Head & Neck Session 3 PDF

The scalp and the face Dr. Israa khalil orfromhairline The scalp is the part of the head that extends from the superciliary arches anteriorly to the superior nuchal lines posteriorly, laterally it continues to the zygomatic arch. From eyebrows to the hair line is common to the face and scalp. It...

The scalp and the face Dr. Israa khalil orfromhairline The scalp is the part of the head that extends from the superciliary arches anteriorly to the superior nuchal lines posteriorly, laterally it continues to the zygomatic arch. From eyebrows to the hair line is common to the face and scalp. It consists of five layers, the first three of which are tightly held together, forming a single unit . The layers can be defined by the word itself: scalp • S- Skin, which is thick, and hair bearing and contains numerous sebaceous glands. In • C- Connective tissue, numerous arteries and veins are found in this layer. The arteries are branches of the external and internal carotid arteries, and a free anastomosis takes place between them. • A- Aponeurosis ,(galea aponeurosis) which is a thin, tendinous sheet that unites the occipital and frontal bellies of the occipitofrontalis muscle . The lateral margins of the aponeurosis are attached to the temporal fascia. theregionoftheanastomosisbetween branches of internal a Whatare carotidartery external • L- Loose connective tissue, which loosely connects the aponeurosis to the periosteum of the skull and facilitates movement of the scalp proper over the calvaria . Because of its consistency infections tend to localize and spread through this layer. Blunt trauma can result in haemorrhage in this layer(blood can spread forward into the face, resulting in black eye). In scalping injuries, this is the layer in which separation occurs. Er f space for I • The black eye occurs when blood from the head trauma leaks into the soft tissue around the eyes. • Head injury resulting in soft tissue damage can cause collection of blood in the loose subaponeurotic layer of scalp . • The blood easily tracks down anteriorly over the eyelids leading to discoloration of the eye known as black eye. The areolar tissue contains a few small arteries and some important emissary veins. The emissary veins are valveless and connect the superficial veins of the scalp with the diploic veins of the skull bones and with the intracranial venous sinuses . • P- Pericranium, which is the periosteum covering the outer surface of the skull bones. O Muscles of the Scalp Occipitofrontalis or frontooccipitalmuscle I It move the scalp, wrinkle the forehead, and raise the eyebrows. • The frontal bellies of the occipitofrontalis can raise the eyebrows in expressions of surprise or horror. 9 41 c.fi i es tween • The two frontal bellies are much larger than the occipital bellies. • The two frontal bellies come close together in the median plane; the midline fibres blend with the procerus muscle . • while the two occipital bellies are separated by a gap of aponeurosis (galea aponeurotica). • The two bellies are supplied by facial nerve. th Sensory Nerve Supply of the Scalp • The supratrochlear nerve, a branch of the ophthalmic division of the trigeminal nerve, It passes backward and reaches nearly as far as the vertex of the skull. 5th • The supraorbital nerve, a branch of the ophthalmic division of the trigeminal nerve, it supplies the scalp as far backward as the vertex. 5th • The zygomaticotemporal nerve, a branch of the maxillary division of the trigeminal nerve, supplies the scalp over the temporal region . • The auriculotemporal nerve, a branch of the mandibular division of the trigeminal nerve . It supplies the skin over the temporal region. • The lesser occipital nerve, a branch of the cervical plexus (C2), supplies the scalp over the occipital region . • The greater occipital nerve, a branch of the posterior ramus of the second cervical nerve, supplies the scalp as far forward as the vertex of the skull . in dauto aterm Arterial Supply of the Scalp The scalp has a rich supply of blood to nourish the hair follicles, and, for this reason, the smallest cut bleeds profusely, the following arteries are present: 1 • The supratrochlear and the supraorbital arteries, branches of the ophthalmic artery . L • The superficial temporal artery, the smaller terminal branch of the external carotid artery, . It divides into anterior and posterior branches, which supply the skin over the frontal and temporal regions. 3 • The posterior auricular artery, a branch of the external carotid artery, supply the scalp above and behind the auricle . a • The occipital artery, a branch of the external carotid artery, ascends from the apex of the posterior triangle . It supplies the skin over the back of the scalp to the vertex of the skull. atern atcarotidartery E 8 E 8 wasting y Venous Drainage and Lymphatic Drainage of the Scalp • The supratrochlear and supraorbital veins unite at the medial margin of To the orbit to form the facial vein. • The superficial temporal vein unites with the maxillary vein in the substance of the parotid gland to form the retromandibular vein . • The posterior auricular vein unites with the posterior division of the retromandibular vein, to form the external jugular vein . • The anterior division of retromandibular vein with facial vein drains into a the internal jugular vein. drain into v injugularforamen • Lymph vessels in the anterior part of the scalp and forehead drain into the submandibular lymph nodes . Drainage from the lateral part of the scalp above the ear is into the superficial parotid nodes; Vessels in the back of the scalp drain into the occipital nodes. The Face Face to face meeting is an important initial contact between individuals. part of this exchange is the use of facial expressions to convey emotions. • The skin of the face possesses numerous sweat and sebaceous glands. skinsothereis the Itmeansallmusclesoffacialexpressionsinsertedinto • The muscles underlying the skin of the face are attached to the dermis of skin. fasia andall ofthemsupplied by E • No deep fascia is present on the face. É Sensory Nerves of the Face • The skin of the face is supplied by branches of the three divisions of the 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 . • These nerves not only supply the skin of the face, but also supply proprioceptive fibres to the underlying muscles of facial expression, the mouth, teeth, nasal cavities, and paranasal air sinuses. Trigeminal facial sensory motor Ophthalmic Nerve • The ophthalmic nerve supplies the skin of the forehead, the upper eyelid, the conjunctiva, and the side of the nose down to and including the tip. • Five branches of the nerve pass to the skin. ✔ The lacrimal nerve . ✔ The supraorbital nerve. ✔ The supratrochlear nerve. ✔ The infratrochlear nerve. ✔ The external nasal nerve Maxillary Nerve • The maxillary nerve supplies the skin on the side of the nose, the lower eyelid, the cheek, the upper lip, and the lateral side of the orbital opening. • Three branches of the nerve pass to the skin. • The infraorbital nerve is a direct continuation of the maxillary nerve. • The zygomaticofacial nerve . • The zygomaticotemporal nerve . Mandibular Nerve • The mandibular nerve supplies the skin of the lower lip, the lower part of the face, the temporal region, and part of the auricle. It then passes upward to the side of the scalp. • Three branches of the nerve pass to the skin. • The mental nerve o • The buccal nerve. • The auriculotemporal o nerve we have 2 buccalnerves inthefa buccal branchofmandibularnerve offacialnerve buccalbranch inferior partofnasalseptum The3rdregionofanastomosisattheanterior Theathregionis inparotedgland Arterial Supply of the Face The face receives a rich blood supply from two main vessels: the facial and superficial temporal arteries 1. The facial artery arises from the external carotid artery, arched over the submandibular salivary gland, it curves around the inferior margin of the body of the mandible at the anterior border of the masseter muscle. It is here that the pulse can be easily felt . It runs upward in a tortuous course toward the angle of the mouth. It then 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 to form angular artery . III p em internal 8 Branches off thatsupplies artery • The submental artery . • The inferior labial artery . • The superior labial artery . • The lateral nasal artery . s qgyggeg.no enom anastomoses 2. The superficial temporal artery , the smaller terminal branch of the external carotid artery. 3. The transverse facial artery, a branch of the superficial temporal artery, arises within the parotid gland. It runs forward just above the parotid duct . 4. The supraorbital and supratrochlear arteries, branches of the ophthalmic artery. of ad 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 . It is connected to the superior ophthalmic vein . By means of the superior ophthalmic vein, the facial vein is connected to the cavernous sinus this connection is of great clinical importance because it provides a pathway for the spread of infection from the face to the cavernous sinus. • The facial vein joined the pterygoid venous plexus by the deep super facial vein and to the cavernous sinus by the superior o ophthalmic vein. 0 Lymph Drainage of the Face • The anterior part of the face drains into the submandibular lymph nodes • The lateral part of the face, is drained into the parotid lymph nodes. • The central part of the lower lip and the skin of the chin are drained into the submental lymph nodes. imp Muscles of the Face (Muscles of Facial Expression) dermisoftheskin The muscles of the face are embedded in the superficial fascia, and most of them arise from the bones of the skull and inserted into the skin . The orifices of the face, namely, the orbit, nose, and mouth, are guarded by the eyelids, nostrils, and lips, respectively. It is the function of the facial muscles to • Serve as sphincters or dilators of these structures. • A secondary function of the facial muscles is to modify the expression of the face. All the muscles of the face are supplied by branches of the facial nerve. Muscles of the Eyelids(Orbital group) • The sphincter muscle of the eyelids is the orbicularis oculi is a large muscle that surrounds orbital orifice, it has two major parts The outer orbital part that incircles the orbital orifice. The inner palpebral part is in the eyelids. forcefully • The dilator muscles are the levator palpebrae superioris and the occipitofrontalis . • The corrugator supercilli is deep to the eyebrow and the orbicularis oculi muscle draws the eyebrows medially and downward causing vertical wrinkles above the nose. Ige Muscles of the Nostrils • The nasalis is the largest muscle of nasal group which is active when the nares are flared. • It consist of a transverse part (compressor naris) the and an alar part (the dilator naris). • Procerus is small muscle superficial to the nasal bone and is active when an individual frown. It produce transvers wrinkles over the bridge of the nose. Muscles of the Lips and Cheeks • The sphincter muscle of the lip is the orbicularis oris, which consist of fibres proper to itself and fibers that are added to these from the dilators, the bulk of orbicularis muscle is formed of extrinsic fibres, most of these come from the buccinator. The buccinator converge toward the modiolus. • The dilator muscles consist of a series of small muscles that radiate out from orbicularis oris, some inserted into the lips, some into the modiolus. All contracting together open the lip into the widest possible circle 8 X Dilator Muscles of the Lips The dilator muscles radiate out from the lips, and their action is to separate the lips. The muscles arise from the bones and fascia around the oral aperture and converge to be inserted into the substance of the lips, the muscles are named as follows: • Levator labii superioris alaeque nasi • Levator labii superioris • Zygomaticus minor • Zygomaticus major • Levator anguli oris (deep to the zygomatic muscles) • Risorius • Depressor anguli oris • Depressor labii inferioris • Mentalis Muscle of the Cheek The buccinator forms the muscular component of the cheek. It is in the space between the mandible and the maxilla deep to the other facial muscles in the area the fiber of this muscle pass toward the corner of the mouth to insert into the lips, blending with fibers from the orbicularis oris in a unique fashion. • Action: Compresses the cheeks and lips against the teeth Buccinator Q Is is the facial muscle and accessorymuscle for mastication Buccinator muscle A Both of them of Mastication or facial expression Other muscles of the facial expression • The platysma is a large, thin sheet of muscle in the superficial fascia of the neck, more of its medial fibers insert on the mandible, whereas the lateral fibers join with muscles around the mouth. • The platysma tenses the skin of the neck and can move the lower lip and corners of the mouth down. Allofthesestructureisattachedtothecornerofthemouth tornades Facial Nerve As the facial nerve runs forward within the substance of the parotid salivary gland , it divides into its five terminal branches . • The temporal branch • The zygomatic branch • The buccal branch emerges from the anterior border of the gland below the parotid duct. • The mandibular branch • The cervical branch • The facial nerve supplies all the muscles of facial expression. It does not supply the skin, but its branches communicate with branches of the trigeminal nerve.