Hyoid bone

The hyoid bone ( hyoid ) is a small curved bone floor of the mouth under the tongue. It is not connected to the rest of the skeleton, but merely suspended in the muscles and ligaments. There is a lack of this basic intuition in most models for human skeleton. The hyoid bone is a U- shape and is in humans approximately 2 to 3 cm in size. Embryo arises from the hyoid bone to the cartilage of the second and third branchial arch.

Anatomy

The hyoid bone is among the people of an unpaired central piece ( body ) and two pairs of lateral appendages ( horns ). The posterior pair of lateral extensions ( Cornu majus) is larger and more connected to the larynx, the anterior cornu suspended minus smaller and the styloid process of the temporal bone ( styloid process ). In primates and humans, the upper part of the band between the front horn and the temporal bone is ossified and forms so the above Styloid.

In the non-primate, the hyoid bone is divided into six sections: tympanometry, Stylo, epi, Cerato, Basi and Thyreohyoid. The unpaired Basihyoid corresponds to the body, the big horns represent the two thyrohyoid, the two small horns are represented by the two Ceratohyoidea. These five sections present the hyoid bone in the strictest possible sense, as suspensory addition there are the pair of Epi and Stylo and Tympanohyoidea that form the Zungenbeinast of each page. The Tympanohyoidea consist of cartilage or ossified cartilage and are fixed on an adhesive tape on the skull.

Both pairs of horns are larger in the lower vertebrates and probably represent the remains of the hyoid and first branchial arch yet fully developed in fish, while the so-called body, which sometimes consisting of a plurality of series -lying parts, representing the unpaired middle part of the hyoid arch.

The hyoid bone can be palpable through the skin. By imaging examination process, it can be represented.

Function

The hyoid bone is fixed by ligaments and muscles in the skull base region. This gives it figuratively speaking, a swing function. On the underside of the swing larynx and trachea are suspended with movement optimization. This has a favorable effect on the functions of speech, swallowing, breathing and coughing.

A fracture of the hyoid bone is an indication for violence against the neck ( strangulation ), the bone is therefore investigated of suspicion for an autopsy.

Muscles

The hyoid bone is the starting point for many muscles, which are divided according to the location of its origin to the bone in two groups:

Suprahyale muscles: She pulls the hyoid bone upwards and is involved in the act of swallowing.

  • Musculus geniohyoideus, origin: chin ( lower jaw), Innervation: Ansa cervicalis and hypoglossal nerve (XII )
  • Digastric muscle with Venter anterior Origin: mandible Innervation: mylohyoid nerve (V3) and Venter posterior Origin: mastoid process, innervation: Ramus digastric (facial nerve )
  • Mylohyoid muscle, originating from the mandible Innervation: mylohyoid nerve
  • Musculus stylohyoideus, Origin: styloid process of the temporal bone, innervation: Ramus stylohyoid (VII )

Infrahyale muscles: She pulls the hyoid bone down. All the muscles of the group are innervated by the ansa cervicalis.

  • Musculus omohyoideus, origin: scapula
  • Musculus sternohyoideus, Origin: back of the manubrium sternum
  • Musculus sternothyroideus, origin: as the latter. He is the only muscle of the group not the hyoid bone, but the thyroid cartilage.
  • Thyrohyoid muscle, originating from the thyroid cartilage. He serves as a continuation of sternothyroid.
Palatine bone Nasal bone Vomer Occipital bone
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