The Neck

Lecture Objectives Define the boundaries of the neck. Describe the fasciae of the neck. Summarize the main arteries, veins, nerves and lymph nodes of the neck. List the muscles of the neck. Describe the neck triangles. Describe the key muscles creating the triangles, mainly, sternomastoid, omohyoid and digastric. Study the boundaries and content of each triangle.

Boundaries of the Neck Superior margin Inferior margin Root of the neck

Cervical Vertebral Muscles Suboccipital and deep neck muscles Mainly extends head and neck Rectus capitis posterior major m. Rectus capitis posterior minor m. Oblique capitis inferior m. Oblique capitis superior m.

Cervical Prevertebral Muscles Anterior vertebral muscles Mainly flexes head and neck Longus coli m. Longus capitis m. Rectus capitis anterior m. Anterior scalene m. Lateral vertebral muscles Mainly laterally flex head and neck Rectus capitis lateralis m. Splenius capitis m. Levator scapulae m. Middle scalene m. Posterior scalene m.

Cervical fascia Superficial fascia Deep fascia: Investing layer Pretracheal layer Prevertebral layer Carotid sheath

Cervical Fascia Superficial fascia Deep fascia: platysma Investing layer Trapezius & SCM Pretracheal layer Visceral part ‐ Thyroid & parathyroid Buccopharyngeal fascia ‐ pharynx Muscular part ‐ Infrahyoid mm.

Cervical Fascia Deep fascia (continue…) Prevertebral layer Posterior to pharynx & esophagus Vertebral mm. Continue as axillary sheath Carotid sheath Thickening of the other layers Common & internal carotid aa. Intrnal jugular v. Vagus n. Deep cervical lymph nodes

Cervical Fascia: Extensions Alar fascia Division from prevertebral fascia From skull to T2 (merge with buccopharyngeal fascia) Buccopharyngeal fascia Superior & posterior continuation of the pretracheal fascia

Cervical Fascia: Spaces Retropharyngeal space Between buccopharyngeal fascia and prevertebral fascia Spread of infections (Real) Retropharyngeal space Between the alar fascia and buccopharyngeal fascia Allow movement of pharynx, larynx, and trachea during swallowing Continuous with superior mediastinum to T2 Danger space Between the alar fascia and the prevertebral fascia Continuous with mediastinum

Neck Triangles: Boundaries Anterior triangle Anterior to SCM Carotid triangle Digastric triangle Submental triangle Muscular triangle Posterior triangle Posterior to SCM Anterior to trapezius Occipital triangle Supraclavicular triangle

Neck Triangles: Content

Sensory Innervations of the Neck

Root of the Neck

Arteries of the Head and Neck

Veins of the Head and Neck

Principal groups of lymph nodes Lymph drainage of Head and neck Regional lymph nodes Occipital Retroauricular Parotid Buccal Submandibular Submental Anterior cervical Laryngeal Tracheal Superficial cervical Deep cervical Jugular trunk

Occipital Triangle Above the inferior belly of omohyoid m. Spinal accessory nerve (XI) Junction of the superior & middle thirds of the posterior border of SCM → junction between middle & lower thirds of the anterior border of trapezius Injury

Anterior Triangle Carotid triangle Submandibular (digastric) triangle Carotid sheath Between sternocalvicular joint and the mid point between mastoid and angle of mandible Hypoglossal nerve Cervical sympathetic trunk Submandibular (digastric) triangle Submandibular gland Submandibular lymph nodes

Surface Anatomy of the Neck Hyoid bone – C3 Posterior to the mandible Laryngeal prominence (Adma’s apple)‐ tip (C4) Vocal cords – at the middle Cricoid cartilage – C6 Cricothyroid ligament Cricothyrotomy First tracheal cartilage Tracheostomy Thyroid gland Isthmus – 2nd – 4th tracheal rings

Tracheostomy