ANAT 212 Test 1 Full Notes PDF

ANAT 212 IMPORTANT INFORMATION YOU NEED TO KNOW ABOUT ANAT212 Osteology: Cervical and Skull Vertebrae  Cervical and Skull Vertebrae The skull literally have 6 aspects: a. Lateral Aspect b. Anterior Aspect c. Posterior Aspect d. Superior Aspect e. Inferior Aspect f. Interi...

ANAT 212 IMPORTANT INFORMATION YOU NEED TO KNOW ABOUT ANAT212 Osteology: Cervical and Skull Vertebrae  Cervical and Skull Vertebrae The skull literally have 6 aspects: a. Lateral Aspect b. Anterior Aspect c. Posterior Aspect d. Superior Aspect e. Inferior Aspect f. Interior Aspect Anterior Aspect The anterior aspect is made up of Frontal, Maxilla, Mandible, Zygomatic, Orbit and Nasal Region. The area at which the nasal bones meet the frontal bone is called Nasion. N Both mandible and maxilla have alveolar process which form sockets for teeth. Mandible: Inferior Alveolar process Maxilla: Superior Alveolar process Lateral Aspect It is made up of cranial and facial bones. From this aspect, the superior and inferior temporal lines are visible. The area at which the saggital sature and coronal sature meet is called Bredma. The are at which the saggital sature meet the lambdoid sature is called Lambda. Area at which the Sphenoid, Parietal, Temporal and frontal bone meet is called Pterion. Posterior Aspect t is made up of Occipital bone, part of Parietal bone and Mastoid process of Temporal bone. Occipital External Protuberance Is visible from this aspect. There are also Superior and Inferior Nuchal Lines.  Superior Aspect It is made up of parietal, frontal and occipital bone. It is also known as Calvaria. The most superior point of the skull on the saggital sature is known as the Vertex. Inferior Aspect It is made up of palatine, Sphenoid, vomer, temporal and occipital bone. Known as Base. Internal Aspect The internal aspect of the skull is divided into 3 cranial fossa: a. Anterior Cranial Fossa b. Middle cranial Fossa c. Posterior Cranial Fossa (a) Anterior Cranial Fossa It is formed by Frontal, Ethmoid and Sphenoid bone. Contain the Frontal Crest at which the Falxi cerebri attaches. Also contain the cribriform plate which have: (1) Crista Galli (2) Cribriform foramen (b) Middle Cranial Fossa It is made up of Sphenoid (Greater wing), Temporal bone (squamous and petrous). The fossae contain foraminas like Supraorbital fissure,optic canal, Rotondum, Ovale, spinosum and lacerum. (c) Posterior Cranial Fossa It is made up of Occipital bone, Sphenoid bone and temporal bone. Contain foraminas like Jagular foramen, Hypoglossal canal, Foramen magnum.  CERVICAL VERTEBRAE They form bony skeleton of the neck, between the thorax and skull. They have an oval Foramen Transversarium which is absent in C7. Vertebral Arteries passes through Foramen Transversarium. The transverse process ends in two projections: a. Anterior Tubercle In C6 the anterior tubercle is also known as Carotid tubercle. b. Posterior Tubercle Classification of Cervical Segment The cervical segment can be classified into 2 types: a. Typical segments: C3, C4, C5, C6 Vertebral bodies are small and wider from side to side. Vertebral foramen is large and triangular. Their spinal processes is bifid. b. Atypical Segment: C1, C2, C7 Atypical Segment: Atlas or C1 It is named after Greek God Atlas. The atlas have no vertebral body. It also does not have spinous process but have anterior and posterior arch. It has short Anterior arch that gives rise to anterior tubercle. The Anterior turbecle gives attachment to the longus colli muscles. The upper border of the arch gives attachment to Anterior atlanto-occipital membrane. Process The posterior arch have: a. Groove for vertebral artery at the root of the arch. b. The upper border give attachment to posterior atlanto-occipital membrane. c. Lower border give attachment for ligament flava from axis. d. The pair of dimples give attachment to rectus capitis posterior minor  Atypical Segment: Axis or C2 This segment provide pivot around which dense and head rotate. It has a cylindrical facet which make a synovial joint with atlas [C1] and is called Dens. The apex of the dens give attachment to Apical ligament. Borders of the dens give attachment to Alar ligament  MUSCLES OF THE NECK: SUBOCCIPITAL TRIANGLE  SUBOCCIPITAL TRIANGLE It is found in the occipital region. The Posterior atlanto-occipital membrane and posterior arch of Atlas make the floor of the suboccipital triangle. The triangle’s contents are: a. 3rd part of vertebral artery b. Suboccipital nerve [ Dorsal ramus of C1] c. Suboccipital plexus of veins. The suboccipital triangle is made up of 4 main muscles: a. Rectus capitis posterior Minor b. Rectus capitis Posterior Major c. Obliquus capitis Superioris d. Obliquus capitis Inferioris Rectus Capitis Posterior Major Originate: Spine of axis Insertion: Lateral area below the inferior nuchal line Nerve supply: Suboccipital Nerve Action: Turns face to same side Rectus Capitis Posterior Minor Originate: Posterior Turbecle of atlas Insertion: Medial Area below the inferior nuchal line Nerve supply: Suboccipital Nerve Action: Extend the head OBLIQUUS CAPITIS SUPERIORIS Originate: Transverse process of Atlas Insertion: Lateral area between nuchal lines Nerve supply: Suboccipital Nerve Action: Laterally Bends the head  OBLIQUUS CAPITIS INFERIORIS Originate: Spine of Axis Insertion: Transverse process of atlas Nerve supply: Suboccipital Nerve Action: Turns the face into same side Structure relations to Suboccipital Triangle (1) Suboccipital Nerve (Dorsal ramus of C1) emerges between posterior arch and vertebral artery Supply the 4 muscles of suboccipital triangle. (2) Greater Occipital Nerve This is branch of the dorsal ramus of Axis/C2. Supply the semispinalis and scalp. (3) Third Occipital Nerve Medial branch of dorsal ramus of C3. supply the skin at the back of the neck up to external occipital protuberance. (4) 3rd Part of Vertebral artery Vertebral artery is branch of subclavian artery and has 4 parts. (5) Occipital artery Branches from External Carotid Artery. Has 3 branches: a. Mastoid b. Meningeal c. Muscular (6) Deep Cervical artery Branch of the costocervical trunk of subclavian artery. ascends with descending branch of occipital artery SUPERFICIAL AND DEEP MUSCLES OF THE BACK  SUPERFICIAL MUSCLES There are 2 types of muscles of the back: a. Extrinsic b. Intrinsic (a) Extrinsic Muscles These involve the superficial and deep muscles of the back. There are 4 main superficial muscles of the back: a. Trapezius Muscle b. Latissimus Dorsi Muscle c. Rhomboids Minor and Major d. Levator Scapulae TRAPEZIUS MUSCLE Originate: Occipital bone, Medial nuchal line and spinous process of C7 - T12 Insertion: Lateral cavicle Innervation: Accessory nerve (CN IX) Function: Elevate, retract and depress the scapula. LATISSIMUS DORSI MUSCLE Originate: Spinous processes of T7 - T12, 9th - 12th ribs, Iliac crest and inferior angle of the Scapular. Insertion: Lateral cavicle Innervation: Thoracodorsal Nerve Function: Extends, adducts and medially rotate the humerus at shoulder joint. LEVATOR SCAPULAE Originate: Posterior tubercles of the transverse processes of C1 - C4. Insertion: Medial border of Scapulae Innervation: Dorsal scapulae nerve of C5+C3 and Cervical nerve of C4 Function: Elevate and retracts the scapula, Tilt the glenoid cavity.  RHOMBOIDS MINOR AND MAJOR Originate: Minor: Nuchal Ligament and spinous process of C7 - T1 Major: Spinous process of T2 - T5. Insertion: scapulae Innervation: Dorsal scapulae nerve of C5 Function: Retracts the scapula to vertebral column. INTERMEDIATE MUSCLES There are 2 main intermediate Muscles of the back: a. Serratus Posterior Superior b. Serratus Posterior Inferior SERRATUS POSTERIOR SUPERIOR Originate: Nuchal ligament and spinous processes of C7 - T3. Innervation: Ventral Rami of intercoastal nerve of T2 - T5 Function: Elevate the ribs during respiration. SERRATUS POSTERIOR INFERIOR Originate: spinous processes of T11- T12 and L1 -L2. Innervation: Ventral Rami of intercoastal nerve of T9 - T12 Function: Depress ribs 9th- 12th during Expiration. DEEP MUSCLES (b) Intrinsic Muscles The involve deep muscles in the back. They are divided into 3 layers. First Layer a. Splenius Capitis Originate: From vertebrae C7 - T3. Insertion: mastoid process and lateral aspect of superior nuchal line. Function: Helps in neck rotation and Extending. b. Splenius Cervicis Originate: From vertebrae T3 - T6. Insertion: Spinous process of C2 - C4. Function: Helps in neck rotation and Extending.  Second Layer a. Iliocostal Cervicis Divided into 3 parts: i. Iliocostal cervicis ii. Iliocostal Thoracis iii. Iliocostal lumborum b. Longissimus Muscles Divided into 3 parts: i. Longissimus cervicis ii. Longissimus Thoracis iii. Longissimus lumborum c. Spinalis Muscles Divided into 3 parts: i. Spinalis cervicis ii. Spinalis Thoracis iii. Spinalis lumborum ATLANTO-OCCIPITAL AND ATLANTO-AXIAL JOINT  ATLANTO-OCCIPITAL JOINT This is an ellipsoid/condyloid joint. This is a joint between the occipital bone [occipital condylar]and Atlas [superior articular facet] It has Fibrous capsule which surrounds the joint. It also have the anterior and posterior atlanto-occipital membrane. Movements: Flexion/extension e.g. nodding ATLANTOAXIAL JOINT This is the joint between Atlas and the Axis vertebrae. There are 3 joints involved here: a. 2 x Lateral atlantoaxial joint b. 1 x Median atlantoaxial joint a. Lateral atlantoaxial joint This is joint between the superior articular face of the Axis and the inferior articular facet of the Atlas. This is a type of Gliding Joint. This joint is stabilized by the Anterior Longitudinal Ligament. The Ligament flava provide stability and support to the joint. a. Median atlantoaxial joint This joint is made up by the Dens of the Axis and the anterior arch of the atlas. This is a Synovial joint. Has loose capsule ligament that allow movement. Main support of the joint is from Transverse Ligament. All the 3 joints provide Rotatory movement to the axis. Blood supply: Vertebral Artery Nerve Supply: C1 Nerve LIGAMENTS Anterior Longitudinal Ligament [ ALL] Runs from the skull to the front of sacrum. This ligament prevent the spine from bending too backward Posterior Longitudinal Ligament [ PLL] Runs from the skull to the back of sacrum. This ligament prevent the spine from bending too forward Ligament Flava Found in between the laminae on each side of spine. It prevents the separation of vertebrae during bending forward. Supraspinous Ligament connect the tip of spinous processes from C7 to Sacrum. Nuchal Ligament Continuous from supraspinous ligament and starts from C6 to the Skull. Attach from the external protuberance to the foramen magnum. Provide support to head and muscle attachment. DEVELOPMENT OF THE FACE  DEVELOPMENT OF FACE The development of face occurs between 4th and 6th week of embryonic development. But the palatine development occurs between 6th and 8th week. It involves 2 main Important Tissues: a. Pharyngeal arches They are also known as Brachial archies. They are small bulges of Mesoderm. That appear in 4th week of development. b. Neural Crest cells They move into the Pharyngeal / branchial archies and helps and form bones, cartilages and other tissues. Development of face starts from 3 structures: a. Frontonasal process b. Maxillary process c. Mandibular process FACIAL SWELLING AND UPPER LIP Nasal development start with raised bump on the side called Nasal Placodes. The Nasal placodes invaginate to form Nasal pits and Medial and Lateral Nasal Processes. As the maxillary process expands medially, it pushes the nasal processes to the middle. -The Maxillary process and the lateral Nasal process are separated by Nasolacrimal/Naso-optic groove. -The Mandibular Process and the Medial Nasal Process are separated by the Buconasal Groove. At the end of 6th week, The maxillary process fuse with the Medial nasal to form Upper lip. The medial nasal swelling fuse together to form Intermaxillary Segment. The cord Nasolacrimal duct forms from Ectoderm. The Lateral Nasal process forms the Lateral Nasal Wall. The Mandibular process fuses to form Lower jaw, Lower lip and Lower teeth. The Mandibular and Maxillary process fuse to form the Cheeks. By the 8th week, The Primitive shelves migrate upwards and soon they take a horizontal positioning above the tounge. They then fuse together to form Secondary Palatine. Also on the 8th week, the Oronasal Membrane Which is the membrane that separate the nasal cavity from Oral cavity disappear, forming the Primitive Choana which connects the two cavities. The Paranasal sinus Develop from the lateral wall of nasal cavity. FACIAL NERVE  FACIAL NERVE This is Cranial Nerve VII. It has Motor, Special sensory and Parasympathetic functions. The nerve arises from the Pons. It forms a loop around the Abducents Nucleus forming the Facial Colliculus. It starts as Large motor and small sensory root. They travel through Internal Acoustic meatus They enter the Facial Canal. Within the facial canal: a. The two roots fuse to form one root. b. Geniculate ganglion forms. c. 3 branches formed: i. Greater Petrosal Nerve ii. Nerve to stapedius muscle. iii. Chord tympani. The Facial nerve exits the cranium through Stylomastoid Foramen. Outside the cranium, the facial nerve first gives the branch Posterior Auricular nerve. It then branches to 2 branches: a. Nerve to posterior belly of digastric muscle b. Nerve to stylohyoid muscle The main trunk of the facial nerve is then called motor trunk. It travels to the parotid gland but It doesnot supply the parotid gland. In the parotid gland it divides into 5 branches. a. Temporal branch b. Zygomatic branch c. Buccal branch d. Marginal Mandibular e. Cervical branch The main trunk of the facial nerve is then called motor trunk. It travels to the parotid gland but It doesnot supply the parotid gland. In the parotid gland it divides into 5 branches. a. Temporal branch b. Zygomatic branch c. Buccal branch d. Marginal Mandibular e. Cervical branch Motor Function: -Nerve to stapedius muscle -Posterior Auricular nerve -Nerve to posterior belly of digastric muscle -Nerve to stylohoid muscle Special Sensory Function: -Chorda tympani: Responsible for taste in ant 2/3 of the tougue Parasympathetic Function: -The greater petrosal nerve give parasympathetic fibers to the mucous gland and lacrimal gland.[ Deep petrosal nerve give the sympathetic fibers] MUSCLE OF FACIAL EXPRESSION  AROUND SCULP a. Occipito-Frontalis Muscle Contain 4 thin layers: 2 x Frontal and 2 x Occipital Function: Elevate eyebrows, moves scalp and provide vertical wrinkles. Innervation: -Frontal: Temporal branch of facial nerve -Occipital: Posterior auricle branch of facial nerve AROUND THE EYE a. Orbicularis Oculi This muscle have 3 parts: a. Orbital part: Origin: Frontal bone, frontal process of Maxilla, Medial Palpebral ligament Function: Closes the eyelid tightly and shade eye from bright light. b. Palpebral part: Origin: Medial palpebral ligament Function: Closes the eyelid smooth e.g. blinking. c. Lacrimal Part: Origin: Lacrimal crest and lacrimal bone Function: Dilate the lacrimal sac producing tears. Innervation: Temporal and zygomatic branch of facial nerve. b. Corrugator Supercili Origin: Bony ridge above the eye. function: It wrinkles the skin vertically in the forehead. Innervation: Temporal branch of facial nerve. AROUND THE NOSE a. Nasalis Muscle It has two parts; i. Transverse part: origin: Maxilla and incisive fossa function: Compress the nostrils ii. Alar part Origin: Maxilla function: Draws the cartilage downward which open the nostrils. Innervation: Buccal and Zygomatic branch of facial nerve. b. Procerus Origin: Superficial to the nasal bone. function: It becomes active during running and concentration. Innervation: Temporal and Zygomatic branch of facial nerve. c. Depressor Septi Nasi Origin: Maxilla above central incisor. function: Assist in widening the nostrils. Innervation: Buccal branch of facial. d. Levator Labii Superioris Alaque Nasi Origin: Frontal process of the Maxilla. function: Helps in flaring the Nostrils. Innervation: Buccal and zygomatic branch of facial. AROUND THE MOUTH a. Orbicularis Oris Origin: Midline of the Maxilla and midline of Mandibular. function: It narrows the mouth and close the lips. Innervation: Buccal and Mandibular branch of facial. b. Buccinator Muscle Origin: Muscular part of the cheek. function: Keep the teeth out of the vestibule. Innervation: Buccal branch of facial nerve. c. Upper Group Muscles i. Risorius muscle Origin: Lateral corner of the mouth. function: Pull the corner of the mouth up e.g. grinning. Innervation: Buccal branch of facial nerve. ii. Zygomaticus minor and Major Origin: They both originate from zygomatic bone. function: Raise the corner of the mouth up e.g. smile. Innervation: Zygomatic and Buccal branch of facial nerve. iii. Levator labii superioris Origin: Maxilla and zygomatic bone. function: Elevate and everts the upper lip. Innervation: Zygomatic and Buccal branch of facial nerve. iv. Levator Anguli Oris Origin: Maxilla. function: Elevate corner of mouth and depress furrow between nose and mouth. Innervation: Zygomatic and Buccal branch of facial nerve. d. Lower Group Muscles i. Depressor Anguli Oris Origin: Mental tubercle of the mandible. function: Depresses the angle of mouth. Innervation: Mandibular and Buccal branch of facial nerve. ii. Depressor labii inferioris Origin: Oblique line of the mandible. function: Depresses the lower lip and moves it laterally. Innervation: Mandibular branch of facial nerve. iii. Mentalis muscle Origin: Incisive fossa of the mandible. function: Raises and protrudes the lower lip causing skin to wrenkles. Innervation: Mandibular branch of facial nerve. AROUND THE NECK a. Platysma Origin: Upper Pectoral and deltoid fascia. function: Depress the mandibular and draw the corner of the mouth downward. Innervation: Cervical branch of facial nerve. PAROTID GLAND  PAROTID GLAND This is the largest Salivary gland. It contributes about 25% of the saliva volume. It is located in the Parotid facial Space. It is enclosed by the capsule Parotid capsule. The Submandibular gland is separated from the Parotid Gland by the Stylomandibular Gland. RELATIONS TO PAROTID GLAND 1. Apex of the Gland Posterior Belly of Digastric Muscle Cervical branch of Facial Nerve 2 divisions of Retromandibular Nerve 2.Superior Surface External Acoustic meatus Temporomandibular joint Superficial Temporal Vessels Auriculotemporal nerve 3.Superficial Surface Skin Superficial Fascia Parotid Fascia Deep Lymph Nodes 4. Anteromedial Surface Masseter Temporomandibular joint Ramus of Mandible Medial Pterygoid Facial nerve 5. Posteromedial Surface Mastoid process Sternocleidomastoid muscle Posterior belly of digastric muscle Styloid process External carotid artery Internal carotid artery 6. Anterior border Parotid duct Terminal branches of the facial nerve Transverse facial vessels 7. Posterior border overlaps sternocleidomastoid muscles 8. Medial border Lateral wall of the pharynx Parotid Duct [ Stensen’s Duct] This is the structure that carries saliva from parotid duct to the mouth. It is 5cm long. It runs between the buccinator and mucosa and open in the vestibule of mouth in are called Parotid pupillae. Blood Supply It is supplied by the branches of the External Carotid Artery. -Posterior auricular, Transverse Facial, Maxillary and Superficial Temporal Artery. Venous Drainage The parotid is primarily drained through Retromandibular vein formed by Superficial Temporal and Maxillary vein. Nerve supply Innervation of Parotid gland comes from Glossopharyngeal nerve [CN VIII] and The Auriculotemporal nerve then supply the parotic gland from Otic ganglion. Parasympathetic Supply: Start in the inferior Salivatory nucleus located in the Dorsal aspect of the pons. The signal is sent via the Glossopharyngeal nerve through the tympanic branch. This branch form the tympanic plexus and continues lesser petrosal nerve. The signal then reaches the otic ganglion where it synapse. The post ganglionic fibers hitch a ride on the Auriculotemporal nerve to the parotid gland stimulating saliva production. Sympathetic Supply [ Vasomotor]: External Carotid Artery Plexus TRIGEMINAL NERVE  TRIGEMINAL NERVE This is the largest Cranial Nerve. It has Sensory and motor fibers. The Trigeminal Nerve has 4 Nucleus: a. Main sensory -Found posterior to the pons and lateral to motor nucleus. b. Spinal Nucleus -Extend downward through the Medulla oblongata. c. Motor nucleus -Have unipolar cells and extend inferiorly to the pons. d. Mesencephalic Nucleus -Situated in the pons medially to the main sensory. Course of the Nerve Originate from the pons with two roots covered with protective layer called Pia- arachnoid. The sensory root of the nerve expands to form The Trigeminal Ganglion. Three branches of the nerve then arises from the ganglion: -Ophthalmic, Maxillary and Mandibular branches. The trigeminal Ganglion is made up of Pseudounipolar Cells. It is made up in the Meckel/trigeminal Cave. Sensory component of Trigeminal nerve The pseudounipolar cells divide into 2 processes: a. Peripheral process b. Central process In the Pons, Half of the fibers split into ascending and descending branches. a. Ascending tracts: Terminate in the Main sensory nucleus. They are responsible for Touch and pressure. b. Descending Tract: Terminate in the Spinal nucleus. They are responsible for pain and temperature. The propioceptive impulse from muscles of mastication are carried by unipolar cells in the mesencephalic nucleus. Axons from the 3 Nucleus cross the trigeminal meniscus to terminate in the ventral posteriomedial nucleus of the Thalamus. Then postfibers travel through genu of internal capsule to the postcentral gyrus. Motor component of Trigeminal nerve The motor nucleus supllies muscles of mastication, Tensor Tympani, Tensor veli palatine. OLPHTHALMIC NERVE [CNVa/CNVi] This nerve travels laterally to cavernous sinus and gives off Recurrent Tentorial branch. It exits the skull through the Superior Orbital Fissure. It supplies structures derived from frontonasal process. The nerve then Forms 3 Other branches: a. Frontal Nerve b. Lacrimal Nerve c. Nasocilliary nerve (1) Frontal Nerve -Have 2 main branches: i. Supraorbital [ upper eyelid, conjuctiva, scalp] ii. Supratrochlear [ upper eyelid, conjuctiva, forehead] (2) Lacrimal Nerve -Provide sensation to lacrimal gland, upper eyelid, conjuctiva. It also have parasympathetic fibers to lacrimal gland. (3) Nasocilliary Nerve -It gives off 3 branches: i. Anterior Ethmoid nerve: Mucous membrane of frontal, Ethmoid and sphenoid sinuses and Nasal Cavity. ii. Posterior Ethmoid Nerve: Mucous membrane of sphenoid sinus. iii. Infratrochlear nerve: Bridge of the nose, Upper eyelid, conjuctiva. iv. Long ciliary nerve: Have sympathetic fibers to dilator pupilae muscles MAXILLARY NERVE [CNVb/CNVii] The maxillary nerve exits the cranium through Foramen Rotondum. It emerges through the Infraorbital foramen as Infraorbital nerve. In the pterygopalatine fossae, the maxillary nerve gives out the Zygomatic Nerve. The Zygomatic nerve then branches out to: a. Zygomaticofacial nerve: Supplies the prominence of the cheeks. b. Zygomaticotemporal nerve: Supplies the skin on the temples. The infraorbital nerve gives rise to 6 more branches: a. Anterior, Middle and posterior Superior alveolar process. b. Palpebral nerve c. Nasal nerve [ External and internal nasal nerve] d. Superior Labial nerve MANDIBULAR NERVE [CNVc/CNViii] This is a 3rd branch of Trigeminal Nerve. It has both sensory and motor function. Its start with 2 roots that fuse together and travel through the Foramen Ovale. They give off: a. Middle Meningeal Branch: Travel through Spinosum and supply the dura matter. b. Nerve to Medial Pterygoid: Supplies the medial pterygoid muscle. c. Posterior Trunk Branches [Sensory] i. Auriculotemporal nerve: Supply skin over the temple and the auricles. ii. Lingual nerve [ hitch hiked by chorda Tympani]: Provide sensation to the anterior 2/3 of the toungue. iii. Inferior Alveolar Nerve: Emerges through Mandibular foramen. (1) Mental foramen: skin of chin and mucous membrane of lower lip (2) Incisive branch: Gums of canines and incisors (3) Inferior Dental branch: Lower teeth and gums. (4) Mylohyoid branch: Mylohyoid muscles and anterior belly of digastric Muscle. d. Anterior Trunk branches [motor] i. Buccal Nerve [only sensory nerve here]: Skin and mucous membrane of buccinator and labial aspect of the gums of the molar and premolar teeth. ii. Messeteric Nerve: pass through mandibular notch and supply the messeteric muscle and temporomandibular joint. iii. Deep Temporal nerve [Anterior and Posterior]: supplies the deep surface of the temporalis. iv. Nerve to lateral pterygoid muscle: Supply the deep surface of the pterygoid muscle. THE BONY ORBIT  THE BONY ORBIT The bony orbit is formed by 7 bones; Maxilla, zygomatic, Lacrimal, Palatine, Sphenoid, Frontal and Ethmoid bone. a. The Apex The apex of the bony orbit is made up of optic canal in the Lesser wing of sphenoid. b. The Base Formed by the Frontal bone (superiorly), Frontal process of Zygomatic bone(laterally), Zygomatic process of Maxilla & zygomatic bone (Inferiorly) and Frontal process of Maxilla (Medially). c. The Roof Formed by the Orbital part of Frontal bone. In the anterolateral area, there is shallow lacrimal fossae, in the anteromedial area, there is frontal sinus and trochlea fovea. d. Medial Wall Formed mainly by Orbital plate of Ethmoid bone. It is also formed by Frontal process of maxilla, Lacrimal bone and greater wing of sphenoid. e. Floor Formed by Maxilla, zygomatic and Lacrimal Bone. Separated from the lateral wall by the Inferior Orbital Fissure. f. Lateral Wall This is the strongest and the thickest because of Trauma. Mad up of Zygomatic bone and Greater wing of Sphenoid. The posterior part separate the Orbit from Temporal bone and middle cranial fossae. THE MUSCLES OF EYEBALL The Eyeball is controlled by 6 extrinsic Muscles. It mainly consist of 3 Layers: a. Fibrous Layer: Sclera and Cornea b. Vascular Layer: Choroid, Ciliary Body and Iris. c. Inner Layer: Optical part and Non-visual part. It also have connective tissues like Bulbar Fascia at the back and Bulbar conjuctiva at the front. The space between the Bulbar Fascia and the eyeball is called Episcleral Space It allows Movement.  EXTRINSIC MUSCLES OF EYEBALL a. SUPERIOR OBLIQUE MUSCLE ORIGIN: Body of sphenoid , above and medial to optic canal. INSERTION: Superior Surface of Eyeball. INNERVATION: Trochlear Nerve FUNCTION: Depress, Abducts And Medially rotate the eyeball. b. SUPERIOR RECTUS MUSCLE ORIGIN: Superior part of common tendinous ring. INSERTION: Anterior half of eyeball, superiorly. INNERVATION: Oculomotor Nerve FUNCTION: Elevate, Adducts And Medially rotate the eyeball. c. LATERAL RECTUS MUSCLE ORIGIN: lateral part of common tendinous ring. INSERTION: Anterior half of eyeball, Laterally. INNERVATION: Abducent Nerve FUNCTION: Abducts the eyeball. d. MEDIAL RECTUS MUSCLE ORIGIN: Medial part of common tendinous ring. INSERTION: Anterior half of eyeball, Medially. INNERVATION: Oculomotor Nerve FUNCTION: Adducts the eyeball. e. INFERIOR RECTUS MUSCLE ORIGIN: Inferior part of common tendinous Ring. INSERTION: Anterior Half of the eyeball, Inferiorly. INNERVATION: Oculomotor nerve FUNCTION: Depress, Abducts And Laterally rotate the eyeball. f. INFERIOR OBLIQUE MUSCLE ORIGIN: Medial Floor of the orbit, posterior to the rim, Maxilla lateral to Nasolacrimal groove. INSERTION: Inferior surface of the Eyeball. INNERVATION: Oculomotor nerve FUNCTION: Elevate, Adducts And Laterally rotate the eyeball. g. LEVATOR PALPEBRAE SUPERIORIS ORIGIN: lesser wing of Sphenoid Bone, Anterior to Optic canal. INSERTION: Anterior [Surface of Tarsal Plate. INNERVATION: Oculomotor nerve FUNCTION: Elevate upper eyelid.  BLOOD SUPPLY TO THE ORBIT Mainly supplied by the Ophthalmic artery and the Infraorbital artery. The Ophthalmic artery divides into 10 branches: a. Lacrimal Artery: Supplies the lacrimal gland, conjuctiva and lateral sides of eyelid. b. Central Retinal Artery: Supply the Retina except the cones and rods. c. Short Posterior Ciliary Artery: Supplies the choroid, Rods and Cones. d. Long Posterior Ciliary Artery: Supplies the ciliary body and the iris. e. Muscular arteries: Supply Iris, Ciliary body and Superior, Inferior, Lateral and Medial Rectus Muscle. f. Supraorbital Artery: Supply forehead and Scalp. g. Posterior Ethmoidal Artery: Supply posterior Ethmodial Cells. h. Anterior Ethmoidal Artery: Supply Anterior and Middle Ethmoidal Cells, Frontal Sinus, Nasal Cavity and skin of Nose.. Medial Palpebral Artery: Supply eyelids. J. Dorsal Nasal Artery: Supply upper surface of the nose. k. Supratrochlear artery: Supply fore head and scalp. The Infraorbital Artery Originate from 3rd part of Maxillary artery [Branch of Eternal Carotid Artery]. It supply the Inferior Rectus and inferior Oblique Muscle. VENOUS DRAINAGE OF THE ORBIT The orbit is drained by the Superior and Inferior ophthalmic vein and it drains to the carvenous sinus.  OCULOMOTOR NERVE, TROCHLEAR NERVE AND ABDUCENT NERVE.  OCULOMOTOR NERVE The nucleus of the Oculomotor Nerve is located in the Periaqueductal grey matter. It is made up of 2 components. a. GSE (General Somatic Efferent): It is located ventromedially. b. GVE (General Visceral Efferent/ Edinger-Westphal): Located dorsomedial. The Edinger-Westphal nucleus provide parasympathetic fibers to the eye, helps and constrict the eye and adjust the lens. Emerges in the Interpeduncular cistern [interpeduncular fossae]. Move between Posterior Cerebral artery and Superior Cerebellar Artery and runs along Posterior Communicating Artery. It travels in the Lateral wall of Cavernous sinus above the Trochlear Nerve. Its then picks up sympathetic fibers from internal carotid plexus. Then it enter the Supraorbital fissure within the common tendinous ring divides into 2 branches. The superior branch: Enter the superior Rectus where it supplies and also enter the levator palpebrae superioris and supply it. The Inferior branch: Further divides into 3 branches. Medial rectus, Superior rectus and inferior Oblique. The fibers to the Inferior oblique are long because they contain all the fibers from Edinger-Westphal nucleus. These fibers enter the Ciliary ganglion and synapse. The postsynaptic fibers are distributed via the short ciliary nerve to sphincter pupillae and ciliary muscles. OCULOMOTOR NERVE The nucleus of trochlear nerve is located in the Periaqueductal grey matter in level of inferior colliculus. The only cranial nerve that exits the cranial nerve dorsally and of which its nerve fibers are crossing. Emerges Between the posterior Cerebral artery and Superior cerebellar artery and move in lateral wall of cavernous sinus below Oculomotor Nerve and it enters the Supraorbital fissure. Passes medial above the levator palpebral superioris and enter the orbital surface of the Superior Oblique Muscle and supply it.  ABDUCENT NERVE The nucleus of the Abducent is located in the lower pons. It travels in the subarachnoid space between the pons and clivus. Lies in the cavernous sinus next to internal carotid artery. Exits through Supraorbital fissure within cone of muscles below the inferior branch of Oculomotor nerve. It then enters the lateral Rectus and supply it. VISUAL PATHWAYS The light that enters is determined by Photoreceptors in the Retina. The Retina have 2 halves: a. Nasal (Medial): Cells here send the axons to opposite side of optic chiasma. b. Temporal (Lateral): Cells here send axons to same side. The visual information exits the eye through the optic nerve. In the Optic chiasma the Some axons cross to other side [Nasal] Forming Optic Tract. The Optic tract reaches the Lateral Geniculate Ganglion in the thalamus. From the Lateral Geniculate ganglion, fibers spread out as optic radiation to Calcarine cortex in the Occipital Lobe. In the occipital lobe, the conscious visual perception occurs in the Primary visual Cortex. a. The association visual cortex processes Form, color and movement. b. Temporal lobe connections help with High-resolution object recognition. c. Parietal Cortex connection analyzes motion and positional relationships of objects in the visual scene. THE VISUAL FIELD The fovea is located in the center of Macula Lutea of the Retina and it is packed with cone cells which are responsible for vision. RIGHT EYE Temporal Retina: Left Visual Nasal Retina: Right Visual LEFT EYE Temporal Retina: Right visual Nasal Retina: Left Visual EMBRYOLOGY OF THE EYE  OPTIC PRIMORDIUM The development of the Eye begins as the Optic Primordium in the earliest stage. By the 18th day of development the Primary Optic Vesicle develops from the structure. The Primary Optic Vesicle invaginates to form the Optic Cup. The Optic cup consist of 2 layers: a. Outer Layer: Becomes the Retinal Pigment Epithelium. b. Inner Layer: Becomes the Neural Retina which has photoreceptors, bipolar and ganglion cells. The space between the layers is called Intraretinal Space. RETINA DEVELOPMENT The Optic cup consist of 2 layers: a. Outer Layer: Becomes the Retinal Pigment Epithelium. b. Inner Layer: Becomes the Neural Retina which has photoreceptors, bipolar and ganglion cells. The Pars Optica Retinae is found in the Neural Retina. It consist of cells that develops into Rods and cones. Next to Photoreceptors, there is Mantle Layer That produces neurons and cells. It forms 3 layers: a. Outer nucleus Layer: Contain Cell bodies for the photoreceptors axons. b. Inner Nucleus Layer: Contain Bipolar cells. c. Ganglion Cell Layer: Contain ganglion for the axons that form Optic nerve. Fibrous Layer is found in the surface of the optic nerve and contains axons from deeper layer that converges towards the Optic Stalk forming the Optic Nerve. Lens Primordium The Lens Primordium is the earliest stage of the development of the Lens. The optic vesicle induces the Surface Ectoderm to thicken and form the Optic Placode. The optic placode invaginates to form the Optic Pits. The optic pits pinches off to form lens Vesicle. The cell in the posterior part of Lens Vesicle elongate the fibers which fill out the vesicle and form the Nucleus of the Lens. The lens grows until age 20. optic stalk development As the optic vesicle extend outward, the proximal part of each vesicles constrict forming the Optic Stalk. The optic stalk allow connection of fore brain and the Optic cup. The ventral surface of the Optic stalk invaginates forming the Choroidal fissure. The Choroidal fissure allow the Hyaloid artery to pass through and supply the Retina.  Ciliary body and iris development The retina have Pars Ceca Retinae which is the fifth layer of the eye and stays as one thick cell. It divides into 2: a. Pars Iridica retinae: Forms the inner layer of the Iris. b. Pars Ciliaris Retinae: Contributes in formation of the Ciliary Body. The Iris is made up of: a. External layer that have pigment. b. Internal Layer with no pigment. c. highly vascularized connective tissue with papillae muscles intrinsic muscles a. Pupillae Muscles The region between the optic cup and the Surface epithelium is filled with loose mesenchyme tissue and; Sphincter and Dilator pupillae muscle form in this tissue from Ectoderm. b. Ciliary Muscles The Pars Ciliaris Retinae is formed from Mesoderm. The ciliary muscle is formed from Mesenchyme outside and connected to lens by suspensory ligament/zonula. CHOROID and SCLERA By 5th week the Eye Primordium is surrounded by the Mesenchyme. The mesenchyme then differentiate into 2 layers: a. The outer layer forms the Sclera and becomes continuous to the dura mater. b. The inner layer forms the Choroid [highly vascularized layer] CORNEA Derived from surface Ectoderm. contain the tissue layer, Substantia Propia [Stroma] middle layer of the cornea that forms epithelial layer that borders the anterior chamber of the eye. VITREOUS BODY The mesenchyme invades the optic cup through the Choroid fissure. Inside, the mesenchyme forms the hyaloid vessels that supply the lens and form the vascularized layer of the retina. The mesenchyme also form network fibers between the retina and lens. The spaces in between is filled with transparent, gelatinous substance forming the Vitreous Body. During fetal development the hyaloid vessels disappear. LACRIMAL APPARATUS  Lacrimal Gland This is serous gland located in lacrimal fossae. The sensory innervation is Lacrimal nerve of Ophthalmic nerve. It has 2 parts: a. Orbital Part [Large and deep] b. Palpebral Part [Small and superficial] Both these parts are separated by Lateral Extension of Levator Palpebral Superioris. ORBITAL PART a. Superior Surface: Frontal Bone b. Inferior Surface: Levator palpebral superioris and Lateral Rectus c. Anterior Border: Septum Orbitale d. Posterior Border: orbital fat, level with posterior pole e. Lateral Extremity: Lateral Rectus f. Medial Extremity: On levator palpebral Superioris PALPEBRAL PART Found beneath Levator aponeurosis. Lacrimal Gland INNERVATION a. Parasympathetic The Preganglionic fibers travel by Greater petrosal nerve and nerve to pterygoid canal [vidian nerve] and synapse at Pterygopalatine ganglion. Postganglionic fibers travel by Zygomatic nerve of Maxillary branch of Trigeminal nerve. They the hitch hike on the Lacrimal nerve of Ophthalmic branch of facial nerve to reach lacrimal gland. They stimulate Tear production. b. Sympathetic The originate from cervical ganglion and travel via carotid plexus and deep petrosal nerve and meet the parasympathetic fibers in the Pterygoid Canal and they travel the same route. They inhibit tear production. Lacrimal Gland PASSAGE a. Lacrimal Punctum: Located near border of the eyelid. b. Lacrimal Canaliculi: start at punctum and carries tears to lacrimal sac. c. Lacrimal sac: Covered by Lacrimal Fascia with upper part as fundus and narrows as nasolacrimal duct. The nasolacrimal duct opens in the inferior meatus of the nose, draining tears to nasal cavity.  TEAR PRODUCTION AND DRAINAGE Normal tear production is from the Accessory Lacrimal Gland. Excessive tear production such as crying is caused by Reflex Nervous Stimulation of Main Lacrimal Gland. Excessive tears drains in to the nasolacrimal duct. ANATOMY OF THE NOSE  ANATOMY OF THE NOSE The functions of nose involves, Olfaction, Respiration, Humidification of Air. It has 2 parts: a. External Nose b. Nasal Cavity External nose NASAL Cavity The Nasal Cavity is divided into 3 Areas: a. Olfactory Area b. Vestibule Area c. Respiratory Area The lateral wall of Nasal cavity has 3 bony Projections called conchae. [Superior, Middle, Inferior conchae] Between the Conchae there are Meatus [Superior, Middle, inferior meatus] There Spheno-Ethmodial Recess is found between the Superior conchae and the Roof of Nasal Cavity.  Nerve Supply Olfaction supply: Olfactory nerve [CN I] General Sensation: Trigeminal Nerve Glands: Parasympathetic fibers from Facial Nerve BLOOD Supply a. Anterior Ethmoidal Artery [From Ophthalmic artery]: Supply anterior nasal septum and lateral wall of nasal cavity and frontal sinus and ethmoidal sinus. b. Posterior Ethmoidal Artery [Ophthalmic Artery]: Supply posterior Nasal Septum and lateral wall of nasal cavity, sphenoidal sinus and ethmoidal sinus. c. Sphenopalatine artery [Maxillary Artery]: Supply d. Greater Palatine Artery [ Maxillary artery]: Supply hard palatine and medial wall of the nose. PARANASAL AIR SINUS There are 4 main paranasal air sinus, Frontal, Maxillary, Sphenoid and Ethmoid air sinus. Importance of Paranasal Air sinus: a. Imparting resonance to voice. b. Humidifying and warming inspired air. c. Increasing olfactory area. d. Providing thermal insulation to vital parts. FRONTAL AIR sinus Location: Diploe of frontal bone; opens in hiatus semilunaris in middle meatus. Nerve Supply: Supraorbital nerve Blood Supply: Anterior Ethmoidal artery MAXILLARY AIR sinus Location: Deep bodies of Maxilla; drained by Maxillary ostia in middle meatus. Nerve Supply: Anterior, Middle, Posterior alveolar nerves Blood Supply: Maxillary artery SPHENOdiAL AIR sinus Location: Separated by body septa; drains into spheno-ethmoidal recess. Nerve Supply: Posterior Ethmoidal nerve Blood Supply: Posterior Ethmoidal artery  ethmoidal AIR sinus Location: small spaces in ethmoid bone. Divided into 3: anterior, middle and posterior ethmoidal cells. Nerve Supply: Anterior and posterior ethmoidal branches. Blood Supply: Anterior and Posterior Ethmoidal arteries.