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Anatomy

- The forehead is formed by the smooth, broad, convex plate of bone called the frontal squama.
- In foetal skulls, the halves of the frontal squama are divided by a metopic suture.
- In most people, the halves of the frontal bone begin to fuse during infancy and the suture between is usually not visible after 6 years of age.
- The frontal bone forms the thin roof of the orbits (eye sockets).
- Just superior to and parallel with each supraorbital margin is a bony ridge, the superciliary arch, which overlies the frontal sinus. This arch is more pronounced in males.
- Between these arches there is a gently, rounded, medial elevation called the gabella; this term derives from the Latin word glabellus meaning smooth and hairless. In most people, the skin over the gabella is hairless.
-The slight prominences of the forehead on each side, superior to the superciliary arches, are called frontal eminences (tubers).
- The supraorbital foramen (occasionally a notch), which transmits the supraorbital vessels and nerve is located in the medial part of the supraorbital margin.
- The frontal bone articulates with the two parietal bones at the coronal suture.
-It also articulates with the nasal bones at the frontonasal suture. At the point where this suture crosses the internasal suture in the medial plane, there is an anthropological landmark called the nasion . The depression is located at the root of the nose, where it joins the cranium.
- The frontal bone also articulates with the zygomatic, lacrimal, ethmoid, and sphenoid bones.
In about 8% of adult skulls, a remnant of the inferior part of the metopic (interfrontal) suture is visible. It may be mistaken in radiographs for a fracture line by inexperienced observers.
- The superciliary arches are relatively sharp ridges of bone and a blow to them may lacerate the skin and cause bleeding.
- Bruising of the skin over a superciliary arch causes tissue fluid and blood to accumulate in the surrounding connective tissue, which gravitates into the upper eyelid and around the eye. This results in swelling and a "black eye".
- Compression of the supraorbital nerve as it emerges from its foramen causes considerable pain, a fact that may be used by anaesthesiologists and anaesthetists to determine the depth of anaesthesia and by physicians attempting to arouse a moribund patient.

 

Ligaments of the Joint

  • The fibrous capsule is thickened laterally to form the lateral (temporomandibular) ligament. It reinforces the lateral part of this capsule.
  • The base of this triangular ligament is attached to the zygomatic process of the temporal bone and the articular tubercle.
  • Its apex is fixed to the lateral side of the neck of the mandible.
  • Two other ligaments connect the mandible to the cranium but neither provides much strength.
  • The stylomandibular ligament is a thickened band of deep cervical fascia.
  • It runs from the styloid process of the temporal bone to the angle of the mandible and separates the parotid and submandibular salivary glands.
  • The sphenomandibular ligament is a long membranous band that lies medial to the joint.
  • This ligament runs from the spine of the sphenoid bone to the lingula on the medial aspect of the mandible.

Veins of the Face

The Supratrochlear Vein

  • This vessel begins on the forehead from a network of veins connected to the frontal tributaries of the superficial temporal vein.
  • It descends near the medial plane with its fellow on the other side.
  • These veins diverge near the orbits, each joining a supraorbital vein to form the facial vein near the medial canthus (angle of the eye).

 

The Supraorbital Vein

  • This vessel begins near the zygomatic process of the temporal bone.
  • It joins the tributaries of the superficial and middle temporal veins.
  • It passes medially and joins the supratrochlear vein to form the facial vein near the medial canthus.

 

The Facial Vein

  • This vein provides the major venous drainage of the face.
  • It begins at the medial canthus of the eye by the union of the supraorbital and supratrochlear veins.
  • It runs inferoposteriorly through the face, posterior to the facial artery, but takes a more superficial and straighter course than the artery.
  • Inferior to the margin of the mandible, the facial vein is joined by the anterior branch of the retromandibular vein.
  • The facial veins ends by draining into the internal jugular vein.

 

The Superficial Temporal Vein

  • This vein drains the forehead and scalp and receives tributaries from the veins of the temple and face.
  • In the region of the temporomandibular joint, this vein enters the parotid gland.

 

The Retromandibular Vein

  • The union of the superficial temporal and maxillary veins forms this vessel, posterior to the neck of the mandible.
  • It descends within the parotid gland, superficial to the external carotid artery but deep to the facial nerve.
  • It divides into an anterior branch that unites with the facial vein, and a posterior branch that joins the posterior auricular vein to form the external jugular vein.

Nerves of the Palate

  • The sensory nerves of the palate, which are branches of the pterygopalatine ganglion, are the greater and lesser palatine nerves.
  • They accompany the arteries through the greater and lesser palatine foramina, respectively.
  • The greater palatine nerve supplies the gingivae, mucous membrane, and glands of the hard palate.
  • The lesser palatine nerve supplies the soft palate.
  • Another branch of the pterygopalatine ganglion, the nasopalatine nerve, emerges from the incisive foramen and supplies the mucous membrane of the anterior part of the hard palate.

  • This is the posterior curtain-like part, and has no bony support. It does, however, contain a membranous aponeurosis.
  • The soft palate, or velum palatinum (L. velum, veil), is a movable, fibromuscular fold that is attached to the posterior edge of the hard palate.
  • It extends posteroinferiorly to a curved free margin from which hangs a conical process, the uvula (L. uva, grape).
  • The soft palate separates the nasopharynx superiorly and the oropharynx inferiorly.
  • During swallowing the soft palate moves posteriorly against the wall of the pharynx, preventing the regurgitation of food into the nasal cavity.
  • Laterally, the soft palate is continuous with the wall of the pharynx and is joined to the tongue and pharynx by the palatoglossal and palatopharyngeal folds.
  • The soft palate is strengthened by the palatine aponeurosis, formed by the expanded tendon of the tensor veli palatini muscle.
  • This aponeurosis attaches to the posterior margin of the hard palate.

The Lips

  • These are mobile muscular folds that surround the mouth, the entrance of the oral cavity.
  • The lips (L. labia) are covered externally by skin and internally by mucous membrane.
  • In between these are layers of muscles, especially the orbicularis oris muscle.
  • The upper and lower lips are attached to the gingivae in the median plane by raised folds of mucous membrane, called the labial frenula.

Sensory Nerves of the Lips

  • The sensory nerves of the upper and lower lips are from the infraorbital and mental nerves, which are branches of the maxillary (CN V2) and mandibular (CN V3) nerves.

 
Anterior 2/3 of tongue Posterior 1/3 of tongue
Motor Innervation All muscles by hypoglossal nerve (CN XII) except palatoglossus muscle (by the pharyngeal plexus)
General Sensory Innervation
Lingual nerve (branch of mandibular nerve CN V3) Glossopharyngeal nerve (CN IX)
Special Sensory Innervation
Chorda tympani nerve (branch of facial nerve) Glossopharyngeal nerve (CN IX)

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