Ppt of anatomy of neck & ML imp

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  • The anatomy of the neck.
  • Ppt of anatomy of neck & ML imp

    1. 1. Anatomy of Neck & itsMedicolegal importance.Presenter Dr Gopal G HargiPG in FM& T
    2. 2.  Neck is a very prominent & vital part .Eventrivial injuries can cause death withoutshowing any signs. There are very vitalstructures in a relatively small & unprotectedanatomic region making it very vulnerable tofatal injuries. Moreover the Neck is an area which can beeasily grasped and immobilized
    3. 3. Anatomy and Physiology
    4. 4.  Lower border of mandible lies b/w C2 & C3. The front of the lower pharynx & upperoesophagus lie the larynx & trachea. On each side of the pharynx is the carotidsheath,containing the common & internalcarotid arteries & the IJV with the cervicalsympathetic trunk behind it. The Platysma –a broad flat sheet of musclelies superficial to the layers of fascia.
    5. 5.  Coll’s fascia :The space among the structures ofneck are filled with loose areolar tissue.Thestructures of the neck are mostly supplied to moveup & down .This fascia is a laminar condensation of looseareolar tissue in neck produced by the movementsof these structures. These laminar condensations take different namesin different regions & are continuous with eachother or indirectly. These loose areolar tissue form sheaths whichenclose muscles and their moving structures
    6. 6. MODIFICATIONS/LAMINAE/EXTENSIONS OF DEEPCERVICAL FASCIAHAS 7 MODIFICATIONS1. INVESTING LAYER2. PRETRACHEAL LAYER3. PREVERTEBRAL LAYER4. CAROTID SHEATH5. BUCCOPHARYNGEAL FASCIA6. TEMPORAL FASCIA7. PHARYNGOBASILAR FASCIA
    7. 7. INVESTING LAYER ATTATCHMENTS ABOVE- EXTERNAL OCCIPITAL PROTUBERANCE,MASTOID PROCESS, EXTERNAL ACOUSTICMEATUS, BASE OF THE MANDIBLE BELOW- SPINE OF SCAPULA, ACROMION PROCESS, CLAVICLE, MANUBRIUM STERNI FRONT- HYOID BONE & CONTINUOUS WITH THE FASCIA OF THE FASCIA OF THE OPPOSITESIDE BEHIND- 7TH CERVICAL VERTEBRA, LIGAMENTUM NUCHAE
    8. 8.  CCA ,arises from the left side of AOA. It lies in the medial part of carotid sheath . Upper border of C4 the CCA bifurcates. The carotid pulse can be felt by pressing againstthe anterior tubercle of the tranverse process ofC6 vertebra. ICA ,at its commencment there is a bulge , here the arterial wall is thin & contains thebaroreceptors which is supplied by the 9th & 10thnerves which control the CVS . carotid body is a small structure behind thebifurcation of CCA & contains baroreceptors whichmaintain oxygen saturation.
    9. 9.  IJV forms a jugular arch in the suprasternalspace i.e between the sternal & clavicularhead of sternocleadomastoid tendon. Larynx lies below the hyoid bone in themidline of the neck at the level of C4-C6vertebra.
    10. 10.  The AJV commences beneath the chin & passesdownwards ,side by side beneath the platysma tothe suprasternal region.Here they pierce the deepfascia & come to lie in the suprasternal space. Carotid sheath consists of a network of areolartissue that surrounds the carotidarteries(c&i),IJV,Vagus nerve & some deep cervicallymph nodes. It is thin where it overlies the IJV ,allowing thevein to dilate during increased blood flow.
    11. 11.  The thyroid gland is situated low down at the frontof the neck.The 2 symmetrical lobes are connectedby isthmus which lie in front of 2nd,3rd & 4thtracheal rings. Trachea begins at the level of C6 vertebra incontinuity of the larynx,The cervical part lies inthe midline of the neck ,in contact with the frontof the oesophagus. Oesophagus commences in continuity with thepharynx at the level of lower border of the cricoidcartilage(C6).
    12. 12.  Hyoid bone lies free ,suspended by muscles & sovery mobile .Above its attached to floor of mouth &tongue,larynx below,behind to epiglottis &pharynx.It lies at the level of C3 vertebra. Vertebral artery arises from subclavian artery &passes up to traverse the foramen of transverseprocess of upper 6 cervical vertebras.On emergingfrom foramen the artery enters the skull throughforamen magnum .It pierces the spinal dura mater & archnoid and atthe lower border of pons forms the basillar artery.
    13. 13.  For judging the severity of the injuries to the neckits divided into 3 zones. Zone I• highest mortality Zone II• most frequent site of injury• lower mortality Zone III• neurological• distal carotids• pharyngeal injuries
    14. 14. Zones of the Neck
    15. 15.  (Zone 1)Thoracic inlet (clavicle)to cricoidcartilagesignificant injury in the zone I region may be hiddenfrom inspection of the chest or the mediastinum. subclavian vessels brachiocephalic veins common carotid artery jugular vein aortic arch Trachea esophagus Lung apices c spine spinal cord CN roots
    16. 16. Zone 2 Carotid and vertebralarteries jugular veins pharynx larynx trachea esophagus c spine spinal cordCricoid cartilage to angle of mandible
    17. 17. Zone 3 Salivary glands parotid gland esophagus trachea c spine Carotid arteries jugular veins CN IX - XIIAngle of mandible to base of skull
    18. 18.  Injury above the level of C4 –rapid death Due to disruption of CV centre. Causes- Hyperextension & hyperflexionAtlanto-occipital injury---fatal: widening of spacewith some blood palpated as ‘loosening ‘Of the junction with widening.Severe form thearticulating condyles of atlas can be seen withinforaen magnum.C1-C2 injury-- neurogenic shock ,odontoin is #C2-C3 #( HANGMAN #) rapid
    19. 19.  Injuries over the region of neck A) Homicidal: a)strangulation i)Ligature ii) Manual c)bansdola e)mugging f)penetrating injuries a) knife b) gunshot g)cut throat injuries h)blunt force impact i) homicidal ii) accidental
    20. 20.  Blunt force impact to the side of neck Shearing excessive rotation/ hyperextension◦ distention and stretching Tearing of Vertebral Artery The carotids too get dissected ,veins damaged Blood tracks along upper part of vessel & entersthe cranial cavity producing massive SAH .
    21. 21. Impact Anterior Neck Impact Anterior Neck Crush larynx or trachea; cricoid ring compress esophagus against spinal column sudden increased intratracheal pressure againstclosed glottis (seatbelt), crush bruise (clotheslinetackle) rapid acceleration/ deceleration results in trachealinjury
    22. 22.  B) Suicidala)Hanging b)postural asphyxiation◦ children with neck over object and body weight producescompression C)Accidentali)carotid sleepers ii)bar arm control a)choking b)RTA : rapid deceleration  hyperflexion,hyperextension, and rotation  vascular structuresare stretched over the cervical spine  shearingforces create intimal tears in the vessel wallc)toxic gas inhalation D)Judicial or justified hanging
    23. 23. Cause of death in hanging Asphyxia Venous congestion Cerebral oedema # vertebra Significant cervical spine and spinal cord damagecan occur in hangings that involve a fall from adistance greater than the body height.Cause of death in strangulation Vagal inhibition Asphyxia Cerebral anoxia & Venous congestion
    24. 24.  Other consequences of Neck TraumaSubcutaneous emphysema Tension pneumothorax Traumatic asphyxia◦ Penetrating Trauma Esophagus or Trachea Vagus nerve disruption◦ Tachycardia & GI disturbances Thyroid & Parathyroid glands◦ High vascular
    25. 25.  More than 95% of penetrating neck wounds resultfrom guns and knives, with the remainder resultingfrom motor vehicle accidents, householdinjuries, industrial accidents, and sporting events gun shot wound (GSW) sustain greater injury thanthose with stab wounds because of a bullets abilityto penetrate deeper and cause cavitation, thusdamaging structures lying outside the tract of themissile. Injury to the blood vessels can also result fromexternal compression or mural contusion. Thrombosis is the most common complication ofblood vessel injury, occurring in 25-40% ofpatients.
    26. 26.  Blunt trauma to the neck typically results frommotor vehicle crashes but also occurs with sports-related injuries (eg, clothesline tackle),strangulation, blows from the fists or feet, andexcessive manipulation In motor vehicle crashes, thrusting forward withthe head extended, forcing the anterior neckagainst the steering column. Cerebral vessel andlaryngeal injuries secondary to shoulder strapcompression have occurred. Direct forces can shear the vasculature producingshearing damage and resultant thrombosis
    27. 27.  Laryngotracheal Injuries in BNT Although not prevalent, it is second to onlyintracranial injury as the most common cause ofdeath among patients with head and neck traumaand is a clinically important injury.◦◦ 60% of all external laryngotracheal traumas are due toblunt neck trauma. The final common pathway of laryngotrachealinjury is compressive force on the larynx leads toinjury. This is modified by the degree of laryngealcalcification present;
    28. 28.  Dissection of neck Before exploring the neck the thorax and theskuull should be opened and the viscera removed After cutting the skin ,the ant cervical strapmuscles are cut and examined Expose the thyroid cartilage & trachea Following this ,the tongue ,hyoid bone & the larynxare removed as unit. Examine the hyoid bone after separating fromthyroid cartilage & soft tissues removed See for periosteal haemorrhages & # .Palpate the sup horn of thyroid cartilage .Examinelamina of thyroid cartilage & cricoid cartilage forinjury. Open thyroid cartilage posteriorly & examinemucosa of larynx
    29. 29.  Triticeous cartilage are little cartilaginousnodules embedded in the thyroidhyoidligsment .These may be confused with a # ofsuperior horn of thyroid cartilage Thank You

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