convergent strabismus

34
Q

What is the functional loss due to an oculomotor nerve palsy?

A

Will result in loss of function of:
–> Levator palpebrae superioris
–> Inferior oblique
–> Superior, inferior and medial rectus
–> Sphincter pupillae

Muscle has ‘down and out’ position as well as ptosis (drooping of eyelid) and mydriasis (pupil dilatation)

Pupillary dilatation is caused by the denervation of the parasympathetic fibres which are carried along with the nerve

35
Q

What is the functional loss due to a trochlear nerve palsy?

A

-Denervation of superior oblique muscle
-Eye has downwards and inwards position
-Patient presents with diplopia

Note: may find head tilting a good compensatory position

36
Q

What are the main actions of the extraocular muscles?

A

Levator palpebrae superioris:
–> elevates upper eyelid

Superior rectus
–> elevates, adducts, rotates globe medially

Inferior rectus:
–> depresses, adducts, rotates globe medially

Lateral rectus:
–> abducts globe

Medial rectus:
–> adducts globe

Superior oblique
–> Depresses, abducts and rotates globe laterally

Inferior oblique
–> Elevates, abducts and laterally rotates globe

37
Q

What are the origins and insertions of the extra-ocular muscles?

A

Origin

Levator palpebrae superioris–> lesser wing of sphenoid

Superior oblique –> body of sphenoid

Inferior oblique –> floor of orbit

Recti–> common tendinous ring

Insertion

Levator palpebrae superioris –> tarsal plate

All others –> sclera

38
Q

What is orbital cellulitis?

A

-Refers to inflammation affecting tissues around the eye
-Can be pre or post septal depending on relationship to the orbital septum
-Usually associated with sinusitis, local soft tissue infection or trauma to face and URTI

39
Q

What is the management of orbital cellulitis?

A

-IV abx
-Nasal decongestants
-Drainage of any abscess

40
Q

Name two complications of orbital cellultitis

A

-Abscess can cause visual compromise
-Can spread intracranially to cause cavernous sinus thrombosis

41
Q

Name the parts of the cranial fossa

A

The cranial fossa is divided into 3 parts:
-Anterior fossa
-Middle fossa
-Posterior fossa

42
Q

Describe the bony boundaries of the anterior cranial fossa

A

Boundaries of the anterior cranial fossa are:
-Anterior: internal surface of frontal bone
-Posteromedial: anterior border of prechiasmatic sulcus of sphenoid (also called limbus)
-Posterolateral: lesser wings of the sphenoid bone
-Floor: Orbital part of frontal bone, ethmoid bone and anterior aspects of body and lesser wings of sphenoid

43
Q

Describe the bony boundaries of the middle cranial fossa

A

-Anteromedial: chiasmatic sulcus and limbus of sphenoid
-Anterolateral: lesser wings of sphenoid
-Posteromedial: dorsum sellae of the sphenoid
-Posterolateral: petrous part of the temporal bone
-Floor: body and greater wing of sphenoid; squamous and petrous parts of temporal bone

44
Q

Describe the bony boundaries of the posterior cranial fossa

A

-Anteromedial: dorsum sellae of sphenoid
-Anterolateral: petrous part of temporal bone
-Posterior: internal surface of squamous part of occipital bone
-Floor: mastoid part of temporal bone; squamous, condylar and basilar parts of occipital bone

45
Q

Name the foramina within the anterior cranial fossa and what structures pass through them

A

Foramen caecum
–> nasal emissary vein

Cribriform plate foramina
–> olfactory nerve

Anterior and posterior ethmoidal foramina
–> anterior and posterior ethmoidal vessels and nerves

46
Q

Name the foramina within the middle cranial fossa and what structures pass through them

A

Optic canal:
–> optic nerve
–> ophthalmic artery
–> central rentinal artery and vein

Superior orbital fissure
–> oculomotor nerve (superior and inferior divisions)
–> Trochlear nerve
–> ophthalmic branch of trigeminal nerve
–> abducens nerve
–> superior and inferior ophthalmic veins
–> sympathetic fibres

Foramen rotundum
–> V2

Foramen ovale
–> otic ganglion
–> v3
–> accessory meningeal artery
–> lesser petrosal nerve
–> emissary veins

Foramen spinosum
–> meningeal branch of maxillary nerve
–> middle meningeal artery and vein

Foramen lacerum
–> Filled with cartilagenous plate. ICA runs over it

Carotid canal
–> internal carotid artery

47
Q

Name the foramina within the posterior cranial fossa and what passes through them

A

Stylomastoid foramen
–> 7, 8
–> labyrinthine artery

Jugular foramen
–> 9,10, 11
–> Inferior petrosal and sigmoid sinuses uniting to form jugular vein

Hypoglossal canal
–> 12

Foramen magnum
–> Arteries: vertebral arteries forming basilar artery, anterior and posterior spinal arteries
–> veins: spinal veins
–> nerve: spinal part of accessory nerve (ascends up and joins cranial part of accessory nerve to exit through jugular foramn)
–> soft tissue: end of medulla, beginning of spinal cord, meninges

48
Q

Name the cranial sutures

A

Metopic, sagital, lambdoid, coronal, squamosal

49
Q

Describe why the suture lines are important in the context of suspected NAI in children

A

-Persistent cranial sutures should not be mistaken for fracture during interpretation of XR or CT scans

50
Q

Which condition can result in early fusion of cranial suturesa?

A

-Craniosynostosis
-Note: saggital synostosis is the most common form resulting in ‘boat shaped’ skull

51
Q

What is a basal skull fracture?

A

Fracture that can involve one or more of the following bones: temporal (commonest bone involved), occipital , sphenoid or ethmoid bones

52
Q

What are the signs and symptoms of a basal skull fracture?

A

-Battle’s sign (bruising of mastoid process)
-Racoon eyes (bruising of periorbital region)
-Symptoms: CSF rhinorrhea, haemotympanum, deafness and bleeding from the nose and ears, anosmia, facial nerve palsy

53
Q

What is the clinical relevance of the danger triangle of the face?

A

-Area from corners of mouth to bridge of nose, including nose and maxilla
-As there are no valves in the veins draining this area, retrograde infections from nasal area can spread to cranial cavity causing cavernous sinus thrombosis, meningitis or brain abscess

54
Q

What are the complicaitons of cavernous sinus thrombosis?

A

Can cause symptoms related to both orbital and cranial nerve involvement:

–> orbital symptoms include periorbital oedema, ptosis, chemosis, proptosis and photophobia
–> cranial nerve palsies: 3-V2 can occur with 6th nerve to be first nerve to be commonly affected
–> this is because abducens nerve lies in middle of cavernous sinus as oposed to other nerves that lie along lateral wall of cavernous sinus