Variations and Bony Landmarks of the Maxillary Artery: a Cadaveric Study

Abstract

BACKGROUND: The maxillary artery (MA) is known to vary in the branching pattern, relation with the lateral pterygoid muscle (LPM) and its distances from conventional bony landmarks. These variations pose surgical challenges in procedures around the temporomandibular joint (TMJ) and infratemporal fossa and, therefore, their knowledge is vital. Data on African populations are scanty. Therefore, this cadaveric study sought to provide information pertaining the MA in a Kenyan population. STUDY OBJECTIVE: To describe the variations and anatomical landmarks of the MA. STUDY DESIGN AND POPULATION: This was a descriptive cross-sectional cadaveric study, carried out in the department of human anatomy at the University of Nairobi. Cadavers of adults available in the University of Nairobi Human Anatomy dissection laboratory with intact structures in the parotid and infratemporal region were included in the study. STUDY DURATION: The study was conducted between November 2015 and May 2016. MATERIAL AND METHODS: Ninety three (93) hemi-sections from 48 cadavers were used for the study. The side of the face dissected was noted. Dissection of the infratemporal fossa was done to expose the MA and its branches on both the right and left sides. The distance of the MA from the articular eminence, mandibular neck, mandibular notch and pterygoid fovea were measured in millimetres (mm) using digital Vernier calipers and protractor. The relationship of the MA with the LPM was noted and the branching pattern of the first part of the MA was described. DATA MANAGEMENT: Photo-macrographs were used to demonstrate the variations in branching and relationship of the MA with the LPM. Data were coded and analyzed using the Statistical Package for Social Science (SPSS) version 17.0 and presented in tables.

Independent paired student’s t test was used to test the level of significance for the parametric data. RESULTS: The average perpendicular distances between the MA and the posterior cortex at the centre of the condylar neck of the mandible, inferior most part of the mandibular notch, inferior part of the articular eminence and inferior part of the pterygoid fovea were determined as 8.58±2.69 mm, 5.76±2.8 mm, 14.20±3.89 mm and 14.28±6.62 mm respectively. Out of the 93 hemi-sections dissected 67% of the MA was within the parotid gland while 33% of the MA was medial to the gland. Thirty five of the MA had a medial relationship to the LPM while 58 of the MA had a lateral relationship to the LPM. Four (8.9%) of the cadavers showed asymmetry whereby the MA passed on the medial side of the LPM on one side while on the other side it passed on the lateral aspect of the LPM. Six (6.5%) hemi-sections had the middle meningeal artery (MMA) and the inferior alveolar artery (IAA) originating from a common trunk on the MA. The accessory meningeal artery (AMA) was absent in 3 (3.2%) hemi-sections on the right side and in 2 (2.2%) on the left side. On the right, the MMA branched off from the MA before the IAA in 18 (37.5%) of the hemi-sections whereas in 27 (56.3%) of the hemi-sections it was given out after the IAA. On the left side the MMA was given off before the IAA in 10 (22.8%) of the hemi-sections and branched off after the IAA in 32 (71.1%) of the hemi-sections. CONCLUSION: The variations of the MA in this population displayed patterns comparable to other populations. The distance of the MA to selected bony landmarks between the right and left sides was comparable. Remarkably, in this Kenyan sample population, the MA passed significantly further from the articular eminence compared to other populations. Majority of the MAs were within the parotid gland in this population. There was high prevalence of the MA passing lateral to the LPM which was consistent with studies done

elsewhere. A branching pattern similar to other studies was observed on the first part of the MA.