Head and Neck

Question 1

What are the borders and components of Scalene Triangle of the Neck

Answer 1

Borders: 1st rib, anterior and medial scenic muscles
Components: Brachial plexus and subclavian a.

Question 2

What is Thoracic outlet syndrome? What are the causes and symptoms?

Answer 2

Compression of the trunks of the
brachial plexus and the subclavian artery within the scalene triangle.

Causes:

• Pancoast tumor
• Cervical rib
• Hypertrophy of the scalene muscles

Symptoms:
• Numbness and pain on medial aspect of the forearm and hand
• Weakness of the muscles supplied by ulnar nerve in the hand (claw
hand)
• Decreased blood flow into upper limb, indicated by weakened radial
pulse

Question 3

What is the most significant artery of the

external carotid system?

Answer 3

Middle meningeal artery. It arises from the
maxillary artery in the infratemporal
fossa and enters the skull through the
foramen spinosum to supply skull and
dura. Lacerations of this vessel result
in an epidural hematoma.

Question 4

What are the components of Pharyngeal Apparatus of Embryo?

Answer 4

• Pharyngeal arches (1, 2, 3, 4, and 6) composed of mesoderm and neural crest
• Pharyngeal pouches (1, 2, 3, 4) lined with endoderm
• Pharyngeal grooves or clefts (1, 2, 3, and 4) lined with ectoderm

Question 5

What are the components of the pharyngeal arches?

Answer 5

1st arch: Trigeminal: mandibular nerve
Four muscles of mastication:
Plus:
• Digastric (anterior belly)
• Mylohyoid
• Tensor tympani
• Tensor veli palatini
Maxilla
Mandible
Incus
Malleus

2nd arch: VII nerve
Muscles of facial expression:
Plus:
• Digastric (posterior belly)
• Stylohyoid
• Stapedius
Stapes
Styloid process
Lesser horn and upper body of hyoid bone

3d arch: IX nerve 
Right and left common carotid arteries
Right and left internal carotid arteries
Stylopharyngeus muscle 
Greater horn and lower
body of hyoid bone

4th arch: X nerve:
– Superior laryngeal nerve
– Pharyngeal branches
Right subclavian artery (right arch)
Arch of aorta (left arch)
Cricothyroid muscle
Soft palate
Pharynx (5 muscles)
Thyroid cartilage

6th arch: X nerve
Recurrent laryngeal nerve
Right and left pulmonary arteries
Ductus arteriosus (left arch)
Intrinsic muscles of larynx
(except cricothyroid muscle)
All other laryngeal cartilages

Question 6

What are the Adult Structures Derived From the Fetal Pharyngeal Pouches?

Answer 6

1st pouch: Epithelial lining of auditory tube and middle ear cavity
2nd pouch: Epithelial lining of crypts of palatine tonsil
3d pouch: Inferior parathyroid (IP) gland, Thymus (T)
4th pouch: Superior parathyroid (SP) gland, C-cells of thyroid

Question 7

How does thyroid gland develop?

Answer 7

It develops from the thyroid diverticulum, which forms from the midline endoderm in the floor of the pharynx.
• The thyroid diverticulum migrates caudally to its adult anatomic position in the neck but remains connected to the foregut via the thyroglossal duct, which is later obliterated.
• The former site of the thyroglossal duct is indicated in the adult by the foramen cecum.

Question 8

How is tongue innervated?

Answer 8

Sensory:
Post. 1/3: general sensation - IX, taste - IX
Ant. 1/3: general sensation - V (mandibular), taste - VII (chorda tympani)

Motor: XII

Question 9

When does cleft lip and cleft palatine occur?

Answer 9

Cleft lip: the maxillary prominence fails to fuse with the medial nasal prominence
Cleft palatine: the palatine shelves fail to fuse with each other or the primary palate

Question 10

What is First arch syndrome?

Answer 10

Abnormal formation of pharyngeal arch 1 because
of faulty migration of neural crest cells, causing facial anomalies. Two well-described syndromes are Treacher Collins syndrome and Pierre Robin sequence. Both defects involve neural crest cells

Question 11

What is Treacher Collins syndrome?

Answer 11

Mandibular hypoplasia, zygomatic hypoplasia, down-slanted palpebral fissures, colobomas, and malformed ears

Question 12

What is Pierre Robin sequence?

Answer 12

Triad of poor mandibular growth, cleft palate, and a posteriorly placed tongue

Question 13

When does pharyngeal fistula occur?

Answer 13

When pouch 2 and groove 2 persist, thereby forming a fistula generally found along the anterior border of the muscle

Question 14

When does pharyngeal cyst occur?

Answer 14

When pharyngeal grooves that are normally obliterated persist, forming a cyst usually located at the angle of the mandible

Question 15

When does ectopic thyroid, parathyroid, or thymus occur?

Answer 15

Results from abnormal migration of these glands from their embryonic position to their adult anatomic position. Ectopic thyroid tissue is found along the midline of the neck. Ectopic parathyroid or thymus tissue is generally found along the lateral aspect of the neck. May be an important issue during neck surgery

Question 16

Whe does thyroglossal duct cyst or fistula occur?

Answer 16

Occurs when parts of the thyroglossal duct persist, generally in the midline near the hyoid bone. The cyst may also be found at the base of the tongue (lingual cyst).

Question 17

When does jugular foramen syndrome occur? What are the symptoms and which CN are altered?

Answer 17

May be caused by a tumor pressing on CN IX, X, and XI. Patients present with hoarseness, dysphagia (CN IX and X), loss of sensation over the oropharynx and posterior third of the tongue (CN IX), and trapezius and sternocleidomastoid weakness (CN XI). The nearby CN XII may be involved, producing tongue deviation to the lesioned side.

Question 18

What are the Cranial Meninges?

Answer 18

• pia mater ( cannot be dissected)
• arachnoid (lines the inner surface of dura mater)
• dura mater
  v periostal layer (can be easily pealed away)
  v meningeal layer (fused with periostal layer, they form the dural venous sinuses and connective tissue foldings:)
  1) fall cerebri
  2) diaphragma sellae
  3) tentorium cerebelli

Question 19

What are the potential cranial spaces?

Answer 19

• epidural: between periostal layer and bone
• subdural: between meningeal layer and arachnoid
• subarachnoid: between arachnoid and pia mater

Question 20

Which important structures pass through cavernous sinus and could be damaged if there is sinus thrombosis? Which CN is affected the first?

Answer 20

• III CN
• IV CN
• VI CN (is affected the first)
• V CN (Ophtalmic and maxillary)

Question 21

Which vessels are altered if there is Epidural Hematoma? What is the radiological sign of it?

Answer 21

• middle meningeal a. (branch of maxillary a. of I. carotid a.)
• lens-shaped on X-Ray

Question 22

Which vessels are altered if there is Subdural Hematoma? What is the radiological sign of it?

Answer 22

• bridging veins

- crescent-shaped on X-Ray

Question 23

Which vessels are altered if there is Subarachnoid Hemorrhage?

Answer 23

Aneurism of Willi’s circle (usually anterior part)