The Muscles of Facial Expression

• These lie in the subcutaneous tissue and are attached to the skin of the face.
• They enable us to move our skin and change our facial expression. They produce their effects by pulling on the skin but do not move the facial skeleton.
• These muscles surround the facial orifices and act as sphincters and dilators.
• All facial muscles receive their innervation from the branches of the facial nerve (CN VII)-temporal, zygomatic, buccal, marginal mandibular, cervical.

-> This is a wedge-shaped bone (G. sphen, wedge) is located anteriorly to the temporal bones.
-> It is a key bone in the cranium because it articulates with eight bones (frontal, parietal, temporal, occipital, vomer, zygomatic, palatine, and ethmoid).
-> It main parts are the body and the greater and lesser wings, which spread laterally from the body.
-> The superior surface of its body is shaped like a Turkish saddle (L. sella, a saddle); hence its name sella turcica.
-> It forms the hypophyseal fossa which contains the hypophysis cerebri or pituitary gland.
-> The sella turcica is bounded posteriorly by the dorsum sellae, a square plate of bone that projects superiorly and has a posterior clinoid process on each side.
-> Inside the body of the sphenoid bone, there are right and left sphenoid sinuses. The floor of the sella turcica forms the roof of these paranasal sinuses.
-> Studies of the sella turcica and hypophyseal fossa in radiographs or by other imaging techniques are important because they may reflect pathological changes such as a pituitary tumour or an aneurysm of the internal carotid artery. Decalcification of the dorsum sellae is one of the signs of a generalised increase in intracranial pressure.

The Lateral Wall of the Orbit

• This wall is thick, particularly its posterior part, which separates the orbit from the middle cranial fossa.
• The lateral wall is formed by the frontal process of the zygomatic bone and the greater wing of the sphenoid bone.

• Anteriorly, the lateral wall lies between the orbit and the temporal fossa.

• The lateral wall is partially separated from the roof by the superior orbital fissure.

The Meatus of the Nose

Sphenopalatine Recess

• This space is posterosuperior to the superior concha.
• The sphenoidal sinus opens into this recess.

Superior Meatus

• This is a narrow passageway between the superior and middle nasal conchae.
• The posterior ethmoidal sinuses open into it by one or more orifices.

Middle Meatus

• This is longer and wider than the superior one.

• The anterosuperior part of this meatus lead into a funnel-shaped opening, called the infundibulum, through which the frontonasal duct leads to the frontal sinus.
• There is one duct for each frontal sinus and since there may be several, there may be several frontonasal ducts.

• When the middle concha is removed, rounded elevation called the ethmoidal bulla (L. bubble), is visible
• The middle ethmoidal air cells open on the surface of the ethmoidal bulla.

• Inferior to this bulla is a semicircular groove called the hiatus semilunaris.
• The frontal sinus opens into this hiatus anterosuperiorly.
• Near the hiatus are the openings of the anterior ethmoid air cells.
• The maxillary sinus also opens into the middle meatus.

Inferior Meatus

• This is a horizontal passage, inferolateral to the inferior nasal concha.
• The nasolacrimal duct opens into the anterior part of this meatus.
• Usually, the orifice of this duct is wide and circular.

The Oropharynx

• The oral part of the pharynx has a digestive function.
• It is continuous with the oral cavity through the oropharyngeal isthmus.
• The oropharynx is bounded by the soft palate superiorly, the base of the tongue inferiorly, and the palatoglossal and palatopharyngeal arches laterally.

• It extends from the soft palate to the superior border of the epiglottis.

The Palatine Tonsils

• These are usually referred to as "the tonsils".
• They are collections of lymphoid tissue the lie on each side of the oropharynx in the triangular interval between the palatine arches.

• The palatine tonsils vary in size from person to person.
• In children, the palatine tonsils tend to be large, whereas in older persons they are usual small and inconspicuous.
• The visible part of the tonsil is no guide to its actual size because much of it may be hidden by the tongue and buried in the soft palate.

• This is the second cranial nerve (CN II) and is the nerve of sight.