Nasal Septum

INTRODUCTION:
  • The nasal septum separates the left and right airways in the nose, dividing the two nostrils.
  • It is depressed by the depressor septi nasi muscle
DEVELOPMENT:
  • At an early period the septum of the nose consists of a plate of cartilage, the ethmovomerine cartilage.
  • The postero-superior part of this cartilage is ossified to form the perpendicular plate of the ethmoid; its antero-inferior portion persists as the septal cartilage, while the vomer is ossified in the membrane covering its postero-inferior part.
  • Two ossification centers, one on either side of the middle line, appear about the eighth week of fetal life in this part of the membrane, and hence the vomer consists primarily of two lamellae.
  • About the third month these unite below, and thus a deep groove is formed in which the cartilage is lodged.
  • As growth proceeds, the union of the lamellae extends upward and forward, and at the same time the intervening plate of cartilage undergoes absorption.
  • By the onset of puberty the lamellae are almost completely united to form a median plate, but evidence of the bilaminar origin of the bone is seen in the everted alae of its upper border and the groove on its anterior margin.
ANATOMY:
  • Columellar septum
  1. It is formed of columella
  2. Containing the medial crura of alar cartilages united together by fibrous tissue
  3. Covered on either side by ski
Membranous septum:
  1. It lies b/w columella and caudal border of septal cartilage No bony or cartilaginous support Above two parts freely movable from side to side 
Septum proper:
  • Consist of osteocortilaginous frame work
  • Its main Constitutes are:-
  1. Perpendicular plate of ethmoid
  2. vomer bone
  3. Large septal cartilage (quadrilateral) wedged between the above two bones anteriorly
  • Minor contributions
  1. Crest of nasal bone
  2. Nasal spine of frontal bone
  3. Rostum of sphenoid
  4. Crest of palatine bone
  5. Crest of maxilla and anterior nasal spine of maxilla
BLOOD SUPPLY:
ARTERIAL SUPPLY:

  • Internal carotid system:
  1. Branches of opthalmic artery
  2. Anterior ethmoidal artery 
  3. Post ethmoidal artery 

  • External carotid artery system:

  1. Spheno palatine artery (maxillary)
  2. Nasopalotine branches
  3. Post nasal septal branches
  4. Septal branch of great palatine artery (maxillary)
  5. Septal branch of superior labial artery(Facial) 
LITTLE’S AREA (KIESSEL BACH’S PLEXUS)
  • Most common cause for nose bleeding is trauma to little's area
  • Most common site for nose bleeding in children
  1. Anterior ethmoidal
  2. Septal branch of supeior labial
  3. Septal branch of sphenopalotine
  4. Septal branch of greater palatine
VENOUS DRAINAGE:

  • Posteriorly through sephenopalatine veins into pterygoid venous plexus
  • Anteriorly drain into facial veins
  • Superiorly in ethmoidal veins
NERVE SUPPLY OF NASAL SEPTUM:
  • Olfactory nerves

  1. Carry sense of smell
  2. Supply olfactory region of nose
  3. Can Carry sheath of dura, archnoid and pia matter

  • Nerves of common sensation

  1. Anterior ethmoidal nerve
  2. Branches of nasopalatine nerve
  3. Branches of infra orbital nerve 

  • Autonomic nerve:
  1.  Parasympathetic nerve fibers supply nasal glands and control nasal secretions
  2. Greater superfacial petrosal nerve. Sympathetic nerve fibers
  3. Upper two thoracic segments
  4. Deep petrosal nerve 
LYMPHATIC DRAINAGE:
  • Submandibular lymph nodes
  • Rest of nasal cavity drain into upper jugular nodes directly or through retropharyngeal nodes 
Exam Question
  • Kiesselbach's area or little's area involves 4 arteries anastomosis that are Anterior ethmoidal,Septal branch of supeior labial,Septal branch of sphenopalotine & Septal branch of greater palatine Anterior ethmoidal artery supplying nasal septum is a branch of opthalmic artery
  • Kisselback's plexus is situated on the nasal septum
  • Structures that forms nasal septum are columella, Membranous septum, ethmoid, vomer bone, septal cartilage, Crest of nasal bone, Nasal spine of frontal bone,Rostum of sphenoid, Crest of palatine bone & Crest of maxilla and anterior nasal spine of maxilla
  • Ethmoid, vomer bone,nasal bone,frontal bone,sphenoid, palatine bone & maxilla are the bone contributing in formation of nasal septum.
  • Anterior half of the nasal septum drain to the submandibular node
  • Most common cause for nose bleeding is trauma to little's area
  • Most common site for nose bleeding in children is little's area

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