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Case based learning triangles of neck region
1. Case based learning
Triangles of neck region
By
Dr. Abdul Waheed Ansari
Chairperson & Prof. Anatomy,
RAK COLLEGE OF MEDICAL SCIENCES
RAKMHSU.
12/18/2014 1
2. The learning outcomes for this CBL are
• The effects of compression of the neurovascular
bundle of neck is usually involved in masses arising
from the triangles of neck.
• The effects of injuries to hypoglossal, accessory,
vagus, glossopharyngeal, lingual branch of
trigeminal.
• The involvement of cervical groups of lymph nodes
during infections and inflammations of salivary
glands, oral cavity and tongue.
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3. Neck region is divided into anterior and posterior
triangles with the help of sternocleidomastoid muscle
• The posterior triangle is
bounded by sternomastoid,
clavicle, trapezius and mastoid
process.
• The anterior triangle is having
sternomastoid,midline and
base of mandible.
• The anterior triangle is further
subdivided into sub mental,
submandibular, muscular and
carotid triangles.
• The contents of these triangles
are glands, vessels and nerves.
• Tumors arising from neck area
will be pressing these
neurovascular elements.
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4. A Clinical case of inflamed palatine tonsil
• A 5 year old girl was taken to the primary health
care physician with complaints of sore throat,
running nose and high temperature.
• Her mother also complained that she had
difficulty in swallowing.
• Physician examined her throat and found that the
tonsils were enlarged and congested.
• Which groups of lymph nodes often becomes
easily palpable when palatine tonsils are inflamed?
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5. Cervical groups of lymph nodes
• The head and neck areas are drained by superficial and deep cervical
groups of lymph nodes.
• These lymph nodes are situated in superficial and deep fascia in a cervical
collar distribution.
• The head area above the parotid gland is drained into preauricular or
parotid group of lymph nodes.
• Below this the lymphatic's reach the submandibular group of lymph
nodes.
• From the central area of face and tongue the lymph is drained in to sub
mental group of nodes.
• The palatine tonsils lymphatic reach the deep cervical-jugulo-digastric
group of lymph node.
• From the posterior aspect of scalp it reaches, mastoid group, occipital
group or posterior auricular group.
• The supraclavicular group of lymph nodes receive lymph from various
abdominal organs- malignancy arising from stomach & uterus may have
supraclavicular lymph nodes enlargements.
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7. A clinical case of spinal accessory
nerve injury
• An abscess was surgically removed from the middle
of the posterior triangle on the right side.
• During recovery the patient noticed that her
shoulder drooped and she could no longer raise her
right hand above her head to brush her hair.
• Which nerve has been cut?
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9. The accessory nerve is the XI cranial
nerve
• It arises from its nucleus in brain stem- the nucleus
ambiguous.
• The accessory nerve has two roots, a cranial root and
a spinal root.
• The spinal accessory enters the cranial cavity through
foramen magnum and joins the cranial root and leave
the cranial cavity through the foramen rotundum.
• In the neck it supplies the sternomastoid and trapezius
muscles.
• It runs in the posterior triangle of neck.
• Injury to this nerve leads to drooping of the shoulder.12/18/2014 9
10. Congenital torticollis is wry neck- a clinical
condition due to tumor of sternomastoid
• Spasmodic Torticollis (ST) is
a painful and debilitating
neurological movement
disorder.
• Approximately 3 in every
10,000 people – about
90,000 people in the United
States – are known to suffer
from ST.
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11. The cervical plexus are formed under the
posterior triangle
• The following nerves arise
from the cervical plexus:-
1.Lesser occipital nerve
2.Great auricular nerve
3. Transverse cervical nerve
4. Supraclavicular nerves
• The lesser occipital nerve carry
sensations from the occipital
area of scalp.
• The great auricular nerve carries
sensation from areas around
parotid gland.
• The transverse cervical nerve
carries sensation from midline to
the sternal notch/jugular notch.
• The supraclavicular nerves carry
sensation from chest wall until
the sternal angle.12/18/2014 11
12. Superficial cervical plexus is seen emerging behind the posterior border of the
sternocleidomastoid muscle at the intersection of the muscle with the external jugular
vein
• 1. transverse cervical nerve
• 2. lesser occipital nerve
• 3.supraclavicular nerves
• 4. external jugular vein.
• 5. Greater auricular nerve.
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13. A clinical case of
mumps
• A mother brings her 5 year
old son to pediatric
hospital with complains of
her son having fever and
swelling around his neck.
• The pediatrician informed
her that her son is having
mumps infection.
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14. A submandibular triangle
1 = digastric m., 2 = submandibular
gland; 3 = lingual a., 4 = hypoglossal n.;
5 = mylohyoid m.; 6 =stylohyoid m.;
7 = facial artery
Is bounded by the mandible above
and the digastric muscle below.
Contents are:-
• Submandibular gland and duct
• Hypoglossal (XII)
• Mylohyoid ( V3)
• Lingual nerve (V3)
• Ganglion submandibulare
• Facial artery, which passes behind
submandibular gland and gives the
sub mental branch
• Lingual artery
• Facial vein, which passes in front
of submandibular gland
• Submandibular lymphatic nodes
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15. The hypoglossal nerve is a XII cranial, motor nerve to muscles of
tongue
• The hypoglossal nucleus is
situated in the floor of VI ventricle-
medulla.
• The nerve exits through the
hypoglossal foramen and runs
below the tongue in the
submandibular triangle and
supplies the musculature of
tongue.
• Injury to the hypoglossal nerve will
deviate the tongue towards the
side of lesion.
• Left hypoglossal nerve injury and
paralysis of the left side of the
tongue.
• A month before this picture was taken,
this patient's left hypoglossal nerve
was injured during surgery on his
carotid artery (carotid
endarterectomy).
• This was immediately followed by
deviation of the tongue to the same
side as the injury.
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16. The lingual nerve is a branch from
trigeminal nerve
• It is a sensory nerve to anterior 2/3rd
of tongue and carries general
sensation of touch, pain and
temperature.
• The special sensation of taste from
anterior 2/3rd of tongue is carried by
chorda tympani branch of facial nerve.
• The chorda tympani nerve joins the
lingual nerve in the infratemporal
fossa.
• The chorda tympani nerve also carry
secretomotor fibers for submandibular
and sublingual salivary glands.
• The lingual nerve can be injured
during tooth extraction.
• As a result of injury taste and general
sensation from anterior 2/3rd tongue
will be lost.
There will be Loss of secretion from
submandibular and sublingual glands
ipsilateral to the lesion apart from Loss of
taste from anterior 2/3 of tongue
ipsilateral to the lesion.
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17. The carotid triangle of neck
• It is bounded by the:
• Superior belly of the omohyoid
muscle
• Posterior belly of the digastric muscle
• Anterior edge of the
sternocleidomastoid muscle
• floor: portion of the thyrohyoid,
hyoglossus and inferior and middle
constrictor muscles
• Contents are parts of the common
and internal carotid A., external
carotid A. and 3 of its branches and
corresponding tributaries of the
internal jugular V.
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18. The carotid vessels are the main blood
vessels for brain, head and neck areas.
• The left common carotid arises from arch
of aorta.
• The right is a branch from brachiocephalic
trunk.
• The common carotid vessel is enclosed in
carotid sheath ( which is a modified deep
fascia of neck). The other structures
enclosed in the carotid sheath are internal
carotid artery, internal jugular vein and
vagus nerve.
• The common carotid divides into external
and internal branches at the level of upper
border of thyroid cartilage.
• There are 8 branches arising from
external carotid, 2 terminal branches, 2
dorsal branches and remaining 4 are
ventral branches.
• The internal carotid enters the cranial
cavity to supply the brain through the
carotid canal, that passes through the
petrous temporal bone.
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20. 12/18/2014 20
• A 68-year-old female noticed a 2.5 x 1.5 cm neck lump
superficial to the left sternocleidomastoid (SCM) muscle.
• Relevant past medical history included a lumpectomy for
malignant breast neoplasm in 2003.
• Ultrasound confirmed a solid lesion superficial to the left
SCM.
• CT showed an enhancing lobulated mass lesion splaying the
left internal and external carotid artery and compressing the
left internal jugular vein, it extended posteriorly curling
behind the SCM muscle and terminated in a superficial
component overlying the muscle.
• In view of her previous history of breast carcinoma core
biopsy was performed with histology suggestive of metastatic
carcinoma possibly a neuroendocrine tumour.
• Immunohistochemistry confirmed neuroendocrine
differentiation typical for paraganglioma.
• Twenty four hour urinary catecholamine studies were normal.
21. The glossopharyngeal nerve is a mixed
cranial nerve
• It carries motor fibers to the sphincters
of pharynx and sensations-both
general and special sensation of taste
from posterior 1/3rd of mucus
membrane of tongue.
• It has sensory nucleus arising from
nucleus of tractus solitarius from the
brain stem.
• The motor fibers are arising from
nucleus ambiguues from medulla.
• The glossopharyngeal nerve leaves
the cranial cavity from jugular foramen.
• It is vulnerable for injury during
tonsillectomy, as posterior to the
tonsillar fossa this nerve is related and
may get injured during surgery.
• As a result of such injury there will be
loss of general and taste sensation
from posterior 1/3rd of tongue along
with dysphagia problems.
• Cranial Nerve 9 Dysfunction: Patient has
suffered stroke, causing loss of function of
left CN 9. As a result, uvula is pulled
towards the normally functioning (ie right)
side.
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22. The muscular triangle
• The boundaries of the muscular
triangle are:
• Superiorly: The hyoid bone
• Medially: Imaginary midline of
the neck
• Supero-laterally: Superior belly
of the omhyoid muscle
• Infero-laterally: Inferior portion
of the sternocleidomastoid
muscle.
• It does however contain some
muscles – the infrahyoid
muscles, the pharynx, and the
thyroid, parathyroid glands.
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23. The submental triangle
• The submental triangle in the
neck is situated underneath
the chin.
• Its main content is the
submental lymph nodes,
which filter lymph draining
from the floor of the mouth
and parts of the tongue.
• It is bounded:
Inferiorly – Hyoid bone.
Medially – Imaginary sagittal
midline of the neck.
Laterally – Anterior belly of the
digastric.
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