Nasal Septum: Anatomy

Nasal septum consists of three parts:
1. Columellar septum. It is formed of columella
containing the medial crura of alar cartilages united
together by fibrous tissue and covered on either side by
skin.
2. Membranous septum. It consists of double layer
of skin with no bony or cartilaginous support. It lies
between the columella and the caudal border of septal
cartilage. Both columellar and membranous parts are
freely movable from side to side.
3. Septum proper. It consists of osteocartilaginous
framework, covered with nasal mucous membrane.
Its principal constituents are:
(i) the perpendicular plate of ethmoid
(i i) the vomer, and
(iii) a large septal (quadrilateral) cartilage wedged
between the above two bones anteriorlv. Other
bones which make minor contribution- at the
periphery are: crest of nasal bones, nasal spine of
frontal bone, rostrum of sphenoid, crest of palatine
bones and the crest maxilla, and the anterior nasal
spine of maxilla.
Septal cartilage not only forms a partition between the
right and left nasal cavities but also provides support to the
tip and dorsum of cartilaginous part of nose. Its destruction,
e.g. in septal abscess, injuries, tuberculosis or excessive
removal during septal surgery, leads to depression of lower
part of nose and drooping of the nasal tip .
Septal cartilage lies in a groove in the anterior edge of
vomer and rests anteriorly on anterior nasal spine. During
trauma, it may get dislocated from anterior nasal spine or

vomerine groove causing caudal septal deviation or septa
spur respectively. This compromises the nasal airway.
Septal cartilage is also intimately related to the upper lateral
cartilages of nose and is in fact fused with them in the
upper third. For this reason septal deviation may be associated
with deviation of cartilaginous part of external nose.

Blood Supply:

Internal Carotid System
(a) Anterior ethmoidal artery} Branches of ophthalmic
(b) Posterior ethmoidal artery artery
External Carotid System
(a) Sphenopalatine artery (branch of maxillary artery)
gives nasopalatine and posterior medial nasal
branches.
(b) Septal branch of greater palatine artery (Br. of maxillary
artery).
(c) Septal branch of superior labial artery (Br. of facial
artery) .

Nerve supply:

Nasal septum is supplied by branches of sphenopalatine ganglion and the anterior ethmoidal nerve.

Little's area or Kiesselbach's plexus: This is the vascular
area in the antero-inferior part of nasal septum ju •
above the vestibule. Anterior ethmoidal, sphenopalatine
greater palatine and septal branch of superior labial arteries
and their corresponding veins form an anastomostis
here. This is the commonest site for epistaxis. This is also
the site for origin of the "bleeding polypus" (haemangioma)
of nasal septum.