TONGUE

The tongue is a muscular organ located on the floor of the oral cavity, attached to the mandible and the hyoid bone by muscles. It plays a crucial role in taste, swallowing, speech, and mastication.

• Location and Attachment: The tongue is located in the oral cavity and is attached to the mandible by the lingual frenulum and to the hyoid bone by the styloglossus muscle.

• Structure: The tongue consists of intrinsic and extrinsic muscles, taste buds, and mucous membranes. The intrinsic muscles (superior and inferior longitudinal, transverse, and vertical) are responsible for tongue movement, while the extrinsic muscles (genioglossus, hyoglossus, and styloglossus) assist in tongue movement and attachment.

• Innervation: The tongue is innervated by the lingual nerve (a branch of the mandibular division of the trigeminal nerve) for general sensations and the chorda tympani (a branch of the facial nerve) for taste sensations.

• Blood Supply: The tongue is supplied by the lingual artery (a branch of the external carotid artery) and the sublingual artery (a branch of the facial artery).

• Development: The tongue develops from the first pharyngeal arch and the lingual swellings, which fuse to form the tongue.

• Muscle Action Sequence: The sequence of tongue movements is as follows:

  • Lateral Movement: The genioglossus muscle (extrinsic) contracts to elevate the tongue on the side of contraction, while the hyoglossus and styloglossus muscles (extrinsic) relax.
  • Medial Movement: The genioglossus muscle contracts to depress the tongue in the midline, while the hyoglossus and styloglossus muscles relax.
  • Anterior Movement: The genioglossus and hyoglossus muscles contract to elevate the anterior part of the tongue, while the styloglossus muscle relaxes.
  • Posterior Movement: The styloglossus muscle contracts to elevate the posterior part of the tongue, while the genioglossus and hyoglossus muscles relax.

TONGUE

The tongue is a vital organ in the oral cavity, playing a crucial role in taste, speech, and swallowing. It is a muscular, fibromuscular structure that is attached to the floor of the mouth by the lingual frenulum.

Parts and Features of the Tongue

• Body of the Tongue: The largest part of the tongue.
• Root of the Tongue: The base of the tongue, attached to the floor of the mouth.
• Apex of the Tongue: The tip of the tongue.
• Lateral Sides: The sides of the tongue.
• Papillae: Small bumps on the surface of the tongue that contain taste buds.
• Fissures: Grooves on the surface of the tongue.
• Plica Fungiformis: A fold of mucous membrane on the lateral sides of the tongue.
• Plica Circumvallata: A fold of mucous membrane on the posterior part of the tongue.

Blood Supply of the Tongue

• Arteries: The lingual artery (branch of the external carotid artery) supplies the tongue.
• Veins: The lingual veins (drain into the internal jugular vein) drain the tongue.

Nerve Supply of the Tongue

• Sensory: The lingual nerve (branch of the mandibular nerve) supplies the anterior two-thirds of the tongue.
• Motor: The hypoglossal nerve supplies the extrinsic and intrinsic muscles of the tongue.
• Taste: The chorda tympani nerve (branch of the facial nerve) supplies the anterior two-thirds of the tongue, while the glossopharyngeal nerve supplies the posterior one-third.

Applied Anatomy of the Tongue

• Lingual Frenulum: The lingual frenulum is a fold of mucous membrane that attaches the tongue to the floor of the mouth.
• Tongue Movement: The tongue moves due to the action of the extrinsic and intrinsic muscles.
• Taste: The tongue has taste buds that detect four basic tastes: sweet, sour, salty, and bitter.
• Swallowing: The tongue plays a crucial role in swallowing by propelling food into the esophagus.

Developmental Process of the Tongue

• Embryonic Development: The tongue develops from the first pharyngeal arch.
• Fusion of Buds: The lingual and palatal processes fuse to form the tongue.
• Differentiation: The tongue differentiates into the body, root, and apex.

Muscle Action Sequence of the Tongue

• Intrinsic Muscles: The intrinsic muscles of the tongue (superior longitudinal, inferior longitudinal, transverse, and vertical) act to change the shape of the tongue.
• Extrinsic Muscles: The extrinsic muscles of the tongue (genioglossus, hyoglossus, and styloglossus) act to move the tongue.
• Muscle Action: The muscles of the tongue act in a coordinated manner to move the tongue and change its shape.