1.2 Anterior triangle of neck

Question 1

what does the carotid triangle contains?

Answer 1

common carotid artery (which bifurcates into external and internal carotid arteries), IJV, hypoglossal (XII) and vagus (X) nerves

Question 2

what are the boundaries of the carotid triangle?

Answer 2

posterior belly of digastric, anterior border of SCM, superior border of omohyoid

Question 3

what does the muscular triangle contain?

Answer 3

infrahyoid (strap) muscles, the pharynx and the thyroid and parathyroid glands:

Question 4

what are the boundaries of the muscular triangle

Answer 4

midline of neck (media), superolateral (superior belly of omohyoid), inferolateral (inferior portion of SCM)

Question 5

what does the submental triangle contain?

Answer 5

submental lymph nodes (filter lymph from the floor of the mouth and parts of the tongue):

Question 6

what are the boundaries of the submental triangle?

Answer 6

hyoid bone (inferior), anterior belly of digastric (lateral), midline of neck (medial), base (mylohyoid muscle- runs from mandible to hyoid bone)

Question 7

what does the submandibular triangle contain?

Answer 7

submental lymph nodes (filter lymph from the floor of the mouth and parts of the tongue):, facial vessels

Question 8

what are the boundaries of the submandibular triangle?

Answer 8

superior (body of the mandible), anterior (anterior belly of digastric), posterior (posterior belly of digastric)

Question 9

what is the innervation of the infrahyoid (strap) muscles

Answer 9

• Omohyoid, sternohyoid, sternothyroid: Anterior rami of C1-C3 (branch of ansa cervicalis)
• thyrohyoid: anterior ramus of C1 (hypoglossal nerve)

Question 10

Thyroid surgeries of large goitres:

• to access the thyroid gland, the infrahyoid muscles must be divided (cut) as they lie superficial to the gland
• Must be cut at the _________________because the nerv e supply to these muscles are at the lower end –> avoid cutting the nerves

Answer 10

upper end (closer to the chin)

Question 11

what is the innervation of the suprahyoid muscles?

Answer 11

• mylohyoid: mylohyoid nerve (branch of inferior alveolar nerve- CN V3)
• anterior belly: mylohyoid nerve (CNV3)
• Posterior belly: facial nerve (CN VII)

Question 12

carotid sheath is a tubular fascial investment which extends from the cranial base to the root of the neck, surrounding the major vessels in the neck:
• From medial to lateral: common and internal carotid arteries (ECA pierces through sheath) → vagus nerve (CN X) → internal jugular vein (IJV)
• _________ is embedded in the anterior wall, while the ___________ lies posterior to the sheath

Answer 12

Ansa cervicalis;

cervical sympathetic chain

Question 13

where is the superior loop of ansa cervicalis fibers derived from and what does it supply

Answer 13

C1 fibres (accompanying hypoglossal nerve/CN XII before separating in the carotid triangle)
• Supplies superior belly of omohyoid, upper parts of sternothyroid and sternohyoid

Question 14

where is theinferior superior loop of ansa cervicalis fibers derived from and what does it supply

Answer 14

Derived from C2 – C3 fibres

• Supplies inferior belly of omohyoid, lower parts of sternothyroid and sternohyoid

Question 15

he common carotid arteries have different origins on the left and right side:
• Left CCA arises directly from the aortic arch (as the 2nd major branch), while the right CCA arises from the brachiocephalic trunk (bifurcates)
• Ascends in the carotid sheath (in carotid triangle) with IJV and vagus nerves (CN X)
• Bifurcates into the external (ECA) and internal (ICA) carotid arteries at the ___________________

Answer 15

upper border of the thyroid cartilage (level of C4)

Question 16

what are the external carotid artery branches in the neck

Answer 16

Superior thyroid artery
Ascending lingual artery
Lingual artery
Facial artery (tortuous cause in face) 
Occipital artery 
Posterior auricular artery
Maxillary artery
Superficial temporal artery

Question 17

carotid sinus

• where is it
• what does it do

Answer 17

• slight bulge at bifurcation of CCA and comencement of ICA
• contains baroreceptors (detects pressure changes in blood passing to brain)
• passes to medullary cardiovascular centre

Question 18

carotid sinus

• where is it
• what does it do

Answer 18

• Structure lying betwee
• Contains chemoreceptors (detect pH changes in blood passing to brain)
• Passes to medullary respiratory centre

Question 19

where can the carotid pulse be found?

Answer 19

anterior border of the SCM at the level of the superior border of the thyroid cartilage:

Question 20

what are the tributaries of the IJV

Answer 20

Middle thyroid vein (within the skull; site of IPSS for ACTH levels),
Superior thyroid vein
Lingual vein
Facial vein
Pharyngeal vein
Inferior petrosal sinus

Question 21

The IJV is crossed superficially by the_______________ at the upper end:
• Runs downwards deep to the SCM, and posterior to the ICA at the level of C2
• From the level of C4, it lies lateral to the ICA then CCA within the carotid sheath
• Vagus nerve lies deep to and in between the ICA/CCA and IJV in the carotid sheath

Answer 21

spinal accessory nerve (CN XI)

Question 22

Central line/central venous catheter is a catheter placed into a large vein to administer medications or fluids (cannot be orally administered or would damage a smaller peripheral vein), obtain blood tests, and measure central venous pressure:
• Typically inserted at the right/left IJV or the right/left subclavian veins
• IJV follows a line extending from the inferior aspect of the external acoustic meatus to the sternal end of the clavicle (passing between the ___________________) → landmark for insertion of central line

Answer 22

sternal and clavicular heads of SCM

Question 23

where are the horizontal groups of lymph nodes (from anterior to posterior)

Answer 23

submental, submandibular, pre-auricular/parotid, mastoid, occipital

Question 24

where are the superficial vertical lymph nodes?

Answer 24

Extend along the EJV; draining the parotid glands and lower parts of the ear into the deep cervical nodes

Question 25

where are the deep vertical lymph nodes?

Answer 25

Extend along the IJV from the base of skull to root of neck (drains superficial nodes):
• Jugulo-digastric nodes: along posterior belly of digastric muscle
• Jugulo-omohyoid nodes: at the intermediate tendon of omohyoid