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SSN ANATOMY 5 ANSWER KEY
January 30, 2003
Superficial Head & Neck: The beginnings…
1. What are the layers of the scalp?
Skin
Connective tissue: dense, superficial arteries and veins
Aponeurosis: frontalis, occipitalis, anterior and superior auricularis
Loose connective space: DANGER SPACE! Deep arteries & veins that communicate
with diploic veins (and so to the dural sinuses), eyelids, superior nuchal line (posterior),
temporal line (lateral)
Periosteum
2. CRANIAL FOSSAE!
Foramen
Olfactory Foramina
Location
Ethmoid Bone
Contents
- Olfactory n
Foramen Cecum
Optic Canal
btw ethmoid and frontal bones
Sphenoid bone
-
Superior Orbital Fissure
Sphenoid bone
Foramen Rotundum
Foramen Ovale
Foramen Spinosum
Foramen Lacerum
Sphenoid bone
Sphenoid bone
Sphenoid bone
btw Sphenoid and temporal b.
Hiatus of Facial Canal
Internal Auditory Meatus
Temporal bone
Temporal bone
Jugular foramen
btw Temporal and occipial b.
Emissary vein
- CN II – Optic Nerve
- Opthalmic artery
- Central vein of retina
- CN III – Oculomotor Nerve
- CN IV – Trochlear Nerve
- CN VI – Abducens Nerve
- CN V1 – Opthalmic Nerve
- Superior Opthalmic Vein
CN V2 – Maxillary Nerve
- CN V3 – Mandibular Nerve
- Middle meningeal artery
- Carotid artery (runs across, not
through foramen)
- Greater superficial petrosal n
- Greater superficial petrosal n
- CN VII – Facial Nerve
- CN VIII – Vestibulocochlear N
-
CN IX – Glossopharyngeal N
CN X – Vagus N
- CN XI – Spinal Accessory N
(returns from C1-C5 via foramen
magnum)
- Internal jugular vein
- CN XII – Hypoglossal N
-
Hypoglossal Canal
Occipital bone
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3. CSF! Please label the following, and trace the path of CSF through the ventricular system
and then the path of fluid in the venous system.
Straight Sinus
Superior Sagittal Sinus
Transverse Sinus
Lateral Ventricle
Third Ventricle
Fourth Ventricle
Cerebral Aqueduct
Foramen of Monro
Foramen of Magendie
Subarachnoid Space
Choroid plexus
Superior sagittal sinus
Arachnoid Villi
Choroid Plexus
Foramina of Luschka
Arachnoid Villi
Subarachnoid
Space
Straight sinus
Lateral
Ventricle
Foramen of
Monro
Third
Ventricle
Transverse sinus
Fourth ventricle
Cerebral
aqueduct
Foramen of Magendie (Medial)
Foramina of Luschka (Lateral)
VENTRICULAR DRAINAGE:
2 Lateral Ventricles ---via Foramen of Monro 3rd Ventricle ---via cerebral aqueduct
ventricle
(1) central canal of spinal cord
(2) via Foramen of Magendie/2 Foramina of Luschka Cisterna Magna
subarachnoid space ---via arachnoid villi superior sagittal sinus
2
4th
4. CRANIAL NERVES: Start learning this NOW!
Name
Motor/Se
nsory
Function
Foramen
I
Sensory
Smell
Cribriform Plate in
Ethmoid
II
Sensory
Sight
Optic Canal/Foramen
III
Motor (& PS)
Superior Orbital
Fissure
IV
Motor
All extraocular muscles except superior
oblique (CN IV) & lateral rectus (CN
VI)
Superior oblique m
V
Both M & S
V1 Sup. Orb. Fissure
V2 Foramen Rotundum
V3 Foramen Ovale
VI
Motor
M: Muscles of mastication
Tensor Tympani, Tensor Veli Palatini
(via mandibular N.)
S: Facial Sensation (including teeth,
eye)
Lateral rectus m
VII
Both M & S
M: Muscles of facial expression
Stapedius
S: Ears, Taste (anterior 2/3 of tongue)
Internal Acoustic
Meatus
VIII
Sensory
Hearing / Balance
Internal Acoustic
Meatus
IX
Both M & S
(& PS)
M: Stylopharyngeus
S: Gag reflex, external acoustic meatus
Taste (posterior 1/3 of tongue)
Jugular Foramen
X
Both M & S
(& PS)
Jugular Foramen
XI
Motor
M: Muscles of the palate/larynx/pharynx
(except tensor veli palatine – CN VII,
stylopharyngeus – CN IX)
S: Throat sensation, cough reflex
External acoustic meatus
Taste (epiglottis)
M: Trapezius, Sternocleidomastoid m
XII
Motor
M:Tongue muscles (except
palatoglossus – CN X)
Hypoglossal Canal
3
Superior Orbital
Fissure
Superior Orbital
Fissure
Jugular Foramen
5. CRANIAL NERVES: A Developmental Approach
Branchial Arch Derivatives (the cranial nerves that have both sensory and motor functions.)
Branchiomeric nerves: have
Pretrematic branches : Sensory
Post-trematic branches: Both
Branchia
l Arch
First Arch
Bone
Muscle
- Mandible
- Mm
- Sphenomandibular
lig.
- Malleus
- Incus
Second
Arch
- Hyoid
Third Arch
Fourth Arch
lesser horn
- Stylohyoid ligament
- Styloid process
- Stapes
- Hyoid body and
greater horn
- Laryngeal
Cartilages
of mastication
tympani m.
- Tensor palatini m.
- Mylohyoid m.
- Digastric (ant. belly)
- Mm of facial expr.
- Stylohyoid m.
- Digastric (post. belly)
- Stapedius m.
- Stylopharyngeus m.
- Tensor
- Pharyngeal
mm.
m.
- Cricothyroid
Sixth Arch
- Laryngeal
Cartilages
- Laryngeal
mm.
Innervation (Pre and
Post)
CN: Trigeminal Nerve (V)
Pre: Maxillary N (S)
Post: Mandibular N (M&S)
CN: Facial N (VII)
Pre: Chorda tympani (S)
Post: Facial N proper (M&S)
CN: Glossopharyngeal N (IX)
Pre: Tympanic Branch (S)
Post: Glossopharyngeal N
(M&S)
CN: Vagus N (X)
Pre: Pharyngeal branches(S)
Post: Superior laryngeal N
(M&S)
CN: Vagus N (X)
Pre: ???
Post: Recurrent laryngeal N
6. HEMATOMAS!
Subdural:
Anatomy:
Shearing of veins crossing through arachnoid layer → Extravasation of
blood into subdural space, which is normally a “potential” space between
the dura mater and arachnoid mater.
Cause: Can occur with sudden jarring or blow to the head
Symptoms: Low pressure venous bleed, can be asymptomatic or gradually symptomatic
→ Range from various levels of alertness to transient loss of consciousness
Epidural:
Anatomy:
Tearing of middle meningeal artery → Extravasation of blood into the
potential space between the two layers of the dura mater.
Cause: Fracture of the temporal or parietal bone
Symptoms: High pressure arterial bleed, rapidly causes symptoms associated with brain
compression. Transient loss of consciousness, lucid interval (minutes to
hours), death.
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Subarachnoid:
Anatomy:
Rupture of cerebral artery passing in subarachnoid space on the surface of
the brain.
Cause:
Rupture of berry aneurysm, usually found at bifurcations on the circle of
Willis
Symptoms: “Worst headache of my life,” nausea, vomiting. Blood in CSF on spinal
tap.
7. EXTRAOCULAR MUSCLES!
(What do they do to the eyeball? And what is the innervation?.)
Muscle
Primary
Action
Secondary
Action (Normally
Innervation
canceled out)
Superior Rectus
Elevation
Adduction / intorsion
Inferior Oblique
Elevation
Abduction / extorsion
Inferior Rectus
Depression
Adduction / extorsion
Superior Oblique
Depression
Abduction / intorsion
Medial Rectus
Adduction
-
Lateral Rectus
Abduction
-
Levator Palpebrae Superioris
Raises upper
eyelid
-
5
Superior branch of
CN III
Inferior branch of CN
III
Inferior branch of CN
III
Trochlear N (CN IV)
Superior branch of
CN III
Abducens N (CN VI)
Superior branch of
CN III
8. Cervical Plexus! Please label the following:
CN XII
Transverse Cervical N.
Supraclavicular N.
Mm of Tongue
Lesser Occipital N.
Sternothyroid m.
Phrenic N.
Omohyoid m.
SENSORY
MOTOR
Hypoglossal N
Muscles
of Tongue
C1
Greater auricular N
Lesser occipital N
Transverse Cervical N
Supraclavicular N
Sternohyoid m.
Ansa Cervicalis
Geniohyoid /Thyrohyoid Mm
Greater Auricular N.
Ansa
Cervicalis
C2
C3
Geniohyoid
Thyrohyoid
Sternohyoid
Sternothyroid
C4
Omohyoid
C5
Phrenic N
NOTE: Figure does not include innervation to SCM and Trapezius. These muscles receive
two sources of innervation –
1) Spinal Accessory Nerve (C1-C5 coursing back up via foramen magnum, and then
returning via jugular foramen)
2) Nerves directly to muscles via spinal nerves C2-C4 (see Netter 121)
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