Spinal Final: Sec. XV: The Scalp, Face, Orbit Flashcards
What can the five layers of the scalp spell?
Skin, Connective tissue, Aponeurosis, Loose Connective Tissue, Periosteum…SCALP
What are the principal sources of blood to the scalp?
internal carotid and external carotid artery branches
What veins drain the scalp?
superficial temporal, posterior auricular, occipital, and ophthalmic veins
Which divisions of the trigeminal nerve receive sensory information from the scalp?
all 3 divisions; ophthalmic nerve, maxillary nerve, and mandibular nerve
What part of the scalp is innervated by the ophthalmic division/branch of the trigeminal?
scalp above the orbit
What part of the scalp is innervated by the maxillary division/branch of the trigeminal?
scalp above the zygomatic arch
What part of the scalp is innervated by the mandibular divison/branch of the trigeminal?
scalp above and behind the ear
Which ventral rami nerve(s) and cord levels of origin supply the scalp?
greater auricular nerve - C2, C3 ventral rami branches;
lesser occipital nerve - C2 (C3) ventral rami branches
Which dorsal ramus nerve branch (name and cord level of origin) supplies the scalp?
greater occipital nerve - C2, C3 communicating ramus
What is the third layer of the scalp associated with?
muscular component of the scalp
The bellies of the epicranius muscle are connected y what structure?
galea aponeurotica
What specific nerves provide motor control to the scalp muscle?
facial nerve: posterior auricular and temporal branches
What is unusual/unique about the muscles of the face?
they do not act as lever muscles; they do not attach to bone at both origin and insertion
Which muscles lack any attachment to bone?
procerus, risorius, orbicularis oris
“PRO”
What is the embryonic origin of skeletal muscles innervated by the facial nerve?
the skeletal muscle is derived from the branchial arches hence branchial efferent
Most of the seventh cranial nerve will exit the skull via what opening?
the stylomastoid foramen
What is the source of innervation for all muscles of facial expression?
facial nerve branches
Branchial efferent fibers carried in the seventh cranial nerve will innervate what muscles?
muscles of facial expression, muscles of the scalp and auricle, the buccinator, platysma, stapedius, stylohyoid, and posterior belly of the digastric
Which divisions of the trigeminal nerve contain somatic afferent (SA) pathways?
all three
What landmark forms the apex of the orbit?
convergence of the superior orbital fissure and inferior orbital fissure
What are the contents of the optic canal?
optic nerve and ophthalmic artery
What is the name given to the medial wall of the orbit?
lamina papyracea
What opening(s) are located along the lateral wall of the orbit?
superior orbital fissure
What opening accommodates the passage of the ophthalmic nerve and ophthalmic veins between the orbit and cranial vault?
superior orbital fissure
What is contained in the inferior orbital fissure?
maxillary division of trigeminal nerve
Identify the opening(s) found along each wall of the orbit.
superior wall: optic canal
medial wall: anterior ethmoid and posterior ethmoid foramina
lateral wall: superior orbital fissure
inferior wall: inferior orbital fissure
What are the layers of the eyelid?
skin, orbicularis oculi muscle, tarsal plate/tarsus and palpebral conjunctiva
What are the names given to the modified sebacceous gland in the tarsus of the eyelid?
tarsal or Meibomian gland
What is the function of the Meibomian gland?
produces a thick, hydrophobic substance that prevents tears from overflowing onto the cheeks along the margin of the eyelid
What is the name of the gland at the base of the eyelash?
ciliary gland
What are the names given to the modified sebaceous glands of the palpebra?
tarsal gland or Meibomian gland and ciliary gland
What is the name of the mucous membrane attaching to the eyeball?
bulbar conjunctiva
What is the name given to the sac formed between the palpebral and bulbar conjunctiva?
the superior or inferior fornix
Visceral Efferent (VE) pathways innervate what structures?
smooth muscle, cardiac muscle, and glandular tissues
What specific pathways are identified with Visceral Efferent (VE) innervation?
sympathetic and parasympathetic motor pathways
How many neurons are involved in the Visceral Efferent pathways from CNS to target cell?
two motor neurons
What is the location for the second neuron in the Visceral Efferent (VE) pathway?
typically, a ganglion
Which cranial nerves are involved in the Visceral Efferent (VE) parasympathetic pathway to the lacrimal gland?
facial and trigeminal (maxillary and ophthalmic divisions/branches)
What are the names of the ganglion of synapse in the efferent pathway to the lacrimal gland?
pterygopalatine ganglion, sphenopalatine ganglion, Meckel’s ganglion
Parasympathetic stimulation of blood vessels in the lacrimal gland will result in what events?
vasodilation of blood vessels, increased availability of water to secretory units, thinner or more watery product in lumen
Sympathetic fibers synapse in which ganglion in the pathway to the lacrimal gland?
the superior cervical ganglion
Sympathetic stimulation of the lacrimal gland will result in what events?
vasoconstriction of blood vessels, limited availability of water to secretory units, more viscous or thicker product formed in glandular lumen
What cells of the lacrimal gland will cause the product to be released from the secretory unit?
myoepithelial cells
Parasympathetic stimulation of targets in the lacrimal gland will result in what events?
vasodilation of blood vessels, increased availability of water to secretory units, thinner or more watery product in lumen;
constriction of myoepithelial cells leading to release of product from secretory lumen into the duct system
What are the names of the layers of the eyeball?
fibrous tunic, uveal tract, and retina
What are the parts of the fibrous tunic of the eyeball?
cornea and sclera
What are the parts of the uveal tract of the eyeball?
iris, ciliary body, choroid, and pupil
What muscles are present in the iris?
sphincter pupillae and dilator pupillae
What is the innervation of the sphincter pupillae?
oculomotor nerve, parasympathetic pathway
What is the innervation of the ciliaris muscle?
oculomotor nerve, parasympathetic pathway
What is the function of the rod cell?
provide vision in dim light conditions
What is the function of the cone cell?
provide vision in bright light conditions and mediate color vision
What forms the optic nerve?
axons of ganglion cells
What occurs at the optic chiasma?
part of the optic nerve decussates
What is the innervation of the dilator puppillae?
internal carotid artery plexus, sympathetic pathway
What are the chambers of the eyeball in front of the lens?
anterior chamber and posterior chamber
What separates the anterior chamber and posterior chamber in the eyeball?
iris
What is contained in the posterior chamber of the eyeball?
aqueous humor
What is the primary cause of glaucoma?
excess aqueous humor in the chambers in front of the lens
What is the name given to the chamber behind the lens?
vitreous chamber
What fills the vitreous chamber?
vitreous body
What are the functions of the vitreous body?
maintain retinal curvature; allow minimal light distortion from lens to retina
What are the common characteristics in origin and insertion of all rectus extraocular muscles?
they all originate from a common annular tendon in the orbit
they all insert into the sclera in front of the coronal equator of the eyeball
What is the common characteristic regarding the insertion of both oblique extraocular muscles?
both insert onto sclera on the lateral margin of the eyeball behind the coronal equator
Somatic efferent fibers from the left nucleus of the fourth cranial nerve will have an apparent origin from which side?
right side
What are the two unique features of the fourth cranial nerve?
- it is the only CN with an apparent origin from the brains’ dorsal surface;
- it is the only cranial efferent nerve to decussate within the midbrain from its nucleus
The right fourth CN will innervate which side target muscle?
the right side muscle
Intrinsic muscles of the eyeball are innervated by which Visceral Efferent (VE) pathways?
ciliaris and sphincter pupillae are innervated by parasympathetics;
dilator pupillae is innervated by sympathetics
What is the location of synapse for preganglionic parasympathetic efferent fibers of the third CN?
ciliary ganglion
What is the origin for the sympathetic pathway to the dilator pupillae?
lateral horn/intermediolateral cell column T1, T2
Sympathetic fibers synapse in which ganglion in the pathway to the dilator pupillae?
the superior cervical ganglion
From the superior cervical ganglion, how do sympathetic fibers reach the dilator pupillae?
they join the internal carotid artery neurovascular plexus and continue along the ophthalmic artery to the central artery of the retina and enter the eyeball
What provides the major distribution vehicle for sympathetics to the head?
arteries
