exterior of skull (skull views anterior posterior and lateral)

Views of skull
Skull anatomy

1. Exterior of skull

2. The superciliary arches, also known as supraorbital ridges, are the bony ridges located on the frontal bone of the skull, just above the eye sockets. Function: The primary function of the superciliary arches is to provide mechanical protection for the eyes. They act as a physical barrier, shielding the eyes from objects and impacts. Additionally, they are the point of origin for the corrugator supercilii muscle, which draws the eyebrows together and downward, an action used to protect the eyes from bright light or rain.

3. The frontal sinuses are air-filled cavities located within frontal bone of skull just above the eyebrows that: Lighten the skull to reduce its weight. Warm and humidify inhaled air to protect the respiratory tract. Provide immune defense by trapping airborne pathogens in mucus. Act as a "crumple zone" to protect the brain from facial trauma.

4. The supraorbital margin is the superior, or upper, rim of the bony eye socket (orbit). Its primary function is protection. It forms a strong, bony arch that serves as a shield for the eye, protecting it from both direct impacts and trauma from above.

5. The supraorbital foramen is a small opening or notch located within the supraorbital margin. Its main function is to serve as a passageway for the supraorbital nerve, artery, and vein.

6. The superior orbital fissure is a slit-like opening located between the lesser and greater wings of the sphenoid bone . Its primary function is to serve as a conduit for a number of critical nerves and veins that control the eye's movement and provide sensation to the face. The structures passing through this fissure include: Oculomotor nerve (CN III) Trochlear nerve (CN IV) Abducens nerve (CN VI) Ophthalmic nerve (CN V1) Superior ophthalmic vein

7. The inferior orbital fissure is a fissure located on the floor of the orbit between the maxilla and the greater wing of the sphenoid bone. It is the passageway for structures that provide sensation to the mid-face and supply blood to the area. These include: Infraorbital nerve, artery, and vein Zygomatic nerve
Inferior ophthalmic vein:

8. The optic canal is a short, bony passageway located at the back of the eye socket (orbit). Its sole function is to serve as a protected conduit for the structures that connect the eye to the brain and supply it with blood. Specifically, the optic canal transmits two vital structures: Optic nerve (Cranial Nerve II) Ophthalmic artery

9. The duct is located in the nasolacrimal canal, a bony passage in the skull formed by the lacrimal and maxillary bones. It begins at the bottom of the lacrimal sac , which is situated on the side of the nose near the inner corner of the eye. From there, the duct travels downward and slightly backward, eventually opening into the nasal cavity beneath the inferior nasal concha. The sole function of the nasolacrimal duct is Tear Drainage Preventing overflow

10. The infraorbital foramen is a small opening located on the front surface of the maxilla (the upper jawbone), just below the lower rim of the eye socket. Its primary function is to serve as a protected passage for the structures that supply sensation and blood to the mid-face. These include: Infraorbital nerve artery And vein

11. The inferior and middle nasal conchae, along with the superior nasal concha, are curved bony shelves that project from the lateral walls of the nasal cavity. Their collective function is to condition inhaled air before it reaches the lungs. Warming and Humidifying Inhaled Air Filtering Particulates Regulating Airflow: By controlling the blood volume in their tissues, the conchae can swell or shrink, regulating the amount of air passing through the nasal cavity. This helps to optimize the processes of humidification and warming and can respond to different environmental conditions.

12. The nasal septum is the wall of bone and cartilage that divides the nasal cavity into two separate, equal halves. The primary and most straightforward function of the nasal septum is to provide structural support for the nose. It forms the central midline support for the nasal dorsum (the bridge of the nose) and the nasal tip, maintaining the nose's shape and integrity.

13. The mental foramen is a small opening on the outer surface of the mandible (lower jawbone), located below the second premolar tooth. Its function is to serve as a protected passageway for the mental nerve artery and vein

14. Lateral view of the skull

15. The petrous part is the densest and most medial portion of the temporal bone, resembling a pyramid. Its primary function is to house and protect the delicate structures of the inner ear that are responsible for hearing and balance (cochlea semicircular canals and vestibule). It is also a key passageway for several cranial nerves.

16. The mastoid part is the posterior, rough projection of the temporal bone located behind the ear. Its functions are mainly related to muscle attachment and air regulation. Air Regulation and Protection: The mastoid part contains a series of interconnected air cells, which communicate with the middle ear. These air cells help to regulate air pressure in the middle ear and may also play a role in voice resonation.

17. The zygomatic arch is the prominent, bony arch that forms the "cheekbone" on the side of the face. The zygomatic arch has several key functions: Protection : It acts as a physical barrier that helps protect the delicate contents of the eye socket (orbit) from external trauma. Muscle Attachment : The arch provides a crucial attachment site for the powerful masseter muscle, which is the primary muscle used for chewing (mastication). This allows for the forceful closing of the jaw.

18. The masseter muscle is a strong, thick muscle located on the side of the face, connecting the zygomatic arch (cheekbone) to the mandible (lower jaw). It is one of the primary muscles of mastication, or chewing. Primary Functions Elevation of the Mandible Protraction of the Mandible

19. The ramus of the mandible is the vertical, quadrilateral portion of the lower jawbone. There are two rami, one on each side of the face. The ramus plays a crucial role in the mechanics of chewing and jaw movement The primary functions of the ramus are: Muscle Attachment Formation of the Temporomandibular Joint (TMJ): The superior aspect of the ramus features the condylar process, a rounded head that articulates with the temporal bone of the skull. This articulation forms the temporomandibular joint (TMJ), which allows for the complex movements of the jaw, including opening, closing, and side-to-side motion.

20. Posterior view

21. The external occipital protuberance is the prominent, bony bump that you can feel at the base of the skull in the midline of the occipital bone. The protuberance is the anchor for two key structure: Nuchal Ligament: A strong, fibrous ligament that runs down the back of the neck from the protuberance to the cervical vertebrae. It helps to stabilize the head and resist the forward pull of gravity. Trapezius Muscle

22. The occipital condyles are two rounded, bony projections located on the underside of the occipital bone at the base of the skull. Their primary function is to form a movable joint with the top-most vertebra of the spine. This articulation, known as the atlanto -occipital joint, connects the skull to the vertebral column. It is a synovial joint that allows for specific head movements, including: Flexion and Extension: The nodding "yes" motion. Lateral Flexion: Tilting the head from side to side.