Head & Neck Head & Neck anatomy focuses on the structure of the head and neck of the human body, including “ brain, bones, muscles, blood vessels, nerves, glands, sinuses, mouth and teeth”. In this course the focus will be on bones, paranasal sinuses, TMJ, muscles, vascularity, nerve supply, lymphatic drainage, salivary glands, oral cavity (soft and hard tissues).

Head & Neck Head & Neck anatomy I- Skull * Bones - Cranium - Facial - Maxilla - Mandible * TMJ * Paranasal sinuses II- Muscles - Cervical - Facial expressions - Muscles of mastication - Hyoid muscles - Tongue - Soft Palate & pharynx

Head & Neck Bones of the head: The head is positioned upon the superior portion of the vertebral column, attaching the skull upon C-1 (the atlas). The skull can be divided into: Cranium, (8 bones): a) 1-Frontal b) 2-Parietal c) 1-Occipetal d) 2-Temporal e) 1-Sphenoid f) 1-Ethmoid

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Head & Neck a) 2-Zygomatic b) 2-Maxillary c) 2-Palatine d) 2-Nasal 2. Facial bones, (14 bones): a) 2-Zygomatic b) 2-Maxillary c) 2-Palatine d) 2-Nasal e) 2-Lacrimal f) 1-Vomer g) 2-Inferior Conchae h) 1-Mandible

Head & Neck Skull It has several flat irregular bones that protect the brain. The joints (sutures) between the skull bones are fibrous joints, and they don not move in the mature adult skull. The bones have numerous openings for passage of blood vessels, nerves & lymph vessels.

Head & Neck The bones of the upper skull meet along sutures, which provide growing room for the rapidly expanding brain.

Head & Neck I Cranium Frontal bone: Comprised of Forehead. Orbital cavities Prominent ridges above the eyes (supraorbital margins). 2 air filled sinuses open in the nasal cavities.

Head & Neck Parietal bones: These bones form the sides & roof of the skull

Head & Neck Occipital bone: Forms the back of the head & part of the base of the skull.

Head & Neck Its inner surface is deeply concave to occupy the occipital lobes of the cerebrum & cerebellum of the Brain.

Head & Neck The occipital bone has 2 condyles that form a hinge with the first vertebra (The ATLAS). Between the condyles there is foramen magnum through which the spinal cord passes.

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Head & Neck Sphenoid Bone: It is located in the middle portion of the skull & articulate with the temporal, parietal & frontal bones.

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Head & Neck On the superior (upper) part of the sphenoid bone lies the Sella turcica, (on this sella turcica sits the pituitary gland).

Head & Neck Inside the body of the spehnoid bone there are large air sinuses (sphenoid sinuses) with openings in the nasal cavities

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Head & Neck Ethmoid bone: Occupies the anterior part of the base of the skull. It forms parts of the following bones: Orbital cavity Nasal septum Lateral walls of the nasal cavity On the sides of the nasal cavity, there are 2 bony projections (the upper and the lower nasal conchae= turbinates) 1. Frontal bone Nasal bone 2. 3. Lacrimal bone 4. Maxillary bone 5. Zygomatic bone 6. Temporal bone 7. Parietal bone 8. Greater wing of sphenoid bone 9. Zygomatic process of temporal bone 10. Lesser wing of sphenoid bone 11. Ethmoid bone 12. Palatine bone

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Head & Neck Ethmoid bone is a delicate bone & contains many air sinuses and opens in the nasal cavity.

Head & Neck II Facial bones Zygomatic bones: They are called cheek bones. They form the prominence of the cheeks & part of the floor & lateral walls of the orbital cavities.

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Head & Neck Maxilla: It is the upper jaw bone. Originally they are 2 bones, but fuse before birth to form one bone otherwise a cleft palate exists.

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Head & Neck Alveolar ridge is a process projects downwards & carries the upper teeth

Head & Neck Maxillary sinuses: Large sinuses, one on each side opens into the nasal cavities.

Head & Neck Nasal bones: They are 2 small flat bones. They form the greater part of the lateral & superior surfaces of the bridge of the nose.

Head & Neck Lacrimal bones: They are 2 small bones located lateral & posterior to the nasal bones. They form part of the medial walls of the orbital cavities.

Head & Neck Vomer bone: It is a thin flat bone extends upwards from the middle of the hard palate to form the main part of the nasal septum. It articulates with the perpendicular plate of the ethmoidal bone.

Head & Neck Palatine bones: 2 L-shaped bones Horizontal parts: they unit to form the posterior part of the hard palate. Perpendicular parts: they projects upwards to form part of the lateral walls of the nasal cavities. At their upper parts they form part of the orbital cavities.

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Head & Neck Inferior conchae ( turbinated bones): Each conchae is a scroll-shaped bone. It forms part of the lateral wall of the nasal cavity & projects into it below the middle conchae. The superior and middle conchae are parts of the ethmoidal bone.

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Head & Neck Hyoid bone: A horse-shoe shaped bone, lying in the soft tissues of the neck above the larynx & below the mandible. It is an isolated bone that does not articulate with any other bone.

Head & Neck Hyoid bone:

Head & Neck Mandible The ONLY movable bone of the skull. Originally 2 parts, units at midline. Each half has 2 parts Curved body with alveolar ridge that host the lower teeth. Ramus which projects upwards almost at right angle to the body at the posterior end.

Head & Neck The ramus divides at the upper end into 2 parts: Condylar process which articulates with the temporal bone to form the temporomandibular joint (TMJ). Coronoid process that gives attachment to muscles & ligamnets.

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Head & Neck TMJ The mandible articulates with the temporal bone at the temporomandibular joint (TMJ).

Head & Neck The TMJ is formed between the articular surface of the squamous part of the temporal bone & the head of the condyle. It is separated into upper & lower cavities by a fibrocartilagenous disc within the joint. Lateral ptregoid muscle pierces the capsule attaching to the head of the condyle

Head & Neck TMJ Movements possible at this joint include depression and elevation of the mandible, protraction and retraction, side to side movements.

Head & Neck TMJ The joint has an intra-articular disc. The articular disc is attached around its periphery to the inside of the capsule. Anteriorly is attached near the head of the mandible & posteriorly it is attached near the temporal bone.

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Paranasal sinuses: Head & Neck The Paranasal sinuses are air-containing spaces within the skull. The function of the sinuses: The biological role of the sinuses is debated, but a number of possible functions have been proposed: 1. Decreasing the relative weight of the front of the skull, and especially the bones of the face. 2. Increasing resonance of the voice. 3. Providing a buffer against blows to the face. 4. Insulating sensitive structures like dental roots and eyes from rapid temperature fluctuations in the nasal cavity. 5. Humidifying and heating of inhaled air because of slow air turnover in this region.

Head & Neck The sinuses are named for the bones in which they are located. These are: The maxillary sinuses, the largest of the nasal sinuses. The frontal sinuses, located within the forehead just above the left and right eye. The ethmoid sinuses, irregularly shaped air cells separated from the orbital cavity by a very thin layer of bone. The sphenoid sinuses, located close to the optic nerves, where an infection may damage vision.

Head & Neck F= Frontal sinuses; E=Ethmoid sinuses; M=Maxillary sinuses; O=Maxillary sinus ostium; ST=Superior turbinate; T=Middle turbinate; IT= Inferior turbinate; SM=Superior meatus; MM=Middle meatus; S=Septum

Head & Neck Muscles of the head and neck Cervical muscles Seven groups of muscles Cervical muscles Muscles of facial expressions Muscles of mastication Hyoid muscles Muscles of the Tongue Muscle of the soft palate Muscles of the pharynx.

Head & Neck Cervical muscles: Sternocleidomastoid muscle: divides the neck into anterior and posterior cervical triangles. Trapezius muscle: lift the clavicle & scapula (shoulder blade), as when the shoulder are shrugged.

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Head & Neck 2. Muscles of facial expression Paired muscles on each side. Orbicularis oris Buccinator muscle Mentalis muscle Zygomatic major

Head & Neck Orbicularis oris: Closes & puckers the lips. Helps in chewing & speaking by pressing the lips against the teeth.

Head & Neck Buccinator muscle: It compresses the cheeks against the teeth & retracts the angle of the mouth.

Head & Neck Mentalis muscle: Raises & wrinkles the skin of the chin & pushes up the lower lip Zygomatic major muscle: Draws the angles of the mouth upwards & backwards, as in laughing.

Head & Neck Muscles of Mastication Temporalis muscle: raises the mandible & closes the jaws, posterior fibers draw protruding mandible backwards. Masseter muscles: raises the mandible & closes the jaw.

Head & Neck 3. Medial ptreygoid muscles: closes jaw & by acting with lateral ptreygoid on same side, pulls mandible to one side. 4. Lateral ptreygoid muscles: depresses the mandible to open the jaw. when both muscles contract together, the main action is to bring the lower jaw forward, thus causing protrusion of the mandible. If one lateral ptregoid muscle is contracted, the lower jaw shifts to the opposite side, causing lateral deviation of the mandible

Head & Neck Muscles of the floor of the mouth Mylohyoid muscle: forms the floor of the mouth, raises the tongue & depresses the mandible.

Head & Neck 2. Digastric muscles: each digastric muscle (anterior belly + posterior belly) demarcates the superior portion of the anterior cervical triangle. forming with the mandible a submandibular triangle on each side of the neck

Head & Neck 3. Stylohyoid muscle: assist in swallowing by raising the hyoid bone.

Head & Neck 4. Geniohyoid muscle: draw the tongue & hyoid bone forward.

Head & Neck Muscles of the Tongue: 1. Genioglossus muscles: depresses & protrudes the tongue. 2. Hyoglossus muscle: retracts & pulls down the side of the tongue. 3. Styloglossus muscle: retracts the tongue.

Head & Neck Major muscles of the posterior of the mouth 1. Palatoglossus muscle: elevates the base of the tongue, arching the tongue against the soft palate toward the tongue. 2. Palatopharyngeus muscle: forms the posterior pillar of fauces. also serves to narrow the fauces & help to shut off the nasopharynx.

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