Posterior Triangle - Laboratory Identifications

Posterior Triangle - Boundaries and Superficial Veins

1. Superficial temporal v. - passing anterior to external auditory meatus
2. Retromandibular v. - deep to parotid gland, along ramus of mandible
3. Maxillary v. - posterior to neck of mandible, lateral confluence of pterygoid venous plexus
4. External Jugular v. - crossing the sternocleidomastoid
5. Subclavian v. - receiving external jugular, transverse cervical, and suprascapular veins
6. Supratrochlear v - connecting to angular vein (not easily demonstrated), important for possible spread of infection
7. Supraorbital v. - possible route of infection from face to orbit and cavernous sinus
8. Angular v. - possible route of infection from face to orbit and cavernous sinus
9. Infraorbital v. - possible route of infection from face to orbit and cavernous sinus
10. Facial v. - crossing mandible posterior to facial artery and at anterior edge of masseter
11. Internal Jugular v. - note possible communication with facial vein (common facial vein)
12. Anterior jugular v. - branch from facial vein or external jugular vein traveling through anterior triangle
13. Occipital v. - drainage of posterior scalp into external vertebral venous plexus
14. Posterior auricular v. - draining into retromandibular vein to mark beginning of jugular vein
15. Suprascapular v. - draining into external jugular vein
16. Transverse cervical v. - draining into external jugular vein

Posterior Triangle (and lateral face) - Nerves and Superficial Structures

1. Great occipital n. - traversing scalp medial to occipital artery
2. Lesser occipital n. - traversing posterior border of sternocleidomastoid (not crossing)
3. Great auricular n. - crossing sternocleidomastoid heading toward auricle, early branch to parotid region
4. Transverse cervical n. - crossing orthogonal to sternocleidomastoid toward skin of anterior triangle
5. Medial supraclavicular n. - coursing inferior toward sternum, branching from large nerve stalk of cervical plexus
6. Intermediate Supraclavicular n. - coursing inferior toward middle clavicle
7. Lateral supraclavicular n. - coursing inferior toward acromion
8. Spinal accessory n. (CN11) - crossing posterior triangle
9. Nerves surrounding orbital rim
   1. Infratrochlear n.
   2. Supratrochlear n.
   3. Supraorbital n.
   4. Lacrimal n.
   5. Zygomaticofacial n.
   6. Zygomaticotemporal n.
   7. infraorbital n.
   8. Dorsal nasal n. - difficult to find, know it is there and how it came to be there
10. Buccal n. (CN V3) (face) - medial to masseter

Posterior Triangle - Deep Structures

1. Splenius Capitis M. - making up superior floor
2. Levator Scapular M.- floor inferior to splenius capitus
3. Scalenus Posterior - floor inferior to levator scapular
4. Scalenus Medius - posterior border of interscalene triangle
5. Scalenus Anterior - anterior border of interscalene triangle
6. Subclavius - who cares
7. Spinal Accessory N. - entering posterior triangle from upper third of sternocleidomastoid
8. Ventral Root C5 - most superior ventral root in interscalene triangle, branch contributing to phrenic nerve
9. Ventral Root C6 - joined by C5 to form upper trunk brachial plexus
10. Ventral Root C7 - middle trunk
11. Ventral Root C8 - joined by ventral ramus T1 to form lower trunk brachial plexus
12. Spinal Accessory N. - crossing posterior triangle to enter onto anterior surface of trapezius
13. Dorsal Scapular N. - entering posterior triangle through middle scalene
14. Long Thoracic N. - entering posterior triangle through middle scalene, descending posterior to brachial plexus
15. Suprascapular N. - branching from upper trunk and coursing toward scapula
16. Phrenic N. - deep to prevertebral fascia on anterior surface of anterior scalene
17. Subclavian A. - parts one, two, and three
18. Thyrocervical Trunk - within vertebral triangle, distal to vertebral branch of subclavian
19. Transverse Cervical A. - crossing anterior scalene anterior to phrenic nerve
20. Dorsal Scapula A. - branch of transverse cervical artery
21. Suprascapular A. - crossing anterior scalene anterior to phrenic nerve and inferior to transverse cervical artery