Function : It helps in mastication by pressing the cheek against the vestibular surface of the molar teeth. Sucking by decrease intraoral pressure, expelling air from oral cavity as in playing wind.
Orbicularis oculi muscle
It’s a sphincter muscle, acts to close the eyelid, it originates as three parts1– The orbital portion :Originate from the bone of the upper medial orbital margin, encircles the orbital margin & inserts from below into the prominent medial palpebral ligament ( the ligament attach to the lacrimal crest of the maxilla ).2– Palpebral portion : Arises from the medial palpebral ligament & arches laterally within the upper & lower eyelids to form continuous layer with the orbital part. 3– Lacrimal portion:Its a small part ,originate from the lacrimal bone & lacrimal fossa.
Action :
The palpebral part ------ closes the eye lightly as in sleeping or blinking. The orbital part---- screws up or squeeze the lids to give more protection from bright light or sun . The lacrimal part---- draws the eye lids medially to promotes the flow of fluid (tears) through it.Motor nerves of the face :
The muscle of the face are supplied by the facial nerve (7th cranial nerve ). The facial nerve exits from the stylomastoid foramen give two br. 1- Posterior auricular n. 2-Nerve to posterior belly of digastric & stylohyoid muscle. (digastric n.)The facial nerve enter the substance of the parotid gland & break up into five main branches :1– Temporal br.Supply facial M. situated above zygomatic arch in orbit & forehead. (frontalis m.) .2- Zygomatic br.Supply facial M. in the zygomatic, orbital & infraorbital areas.
3- Buccal br. : Supply cheek M. , upper lip & buccinators muscle. 4- Marginal mandibular br.: Supply muscles of the chin & lower lip. 5- Cervical br. : It descends to the neck to supply the platysma muscle.
Arteries of the face :
The face is richly supplied with blood from various arteries & the terminal branches are anastomose freely. The entire blood supply is derived from the internal & external carotid arteries.Facial branches of the ophthalmic artery
1- Supraorbital artery. Supply upper eyelid ,forehead & scalp. 2- Supratrochlear artery. Supply medial portion of upper eyelid , forehead & scalp. 3-Dorsal nasal artery. Companion to infratrochlear nerve , supply medial angle of upper eyelid , the lachrymal sac & upper part of the nose.4- Lacrimal artery. Supply lateral aspect of the upper lid. 5- External nasal artery. Terminal branches of anterior ethmoidal artery ,supply the medial aspect of the external nose. 6- Zygomatic artery. Branches from the lacrimal artery, passes through the zygomatic canal in lateral wall of orbit & divides into two terminal br. Which emerge on the face.
A- Zygomaticofacial artery, emerge through the zygomaticofacial foramen to supply skin of the prominence of the cheek. B- Zygomaticotemporal artery, emerge through the zygomaticotemporal foramen to supply the skin of the temporal region.
Facial branches of the maxillary artery
1- Infraorbital artery: In the face breaks up into : A- Inferior palpebral br. To the lower eyelid. B- Nasal br. To the lacrimal aspect of the nose. C- Superior labial br. To the upper lip.2- Buccal artery : Supply the skin & mucous membrane of the cheek & vestibular gingiva of the lower molar teeth. 3- Mental artery : Branches of inferior alveolar artery, within the mandibular canal , it exits through the mental foramen with the mental nerve to supply chin , lower lip, & the vestibular gingiva of lower anterior teeth.
The branches of the facial artery
The facial artery is a branches of external carotid artery, it leaves the submandibular region of the neck & ascends on the inferior border of the mandible. As it ascends obliquely on the face it follows a tortuous route toward the medial angle of the eye. It supply several branches to the face that anastomose freely with the terminal branches of the maxillary & ophthalmic artery.1- Labial branches :
As the facial artery travels tortuously toward the medial angle of the mouth, it gives : A- Inferior labial artery to the lower lip. B- Superior labial artery to the upper lip. 2- Nasal branches : Given to the side of the nose & anastomose with the nasal branchs of infraorbital artery & external nasal artery .3- Angular artery :
The facial artery ends at the medial angle of the eye as angular artery , its provides branches to the nose & medial aspect of the lids.Facial branches of superficial temporal artery :
Is a terminal branches of external carotid artery. It emerge into the face between the jaw joint & the ear to ascend to scalp. Just below the ear it sends a branche forward as the transverse facial artery below the zygomatic arch .Veins of the face :
The course of the vein in face is posterior to artery , less tortuous course , & travels in opposite direction. The vein of the face follow the same pattern of distribution as the arterial supply, veins in several show more variability in their distribution than the arteries.The veins of the forehead, scalp, & upper lid flow to the superior ophthalmic vein in orbit . The veins of the upper lip , lateral nose & lower lid flow through the infraorbital vein to the pterygoid plexus of vein in infratemporal region.
The facial vein :
The facial vein originates & take tributaries in the following manner : 1- The angular vein : Form at the medial angle of the eye by the union of the supraorbital & supratrochlear veins. The angular veins divides, one division passes into the orbit to drain to the superior ophthalmic vein & the other division remains superficial & passes inferior as facial vein.
2- Facial vein :
Passes posteriorly toward the angle of the jaw & take several tributaries. 3-Nasal vein : Drain the side of the nose & communicate with tributaries of the infraorbital vein . 4- Deep facial vein : Communicate with the pterygoid plexus of veins deep within the infratemporal region.5- Labial vein : Drain the upper & lower lips . The superior labial vein communicates with the infraorbital vein. The inferior labial vein communicates with the mental vein.
The retromandibular vein :
It is formed from two sources : 1- Superficial temporal vein ,drain scalp & side of the head, descends anterior to ear into the parotid gland & unites with the maxillary vein. 2- Maxillary vein ,it is formed from the pterygoid plexus of veins. Joins the superficial temporal vein within the parotid gland to form the retromandibular vein.Retromandibular vein leaves the gland at inferior margion. At the angle of the mandible it divides into the anterior branch & posterior branch. The posterior branch join the posterior auricular vein behind the ear to form The external jugular vein. The anterior branch join the facial vein in the neck to form common facial vein ,the common facial vein drain to int. jugular vein .
The scalp :
The scalp extends from the eye brows back to superior nuchal line .Laterally, the scalp extends down into the temporal fossae.Layers of the scalp :1- Skin :Alayer of thin skin……2- Connective tissue :A thick dense subcutaneous CT is anchored firmly to the skin.3- Aponeurosis : The membranous aponeurosis ( galea aponeurotica ) is an intermediate tendon for the two fleshy bellies of occipitofrontalis (epicranius muscle ). The occipitalis portion originates above the superior nuchal line & inserts into the aponeurosis. Pull the scalp backwards. The frontalis portion originates from the aponeurosis & inserts into the skin above the eye brows. Pull the scalp forwards & produces transverse wrinkling of the brow
4- Loose CT : 5- Periosteum : firmly anchored to the underlying bone. Blood supply : Arises from br. Of ophthalmic A. & ECA. 1- Supraorbital A 2- Supratrochlear A 3- Zygomatico temporal A 4- Superficial temporal A 5- Posterior auricular A 6- Occipital A