17. Head Flashcards
Posterior Triangle
borders
- posterior border: sternocleidomastoid muscle
- anterior border of the trapezius muscle
- superior border of the clavicle.
- roof formed by the platysma and the investing (superficial) layer of the deep cervical fascia.
- floor: splenius capitis and levator scapulae muscles and the anterior, middle, and posterior scalene muscles.
posterior triangle contains this structures
accessory nerve, cutaneous branches of the cervical plexus, external jugular vein,
transverse cervical and
suprascapular vessels,
subclavian vein (occasionally) and artery,
posterior (inferior) belly of the omohyoid, and roots and trunks of the brachial plexus.
nerve to the subclavius and the dorsal scapular, suprascapular, and long thoracic nerves.
posterior triangle is divided into occipital and subclavian (supraclavicular or omoclavicular) triangles by the
omohyoid posterior belly.
Anterior Triangle
boundaries
bounded by the anterior border of the sternocleidomastoid, the anterior midline of the neck, and the inferior border of the mandible.
roof formed by the platysma and the investing layer of the deep cervical fascia.
anterior triangle
futher divided into:
digastric (submandibular), submental (suprahyoid), carotid, and muscular (inferior carotid) triangles.
what muscle divides the anterior triangle
omohyoid anterior belly and the digastric anterior and posterior bellies into the digastric (submandibular), submental (suprahyoid), carotid, and muscular (inferior carotid) triangles.
is a spasmodic contraction or shortening of the neck muscles, producing twisting of the neck with the chin pointing upward and to the opposite side.
Torticollis (wryneck)
torticollis is due to
injury to the sternocleidomastoid muscle or avulsion of the accessory nerve at the time of birth and unilateral fibrosis in the muscle, which cannot lengthen with the growing neck (congenital torticollis)
is an elongation of the styloid process or excessive calcification of the styloid process or stylohyoid ligament that causes neck, throat, or facial pain and dysphagia (difficulty in swallowing).
Eagle’s syndrome
How many skull bones
22
8 cranial bones
14 facial bones
paired cranial bones
parietal
temporal
unpaired cranial bones
frontal
occipital
sphenoid
ethmoid
paired facial bones
palatine lacrimal maxilla nasal inferior nasal concha zygomatic
unpaired facial bones
vomer
mandible
meeting point of frontal and nasal bones
nasion
intersection of the lambdoid and sagittal sutures.
lambda
intersection of the sagittal and coronal sutures.
bregma
craniometric point at the junction of the frontal, parietal, and temporal bones and the great wing of the sphenoid bone.
pterion
craniometric point at the junction of the parietal, occipital, and temporal (mastoid part) bones.
asterion
point on the middle of the nasofrontal suture (intersection of the frontal and two nasal bones).
nasion
most prominent point of the external occipital protuberance, which is used as a fixed point in craniometry
inion
Is a U-shaped bone consisting of a median body, paired lesser horns (cornua) laterally, and paired greater horns (cornua) posteriorly.
Hyoid bone
this part of hyoid
Provides for attachments for the geniohyoid, mylohyoid, omohyoid, and sternohyoid muscles.
body of hyoid
this part of hyoid
Provides attachments for the middle constrictor, hyoglossus, digastric (anterior and posterior) bellies, stylohyoid, and thyrohyoid muscles.
greater horn
Provides attachment for the stylohyoid ligament, which runs from the styloid process to the lesser horn of the hyoid bone.
lesser horn
Is a slender projection of variable length and extends downward and forward from the temporal bone.
stylohyoid
Gives origin to three muscles (stylohyoid, styloglossus, and stylopharyngeus) and two ligaments (stylohyoid and stylomandibular).
styloid process
in Eagle’s syndrome, pain may occur due to
compression of the glossopharyngeal nerve, which winds around the styloid process or stylohyoid ligament as it descends to supply the tongue, pharynx, and neck
pain may be caused by pressure on the internal and external carotid arteries by a deviated and elongated styloid process.
Tx of eagle’s syndrome
styloidectomy
formed by the union of cranial and spinal roots.
Has cranial roots that arise from the medulla oblongata below the roots of the vagus. Has spinal roots that arise from the lateral aspect of the cervical segment of the spinal cord between C1 and C3 (or C1 and C7) and unites to form a trunk that ascends between the dorsal and ventral roots of the spinal nerves in the vertebral canal and passes through the foramen magnum.
Accessory Nerve
thyrohyoid muscle
innervated by
C1 via the hypoglossal nerve
Innervates the infrahyoid (or strap) muscles, such as the omohyoid, sternohyoid, and sternothyroid muscles, with the exception of the thyrohyoid muscle
Ansa Cervicalis
is a temporary loss of consciousness or fainting caused CORRELATES by diminished cerebral blood flow.
carotid sinus syncope
is the excision of atherosclerotic thickening of intima of the internal carotid artery for the prevention of stroke in patients with symptoms of obstructive disease of the carotid artery.
Carotid endarterectomy
s granulomatous inflammation with multinucleated giant cells, affecting the medium-sized arteries, especially the temporal artery. Symptoms include severe headache, excruciating pain in the temporal area, temporal artery tenderness, visual impairment, transient diplopia, jaw claudication, fever, fatigue, and weight loss.
temporal (giant cell) arteritis
temporal (giant cell) arteritis tx
prednisone
skull fracture at pterion may lacerate this artery
middle meningeal artery
skull fracture at pterion may cause this type of hematoma
epidural or extradural hematoma
how does a skull fracture at pterion can cause brainstem copression
compress the lateral part of the cerebral hemsphere –> hernation of the medial part of te temporal lobe -> comperss the brainstem
skull fracture at this area may cause blood or CSF to escape the ear, hearing loss and facial nerve damage
petrous portion of the temporal bone
skull fracture at this area maycause anosmia, periorbital buising,
raccoon eyes, CSF leakage from nose, rhinorrhea
anterior cranial fossa
Skull fracture at this area initially presents as:
•lucid asymptomatic interval –> weakness of limb muscles –> dilated pupil (compression of CNIII)
–> deterioration of cardiovascular and resp fx
skull fracture at pterion
a horizontal fracture superior to maxillary alveolar process
Le Fort I
posterolateral aprts of the maxillary sinuses;
central part of the face separatde from the cranium
Le Fort II
horizontal fracture that passes through the superior orbital fissues, ethmoid and nasal extending to greater wing of sphenoid
maxillae and zygomatic separated from cranium
Le Fort III
Layers of the scalp
skin connective tissue aponeurosis (Galea aponeurotica) loose connective tissue pericranium/ periosteum
the layer that allows free movement of the scalp proper
Loose connective tissue
this layer of scalp contains emissary veins - danger area
Loose connective tissue
differentiates into CNS
neural tube
gives rise to cells that forms the PNS, ANS, cranial, spinal and autonomic ganglia
Neural crest
Neural crest derivatives
sensory ganglia of cranial and spinal nerves neurolemmal sheath of peripheral nerve meninges pigment cells of retina cells of adrenal medulla
Three primary brain vesicles
- forebrain - prosencephalon
- midbrain - mesencephalon
- hindbrain- rhombencephalon
what secondary brain vesicles are formed at 5th week of dev
prosencephalon -> TELENCEPHALON
Rhombencephalon -> METENCEPHALON , MYELENCEPHALON
congenital megacolon
Hirschsprung disease
undelying pathology of Hirschsprung disease
absence of neural crest cell migration
-> aganglionic segment -> failure of peristalsis -> megacolon
Anatomical level of the nervous system
I. supratentorial level
II. infratentorial level/ posterior fossa level
III. Spinal level
IV. Peripheral level
located above the tentorium cerebella
supratentorium level
supratentorial parts of the nervous system
cerebrum basal ganglia thalamus hypothalamus CN I and II
located below the tentorium cerebelli but above foramen magnum
cerebellum
brainstem (midbrain, pons, medulla oblongata)
CN III-XII
this structures are located below the foramen magnum but contained within the vertebral column
spinal level
spinal level
structures
spinal cord
spinal nerves within VC
the brain and spinal cord are surrounded by 3 protective membranes or meninges
a. dura mater
b. subarachnoid mater
c. pia mater
2 layers of the dura mater
endosteal layer
meningeal layer
meningeal layer of the dura mater sends inward 4 septa - which divides the cranial cavity into freely communicating spaces
- falx cerebri
- tentorium cerebelli
- falx cerebelli
- diaphragma sella
Presents several openings: the foramen rotundum, foramen ovale, and foramen spinosum.
Greater Wing of the Sphenoid Bone
Has a deep central depression known as the hypophyseal fossa, which accommodates the pituitary gland or the hypophysis.
Sella Turcica (Turk’s Saddle) of the Sphenoid Bone
downward sloping surface from the dorsum sellae to the foramen magnum.
Clivus
Is a delicate investment that is closely applied to the brain and dips into fissures and sulci. Enmeshes blood vessels on the surfaces of the brain.
Pia Mater
is caused by rupture of the thin-walled lenticulostriate artery, a branch of the middle cerebral artery, producing hemiplegia (paralysis of one side of the body).
cerebral hemorrhage
is due to rupture of cerebral arteries and veins that cross the subarachnoid space. It may be caused by rupture of an aneurysm on the circle of Willis or, less commonly, by a hemangioma (proliferation of blood vessels leads to a mass that resembles a neoplasm).
subarachnoid hemorrhage
is due to rupture of bridging cerebral veins as they pass from the brain surface into the venous sinuses that result from a blow on the front or the back of the head, causing displacement of the brain.
subdural hematoma
is due to rupture of the middle meningeal arteries or veins caused by trauma near the pterion, fracture of the greater wing of the sphenoid, or a torn dural venous sinus
epidural hematoma
may put pressure on the brain and form a biconvex pattern on computed tomography scan or magnetic resonance imaging.
epidural hematoma
Is the sickle-shaped double layer of the dura mater, lying between the cerebral hemispheres.
falx cerebri
is attached anteriorly to the crista galli and posteriorly to the tentorium cerebelli.
falx cerebri
Has a free inferior concave border that contains the inferior sagittal sinus, and its upper convex margin encloses the superior sagittal sinus.
falx cerebri
Is a small sickle-shaped projection between the cerebellar hemispheres.
Falx Cerebelli
Contains the occipital sinus in its posterior border.
Falx Cerebelli
Is attached to the posterior and inferior parts of the tentorium.
Falx Cerebelli
Is a crescentic fold of dura mater that supports the occipital lobes of the cerebral hemispheres and covers the cerebellum.
Tentorium Cerebelli
Has a free internal concave border, which bounds the tentorial notch, whereas its external convex border encloses the transverse sinus posteriorly and the superior petrosal sinus anteriorly.
Tentorium Cerebelli
Is a circular, horizontal fold of dura that forms the roof of the sella turcica, covering the pituitary gland or the hypophysis.
Diaphragma Sellae
Has a central aperture for the hypophyseal stalk or infundibulum.
Diaphragma Sellae
Cavernous sinus thrombosis is the formation of a thrombus in the cavernous CORRELATES sinus and is caused by bacterial infections induced commonly by
Staphylococcus
Dura mater sensory nerve supply
trigeminal = above the tentorium
•headache referred to forehead and face
first 3 cervical nerves - below the tentorium
•headache- referred to the back of the head and neck
potential space that contains the middle meningeal
arteries in the cranial cavity.
epidural space
Is the tough, fibrous, outermost layer of the meninges external to the subdural space, the space between the arachnoid and the dura.
■ Lies internal to the epidural space, a potential space that contains the middle meningeal arteries in the cranial cavity.
dura mater
Is a filmy, transparent, spidery layer that is connected to the pia mater by web-like trabeculations.
arachnoid layer
vascular membrane covered by flattened mesothelial cells ; closely invests the brain covering the gyri and descending into sulci
pia mater
Dejerine - Roussy syndrome or central pain syndrome
Which part of brain is involved
it is a Thalamic infarction
thalamus
