Face and Scalp Anatomy PDF

The Face and scalp Snell clinical anatomy by region 10th edition Page 1515-1538 Lecturer ISLAM ALTARAWNEH Scal p The scalp extends from the superciliary arches anteriorly to the external occipital protuberance and superior nuchal lines posteriorly and to the temporal...

The Face and scalp Snell clinical anatomy by region 10th edition Page 1515-1538 Lecturer ISLAM ALTARAWNEH Scal p The scalp extends from the superciliary arches anteriorly to the external occipital protuberance and superior nuchal lines posteriorly and to the temporal lines laterally. Formed of 5 layers : S-skin: thick layer has hair g and contains numerous sebaceous glands. C-connective tissue: (dense) Highly vascular A-Aponeurosis (epicranial): This is a thin, tendinous sheet that unites the occipital and frontal bellies of the occipitofrontalis muscle. L -Loose areolar tissue : found in subaponeurotic space and it is site for infections spread P-pericranium : is the periosteum covering the outer surface of the skull bones Muscles of the Scalp Occipitofrontalis: Origin:  Frontal belly: Skin and superficial fascia of eyebrows  Occipital belly: Highest nuchal line of occipital bone Insertion: Epicranial aponeurosis Nerve Supply: Facial nerve Action: Moves scalp on skull and raises eyebrows 1-The skin of the face is: Elastic , Vascular, Rich in sweat and sebaceous glands , and it is connected to the underlying bones by loose connective tissue (subcutaneous layer), into which are embedded the muscles of facial expression 2-Superficial fascia of the face Contains: a-facial muscles b-vessels & nerves c-fat tissue (absent in the eye lids but it is well developed in the cheeks) 3-Deep fascia: is absent (except over the parotid gland and fascia covering the buccinator muscle)  Layers of the Face Skin Subcutaneou s Superficial fascia Facial muscles bone Muscles in the face are in two groups : 1. Facial expression muscles. 2. Muscles of mastication Muscles of the facial expression General features 1. all lie within the superficial fascia. 2. They take their origin from the facial bones. 3. They are inserted into the skin. 4. They are arranged around the three openings of the face ( the orbit, nose, and mouth) and act as sphincters or dilators. 5. They are supplied by the facial nerve.  Orbicularis occuli Three large muscles 1 Orbicularis occuli muscle 2 Buccinator muscle 3 Orbicularis oris muscle Orbicularis oris Buccinator  Procerus Levator labii superioris Corrugator supercilii alaeque nasi Nasalis Levator labii superioris Levator anguli oris Zygomaticus major Risorius Zygomaticus minor Depressor labii inferioris Depressor angulai oris Mentalis Platysma Orbicularis The orbicularis oculi is a large muscle that completely oculi surrounds each orbital orifice and extends into each eyelid. It has two major parts: 1-The outer orbital part is a broad ring that encircles the orbital opening Originates medially from the medial palpebral ligament, and the lacrimal bone. 2-The inner palpebral part is in the eyelids and consists of muscle fibers originate from medial palpebral ligament to the lateral ligament. Action: act in eyelid closure The palpebral part closes the eye gently. The orbital part closes the eye more forcefully and produces some wrinkling around the eye Orbicularis Oris Origin : The fibers encircle the oral orifice within the substance of the lips Many of the fibers are derived from the buccinator muscle. Upper part from buccinator cross down to lowerlip and the lower fibers from the buccinator pass upward to the upper lip Some of the fibers arise near the midline from the maxilla above and the mandible below. Insertion: angles of the mouth and lips Nerve supply: Buccal and mandibular branches of the facial nerve Action: Compresses the lips together closes the vestibule of the mouth Buccinat or Origin: Upper fibers: from the maxilla opposite the molar teeth Lower fibers: from the mandible opposite the molar teeth. Middle fibers: from the pterygomandibular ligament Insertion: At the angle of the mouth the central (middle) fibers decussate, those from below entering the upper lip and those from above entering the lower lip the highest (upper) and lowest (lower)fibers continue into the upper and lower lips, respectively, without intersecting. The buccinator muscle thus blends and forms part of the orbicularis oris muscle. The muscle is pierced by the parotid duct. Nerve supply: Buccal branch of the facial nerve Action: Compresses the cheeks and lips against the teeth (prevents accumulation of food in the vestibule during eating returning the food inside the oral cavity.  Facial Nerve As the facial nerve runs forward within the substance of the parotid salivary gland it divides into its five terminal branches 1 The temporal 2 The zygomatic 3 The buccal 4 The mandibular 5 The cervical A-a lower motor neuron lesion Damage to the facial nerve in 1 The internal acoustic meatus (by a tumor) 2 The middle ear (by infection or operation), 3 The facial nerve canal (perineuritis, 4 The parotid gland (by a tumor) 5 Lacerations of the face will cause distortion of the face drooping of the lower eyelid, and the angle of the mouth will sag on the affected side. Bell's palsy B-An upper motor neuron lesion (involvement of the pyramidal tracts and nuclei of the nerve) will leave the upper part of the face normal because the neurons supplying this part of the face receive corticobulbar fibers from both cerebral cortices.  THE MUSCLES OF MASTICATION These muscles are associated with movements of the jaw (temporomandibular joint). There are four muscles: 1. Masseter 2. Temporalis 3. Medial pterygoid 4. Lateral pterygoid Temporalis muscle : origin: from the temporal The muscle is covered by fascia. it has oblique fibers and transverse fibers. Insertion : coronoid process of the mandible. Actions: Elevation of the mandible/closing the mouth( oblique fibers ). Also performs retraction of the mandible moving the jaw posteriorly( transverse fibers). Innervation: Mandibular nerve (V3). Masseter muscle: It is the most powerful muscle of mastication. It is quadrangular in shape Attachments: Origin: from maxillary process of the zygomatic bone and the zygomatic arch. Insertion : to the ramus of the mandible. Actions: Elevation of the mandible (closes the mouth). Clenching of teeth Innervation: Mandibular nerve (V3). Medial Pterygoid has a quadrangular shape with two heads: deep and superficial. It is located inferiorly to the lateral pterygoid muscle. Superficial head Origin :The superficial head originates from the maxillary tuberosity. Deep head The deep head originates from the medial aspect of the lateral pterygoid plate of the sphenoid bone. insertion :Both heads attach to the ramus of the mandible near the angle of mandible. lateral pterygoi Actions: Elevation of the mandible d (closing the mouth). Innervation: Mandibular nerve (V3). Medial pterygoid lateral pterygoid muscle has a triangular shape with two heads: superior and inferior. Origin : The superior head originates from the greater wing of the sphenoid. The inferior head originates from the lateral pterygoid plate of the sphenoid laterally. Insertion : to the neck of the mandible. Actions: Bilateral action – protraction of the mandible and depression of the chin. Unilateral action – ‘side to side’ movement of the jaw. Innervation: Mandibular nerve (V3).  Sensory Nerves of the Face The skin of the face is supplied by three branches of Trigeminal nerve except for the small area over the angle of the mandible and the parotid gland which is supplied by the great auricular nerve branch from cervical plexus  Arterial Supply of the Face The face receives a rich blood supply from two main vessels: The facial artery Superficial temporal artery  External carotid artery FACIAL ARTERY Superficial temporal artery The facial artery Arises from the external carotid artery (branch from common carotid artery) Ascends over the submandibular salivary gland It curves up from the inferior margin of the body of the mandible and runs upward in a tortuous course toward the angle of the mouth ascends deep to the zygomaticus muscles and runs along the side of the nose to the medial angle of the eye, where it anastomoses with the terminal branches of the ophthalmic artery.  2-The superficial temporal artery ascends over the zygomatic arch, where it may be palpated just in front of the auricle, supplies the scalp  Venous Drainage of the Face The facial vein is formed at the medial angle of the eye by the union of The Supraorbital and Supratrochlear veins The facial vein descends behind the facial artery to the lower margin of the body of the mandible and is joined by the The retromandibular vein. The facial vein ends by draining into The internal jugular vein. It is connected to the superior ophthalmic vein which is connected to The cavernous sinus this connection is of great clinical importance because it provides a pathway for the spread of infection from DANGEROUS AREA OF THE FACE (THE LOWER PART OF THE NOSE AND THE UPPER LIP) to the cavernous sinus Infection from the triangular area can cause Thrombosis of the cavernous sinus