Triangles of Head and Neck

Question 1

What are triangles of the neck?

Answer 1

• anatomical spaces bounded by muscles and bone
• surgical reference spaces
• used to describe the position of lymph nodes, palpable masses

Question 2

Anterior triangle (anterior cervical region) divisions

Answer 2

• submental
• submandibular
• carotid
• muscular

Question 3

Posterior triangle (lateral cervical region) divisions

Answer 3

• occiptal
• subclavian (supraclavicular)

Question 4

Posterior triangle boundaries

Answer 4

• posterior: trapezius muscle
• anterior: sternocleidomastoid muscle
• inferior: clavicle

Question 5

Posterior triangle contents (muscles)

Answer 5

• levator scapula
• splenius capitis
• anterior, middle and posterior scalenes
• inf. belly of omohyoid
  
  • divides posterior triangle into occipital triangle and supraclavicular triangle

Question 6

Posterior triangle contents (nerves)

Answer 6

• spinal accessory nerve (CN XI)
• roots of brachial plexus
• suprascapular nerve
• cutaneous branches of cervical plexus:
  
  • supraclavicular nerve
  • great auricular nerve
  • lesser occipital nerve
  • transverse cervical nerve
• phrenic nerve

Question 7

Posterior triangle contents (vessels)

Answer 7

• external jugular
• subclavian vein
• subclavian a. (and branches)
• transverse cervical and suprascapular arteries

Question 8

Sternocleidomastoid (SCM) muscle attachments

Answer 8

• sterno-sternum
• cleido-clavicle
• mastoid-mastoid process

Question 9

Sternocleidomastoid muscle functions

Answer 9

• bilateral: neck flexion, extends head
• ipsilateral: turns head in opposite direction, ipsilateral flexion

Question 10

Erb’s point

Answer 10

cutaneous branches (GSA) from the cervical plexus (VPR’s, C1-C4)

Question 11

Anterior cervical triangle divisions

Answer 11

• submental
• submandibular
• carotid
• muscular

Question 12

Anterior cervical triangle boundaries

Answer 12

• posterior: SCM
• anterior: midline of neck
• superior: inferior border of mandible

Question 13

Anterior cervical triangle contents

Answer 13

• Suprahyoid
  
  • mylohyoid
  • digastric
  • stylohyoid
  • geniohyoid
• Infrahyoid
  
  • sternohyoid
  • sternothyroid
  • thyrohyoid
  • omohyoid

Question 14

Hyoid Complex contains

Answer 14

• infrahyoid muscles= “strap muscles”
• suprahyoid muscles

Question 15

Infrahyoid muscles

Answer 15

• sternohyoid m.
• sternothyroid m.
• thyrohyoid m.
• omohyoid m.
• concentric contractions depress hyoid and larynx
  
  • speaking, pharyngeal phase of swallowing
• isometric/eccentric contractions stabilize hyoid
  
  • allows suprahyoid muscles to depress mandible

Question 16

Suprahyoid muscles

Answer 16

• mylohyoid m.
• digastric m.
• stylohyoid m.
• geniohyoid m.
• concentric contractions:
  
  • if hyoid is fixed by infrahyoid mm.: depress mandible
  • if mandible is fixed by masticatory mm.: elevate hyoid