2. BRANCHIAL OR PHARYNGEAL ARCHES:
Intimately related to
dev. of many str. In
head & neck
Transient embryonic
structures
Undergo substantial
remodelling
3. EMBRYOLOGY OF BRANCHIAL APPARATUS:
Develops around 5-5
WOG
Consists of 5 to 6 pairs
of finger like masses,
branchial arch
Seperated externally
by indentations,
branchial cleft
Pharyngeal pouches
are outpouchings from
foregut region
4.
5. Each arch has its own
1. Central cartilaginous
or skeletal elements
2. Muscular component
3. Aortic arch artery
4. Arch associated CN.
6. DERIVATIVES:
Derivatives of arches, clefts and pouches are
distinct.
To generalise:
• Arch m/s, bones or similar mesodermal
derivatives
• Pouch glandular or str. ass/w digestive tract
14. ANOMALIES OF BRANCHIAL APPARATUS:
Predisposed d/to
complicated
morphodynamics of
branchial arch region
Abnormalities from minor
cyst to major orofacial
malformation
May present as
1. Cyst: seperated & failed
to resorb
2. Sinus: failed to resorb
3. Fistula: persistence of
both cleft and pouch
15. THEORIES OF ORIGIN OF BRANCHIAL CYST:
1. Branchial apparatus theory
2. Cervical sinus theory
3. Thymopharyngeal duct theory
4. Inclusion theory (most accepted)
16. FIRST BRANCHIAL ANOMALIES
Uncommon 1 to 4%
Two types:
Type I:
-ectodermally derived
-duplication of the
external auditory canal
Type II:
-contain both ectoderm
and mesoderm
-hence may contain skin,
adnexa and cartilage
-extends betn mandible
& EAC
17. Clinical features:
• as cyst/sinus/fistula
betn EAC &
submandibular area
• drainage from pit-like
depression at angle of
the mandible
• inflammatory mass in
parotid region
• auricular symptoms &
otorrhoea
18. On CT cystic mass
superficial/within/deep
to parotid salivary
gland
19. Treatment:
• Usu. do not regress & prone to recurrent infection,
hence surgical excision.
• Requirements:
EUM for sinus opening in floor
identification and preservation of the VIIn
partial parotidectomy
excision of skin and cartilage of EAC around the
tract
20. FIG: Resection of cyst by superficial parotidectomy,
exposing VIIn and its branches
21. SECOND BRANCHIAL ANOMALIES:
>90% of branchial anomalies
communicate with oropharynx via
supratonsillar fossa
Cyst>sinus>fistula
Types of second branchial cyst:
23. Clinical features:
• Smooth, soft masses in
lat neck, ant & deep to
SCM (cyst)
• Clear fluid &
transillumiates
• Recurrent neck
infection, often after
URTI (fistula)
• Pain, dyspnoea,
dysphagia
25. Treatment:
• Surgical excision under
GA.
• transverse cervical
incision at level of hyoid
bone + any skin sinuses
in an ellipse of skin
• may require step-ladder
incisions for exposure
• Tract ligated at PBD
• If int opening is present,
tract dissected upto
pharyngeal constrictor
and ligated & divided
• Tonsillectomy may be
required if tract ends in
supratonsillar fossa
26. THIRD BRANCHIAL ANOMALIES:
Ext: as in 2nd
Int: piriform sinus
Course:
• deep to third arch str
(CN IX, carotid vessels)
• superficial to fourth
arch str (SLN, CN XII)
Cysts, lower in neck
than second branchial
cyst
27. Clinical feature: can manifest with
• upper airway compromise in the neonate (large cysts)
• hypoglossal nerve palsy (if infected)
• neck abscess or
• retropharyngeal abscess
28. Investigations:
• Gas in region of upper
pole of thyroid gland
abutting pyriform fossa
on ultrasound or CT is
pathognomonic of 3rd
or 4th branchial
anomalies.
• Fluoroscopic or CT
sinogram/ fistulogram
(course of a tract)
30. Treatment:
• Resection via transverse skin crease incision or via
thyroidectomy approach
• Surgeon should be prepared to have to identify the
RLN & to do partial thyroid lobectomy
• SLN should be preserved superiorly
31. FOURTH BRANCHIAL ANOMALIES:
int: apex piriform sinus
translaryngeal course
under thyroid ala,
beneath inferior
constrictor
exits near cricothyroid
joint, superficial to RLN
& terminates in ant.inf.
region of the neck
32. Clinical features: May
present with
• suppuratuve thyroiditis
• neck abscess
• retropharyngeal
abscess
Investigations: as for
third branchial
anomalies
33. Treatment:
• Excision of cyst and/or
fistula, often combined
with partial
thyroidectomy
• Endoscopic
cauterisation
• Chemocauterization
with 40%
trichloroacetic acid
(TCA) (less invasive and
proposed as 1st line treatment)
34. OTHER CONGENITAL ANOMALIES ASSOCIATED
WITH BRANCHIAL APPARATUS:
Treacher collin
syndrome:
• AD, mutation in chr. 5
• Failed migration of neural
crest cells in 1st branchial
arch.
• sunken cheeks,
• small lower jaw and chin
(micrognathia)
• absent or unusually
formed ears
• downward slanting eyes
• cleft palate may present
35. Pierre Robbins
syndrome:
• Maldevelopment of 1st
pharyngeal arch
• Esp. lower jaw
(micrognathia)
• May have breathing
problem.
36. Hemifacial
microsomia:
• Malformation of 1st
branchial arch and
sometimes 2nd.
• Only one side of face
affected
• TMJ, mastication m/s,
mandible and ear are
often underdeveloped
Fifth and six are rudimentary and not visible on the surface of embryo
It runs parallel to the ear canal and may have a fistula terminating in the postauricular or pretragal regions. It generally does not involve the VIIn. Treatment is by surgical excision of the cyst or fistula and of involved skin and cartilage of the external auditory canal.
It extends between the angle of the mandible and the external auditory canal. The cyst or the external opening is typically located in the neck superior to the hyoid bone i.e. the next branchial arch
A true fistula would follow the course of the recurrent laryngeal nerve around the aorta (left) or subclavian artery (right), to then ascend superficial to the recurrent laryngeal nerve in the paratracheal region; this has never been reported in practice. It then passes behind the thyroid ala and opens into the apex of the pyriform fossa;