I — Sternocleidomastoid; 2 — Clavipectoral triangle; Deltopectoral triangle; 3 — Pectoral fascia; 4 — Nuchal fascia; 5 — Cervical fascia, investing layer; superficial layer; 6 — Submandibular gland; 7 — Platysma; 8 — Hyoid bone; 9 — Internal jugular vein; 10 — External carotid artery;
II — Carotid sheath; 12 — Laryngeal prominence; 13 — Omohyoid; 14 — Cervical fascia, pretracheal layer; 15 — Cervical fascia, prevertebral
layer