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Anatomy

Gross anatomy-study of structures that can be identified with the naked eye; usually involves the use of cadavers

  • Microscopic anatomy (histology)-study of cells that compose tissues and organs; involves the use of a microscope to study the details of the species
  • Developmental anatomy (embryology)-study of an individual from beginning as a single cell to birth
  • Comparative anatomy -comparative study of the animal structure in regard to similar organs or regions

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.

Veins of the Face

The Supratrochlear Vein

  • This vessel begins on the forehead from a network of veins connected to the frontal tributaries of the superficial temporal vein.
  • It descends near the medial plane with its fellow on the other side.
  • These veins diverge near the orbits, each joining a supraorbital vein to form the facial vein near the medial canthus (angle of the eye).

 

The Supraorbital Vein

  • This vessel begins near the zygomatic process of the temporal bone.
  • It joins the tributaries of the superficial and middle temporal veins.
  • It passes medially and joins the supratrochlear vein to form the facial vein near the medial canthus.

 

The Facial Vein

  • This vein provides the major venous drainage of the face.
  • It begins at the medial canthus of the eye by the union of the supraorbital and supratrochlear veins.
  • It runs inferoposteriorly through the face, posterior to the facial artery, but takes a more superficial and straighter course than the artery.
  • Inferior to the margin of the mandible, the facial vein is joined by the anterior branch of the retromandibular vein.
  • The facial veins ends by draining into the internal jugular vein.

 

The Superficial Temporal Vein

  • This vein drains the forehead and scalp and receives tributaries from the veins of the temple and face.
  • In the region of the temporomandibular joint, this vein enters the parotid gland.

 

The Retromandibular Vein

  • The union of the superficial temporal and maxillary veins forms this vessel, posterior to the neck of the mandible.
  • It descends within the parotid gland, superficial to the external carotid artery but deep to the facial nerve.
  • It divides into an anterior branch that unites with the facial vein, and a posterior branch that joins the posterior auricular vein to form the external jugular vein.

The Medial Pterygoid Muscle

  • This is a thick, quadrilateral muscle that also has two heads or origin.
  • It embraces the inferior head of the lateral pterygoid muscle.
  • It is located deep to the ramus of the mandible.
  • Origin: deep head—medial surface of lateral pterygoid plate and pyramidal process of palatine bone, superficial head—tuberosity of maxilla.
  • Insertion: medial surface of ramus of mandible, inferior to mandibular foramen.
  • Innervation: mandibular nerve via medial pterygoid nerve.
  • It helps to elevate the mandible and closes the jaws.
  • Acting together, they help to protrude the mandible.
  • Acting alone, it protrudes the side of the jaw.
  • Acting alternately, they produce a grinding motion.

Sternum

o    Forms the medial part of the anterior chest wall
o    Manubrium (upper part)-clavicle and first rib articulate with the manubrium .
o    Body (middle blade)-second and tenth ribs articulate with the body via the costal cartilages
o    Xiphoid (blunt cartilaginous tip)

Ribs (12 pairs)

o    Each rib articulates with both the body and the transverse process of its corresponding
o    thoracic vertebra
o    The second to ninth ribs articulate with the body of the vertebra above'
o    Ribs curve outward, forward, and then downward
o    Anteriorly, each of the first seven ribs joins a costal cartilage that attaches to the sternum
o    Next three ribs (eighth to tenth) join the cartilage of the rib above
o    Eleventh and twelfth ribs do not attach to the sternum; are called "floating ribs"

 

  • Long bones (e.g.. femur and humerus)
  • Short bones (e.g.. wrist and ankle bones)
  • Flat bones (e.g.. ribs)
  • Irregular bones (e.g.. vertebrae)

Muscles of the Soft Palate

The Levator Veli Palatini (Levator Palati)

  • Superior attachment: cartilage of the auditory tube and petrous part of temporal bone.
  • Inferior attachment: palatine aponeurosis.
  • Innervation: pharyngeal branch of vagus via pharyngeal plexus.
  • This cylindrical muscle runs inferoanteriorly, spreading out in the soft palate, where it attaches to the superior surface of the palatine aponeurosis.
  • It elevates the soft palate, drawing it superiorly and posteriorly.
  • It also opens the auditory tube to equalise air pressure in the middle ear and pharynx.

 

The Tensor Veli Palatini (Tensor Palati)

  • Superior attachment: scaphoid fossa of medial pterygoid plate, spine of sphenoid bone, and cartilage of auditory tube.
  • Inferior attachment: palatine aponeurosis.
  • Innervation: medial pterygoid nerve (a branch of the mandibular nerve).
  • This thin, triangular muscle passes inferiorly, and hooks around the hamulus of the medial pterygoid plate.
  • It then inserts into the palatine aponeurosis.
  • This muscle tenses the soft palate by using the hamulus as a pulley.
  • It also pulls the membranous portion of the auditory tube open to equalise air pressure of the middle ear and pharynx.

 

The Palatoglossus Muscle

  • Superior attachment: palatine aponeurosis.
  • Inferior attachment: side of tongue.
  • Innervation: cranial part of accessory nerve (CN XI) through the pharyngeal branch of vagus (CN X) via the pharyngeal plexus.
  • This muscle, covered by mucous membrane, forms the palatoglossal arch.
  • The palatoglossus elevates the posterior part of the tongue and draws the soft palate inferiorly onto the tongue.

 

The Palatopharyngeus Muscle

  • Superior attachment: hard palate and palatine aponeurosis.
  • Inferior attachment: lateral wall of pharynx.
  • Innervation: cranial part of accessory nerve (CN XI) through the pharyngeal branch of vagus (CN X) via the pharyngeal plexus.
  • This thin, flat muscle is covered with mucous membrane to form the palatopharyngeal arch.
  • It passes posteroinferiorly in this arch.
  • This muscle tenses the soft palate and pulls the walls of the pharynx superiorly, anteriorly and medially during swallowing.

 

The Musculus Uvulae

  • Superior attachment: posterior nasal spine and palatine aponeurosis.
  • Inferior attachment: mucosa of uvula.
  • Innervation: cranial part of accessory through the pharyngeal branch of vagus, via the pharyngeal plexus.
  • It passes posteriorly on each side of the median plane and inserts into the mucosa of the uvula.
  • When the muscle contracts, it shortens the uvula and pulls it superiorly.

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