The Seven Facial Bones: Name and Function
The human face is supported by a specific set of bones that define its structure. There are exactly seven unpaired and paired bones considered true facial bones in standard human anatomy. These include the nasal bones, which form the bridge of the nose; the maxillae (plural of maxilla), which make up the upper jaw and support the upper teeth; the zygomatic bones, commonly called the cheekbones; the lacrimal bones, small and thin, located in the inner orbit near the tear ducts; the palatine bones, which form the back part of the hard palate; the inferior nasal conchae, thin, scroll-like bones inside the nasal cavity that increase surface area for air filtration and humidification; and the vomer, a single thin bone that forms the lower part of the nasal septum. Together, these seven paired or unpaired bones create the bony foundation of the face, protecting sensory organs and providing attachment points for muscles involved in expression and mastication.
Nasal Bones
Each nasal bone is a small, rectangular structure that sits at the upper part of the nose, just below the bridge formed by the frontal bone. Their primary role is to shape the external nose and protect the underlying cartilage.
Maxillae, Zygomatic Bones, and Other Facial Supports
The maxillae are central to the face, forming the upper jaw, the floor of the orbit, and parts of the nasal and oral cavities. The zygomatic bones articulate with the maxilla, temporal, and frontal bones to create the prominent cheek structure. The lacrimal bones contribute to the medial wall of each orbit, while the palatine bones form the posterior portion of the hard palate and part of the orbit floor. The inferior nasal conchae are separate bones within the nasal cavity, and the vomer completes the midline division of the nasal passages.
Not a Facial Bone: The Temporal Bone
Among the options commonly presented in anatomy questions, the temporal bone is typically the bone that is not a facial bone. The temporal bone is a complex, irregular bone located on each side of the skull, below the parietal bones and behind the frontal bone. It plays a critical role in forming the sides and base of the neurocranium, housing the structures of the inner ear, and contributing to the temporomandibular joint (TMJ). Because it is part of the neurocranium that encloses the brain rather than the facial skeleton, it is classified as a skull or cranial bone, not a facial bone.
The Fourteen Facial Bones vs. the Cranial Bones
Human skull anatomy is commonly divided into two functional sets: the facial skeleton (splanchnocranium) and the brain case (neurocranium). The facial skeleton consists of the fourteen bones described earlier, which are positioned anteriorly and form the orbits, nose, and oral cavity. In contrast, the neurocranium includes the calvaria (skullcap) and the cranial base. The cranial bones, such as the frontal, parietal, occipital, sphenoid, ethmoid, and temporal bones, primarily protect the brain and provide structural support for the skull. Understanding this distinction is essential for identifying which bones are facial and which are not. The temporal bone, being part of the neurocranium, does not belong to the facial skeleton.
Key Differences Between Facial and Cranial Bones
- Facial bones form the face and support teeth, while cranial bones enclose and protect the brain.
- There are 14 facial bones, most of which are paired; cranial bones include both paired and unpaired bones but are not counted as facial.
- Examples of cranial bones not facial include the temporal, parietal, and frontal bones.
Quick Comparison: Facial Bone or Not?
| Bone | Facial Bone | Primary Role |
|---|---|---|
| Nasal bone | Yes | Forms the bridge of the nose |
| Maxilla | Yes | Upper jaw, support for teeth and orbit |
| Zygomatic bone | Yes | Cheekbone structure |
| Temporal bone | No | Neurocranium, houses ear structures, forms part of the skull base |
| Mandible | Yes | Lower jaw, only movable skull bone |
| Parietal bone | No | Neurocranium, forms sides and roof of the skull |
Common Misconceptions and Clarifications
Learners sometimes assume that any skull bone involved in an orbit or nasal opening is a facial bone. However, classification depends on embryological origin and functional role. The ethmoid bone, for example, contributes to the orbit and nasal cavity yet is typically categorized as part of the neurocranium due to its position at the cranial base, though it has some debated facial involvement. The sphenoid bone, while centrally located and contributing to multiple fossae, is also a neurocranial bone. By contrast, the mandible, though the only movable skull bone, is unequivocally a facial bone. Understanding these distinctions prevents confusion when identifying which specific bone is not part of the facial skeleton.
Summary and Key Takeaways
To answer the question directly: the temporal bone is commonly the option that is not a facial bone. The seven facial bones—the nasal, maxillae, zygomatic, lacrimal, palatine, inferior nasal conchae, and vomer—form the front part of the skull and the face. The temporal bone belongs to the neurocranium, along with other cranial bones such as the parietal, frontal, and occipital bones. Recognizing this division is foundational for anatomy, dentistry, and related health sciences. Remember that variations exist in anatomical descriptions, but the standard classification used in most educational and clinical contexts excludes the temporal bone from the facial skeleton.