Rerouting the Dissection of the Infratemporal and Submandibular Regions

Abstract

Introduction Teaching and learning in anatomy are necessarily dependent on cadaveric dissection. Skillful dissection is the tool which helps in proper visualization of structures in a cadaver. Proper understanding about the course of lingual nerve, hypoglossal nerve, nerve to mylohyoid, and relations between structures present in infratemporal and submandibular regions is important for medical students. The aim of this study is to describe a modified technique of dissection and evaluate medical students' and teachers' response to this approach. Methods The comparative observational study was conducted bilaterally on six adult cadavers. We compared the method of dissection given in standard textbooks with the modified method introduced. The validity and reliability of the newer method of dissection for teaching purpose was assessed by first-year undergraduate medical students using a questionnaire-based tool and feedback from postgraduate students and senior residents. Results The modified method was described as less time consuming, easy to perform, and allowed extensive exploration of the structures in the infratemporal and submandibular regions. Conclusions Proper understanding of the course and relations between structures present in infratemporal and submandibular regions is important for medical students.The modified approach to infratemporal and submandibular regions will facilitate better understanding of the human anatomy.

Keywords: cadaveric dissection; digastric muscle; genioglossus; gland; hypoglossal nerve; lingual duct; lingual nerve; masseter muscle; mylohyoid; temporalis muscle.

Figure 1. Lines along which the mandible was cut.

Figure 2. Lateral border of the left-side anterior belly of the digastric muscle cleared to place a paramedian cut on the mandible.

A: Cadaveric view of the infratemporal fossa and submandibular region; B: Schematic representation of the cadaveric view; DMa: Anterior belly of the digastric muscle; FA: Facial artery; FV: Facial vein; A: Anterior; P: Posterior; M: Medial; L: Lateral.

Figure 3. Mandible pulled to expose the left-side mylohyoid muscle.

A: Cadaveric view of the submandibular region; B: Schematic representation of the cadaveric view; MHM: Mylohyoid muscle; S: Superior; I: Inferior; M: Medial; L: Lateral; DMa: Anterior belly of the digastric muscle; FA: Facial artery.

Figure 4. Mandible pulled on the left side to expose the sphenomandibular ligament and the nerve to the mylohyoid muscle.

A: Cadaveric view of the submandibular region; B: Schematic representation of the cadaveric view; SML: Sphenomandibular ligament; NM: Nerve to the mylohyoid muscle; ND: Nerve to the anterior belly of the digastric muscle; S: Superior; I: Inferior; M: Medial; L: Lateral; FA: Facial artery; MHM: Mylohyoid muscle.

Figure 5. Structures on the left side, lying in superficial relation to the hyoglossus, submandibular ganglion, and muscles of the styloid apparatus.

A: Cadaveric view of the infratemporal fossa and submandibular region; B: Schematic representation of the cadaveric view; ECA: External carotid artery; SCM: Sternocleidomastoid muscle; DMp: Posterior belly of Digastric muscle; MPt: Medial pterygoid muscle; MA: Maxillary artery;  STA: Superficial temporal artery; HGM: Hyoglossus muscle; HN: Hypoglossal nerve; MHM: Mylohoid muscle; TM: Temporalis muscle; IAN: Inferior alveolar nerve; IAV: Inferior alveolar vessels; LN: Lingual nerve; SMG: Submandibular gland; SLG: Sublingual gland; MPt: Medial pterygoid muscle; SG: Styloglossus muscle; SP: Stylopharyngeus muscle; SH: Stylohyoid muscle; WD: Wharton duct; SMg: Submandibular ganglion.