Osteology of head and face


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Osteology of head and face

  1. 1. The osteology of head & neck
  2. 2. Main bones included: <ul><li>Somatic bones </li></ul><ul><li>Skull with mandible </li></ul><ul><li>Cervical vertebrae (all 7) </li></ul><ul><li>The hyoid bone develop from 2 nd &3 rd brachial arches </li></ul>
  3. 3. The following bones The mandible The hyoid bone The cervical vertebrae
  4. 4. Points to remember <ul><li>Skull cap is developed by intramembraneous ossification i.e. a 1 stage process. </li></ul><ul><li>Base of skull is developed by intracartilaginious ossification i.e. is 2 stage process. </li></ul><ul><li>We cannot feel the weight of brain because it floats in the cerebrospinal fluid. </li></ul><ul><li>All joints are mostly sutures in skull; only a few are primary cartilaginous & 1 pair of synovial joint i.e. TMJ.This is the only mobile joint. </li></ul>
  5. 5. Introduction to skull <ul><li>Definition: skeleton of head is called skull. </li></ul><ul><li>Several bones joint together to form “cranium”. </li></ul><ul><li>Consist of overall 22 bones. </li></ul>
  6. 6. Skull is further divided into two parts: <ul><li>calvaria/ brain box. </li></ul><ul><li>Facial skeleton. </li></ul>
  7. 7. 1. calvaria/brain box <ul><li>Upper of cranium which encloses the brain. </li></ul><ul><li>Composes of the following “8” bones. </li></ul><ul><li>Paired bones </li></ul><ul><li>Parietal </li></ul><ul><li>Temporal </li></ul><ul><li>Unpaired bones </li></ul><ul><li>Frontal </li></ul><ul><li>Occipital </li></ul><ul><li>Sphenoid </li></ul><ul><li>ethemoid </li></ul>
  8. 8. 2. Facial skeleton <ul><li>rest of the skull excluding the calvaria along with the mandible. </li></ul><ul><li>Composed of 14 bones: </li></ul><ul><li>Paired bones </li></ul><ul><li>Maxilla </li></ul><ul><li>Zygomatic </li></ul><ul><li>Nasal </li></ul><ul><li>Lacrimal </li></ul><ul><li>Palatine </li></ul><ul><li>Inferior nasal cocha </li></ul><ul><li>Unpaired bones </li></ul><ul><li>Mandible </li></ul><ul><li>vomer </li></ul>
  9. 9. The face <ul><li>Facial vein communicates with the cranial venous sinuses. Thus infection from the face thus can each the brain. </li></ul><ul><li>The most dangerous area of the face is between the nasal opening and upper lip but the whole face is overall considered dangerous from the infection point of view. </li></ul>
  10. 10. The scalp <ul><li>The extent of scalp: </li></ul><ul><li>Anteriorly :extends from supra orbital margin </li></ul><ul><li>posteriorly:extends from external occipital protuberances and superior nucchal lines </li></ul>
  11. 11. Structure of the scalp <ul><li>Has 5 layers: </li></ul><ul><li>Skin: </li></ul><ul><li>Outermost layer </li></ul><ul><li>Thick and hairy </li></ul><ul><li>Contains large number of sebaceous glands hence liable to have sebaceous cyst </li></ul><ul><li>Richly supplied by blood vessels. </li></ul><ul><li>It is adherent to epicranial aponeurosis through the dense superficial fascia, as in palms and soles </li></ul>
  12. 12. <ul><li>Superiorficial fascia </li></ul><ul><li>Second layer </li></ul><ul><li>Dense and fibrous in middle and thin in the periphery. </li></ul><ul><li>It has vessels and nerves </li></ul><ul><li>Clinical significance: injury to scalp deep up to this layer causes profuse bleeding, bleeding can be arrested by pressing against the skull. inflammation of this layer causes little swelling and more pain. </li></ul>
  13. 13. <ul><li>3.Deep fascia(epicranial aponeurosis/galea aponeurotic) </li></ul><ul><li>Third layer </li></ul><ul><li>Freely movable on the pericranium along with the skin and superficial fascia </li></ul><ul><li>Anteriorly,it has insertion of frontalis muscle and posteriorly insertion of occipitalis and is attached to the external occipital protuberances and to the highest nuctal lines between occipital bellies. </li></ul><ul><li>Each side of aponeurosis is attached to the superior temporal line but sends a thin expansion to the temporal fascia and is attached to the zygomatic arch </li></ul>
  14. 14. <ul><li>4. Alveolar tissue </li></ul><ul><li>Fourth layer </li></ul><ul><li>Extends anteriorly to the eyelids because frontalis muscles doesn’t have any bony attachment;posteriorly to highest and superior nuchal lines and to the superior temporal fascia. </li></ul>
  15. 15. <ul><li>5. Pericranium </li></ul><ul><li>Fifth layer of the scalp </li></ul><ul><li>Loosely attached to the bone </li></ul><ul><li>But at the sutures it is firmly bounded with endocranium. </li></ul>
  16. 16. The scalp layers
  17. 17. Nerve supply (innervations) <ul><li>There are total 10 nerves which supplies scalp and temple. </li></ul><ul><li>5 nerves behind the auricle and 5 infront of the auricle. </li></ul>
  18. 18. <ul><li>5 nerves infront of the auricle are: </li></ul><ul><li>Supratrochelar nerve of the frontal.(optalmic division of the trigeminal nerve) </li></ul><ul><li>Supraorbital nerve of frontal.(optalmic dividion of trigeminal nerve) </li></ul><ul><li>Zygomaticotempral branch of zygomatic nerve(maxillary division of trigeminal nerve) </li></ul><ul><li>Auriculotemporal branch of the mandibular division of trigeminal nerve </li></ul><ul><li>Motor nerve:temporal branch of facial nerve </li></ul><ul><li>5 nerves back of the auricle: </li></ul><ul><li>Posterior division of great auricle nerve (C2,C3) from cervical plexus. </li></ul><ul><li>Lesser occipital nerve of C2 of cervical plexus. </li></ul><ul><li>Greater occipital nerve of division of C2of dorsal ramus </li></ul><ul><li>Third occipital nerve of C3 of dorsal ramus </li></ul><ul><li>Motor nerve:posterior auricular branch of facial nerve. </li></ul>
  19. 20. Arterial supply <ul><li>Two sets of arteries 5 on each side,3 are before backward auricle: </li></ul><ul><li>Pre auricular: </li></ul><ul><li>Supratrochelar –opthalmic branch of internal carotid sheath </li></ul><ul><li>Supraorbicular-opthalmic branch of internal carotid sheath </li></ul><ul><li>Superficial temporal-external carotid sheath </li></ul><ul><li>Two arteries behind the auricle: </li></ul><ul><li>Posterior auricular artery </li></ul><ul><li>Occipital artery </li></ul>