Comprehensive Anatomy of the Left Maxilla: Surface Landmarks and Clinical Significance

The maxilla forms the foundation of the midface, serving as a crucial structural and functional component of the craniofacial complex. This anatomical illustration depicts the lateral (outer) surface of the left maxilla with detailed labeling of key landmarks, foramina, processes, and muscle attachment sites. As one of the principal bones of the facial skeleton, the maxilla contributes to multiple anatomical compartments, including the orbit, nasal cavity, oral cavity, and maxillary sinus. Understanding its complex morphology is essential for dental professionals, maxillofacial surgeons, otolaryngologists, and medical students, as this knowledge underpins both routine clinical procedures and advanced surgical interventions in the midface region.

Lacrimal tubercle: The lacrimal tubercle is a small bony projection located at the anterior portion of the medial orbital wall, serving as an attachment site for the medial palpebral ligament. This anatomical landmark is clinically significant for dacryocystorhinostomy procedures, as it helps surgeons identify the position of the lacrimal sac during surgical access.

Med. palp. lig. (Medial palpebral ligament): The medial palpebral ligament is a fibrous band that attaches to the anterior lacrimal crest of the maxilla and anchors the medial aspect of the eyelids. This structure plays a crucial role in maintaining proper eyelid function and position, with its attachment to the maxilla providing a fixed point from which the orbicularis oculi muscle can effectively contract.

Orbital Surface: The orbital surface of the maxilla forms a significant portion of the floor of the orbit, presenting a smooth, triangular-shaped area that supports the globe of the eye. This thin bony plate separates the orbital contents from the underlying maxillary sinus, creating an anatomical vulnerability that can result in orbital floor fractures (blow-out fractures) following blunt trauma to the eye.

Infra-orbital groove: The infra-orbital groove runs along the orbital floor, continuing anteriorly as the infra-orbital canal, and houses the infraorbital nerve and vessels as they course toward the facial region. This neurovascular pathway is clinically relevant for administering infraorbital nerve blocks and represents a potential route for tumor spread between the orbit and midface.

Dilatator naris posterior: The dilatator naris posterior (dilator naris posterior) is a small facial muscle that attaches to the lateral aspect of the maxilla near the nasal aperture and functions to widen the nostrils during deep breathing. This muscle works synergistically with other nasal muscles to regulate airflow and contributes to facial expressions involving the nose.

Incisive fossa: The incisive fossa is a depression located in the anterior region of the maxillary palatine process, just behind the central incisors, containing the nasopalatine nerve and vessels. This anatomical structure communicates with the nasal cavity via the incisive canal and represents an important consideration during dental implant placement in the anterior maxilla.

Alveolar canals: The alveolar canals are narrow passages within the body of the maxilla that house the superior alveolar nerves and vessels supplying the maxillary teeth and adjacent structures. These neurovascular pathways must be considered during dental procedures, particularly when administering local anesthesia or performing surgical interventions in the posterior maxilla.

Maxillary tuberosity: The maxillary tuberosity is a rounded prominence forming the most posterior aspect of the maxillary alveolar process, located distal to the last molar tooth. This area serves as an attachment site for the pterygoid muscles and contains numerous foramina for the posterior superior alveolar nerves and vessels, representing an important landmark for maxillary nerve blocks.

Incisor: The incisors are the anterior teeth of the dental arch, with the maxillary central and lateral incisors being housed in the anterior portion of the maxillary alveolar process. These teeth, with their chisel-shaped crowns, are specialized for cutting food during the initial phase of mastication and play a significant role in facial aesthetics and speech production.

Canine: The canine tooth occupies the corner position of the dental arch, situated within the canine eminence of the maxillary alveolar process. With its long, stable root and prominently pointed crown, the canine serves to tear food and plays a crucial role in guiding mandibular movements during lateral excursions (canine guidance).

Premolars: The maxillary premolars (first and second) are positioned between the canine and molars, housed within the middle portion of the maxillary alveolar process. These teeth typically feature two cusps and function as transitional elements between the tearing action of canines and the grinding function of molars, combining elements of both designs for effective food processing.

Molars: The maxillary molars (first, second, and occasionally third) occupy the posterior segment of the dental arch, situated in the distal portion of the maxillary alveolar process. These multi-cusped teeth with typically three roots provide the largest occlusal surface area for grinding food and are positioned directly below the maxillary sinus, creating important anatomical relationships relevant to both dental and sinus pathology.

Developmental and Structural Anatomy of the Maxilla

The maxilla represents a complex bone with diverse embryological origins and extensive postnatal development. The dynamic nature of its growth pattern significantly influences facial aesthetics and functional capabilities throughout life.

• The maxilla develops through intramembranous ossification from neural crest-derived mesenchyme, with primary ossification centers appearing around the eighth week of intrauterine life.
• Unlike most bones, the maxilla does not develop from a cartilaginous precursor, instead forming directly from connective tissue membranes.
• The paired maxillae fuse at the intermaxillary suture during early development, creating a unified structure that forms the central component of the midface.
• Postnatal development continues through adolescence, with significant growth occurring at sutures connecting the maxilla to adjacent cranial and facial bones.
• The alveolar process undergoes substantial remodeling in response to tooth eruption, functional demands, and eventually tooth loss, demonstrating the bone’s adaptive capacity.
• Pneumatization of the maxillary sinus continues throughout childhood and adolescence, with the sinus reaching its adult dimensions by approximately 18 years of age.
• Growth modifications of the maxilla can be achieved through orthodontic and orthopedic interventions during childhood and adolescence, taking advantage of its significant growth potential.
• Age-related changes include decreased bone density, reduced vascularity, and altered structural properties that influence both pathological processes and treatment outcomes in older adults.

Topographical Anatomy and Clinical Correlations

The maxilla’s strategic position within the facial skeleton creates numerous clinically significant relationships with adjacent structures. Understanding these topographical associations is essential for diagnostic interpretation and surgical planning.

• The infraorbital foramen, located approximately 1 cm below the infraorbital rim, provides an external landmark for accessing the infraorbital nerve, commonly targeted during regional anesthesia procedures.
• The thin bone separating the maxillary sinus from the orbital floor predisposes to orbital involvement in sinus pathology and creates the characteristic “trap-door” orbital floor fractures following blunt trauma.
• The proximity of maxillary posterior teeth to the sinus floor (often with roots projecting into the sinus) creates bidirectional pathways for infection spread between dental and sinus tissues.
• The pterygomaxillary junction represents an important surgical landmark during Le Fort I osteotomy and serves as a pathway for anesthetic solutions during posterior superior alveolar nerve blocks.
• The canine fossa provides a relatively thin area of bone that offers surgical access to the maxillary sinus through the Caldwell-Luc approach, though endoscopic techniques have largely replaced this traditional method.
• The complex network of anastomoses between branches of the maxillary artery within the maxilla creates challenges for hemostasis during surgical procedures but also provides collateral circulation following vascular compromise.
• The nasopalatine canal, extending from the incisive fossa to the nasal floor, contains neurovascular structures that must be considered during implant placement in the anterior maxilla.
• The maxillary tuberosity region serves as an important landmark for maxillary nerve blocks and represents a potential site for bone harvesting in certain reconstructive procedures.

Functional Considerations of Maxillary Anatomy

The maxilla’s structural design reflects its multifaceted functional roles in mastication, speech, respiration, and facial aesthetics. These functions are dependent on the precise three-dimensional architecture of the bone and its relationships with surrounding tissues.

• The buttress system of the midface, including the nasomaxillary, zygomaticomaxillary, and pterygomaxillary buttresses, distributes masticatory forces throughout the facial skeleton to protect critical structures.
• The alveolar process of the maxilla provides stable housing for the dentition while allowing for the physiological movement of teeth through the relatively spongy bone during orthodontic treatment.
• The maxillary contribution to the hard palate creates a rigid boundary between the oral and nasal cavities, essential for proper speech articulation and preventing nasal regurgitation during swallowing.
• The contour of the anterior maxilla significantly influences facial profile and aesthetics, with prominence of this region being a major determinant of facial harmony in various ethnic groups.
• The extensive maxillary air sinus reduces skull weight while maintaining structural integrity and contributes to voice resonance and air conditioning during respiration.
• Muscle attachments to the maxilla, including the levator anguli oris, levator labii superioris, and nasalis, enable the complex facial expressions that are central to nonverbal communication.
• The infraorbital nerve pathway through the maxilla provides sensory innervation to the midface, creating distinct patterns of hypoesthesia or dysesthesia when compromised by trauma or pathology.
• Growth patterns of the maxilla significantly influence occlusal relationships, with anteroposterior and vertical position of the maxilla relative to the mandible determining Angle’s classification of malocclusion.

Surgical and Clinical Applications

The complex anatomy of the maxilla has direct implications for numerous diagnostic and therapeutic procedures across multiple medical and dental specialties. Precision in these interventions depends on comprehensive anatomical knowledge.

• Maxillary orthognathic surgery, including Le Fort I osteotomy, requires precise identification of the pterygomaxillary junction, descending palatine vessels, and nasal septum to prevent complications.
• Dental implant placement in the maxilla necessitates careful evaluation of available bone height and width, particularly in the posterior region where the maxillary sinus limits vertical dimension.
• Sinus augmentation procedures, including lateral window and transcrestal approaches, modify the maxillary sinus floor to increase available bone volume for implant placement.
• Management of maxillary fractures involves reduction and fixation guided by the buttress reconstruction principle to restore normal occlusal relationships and facial contours.
• Orthodontic anchorage devices, including temporary anchorage devices (TADs) and mini-plates, rely on specific regions of the maxilla that offer adequate bone thickness and density.
• Cleft lip and palate repair addresses congenital defects in maxillary development through staged surgical interventions beginning in infancy and continuing through adolescence.
• The maxillary artery and its branches within the bone pose significant hemorrhage risks during maxillary surgery, particularly in the pterygomaxillary region during Le Fort I procedures.
• Radiographic imaging of the maxilla, including cone-beam computed tomography, provides crucial three-dimensional information for diagnosing pathology and planning invasive procedures.

Conclusion

The maxilla represents one of the most anatomically complex and functionally diverse bones in the human body. Its intricate surface anatomy, as depicted in this illustration, reflects the bone’s multiple roles in the craniofacial complex. From housing the upper dentition to contributing to the orbital floor, from anchoring facial muscles to forming the boundaries of the nasal cavity, the maxilla’s structural design elegantly supports its diverse functions. For healthcare professionals working in the maxillofacial region, comprehensive knowledge of maxillary anatomy is not merely academic but forms the foundation for diagnostic accuracy, treatment planning, and procedural success. As imaging and surgical techniques continue to advance, our appreciation for the nuanced anatomy of this remarkable bone only deepens, driving improvements in clinical outcomes across multiple specialties focused on the maxillofacial region.

1. Maxillary Anatomy Decoded: Comprehensive Guide to Surface Landmarks and Clinical Applications
2. The Left Maxilla: Detailed Anatomy and Functional Significance for Medical Professionals
3. Maxillofacial Surface Anatomy: Complete Analysis of the Lateral Maxilla
4. Essential Maxillary Landmarks: A Surgical and Clinical Anatomy Reference
5. Understanding the Maxilla: Surface Features and Their Clinical Relevance