Skull & Scalp Student Copy PDF

SKULL & SCALP DR ZAHIRRAH BEGAM MOHAMED RASHEED DEPARTMENT OF DIAGNOSTIC CRANIOFACIAL & BIOSCIENCE Specific Learning Outcomes Skull & Scalp 01 | Bones 02 | Positions 03 | Landmarks Enumerates the bones Stat...

SKULL & SCALP DR ZAHIRRAH BEGAM MOHAMED RASHEED DEPARTMENT OF DIAGNOSTIC CRANIOFACIAL & BIOSCIENCE Specific Learning Outcomes Skull & Scalp 01 | Bones 02 | Positions 03 | Landmarks Enumerates the bones State the anatomical Identify bregma, lambda, forming the skull. position of the skull. pterion, and asterion and describe its clinical importance. 04 | Comparison 05 | Layers 06 | Supplies Compare between adult and Describe the layers of the Describe the innervation neonatal skull. scalp and its clinical and blood supply of the importance. scalp.  Skull & Scalp 01 Bones Forming The Skull  SKULL Skull & Scalp Neurocranium – Neurocranium + Viscerocranium = protects the Skull brain Viscerocranium – portion of the skull that creates the face  Skull & Scalp Neurocranium (cranial vault) Viscerocranium 8 bones - ethmoid, (facial bones) - sphenoid, 14 bones - frontal, - vomer, - occipital, - mandible, - parietal (2), - inferior conchae (2), - temporal (2) - nasal (2), - lacrimal (2), - maxilla (2), - palatine (2), Total: 22 bones - zygomatic (2) (21 immobile, 1 mobile which is the mandible ) Structure of Skull Bones Skull & Scalp Suture § External & internal tables Periosteum (compact bone) Outer table § Diploë (spongy bone) Diploë § Periosteum Inner table § Sutures  Skull & Scalp 02 Anatomical Position of The Skull & 03 Landmarks: bregma, lambda, pterion, and asterion Anterior view of the skull – the bones Skull & Scalp (forehead bone) (prominence of cheek) (upper jaw) Anterior view of the skull – features Skull & Scalp Orbital margin (attachment of frontal, zygomatic & maxilla bones) Metopic suture - Persistent frontal suture (9%) - Normally fuse by 5th year Superior orbital fissure (slit between greater & lesser wing of sphenoid bone) Inferior orbital fissure Anterior nasal aperture ant. midline features (formed by maxilla & nasal bones) Intermaxillary suture Symphysis (union of infantile mandible) Anterior view of the skull – important points Skull & Scalp Glabella Nasion (intersection of frontal & nasal bone) Anterior nasal spine Alveolar processes Mental protuberance (prominence of chin) Anterior view of the skull – foramens Skull & Scalp Supraorbital notch/foramen (supraorbital nerve & vessels) Zygomaticotemporal foramen (zygomaticotemporal nerve & vessels) Infraorbital foramen (infraorbital nerve & vessels) Zygomaticofacial foramen (zygomaticofacial nerve & vessels) Mental foramen - Inferior to 2nd premolar teeth - Mental nerve & vessels Lateral view of the skull – the bones Skull & Scalp Lateral view of the skull – important points Skull & Scalp Sa uture gi tta Pterion ls ut nal s - H-shaped suture ur e - Weakest part of the skull Coro - Overlies course of ant. division of middle meninges vessels e ur Nasion sut (intersection of frontal & nasal bone) id do mb La Anterior nasal spine Asterion Pterion Skull & Scalp Pterion Ant. branch of middle meningeal artery Post. branch of middle meningeal artery Middle meningeal artery Meeting point of frontal, parietal, sphenoid & temporal bones Lies over the ant. division of middle meningeal artery Ø Severe trauma (fracture) >>> extradural haematoma Extradural haematoma Skull & Scalp Blood collected between internal surface of skull & meningeal layer of dura mater Exerts local pressure on the underlying precentral gyrus Posterior view of the skull – the bones Skull & Scalp Posterior view of the skull – features Skull & Scalp External occipital protuberance Superior nuchal line - Serve as an attachment point for nuchal ligament and trapezius muscle Inferior nuchal line External occipital crest Posterior view of the skull – important points Skull & Scalp Vertex Sagittal suture Highest point of skull Lambda Junction of sagittal and lambdoid sutures Asterion Lambdoid suture Superior view of the skull – the bones Skull & Scalp Frontal bone Parietal bone Occipital bone Superior view of the skull – important points Skull & Scalp Bregma Junction of coronal & sagittal sutures Coro nal s uture Sagittal suture Parietal foramen Lambda Lambdoid suture Vault of the skull Skull & Scalp Inferior view of the skull Skull & Scalp  Skull & Scalp 04 Adult and Neonatal Skull Neonatal skull Skull & Scalp The skull bones are smooth & unilaminar (absence of diploë) Larger neurocranium relative to the smaller face - due to the growth of mandible, maxillae, & paranasal sinuses Fontanelles Skull & Scalp q is Unossified membranous intervals o Anterior fontanelle o Posterior fontanelle o Sphenoid/anterolateral fontanelle o Mastoid/posterolateral fontanelle Fontanelles Skull & Scalp Anterior fontanelle o Anterior fontanelle Frontal suture - diamond shaped Coronal - bounded: 2 frontal bones & 2 parietal bones suture - fused by the age of 18-24 months o Posterior fontanelle Sagittal suture - triangular shaped - bounded: 2 parietal bones & occipital bone - fused by the end of 1st year Posterior fontanelle o Early closure of fontanelles >>> restriction to brain growth o Late closure of fontanelles >>> increases intracranial pressure  Skull & Scalp 05 Layers of The Scalp Layers of scalp Skull & Scalp S Tightly packed together forming a C single unit A L P Layers of scalp Skull & Scalp o Skin - thick - hairy, contains numerous hair follicles & sebaceous glands o Connective tissue - anchors skin to aponeurosis - contain arteries, veins & nerves Epicranial aponeurosis Frontal belly of o Aponeurosis occipitofrontalis m. Occipital belly of - thin, tendon-like structure occipitofrontalis m. - unites frontal & occipital bellies of occipitofrontalis muscle o Loose areolar tissue - contain valveless emissary veins >>> connects scalp veins to diploic veins & intracranial venous sinuses o Pericranium - periosteum covering external surface of skull bones  Loose areolar tissue – dangerous layer Skull & Scalp Skin Superficial vein of scalp Emissary vein of scalp Connective tissue Diploic vein (situated in the skull bone) Aponeurosis Superior sagittal sinus Loose connective tissue Pericranium (periosteum) Dura matter: Periosteal layer Meningeal layer emissary veins devoid of valves & communicates scalp veins with intracranial venous sinuses Loose areolar tissue – dangerous layer Skull & Scalp superficial spread to deeper structure resulting in osteitis/ meningitis/ infection venous sinus thrombosis from skin  Skull & Scalp 06 Innervation & Blood Supply of The Scalp Nerve supply Skull & Scalp 5 in front of auricle 5 behind of auricle 4 sensory 1 motor 1 motor 4 sensory (from trigeminal N) (from cervical N) o Supratrochlear n. Temporal branch Posterior o Great auricular n. o Supraorbital n. of facial n. auricular branch o Lesser occipital n. o Zygomaticotemporal n. of facial n. o Great occipital n. o Auriculotemporal n. o 3rd occipital n. Nerve supply Skull & Scalp (branch of ophthalmic n., supplies anteromedial forehead) Supratrochlear nerve Supraorbital nerve (branch of ophthalmic n., supplies scalp) (branch of maxillary n., supplies temple) Zygomaticotemporal nerve Temporal branch of facial (motor) Auriculotemporal nerve (branch of mandibular n., supplies skin ant. sup. to the auricle) (ant. rami C2 & C3, supplies post. ear skin & angle of mandible) Great auricular nerve (ant. ramus C2, supplies skin post. to ear) Lesser occipital nerve Posterior auricular nerve (motor) (post. ramus C2, supplies skin of occipital region) Great occipital nerve (post. ramus C3, supplies skin inferior of occipital region) Third occipital nerve Blood supply Skull & Scalp 3 in front of auricle 2 behind of auricle o Supratrochlear a. o Posterior auricular a. o Supraorbital a. o Occipital a. o Superficial temporal a. Blood supply Skull & Scalp Supratrochlear artery Ophthalmic artery (branch of internal carotid artery) Supraorbital artery Superficial temporal artery Posterior auricular artery Branches from external carotid artery Occipital artery  Skull & Scalp THANK YOU!