Lab 21 - Neck & Carotid Sheath

Suggested readings from
Gray's Anatomy for Students, 2nd ed.
Ch. 8, 947-984
Suggested readings from Langman's Medical Embryology:
11th ed - Ch. 16 (Head & Neck): pp. 265-287
12th ed - Ch. 17 (Head & Neck): pp. 260-282

Pre-lab exercise

Before coming to the lab study the cross-section through the neck shown below.

We will discuss this in lecture as well.  This will help you think about what to expect as you dissect this crowded region of the body.

Distinguish the following components:

  1. The outer wrapping of the skin and the cutaneous nerves and vessels.
  2. The vertebral column.
  3. The complex of epaxial muscles.
  4. The three muscle groups representing remnants of the hypaxial musculature:
    1. The rectus cervicis muscle group (equivalent to the rectus abdominis muscle), which includes the geniohyoid, omohyoid, sternohyoid, sternothyroid, and thyrohyoid muscles.
    2. The scalene muscles (cervical equivalents of the intercostals in the thorax and the obliquus muscles in the abdomen).
    3. A layer of long and short prevertebral muscles running along the ventral surface of the neck vertebrae.
  5. The cervical gut and gut derivatives: the pharynx, esophagus, trachea, and the glands of the neck.
  6. The muscles of the pharyngeal arches wrapped around the gut tube.
  7. The facial muscles of the second arch, which spread out beneath the skin of the face, scalp, and neck The slightly deeper sternocleidomastoid and trapezius muscles.

1. Bony landmarks of the neck
Skeletal landmarks in the head and neck are used for locating major blood vessels, glands, muscles, and for locating points of access to the airway. Neurological examination of the cranial and upper cervical nerves is carried out by assessing function in the head and neck. In addition, information about the general status of body health can often be obtained by evaluating surface features, the eye, the oral cavity, and the characteristics of speech.

2. How to outline the anterior and posterior triangles of the neck
The boundaries of the anterior and posterior triangles on each side of the neck are easily established using readily visible bony and muscular landmarks.

Anterior triangles: the base is the inferior margin of the mandible, the anterior margin is the midline of the neck, and the posterior margin is the anterior border of the sternocleidomastoid muscle. The apex points inferiorly and is at the suprasternal notch. The anterior triangles are associated with structures such as the airway and digestive tract, nerves, and vessels that pass between the thorax and head. They are also associated with the thyroid and parathyroid glands.

Posterior triangles: the base is the midline 1/3 of the clavicle, the medal margin is the posterior border of the sternocleidomastoid muscle, and the lateral margin is the anterior border of the trapezius muscle. The apex points superiorly and is immediately posteroinferior to the mastoid process. The posterior triangles are associated with nerves and vessels that pass into and out of the upper limbs.


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