NEET MDS Lessons
Anatomy
Muscle
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Emotion
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Epicranius
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Surprise
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Orbicularisoculi
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Squinting
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Orbicularisoris |
Pouting |
Nasalis
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Smelling
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Zygomaticus
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Smiling
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Buccinator
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Chewing
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Mentalis
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Doubt
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Triangularis
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Sadness
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Platysma
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Sadness
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Masseter
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Chewing
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Temporalis
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Sternness
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Pterygoid
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Conternation
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Genioglossus and Styloglossus
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Swallowing, Speaking, Chewing
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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 Nasal Mucosa
- Mucosa lines the entire nasal cavities except for the vestibule of the nose.
- The nasal mucosa is firmly bound to the periosteum and perichondrium of the supporting structures of the nose.
- It is continuous with the adjoining cavities to which the nasal cavity communicates (e.g., the nasopharynx and paranasal sinuses).
- The inferior 2/3 of the nasal mucosa is called the respiratory area and air passing over this is warmed and moistened before it passes into the lungs.
- The superior 1/3 is called the olfactory area.
The Olfactory Area of Nasal Mucosa
- This area contains the peripheral organ of smell.
- Sniffing draws air into this area
- Olfactory receptor cells (from the olfactory nerve, CN I, are located in the mucosa of this area in the nose.
Nerves to the Respiratory Area of Nasal Mucosa
- The inferior 2/3 of the nasal mucosa are supplied chiefly by the trigeminal nerve (CN V).
- The mucous membrane of the nasal septum is supplied chiefly by the nasopalatine nerve, a branch of the maxillary nerve (CN V2).
- Its anterior portion is supplied by the anterior ethmoidal nerve (a branch of the nasociliary nerve) which is derived from the ophthalmic nerve (CN V1).
- The lateral walls of the nasal cavity are supplied by branches of the maxillary nerve (CN V2); the greater palatine nerve, and the anterior ethmoidal nerve.
Arteries of the Nasal Mucosa
- The blood supply of the mucosa of the nasal septum is derived mainly from the maxillary artery.
- The sphenopalatine artery, a branch of the maxillary, supplies most of the blood of the nasal mucosa.
- It enters by the sphenopalatine foramen and sends branches to the posterior regions of the lateral wall and to the nasal septum.
- The greater palatine artery, also a branch of the maxillary, passes through the incisive foramen to supply the nasal septum.
- The anterior and posterior ethmoidal arteries, branches of the ophthalmic artery, supply the anterosuperior part of the mucosa of the lateral wall of the nasal cavity and nasal septum.
- Three branches of the facial artery (superior labial, ascending palatine, and lateral nasal) also supply the anterior parts of the nasal mucosa.
Veins of the Nasal Mucosa
- The veins of the nasal mucosa form a venous network of plexus in the connective tissue of the nasal mucosa.
- Some of the veins open into the sphenopalatine vein and drain to the pterygoid plexus.
- Others join the facial and infraorbital veins.
- Some empty into the ophthalmic veins and drain into the cavernous sinus.
- 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)
Internal Muscles of the Pharynx
- The internal, chiefly longitudinal muscular layer, consists of 3 muscles: stylopharyngeus, palatopharyngeus, and salpingopharyngeus.
- They all elevate the larynx and pharynx during swallowing and speaking.
The Stylopharyngeus Muscle
- This is a long, thin, conical muscles that descends inferiorly between the external and internal carotid arteries.
- It enters the wall of the pharynx between the superior and middle constrictor muscles.
- Origin: styloid process of temporal bone.
- Insertion: posterior and superior borders of thyroid cartilage with palatopharyngeus muscle.
- Innervation: glossopharyngeal nerve (CN IX).
- It elevates the pharynx and larynx and expands the sides of the pharynx, thereby aiding in pulling the pharyngeal wall over a bolus of food.
The Palatopharyngeus Muscle
- This is a thin muscle and the overlying mucosa form the palatopharyngeal arch.
The Salpingopharyngeus Muscle
- This is a slender muscle that descends in the lateral wall of the pharynx.
- The over lying mucous membrane forms the salpingopharyngeal fold.
- Origin: cartilaginous part of the auditory tube.
- Insertion: blends with palatopharyngeus muscle.
- Innervation: through the pharyngeal plexus.
- It elevates the pharynx and larynx and opens the pharyngeal orifice of the auditory tube during swallowing.
The Articular Capsule
- The capsule of this joint is loose.
- The thin fibrous capsule is attached to the margins of the articular area on the temporal bone and around the neck of the mandible.
-> This bone forms much of the base and posterior aspect of the skull.
-> It has a large opening called the foramen magnum, through which the cranial cavity communicates with the vertebral canal.
-> It is also where the spinal cord becomes continuous with the medulla (oblongata) of the brain stem.
-> The occipital bone is saucer-shaped and can be divided into four parts: a squamous part (squama), a basilar part (basioccipital part), and two lateral parts (condylar parts).
-> These four parts develop separately around the foramen magnum and unite at about the age of 6 years to form one bone.
-> On the inferior surfaces of the lateral parts of the occipital bone are occipital condyles, where the skull articulates with C1 vertebra (the atlas) at the atlanto-occipital joints.
-> The internal aspect of the squamous part of the occipital bone is divided into four fossae: the superior two for the occipital poles of the cerebral hemispheres, and the inferior two, called cerebellar fossae, for the cerebellar hemispheres.