NEET MDS Lessons
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.