401: Dental Triangles of the Neck - Part 1&2

Hyoid bone (it attaches to the muscles)

What bone does not articulate with any other bone?

Hyoid bone

Identify the structure

Region from the inferior edge of mandible of the skull down to clavicles and scapula

What region is considered the "neck"?

C1-C7 spinal nerves pass above correspondingly numbered vertebrae. C8 passes below C7 vertebrae

C1-C7 spinal nerves pass ___________ correspondingly numbered vertebrae. C8 passes ___________ C7 vertebrae

Support the weight of the skull

Provide attachment of muscles that can move the head and skull around in space

What is the purpose of the 7 cervical vertebrae?

Cervical vertebrae are smaller and lighter because they do not support as much weight

How do the cervical vertebrae compare to the other vertebrae?

Bifid (split - all cervical split except for C7)

How would you describe the C4 vertebrae spinous process?

Vertebral foramen

Identify the bone marking at #1

Posterior arch

Identify the bone marking at #2

Spinous process

Identify the bone marking at #3

Transverse foramen

Identify the bone marking at #4

Vertebral body

Identify the bone marking at #5

Vertebral arteries to provide blood supply to brain

What runs through the transverse foramen?

Vertebral arteries

What does the red line indicate?

Dens

Identify the bone marking

C1 (atlas)

What vertebrae supports the weight of the skull?

Transverse process

Identify the marking at #1

Anterior arch

Identify the marking at #2

Articular surface for occipital condyle

Identify the marking at #3

Posterior arch

Identify the marking at #4

Transverse foramen

Identify the marking at #5

Vertebral foramen

Identify the marking at #6

Posterior tubercle

Identify the marking at #7

Anterior tubercle

Identify the marking at #8

C1 vertebrae does not have a vertebral body --> this is where the dens articulates

What does the dashed red line represent?

Dens

Identify the marking at #1

Articular surface for atlas

Identify the marking at #2

Spinous process

Identify the marking at #3

Atlas

What is the name of the C1 vertebrae?

Axis

What is the name of the C2 vertebrae?

Rotation point around which the atlas and skull can rotate as a unit

What is the purpose of the dens?

Primarily flexion/extension and lateral bending of skull of C1

What motion occurs at the atlanto-occipital joint?

Primarily rotation with some flexion/extension, lateral bending of C1 on C2

What motion occurs at the atlanto-axial joint?

Atlanto-occipital joint

What is the joint at #1?

Atlanto-axial joint

What is the joint at #2?

Foramen magnum

What is the red arrow pointing to?

Transverse ligament of atlas

What ligament is at #1?

Alar ligaments

What ligament is at #2?

Posterior longitudinal ligament (runs from the base of skull around foramen magnum and posterior vertebral bodies)

Identify the structure at #1

Cruciate ligament

Identify the structure at #2

Superior longitudinal band

Identify the structure at #3

Transverse ligament

Identify the structure at #4

Inferior longitudinal ligament

Identify the structure at #5

Alar ligaments

Identify the structure at #6

Superior longitudinal band

Transverse ligament

Inferior longitudinal ligament

What bands and ligaments make up the cruciate ligament?

Prevents hyper flexion of cervical column

What is the function of the posterior longitudinal ligament?

Nuchal ligaments

Identify the structure at #1

Supraspinous ligament

Identify the structure at #2

Interspinous ligament

Identify the structure at #3

Anterior longitudinal ligament

Identify the structure at #4

Vertebral artery

Identify the structure at #5

Posterior atlanto-occipital membrane

Identify the structure at #6

Forms septum in posterior neck and prevents hyperflexion of cervical vertebrae

What is the function of the nuchal ligament?

Prevent hyperflexion

What is the function of the supraspinous ligament?

Prevents hyperextension of cervical column

What is the function of the anterior longitudinal ligament?

Atlantoaxial joint

Identify the structure at #1

Lateral portion of C1 (atlas)

Identify the structure at #2

Equal in width and symmetry

As shown in red, how should the disc spaces be between cervical vertebrae?

Cervical spine injury (potentially whip lash)

- Vertebrae slip and stretch spinal cord

What clinical correlation is shown?

Mental process

Identify the structure at #1

Hyoid bone

Identify the structure at #2

Thyroid cartilage

Identify the structure at #3

Cricoid cartilage

Identify the structure at #4

Sternocleidomastoid m.

Identify the structure at #5

Trapezius m.

Identify the structure at #6

Supraclavicular fossa

Identify the structure at #7

Clavicle

Identify the structure at #8

Jugular notch

Identify the structure at #9

Sternum

Identify the structure at #10

1. Visceral compartment anteriorly

2. Bony-muscular compartment, posteriorly

3. 2 neurovascular compartments, laterally (cartoids, IJV, vagnus n.)

What are the three compartments of the neck?

Dens

What is shown at #1?

Investing fascia

Identify the fascia at #1

Superficial fascia

Identify the fascia at #2

Prevertebral fascia

Identify the fascia at #3

Carotid sheath

Identify the fascia at #4

Pretracheal (visceral) fascia

Identify the fascia at #5

Alar fascia

Identify the fascia at #6

Investing fascia

Identify the fascia at #1

Alar fascia

Identify the fascia at #2

Carotid sheath

Identify the fascia at #3

Prevertebral fascia

Identify the fascia at #4

Pretracheal fascia

Identify the fascia at #5

Superficial fascia

Identify the fascia at the star

Investing fascia

Identify the fascia at #1

Platysma muscle

Identify the structure at #2

SCM

Identify the structure at #1

External jugular v.

Identify the structure at #2

Posterior auricular v.

Identify the structure at #1

Retromandibular v.

Identify the structure at #2

External jugular v.

Identify the structure at #3

Internal jugular v. (deep to SCM)

Identify the structure at #4

Brachiocephalic v.

Identify the structure at #5

Subclavian v.

Identify the structure at #6

External jugular v.

What vein does the posterior auricular v. drain into?

External jugular v. (posterior division), Internal jugular v. (anterior division)

What vein does the retromandibular v. drain into?

Subclavian v.

What vein does the external jugular v. drain into?

Brachiocephalic v.

What vein does the subclavian v. drain into?

Brachiocephalic v.

What vein does the Internal jugular v. drain into?

External Jugular Vein Distention

What clinical correlate shows a markedly distended right external jugular vein (EJV) due to elevated central venous pressure (CVP)?