ethmoid bone

Examples of ethmoid bone in the following topics:

• Nose and Paranasal Sinuses

  • The shape of the nose is determined by the ethmoid bone and the nasal septum.
  • The shape of the nose is determined by the ethmoid bone and the nasal septum.
  • The ethmoid bone is the bone that separates the nose from the brain, and supports the shape and structure of the nasal and orbital cavities.
  • On average, the nose of a male is larger than that of a female, due to differences in facial bone structure between genders.
  • These are named according to the bones within which the sinuses lie: surrounding the nasal cavity (maxillary sinuses), above the eyes (frontal sinuses), between the eyes (ethmoid sinuses), and behind the ethmoid bone (sphenoid sinuses).

• Cranial Bones

  • The neurocranium is comprised of eight bones: occipital, two temporal bones, two parietal bones, sphenoid, ethmoid, and the frontal bone.
  • The neurocranium consists of the occipital bone, two temporal bones, two parietal bones, the sphenoid, ethmoid, and frontal bones—all are joined together with sutures.
  • The body that forms the middle of the sphenoid bone articulates with the ethmoid and occipital bone and forms a key part of the nasal cavity; it also contains the sphenoidal sinuses.
  • The ethmoid bone is a small bone in the skull that separates the nasal cavity from the brain.
  • The ethmoid bone forms the medial wall of the orbit, the roof of the nasal cavity, and due to its central location it articulates with numerous bones of the viscerocranium.

• Facial Bones

  • The hyoid bone, ethmoid bone, and sphenoid bones are sometimes included in the viscerocranium.
  • The two lacrimal bones form the medial wall of the orbit and articulate with the frontal, ethmoid, maxilla, and inferior nasal conchae.
  • The lacrimal bones are the two smallest bones located in the face.
  • The two slender nasal bones located in the midline of the face fuse to form the bridge of the noise and also articulate with the frontal, ethmoid and maxilla bones.
  • There are fourteen facial bones.

• Foramina

  • The skull bones that contain foramina include the frontal, ethmoid, sphenoid, maxilla, palatine, temporal, and occipital lobes.
  • Supraorbital foramen: Located in the frontal bone, it allows passage of the supraorbital vein, artery, and nerve into the orbit.
  • Foramen magnum: Located in the occipital bone, it allows the passage of the spinal and vertebral arteries and the spinal cord to pass from the skull into the vertebral column.
  • Foramina of cribriform plate: Located in the ethmoid bone, it allows the passage of the olfactory nerve.
  • Foramen rotundum: Located in the sphenoid bone, it allows passage of the maxillary nerve.

• Paranasal Sinuses

  • The paranasal sinuses (four, paired, air-filled spaces) surround the nasal cavity, and are located above and between the eyes, and behind the ethmoids.
  • The sinuses are named for the facial bones that they are located behind.
  • The frontal sinuses are superior to the orbits and are in the frontal bone.
  • The ethmoid sinuses are formed from several discrete air cells within the ethmoid bone between the nose and the orbits.
  • Decreasing the relative weight of the front of the skull, and especially the bones of the face.

• Orbits

  • The orbital cavity is formed from seven bones.
  • The frontal bone forms the superior border of the orbital rim and also the superior wall (roof) of the orbital surface.
  • The lacrimal and ethmoid bones contribute to the medial wall of the orbit and also to the medial wall of the orbital canal.
  • The small palatine bone contributes to the floor of the orbit.
  • Finally, the sphenoid bone forms the posterior wall of the orbit and also contributes to the formation of the optic canal.

• Olfactory (I) Nerve

  • The olfactory nerves consist of a collection of many sensory nerve fibers that extend from the olfactory epithelium to the olfactory bulb, passing through the many openings of the cribriform plate of the ethmoid bone.

• Human Axial Skeleton

  • The skull consists of 22 bones, which are divided into two categories: cranial bones and facial bones.
  • The eight cranial bones include the frontal bone, two parietal bones, two temporal bones, the occipital bone, the sphenoid bone, and the ethmoid bone.
  • The 14 facial bones are the nasal bones, maxillary bones, zygomatic bones, palatine, vomer, lacrimal bones, inferior nasal conchae, and mandible.
  • The auditory ossicles consist of six bones: two malleus bones, two incus bones, and two stapes, one of each on each side.
  • The cranial bones, including the frontal, parietal, temporal, occipital, ethmoid, and sphenoid bones.

• General Features and Functions of the Skull

  • The skull is formed of several bones which, with the exception of the mandible, are joined together by sutures—synarthrodial (immovable) joints.
  • The adult human skull is comprised of twenty-two bones which are divided into two parts of differing embryological origin: the neurocranium and the viscerocranium.
  • The neurocranium is formed from the occipital bone, two temporal bones, two parietal bones, the sphenoid, ethmoid and frontal bones; they are all joined together with sutures.
  • The facial skeleton contains the vomer, two nasal conchae, two nasal bones, two maxilla, the mandible, two palatine bones, two zygomatic bones, and two lacrimal bones.
  • Neurocranium consists of 8 parts: frontal, sphenoid, ethmoid, occipital, 2 temporal, and 2 parietal bones.

• Gross Anatomy

  • All the bones in the body can be described as long bones or flat bones.
  • Bone is made of bone tissue, a type of dense connective tissue.
  • Cortical bone is compact bone, while cancellous bone is trabecular and spongy bone.
  • The outer shell of the long bone is compact bone, below which lies a deeper layer of cancellous bone (spongy bone), as shown in the following figure.
  • These are flat bone, sutural bone, short bone, irregular, sesamoid bone, and long bone.