Structure
The floor of the mouth is a muscular layer that lies below the tongue and extends between the body of the mandible. It is formed predominately by mylohyoid, a muscle that inserts into both sides of the mandible and attaches the anterior part of the body of the hyoid. Centrally, the geniohyoid overlies the mylohyoid.
The submandibular gland wraps around the posterior edge of mylohyoid, dividing the gland into superficial and deep parts. The sublingual gland lies on the internal surface of mylohyoid, separated from the oral cavity by a layer of mucosa.
Relations
The tongue lies medially and posteriorly
The gingiva and teeth lie anterolaterally
Macroscopic Appearance
The frenulum of the tongue extends from the deep surface to the floor of the mouth, and occasionally to the lingual gingivae.
On each side of the frenulum are the sublingual papillae for the opening of the submandibular ducts.
Microscopic Appearance
The floor of the mouth, being non-masticatory, is lined with a non-keratinising stratified squamous epithelium.
Neurovascular Supply
Arterial Supply
The sublingual artery provides the majority of blood to the floor of the mouth.
Venous drainage
Sublingual veins drain posteriorly to form the deep lingual vein.
Lymphatics
The floor of the mouth may drain to the submental nodes or submandibular nodes.
Innervation
The floor of the mouth receives general sensory input from the lingual branch of the mandibular nerve (V3).
