Objectives - Head

Skull, Scalp, Dura

• You should know the bones and features of the skull as outlined on your skull study sheet. This includes, bones, foramina, processes, air sinuses, venous sinuses.
• You should know all the structures that pass through the major foramina of the skull
• You should understand the developmental differences among the cranial base, the cranial vault and the face. Associated with development of the skull, you should also be familiar with the following:

• Anterior and posterior fontanelles
• Spheno-occipital synchondrosis
• Metopic suture
• Sagittal suture
• Coronal suture
• Lambdoidal suture
• Squamosal suture
• Craniosynostosis
• Mastoid and tympanic development

• What is the function of the sutures in the pre- and post-natal human, and why do they close in adulthood?
• What is the clinical significance of the late development of the mastoid process and tympanic tube?
• Understand the layers of the scalp. Where do the vessels of the scalp run? What is the epicranial aponeurosis?
• Understand, in general, the blood supply to and innervation of the scalp.
• Why do scalp wounds bleed so profusely?
• Why are scalp infections serious and dangerous?
• Understand the meningeal layers of the brain. What is the difference between the cranial "Dura" and the spinal dura? In some areas, the inner and outer layer of cranial "Dura" draw away from another, and the inner layer forms infoldings or relections. Be able to identify and define the following:
  • Falx cerebri
  • Tentorium cerebelli
  • Sellar diaphragm
• When the dura separates as such, venous sinuses are formed between the two layers of cranial dura. Veins from the brain drain into these sinuses. Sometimes sinuses are not associated with dural folds. Be able to identify the following sinuses or structures associated with sinuses and discuss the flow of blood among them. Where applicable, be able to identify bony landmarks for each:
  • Superior sagittal sinus
  • Lacunae laterales
  • Arachnoid villi
  • Inferior sagittal sinus
  • Straight sinus
  • Great cerebral vein
  • Confluence of sinuses
  • Occipital sinus
  • Transverse sinus
  • Sigmoid sinus
  • Internal jugular vein
  • Superior and inferior petrosal sinus
  • Cavernous sinus

• What vessels and nerves run through the cavernous sinus? What is the clinical significance of the cavernous sinus and these relationships?
• Understand the clinical consequences of damage to cerebral veins by a blow to the head, the consequence of a blow to the head that tears a meningeal vessel, bleeding into the subarachnoid space.
• Know the pathways of major emissary veins and their clinical importance.

Cranial Nerves

You should understand the function of each cranial nerve, its pathways, branches, and mechanism of leaving the cranial fossae. You should be intimately aware of the types of fibers each is carrying, where they distribute, and what happens in the case of pathology of each nerve. Your knowledge of each cranial nerve should be intertwined with your knowledge of the function of the region(s) it innervates.

Orbit

• You should be aware of the bones that form the orbit, the foramina within it and the soft tissue structures that reside in it or pass through it.
• You should be able to discuss the structures involved in the lacrimal apparatus and the functioning thereof.
• Trace the flow of tears from the gland that produces them to the nasal cavity.
• What is the nerve supply to the lacrimal gland?
• Know the layers of the eyeball and the structures contained therein.

• What are the functions of the sphincter pupillae? Dilator pupillae? Cilliary muscle? How is each innervated? How might you use this information in clinical testing?
• What is the optic disc?
• The Cornea, Aqueous humor, Lens, and Vitreous humor are said to constitute the refractive media of the eye. What does each contribute to the functioning of the eye? What is accomodation and how is the lens made to accommodate?
• Know the differences among right/ left and temporal/ nasal visual fields. Information from what visual fields are carried in the right and left optic nerves? Information from what visual fields are carried in the right and left optic tracts?
• What are the results of severing or damaging an optic nerve? An optic tract? The optic chiasm?
• Describe the movements of the eye and how each extraocular muscle contributes alone and along with other muscles to production of a particular movement. Understand the innervation of these muscles.
• Be able to identify the arteries, veins and nerves of the orbit.

Face

• The muscles of facial expression arise from the bones of the skull and insert into the connective tissue of the dermis. They must pass through the superficial fascia to do this.
  • From the mesoderm of which branchial arch are the facial muscles derived
  • What is the nerve of this arch and, thus, the nerve supplying these muscles
  • What muscles are responsible for
    • Raising the eyebrows
    • Closing the eyes tightly
    • Smiling broadly
    • Puffing out the cheeks

     

• Explain the following symptoms of facial paralysis:
  • tears rolling down the cheek
  • saliva dribbling down from the corner of the mouth
  • difficulty chewing food
  • disappearance of wrinkles and creases on the face
  • irritation of the cornea or sclera

• Identify the approximate regions of the face that receive sensory innervation from the:
  • opthalmic division of trigeminal
  • maxillary division of trigeminal
  • mandibular division of trigeminal
  • facial nerve

• Trace the sympathetic innervation of the blood vessels of the face from the spinal cord.
• Trace the innervation of the sweat glands of the face from the spinal cord.
• What two major vessels and one nerve are embedded in the posterior region of the parotid gland, and what are their relationships to one another?
• Where does the duct of the parotid gland enter the oral cavity?
• You should understand the pathways, branches and fiber types of the facial nerve. How does it distribute motor, sensory, special sensory, sympathetic, and parasympathetics to the tongue, palate, nasal cavity, face, ear, lacrimal gland, etc.?
• You should understand enough about the development of the face to explain the anatomical/ embryological basis for a cleft palate and the sensory innervation of the face.
• You should understand the branches and distribution of Cranial nerve V to all parts of the eye, face, mandible. You should understand how parasympathetics from other cranial nerves "hitchhike" on Cranial nerve V to get to the many places they need to go.
• Trigeminal neuraligia is a fairly common disorder in which a patient experiences pain in the area of distribution of one part of the trigeminal nerve. You should be able to map out the distribution of the trigeminal nerve's innervation of the face.
• You should be very familiar with the branches of the maxillary nerve to the face and palate.
• The parotid gland is a salivary gland that sits between the ramus of the mandible and the mastoid process, just anteroinferior to the external acoustic meatus. The parotid duct empties into the mouth through a small orifice opposite the second maxillary molar tooth.
  • Trace the sympathetic and parasympathetic innervation to the parotid gland
  • know the relationships of structures passing through and around the region of the parotid gland
• Understand the lymphatic drainage of the face. For example, how does lymph get from the following regions into the venous system:
  • lateral part of the face
  • upper and lower lips and chin

Ear

• Understand the following terms with respect to the structure and/or function of the ear:
  • Auricle
  • Tragus
  • Antitragus
  • Helix
  • Malleus
  • Incus
  • Stapes
  • Tympanic membrane
  • Epitympanic recess
  • Pharyngotympanic tube (bony and cartilaginous parts)
  • Tympanic cavity
  • Internal acoustic meatus
  • Semicircular canals
  • Facial and Vestibulocochlear nerves
  • Oval window
  • Tensor tympani
  • Stapedius
  • Levator veli palatini
  • Tensor veli palatini
  • Chorda tympani
  • Cochlea
  • Semicircular canals
  • Maculae

• What is the function of the pharyngotympanic tube?
• How is sound transmitted through the ear?
• What are the two small muscles attaching to ear ossicles and what are their functions?
• What nerve innervates the stapedius muscle? What is the result of paralysis of this muscle?
• Why does swallowing "pop" your ears?
• What causes motion sickness?
• Understand the innervation of the external auditory meatus and the tympanic membrane.
• Explain the relationship between the auditory tube and the pharynx and the implications of this connection for the passage of infection. What is the function of the auditory tube?
• Explain the differences between the vestibular and hearing aspects of the ear. What nerves are associated with each?

Temporal Region

• You should know, in detail, the origins, insertions, innervations, of the muscles of mastication. Understand the muscular movements associated with chewing.
• You should know, in detail, the branches of the maxillary artery and mandibular nerve in this region (and what they supply) and the spatial relationships among them.
• Why does dental anaesthetic for the lower teeth also anaesthetize the skin of the chin and the lower lip?
• Be able to describe the morphology of the temporomandibular joint. What nerves run very close to the TMJ and may be damaged during traumatic injury of the TMJ?
• What other ligaments serve to support the articulation of the mandible to the skull?

Oral Region, Palate, and Nose

• Know the names of the teeth and be able to identify the following:
  • enamel
  • dentine
  • pulp cavity
  • root
  • periodontal ligament
• How are the teeth and surrounding gingiva innervated?
• Know the major divisions of the oral cavity. What is the function of the oral cavity?
• Know the blood supply, innervation and lymphatic drainage of the lips. Consider the clinical implications of infections, tumors, or other disease of the lips.
• What forms the bony skeleton of the palate?
• Describe the innervation and blood supply to the palate.
• What muscles attach to the palate and how does each affect the position of the palate? What is the innervation of each?
• What are the tonsils and where are they found?
• What is the embryological basis of a cleft lip and/ or cleft palate?
• What is the function of the tongue?
• Describe, in detail, the sensory, special sensory innervation to the tongue. Describe the extrinsic muscles of the tongue and their innervation.
• Be able to describe and locate the different types of papillae on the tongue.
• The submandibular duct opens at the sublingual caruncle on either side of the base of the lingual frenulum. Describe the innervation of the submandibular gland.
• What is the function of the salivary glands and saliva? How is each innervated, and where does each empty saliva?
• Be able to describe the vasculature and innervation to the nasal cavity.
• Describe the nasal conchae, the named spaces between them, and the connections between the nasal cavity and the sphenoid, ethmoid, frontal, and maxillary sinuses, and the orbit. How are the sinuses innervated?

Brain

• You should understand the function of CSF, where it is produced and how it enters the subarachnoid space (pathway).
• Understand the implications of increased intracranial pressure in terms of diagnosing changes in the volume of intracranial contents (e.g. tumors, blood from a ruptured aneurysm, etc.) and the implications of leakage of CSF, as into the nasal cavity.
• We considered three forms of intracranial hemorrhage: 1) extradural, 2) subdural, 3) subarachnoid. Extradural hemorrhages usually result from injuries to the meningeal arteries or veins. Subdural hemorrhages usually occur as a result of tearing of the superior cerebral veins at their point of entrance into the superior sagittal sinus. Subarachnoid hemorrhages usually result from leakage or rupture of an aneurysm on the cerebral arterial circle. Understand the anatomy of each of these possible forms of hemorrhage (why, anatomically, does each type of injury result in each type of hemorrage?) and the implications of each.
• Understand the blood supply to the brain. You should be able to draw and label the Circle of Willis. What areas of the brain will be affected by an embolism in the middle cerebral artery? the anterior cerebral artery?
• You should know the divisions of the brain and the structures located in each. You should be able to recognize these, where applicable in cross-sections and radiological images based on your knowledge of their relationships to one another.
• You should know the general function of each area of the brain we discussed. Consider the implications of a lesion of each.
• Understand the function of the basal ganglia and their role in Parkinson's Disease.
•  Understand the structure and function of the motor tracts we discussed, and be able to trace a motor signal to the extent we did in class.