Masseter (m. Masseter/жевательная мышца)

• Origin. The lower border of the zygomatic arch.

• Insertion. The masseteric tuberosity of the mandible.

• Actions. Closes the mouth and clenches the teeth.

Lateral pterygoid (m. Pterygoideus lateralis/латеральная крыловидная мышца)

• Origin. The lateral plate of the pterygoid process.

• Insertion. The neck of the mandible and the intra-articular disc of the temporomandibular joint.

• Actions. It protrudes the mandible and moves the head of the mandible onto the articular tubercle when the mouth is opened.

Medial pterygoid (m. pterygoideus madialis/медиальная крыловидная мышца)

• Origin. The pterygoid fossa of the pterygoid process of the sphenoid bone.

• Insertion. The pterygoid tuberosity of the mandible.

• Action. It helps to close the mouth.

Nerve supply of the masticatory muscles: the mandibular division of the trigeminal nerve.

The fasciae of the head

The temporal fascia (fascia temporalis/височная фасция)

• This fascia covers the temporal muscle.

• It arises from the temporal line and it is divided into two parts near the zygomatic arch:

• the superficial layer which fuses with the external surface of the arch.

• the deep layer, which fuses with the internal surface of the arch.

• The space between two layers is filled with fatty tissue.

The masseteric fascia (fascia masseterica/жевательная фасция)

This fascia covers the masseter.

The parotid fascia (fascia parotidea/фасция околоушной железы)

This fascia forms the capsule around the parotid gland.

The buccopharyngeal fascia

(fascia buccopharyngea/щёчно-глоточная фасция)

This fascia covers the posterior section of the buccinator, forms the pterygomandibular raphe and is continues with the connective tissue covering the pharyngeal muscles.

THE MUSCLES OF NECK (musculi colli/мышцы шеи)

The superficial muscles

Platysma (platysma/подкожная мышца шеи)

• Origin. The skin over the upper part of the chest, crossing the mandible to blend in with the orbicularis oris.

• Actions. It pulls down the corners of the mouth and has an antisphincteric action on the neck as in loosening a tight collar.

• Nerve supply. The facial nerve.

Sternocleidomastoid

(m. sternocleidomastoideus/грудино-ключично-сосцевидная мышца)

• Origin. The front of the manubrium of sternum (by a narrow rounded tendon) and the medial third of the clavicle.

• Insertion. The mastoid process and the lateral part of the superior nuchal line.

• Actions. It rotates the head to the opposite side and flexes the cervical spine to the same side, thus bringing the ear nearer to the shoulder of the same side. Both muscles acting together can flex the cervical spine against resistance. An accessory muscle of respiration.

• Nerve supply. Spinal accessory nerve.

Suprahyoid muscles

These muscles lie between the mandible and the hyoid bone.

Digastric (m. digastricus/двубрюшная мышца)

• The anterior belly (venter anterior/переднее брюшко) arises from the digastric fossa of the mandible.

• the posterior belly (venter posterior/заднее брюшко) arises from the mastoid notch of the temporal bone.

• Both bellies meet at the intermediate tendon, that attached to the body of the hyoid bone.

Stylohyoid (m. stylohioideus/шилоподъязычная мышца)

• Origin. The styloid process of the temporal bone.

• Insertion. The body of the hyoid bone and it embraces the intermediate tendon of the digastric.

Mylohyoid (m. mylohyoideus/челюcтно-подъязычная мышца)

• Origin. The mylohyoid line of the mandible.

• Insertion. To the body of the hyoid bone and to the tendinous raphe between the inner surface of the body of the mandible and the body of the hyoid bone .

• Two mylohyoid form the floor of the mouth.

Geniohyoid (m. geniohyiodeus/подбородочно-подъязычная мышца)

• Origin. The mental spine of the mandible (this muscle lies above the mylohyoid).

• Insertion. The body of the hyoid bone.

Actions of suprahyoid muscles. These raise the hyoid bone.

Nerve supply of the posterior belly of the digastric muscle and stylohyoid muscle. The facial nerve.

Nerve supply of another suprahyoid muscles. Cervical spinal nerves.