GROSS ANATOMY OF THE SCALP-1.pptx

GROSS ANATOMY OF THE SCALP BY DR. PAUL A. ODEY OUTLINE INTRODUCTION LAYERS AND DESCRIPTION BLOOD SUPPLY NERVE SUPPLY LYMPHATIC DRAINAGE APPLIED ANATOMY PHOTO GALLERY  INTRODUCTION The scalp refers to the layers of skin and subcutaneous tissue that cover the bones of cranial...

GROSS ANATOMY OF THE SCALP BY DR. PAUL A. ODEY OUTLINE INTRODUCTION LAYERS AND DESCRIPTION BLOOD SUPPLY NERVE SUPPLY LYMPHATIC DRAINAGE APPLIED ANATOMY PHOTO GALLERY  INTRODUCTION The scalp refers to the layers of skin and subcutaneous tissue that cover the bones of cranial vault. It is the covering the surface of the head. It extends from the top of your forehead across to the epicranial aponeurosis of the head. Laterally, it reaches down to the external auditory meatus and zygomatic arch. The scalp consists of 5 distincts layers: LAYERS OF THE SCALP Skin Connective tissue Epicranial Aponeurosis Loose connective tissue Pericranium (periostium)  SKIN contains numerous hair follicles and sebaceous glands (thus a common site for sebaceous cysts). The skin of the scalp is highly innervated with blood vessels and sensory receptors known as Pacinian corpuscles. The corpuscles are egg-shaped and comprise many concentric rings of tissue layers. They are innervated with a free nerve ending and therefore work as deep pressure receptors to external stimuli.  DENSE CONNECTIVE TISSUE Also referred to as the superficial fascia, the connective tissue of the scalp is a fibrofatty layer. It is richly vascularised and innervated. This layer forms the bridge between the skin and the epicranial aponeurosis by connecting the two together. Ie. it Connects the skin to the Epicranial aponeurosis. The blood vessels within the layer are highly adherent to the connective tissue thus do not allow free biological activities like vasospasm (constriction to reduce bleeding) which cannot occur if the blood vessels become severed. This results in profuse or excessive bleeding should the scalp become injured.  EPICRANIAL APONEUROSIS The epicranial aponeurosis is a thin, tendon-like structure that connects the occipitalis and frontalis muscles. Known also as the galea aponeurotica, this is an important structure within the scalp. It is a thin but tough layer of fibrous tendinous tissue and is the site at which the occipitofrontalis muscle inserts into the tissue of the scalp. The occipital belly gives rise to it, whereas the epicranial aponeurosis inserts into the frontal belly of the occipitofrontalis. Posterolaterally, it extends between the superior nuchal line and the superior temporal line of the occipital bone.  LOOSE AREOLAR TISSUE This is a thin connective tissue layer that separates the periosteum of the skull from the epicranial aponeurosis. As its name might suggest, this type of tissue forms a loose connection between the epicranial aponeurosis and the pericranium. This allows the other layers of the scalp to slide of over the pericranium. Loose areolar tissue comprises a network of reticular fibers, elastic tissue, and collagen. Since this is a loose connective tissue, cell types vary beyond fibrocytes and can include plasma cells, mast cells, and adipocytes. It contains numerous blood vessels, including emissary veins which connect the veins of the scalp to the diploic veins and intracranial venous sinuses.  PERIOSTEUM The outer layer of the skull bones. It becomes continuous with the endosteum at the suture lines. The pericranium, or periosteum, is the final layer of the scalp. It is a fine membrane which covers the outer surface of the skull. It is made up of dense irregular connective tissue. It has 2 distinct layers; the fibrous layer (outermost) and the cambium layer, which is the innermost layer. The fibrous layer of the pericranium contains fibroblasts. Meanwhile, the cambium layer contains progenitor cells which later develop and form osteoblasts.  BLOOD SUPPLY TO THE SCALP Arterial Supply The scalp receives a rich arterial supply via the external carotid artery and the ophthalmic artery (a branch of the internal carotid). There are three branches of the external carotid artery involved: Superficial temporal – supplies the frontal and temporal regions Posterior auricular – supplies the area superiorly and posteriorly to the auricle. Occipital – supplies the back of the scalp Anteriorly and superiorly, the scalp receives additional supply from two branches of the ophthalmic artery – the supraorbital and supratrochlear arteries. BLOOD SUPPLY TO THE SCALP Venous Drainage The venous drainage of the scalp can be divided into superficial and deep components. The superficial drainage follows the arterial supply: superficial temporal, occipital, posterior auricular, supraorbital and supratrochlear veins. The deep (temporal) region of the skull is drained by the pterygoid venous plexus. This is a large plexus of veins situated between the temporalis and lateral pterygoid muscles, and drains into the maxillary vein. Importantly, the veins of the scalp connect to the diploic veins of the skull via valveless emissary veins. This establishes a connection between the LYMPHATIC DRAINAGE The part of the scalp that is anterior to the auricles is drained to the parotid, submandibular, and deep cervical lymph nodes. The posterior part of the scalp is drained to the posterior auricular (mastoid) and occipital lymph nodes.  NERVE SUPPLY TO THE SCALP The scalp receives cutaneous innervation from branches of the trigeminal nerve or the cervical nerve roots. Trigeminal Nerve Supratrochlear nerve – branch of the ophthalmic nerve which supplies the anteromedial forehead. Supraorbital nerve – branch of the ophthalmic nerve which supplies a large portion of the scalp between the anterolateral forehead and the vertex. Zygomaticotemporal nerve – branch of the maxillary nerve, this supplies the temple. Auriculotemporal nerve – branch of the mandibular nerve which supplies skin anterosuperior to the auricle.  NERVE SUPPLY TO THE SCALP Cervical Nerves Lesser occipital nerve – derived from the anterior ramus (division) of C2 and supplies the skin posterior to the ear Greater occipital nerve – derived from the posterior ramus (division) of C2 and supplies the skin of the occipital region. Great auricular nerve – derived from the anterior rami of C2 and C3 and supplies the skin posterior to the ear and over the angle of the mandible. Third occipital nerve – derived from the posterior ramus of C3 and supplies the skin of the inferior occipital region.  APPLIED ANATOMY DANGER AREA OF THE SCALP The connective tissue layer is considered the “danger area” of the scalp. This is because is contains the emissary veins. These are valveless veins which connect the extracranial veins of the scalp to the intracranial dural venous sinuses. The emissary veins are a potential pathway for the spread of infection from the scalp to the intracranial space.  APPLIED ANATOMY SCALP LACERATIONS Deep lacerations to the scalp tend to bleed profusely for several reasons. These are: The pull of the occipitofrontalis muscle prevents the closure of the bleeding vessel and surrounding skin. The blood vessels to the scalp are adhered to dense connective tissue, preventing the vasoconstriction that normally occurs in response to damage. The blood supply to the scalp is made up of many anastomoses, which contribute to profuse bleeding.  APPLIED ANATOMY CEPHALOHEMATOMA During a difficult birth, bleeding may occur between the neonate's pericranium and calvaria, usually over 1 parietal bone, because of a rupture of multiple minute periosteal arteries. The resulting collection of blood several hours after birth is known as cephalohematoma. APPLIED ANATOMY Because it contains numerous sebaceous glands, the scalp is one of the most common sites for sebaceous cysts. THANKS FOR YOUR ATTENTION  ANATOMY OF THE FACE (SUPERFICIAL AND DEEP STRUCTURES) OUTLINE  INTRODUCTION The human face is the most anterior portion of the human head. It refers to the area that extends from the superior margin of the forehead to the chin, and from one ear to another. The basic shape of the human face is determined by the underlying facial skeleton (i.e. viscerocranium), the facial muscles and the amount of subcutaneous tissue present. The face plays an important role in communication and the expression of emotions and mood. In addition, the basic shape and other features of the face provide our external BONES OF THE FACE BONES OF THE FACE The facial skeleton is also known as the viscerocranium. It is composed of fourteen bones, six paired and two unpaired bones. The bones of the viscerocranium include: Two nasal bones Two maxillae Two inferior nasal conchae Two palatine bones BONES OF THE FACE Two zygomatic bones Two lacrimal bones Mandible Vomer The main function of these bones is to: Give shape to the human face Protect the internal structures. These bones provide openings for the passage of neurovascular structures and bony features for the attachment of facial muscles.  MUSCLES OF THE FACE The facial muscles are also known as the muscles of the facial expression or the mimetic muscles. These muscles are a group of approximately 20 superficial skeletal muscles of the face and scalp divided into five different groups according to their location and function. These groups include: Buccolabial (oral) group: Levator labii superioris, levator labii superioris alaeque nasi, risorius, levator anguli oris, zygomaticus major, zygomaticus minor, depressor labii inferioris, depressor anguli oris, mentalis, orbicularis MUSCLES OF THE FACE Nasal group: Nasalis and procerus muscles. Orbital group: Orbicularis oculi and corrugator supercili muscles. Epicranial group: Occipitofrontalis and platysma muscles. Auricular group: Auricularis anterior, auricularis superior, auricularis posterior muscles. MUSCLES OF THE FACE All facial muscles originate from the bony and fibrous structures of the skull and insert into the skin. The prime function of the facial muscles is to provide a wide range of facial expressions which is important for expressing emotions and mood (e.g. smiling, grinning, frowning). In addition, these muscles help in opening and closing the mouth and eyes, and thus protect the delicate structures of the face. PARTS OF THE FACE The superior part of the human face extends from the hairline to the inferior margin of the orbit. The lateral margins of this portion extend to the temporal region. The superior part of the face can be divided into three separate regions including the frontal, orbital and temporal regions. These regions are characterized by the following: The frontal region, also known as the forehead, is the most superior region of the face that spreads from the hairline to the eyebrows. It is composed mainly of the frontal bone and the overlying muscles including the procerus, occipitofrontalis, depressor supercilii and corrugator supercillii muscles. The muscles are covered by several fat pads (central, middle and lateral) and skin.  PARTS OF THE FACE The orbital region contains the eyes and orbits. Eyes are paired spherically-shaped organs situated in the orbits. The orbits are composed of several cranial bones including the frontal bone superiorly, nasal bone medially, maxilla inferomedially and the zygomatic bone inferolaterally. Each eyeball is cushioned by superior, inferior, and lateral fat pads. The orbit is surrounded by a single muscle known as the orbicularis oculi muscle, while the eyes are enveloped and covered by the eyelids which function to protect the eyes from external factors. The orbicularis oculi muscle closes the eyelids on contraction while the levator palpebrae muscle opens the eyelids. The edges of the eyelids are lined with eyelashes. FACE The middle part of the face region extends from the lower eyelid superiorly to the superior margin of the upper lip inferiorly. This portion of the face is marked by four regions including the nasal, infraorbital, zygomatic and auricular regions. The nasal region is located in the central portion of the human face and, as its name suggests, it features the nose. The nose is the central pyramid-shaped structure, situated in the midline. The base of the nose is formed mainly by the nasal bone and covered by the nasalis muscle. The apex of the nose ends inferiorly in a rounded ‘tip’. The area between the base and apex is the dorsum of the nose which is formed by nasal cartilage. Superficially, the dorsum of the nose is covered by fat pads and skin. FACE The infraorbital region overlies the maxilla, while the zygomatic regions overlie the zygomatic bone. These regions are located lateral to the nose and mark the superior portion of the cheek. The cheek is a prominence that overlies the zygomatic arch and is comprised of muscles and fat. The zygomatic arch is composed of two bones (zygomatic and maxilla). The muscular layer of the cheeks contains several muscles that include the masseter, levator labii superioris alaeque nasi, levator labii superioris, zygomaticus minor, zygomaticus major, risorius, levator anguli oris and buccinator muscles. The muscles of the cheeks are covered by fat pads and overlying skin. The auricular region is the most lateral region of the face. It contains the external ear (auricle). The internal structure of the auricle is made from cartilage and covered by skin. The ears are surrounded by three auricular muscles (anterior, posterior, and superior). FACE The inferior part of the face is bordered superiorly by the superior margin of the upper lip and inferiorly by the inferior border of the chin. The lateral borders of the inferior part of the face are formed by the angles of the mandible on each side. This part can be divided into oral, mental, buccal and parotideomasseteric regions. The oral region surrounds the lips, the most prominent structures in the inferior part of the face. They are divided into two parts: the upper lip and lower lip. The upper lip is associated with the maxilla, while the lower lip, with the mandible. The lips are surrounded mainly by the orbicularis oris muscle which functions in altering the shape of the lips when we speak or eat. The other muscles that facilitate the movements of lips are the risorius, mentalis, depressor labii inferioris, and depressor anguli oris muscles. The movements of the lips allow for actions such as speech, eating, and kissing. FACE The mental region is located inferior to the mouth. It features the chin, a central structure that overlies mental protuberance of the mandible. The buccal region is located just inferior to the infraorbital and zygomatic region, and comprises the inferior portion of the cheek. It mainly refers to the area marked by the buccinator muscle. The inferior border of the buccal region is the jawline, formed by the inferior border of the mandible. The parotideomasseteric region is located lateral to the buccal region. This region is named after the underlying parotid gland and masseter muscle. BLOOS SUPPLY The face is richly perfused by a subdermal plexus formed mainly by musculocutaneous arteries coming from the superficial temporal and facial arteries. The facial artery branches off the external carotid artery, winds around the inferior border of the mandible and ascends along the side of the nose. The superficial temporal artery similarly arises from the external carotid artery and gives off numerous branches which supply different parts of the face including the transverse facial artery and the middle temporal artery. The venous blood of the face drains from the subdermal plexus to the deep venous plexus via communicating veins. NERVE SUPPLY The three divisions of the trigeminal nerve (CN V) are responsible for the somatic sensation of the entire face according to the three embryological origins. The ophthalmic nerve (CN V1) which comes from the frontonasal prominence supplies the anterior scalp, forehead, and nasal dorsum. Deriving from the maxillary prominence the maxillary nerve (CN V2) provides mainly the anterior cheek, the lateral face, the upper lip, the side of the nose, and the lower eyelid. The mandibular nerve (CN V3) originates from the mandibular prominence and supplies the lower lip,chin, and posterior cheek APPLIED ANATOMY Facial clefts The pathological traits of facial growth are many and quite frequent. Lasting complications include facial disfigurement, difficulties hearing, speaking, eating, swallowing, and breathing. The most common and well-known facial anomalies, known as facial clefts, are listed below: Cleft lip: A partial or complete lack of fusion of the maxillary prominence with the medial nasal prominence on one or both sides. Depending on the severity of the lack of fusion, this can result in a partial or complete, unilateral or bilateral cleft lip.  APPLIED ANATOMY Cleft palate: Cleft palates are divided into primary and secondary depending on whether they are in front of or behind the incisive foramen respectively. The primary (or anterior) cleft deformities include lateral cleft lip, upper cleft jaw, and a cleft between the primary and secondary palates. Behind the incisive foramen, the clefts can either be of the secondary palate or known as a cleft uvula. Cleft palates result from a lack of fusion between the palatine shelves. Rarely, a cleft will run from the lip to the secondary palate. APPLIED ANATOMY Oblique facial clefts:When the maxillary prominence fails to merge with the lateral nasal prominence the nasolacrimal duct is exposed. Median (or midline) cleft: This type of anomaly occurs with the incomplete fusion of the two medial nasal prominences in the midline. This particular defect can have much more serious consequences than the others it is associated with cognitive disabilities and brain abnormalities.  FACIAL LACERATIONS:  FACIAL FRACTURES: Facial bone fractures result from direct trauma and usually follow one of only a small number of patterns. The most common configuration of facial fractures include isolated zygomatic arch fractures, 'tripod' fractures, and orbital 'blowout' fractures. ORBITAL BLOWOUT FRACTURES: Trauma to the orbit may lead to increased pressure in the orbit such that the thin bone of the orbital floor bursts. This manifests as the 'teardrop' sign which is due to herniation of orbital contents into the maxillary antrum. FACIAL FRACTION TRIPODS FRACTURE: Trauma to the zygoma may result in impaction of the whole bone into the maxillary antrum with fracture to the orbital floor and lateral wall of the maxillary antrum. The displaced zygoma is detached from the maxillary bone, the inferior orbital rim, the frontal bone at the zygomatico-frontal suture, and from the zygomatic arch. The result is said to liken a 'tripod', but in reality these fractures are often more complex than is appreciated on plain X-ray. 'Quadripod' would perhaps be a more accurate term as four fractures may be visible. APPLIED ANATOMY TRIGERMINAL NEURALGIA: Trigeminal neuralgia (TN), also known as tic douloureux, is a distinctive facial pain syndrome that may become recurrent and chronic. It is characterized by unilateral pain following the sensory distribution of cranial nerve V (typically radiating to the maxillary or mandibular area in 35% of affected patients) and is often accompanied by a brief facial spasm or tic. Chewing, talking, or smiling Drinking cold or hot fluids Touching, shaving, brushing teeth, blowing the nose Encountering cold air from an open automobile window BELLS PALSY BELLS PALSY: Bell palsy, also termed idiopathic facial paralysis (IFP), is the most common cause of unilateral facial paralysis. It is one of the most common neurologic disorders of the cranial nerves. In the great majority of cases, Bell palsy gradually resolves over time, and its cause may be unknown. Acute onset of unilateral upper and lower facial paralysis (over a 48-hr period) Posterior auricular pain Decreased tearing Hyperacusis Taste disturbances Otalgia EARLY SYMPTOMS OF FP Weakness of the facial muscles Poor eyelid closure Aching of the ear or mastoid (60%) Alteration of taste (57%) Hyperacusis (30%) Tingling or numbness of the cheek/mouth Epiphora Ocular pain Blurred vision  DANGEROUS AREA OF THE FACE: The danger triangle on the face, also known as the “triangle of death” or the “nasolabial triangle”, refers to the section of the face from the bridge of the nose to the corners of the mouth. The area is in the shape of a triangle, with the tip of the triangle in the medial position of the eye and the base covering the upper lip. This little portion of the face has a direct connection to the brain; this link is made possible by the cavernous sinus, a web of vast veins located behind the eye sockets. This area is linked through blood vessels to regions of the skull where infections can spread instantaneously and become more critical. Due to the unique nature of the blood supply to the human nose and surrounding area, it is dangerous for infections to occur around this area as it could spread to delicate organs.  If the skin inside this triangle is broken, like from a cut or popped pimple, bacteria can enter the body and cause infection. Due to its proximity to critical portions of the brain, the infection can quickly lead to serious complications, including cavernous sinus thrombosis, meningitis, brain abscess, or even death. Staph infection is one of the major infections in the danger triangle. Cavernous sinus thrombosis is one of the major complications that affect the brain caused by these infections that result in blood clots in the sinus. This shows that Infections resulting from open acne wounds or pulled hair on the face can pose serious health risks. CAN I TAKE A BREAK PLEASE? THANK YOU!