Anatomy of the Neck Flashcards
what are the two main triangles in the neck
posterior and anterior triangle
describe the borders of the posterior triangle
- Posterior border of sternocleidomastoid
- Anterior border of trapezius
- Middle 1/3 of clavicle
describe the borders of the anterior triangle
– Midline of neck from chin to jugular notch
– Anterior border of sternocleidomastoid
– Lower border of mandible and beyond to mastoid process
what are the important structures inside the posterior triangle
- Spinal accessory nerve (CN XI)
- External jugular veins runs superficially over SCM
- Lymph nodes
- Part of subclavian artery
- Brachial plexus, cervical plexus, phrenic nerve
where is the prominence of the external jugular vein
- usually visible above the clavicle for short distances - less than 4cm above the sternal angle
- it disappears as it runs over the SCM
when does the external jugular vein become more prominent
• Become more prominent when you have Heart failure, SVC obstruction, enlarged supraclavicular lymph nodes, raised intra-thoracic pressure
what does the external jugular vein helps assess
• The EJV helps assess mean right arterial pressure which is identical to central venous pressure
what does the spinal accessory supply
• Somatic motor fibres to accessory muscles of breathing (SCM and trapezius)
where is the spinal accessory
- nerves forms from C1-5 spinal cord rootlets
• Ascend into cranial cavity via foramen magnum
• Exit through the jugular foramen
the spinal accessory nerve is a purely..
motor neurone
recent evidence regarding the spinal accessory nerve
Recent evidence suggests that the accessory nerves lacks a cranial root and has no connection to the vagus nerve but needs confirmation
what happens if there is spinal accessory nerve damage
- Weakened shrugging shoulder, atrophy of trapezius, drooping of shoulder
- Passive shoulder movements within normal range
- Uni-lateral lesion usually does not produce an abnormal head position
- Weakeness in turning head to opposite side against resistance
what can cause spinal accessory nerve damage
- Subcutaneous course – injury lymph node surgery
where is the cervical plexus to and from
C1-C4
what is the anasa cervicalis
- prat of the cervical plexus
- C1-C3
- it is the motto to the infra hyoid muscles
describe the branching of the cervical plexus
- Cutaneous branches emerge around middle of the posterior border of SCM
- Phrenic nerve C3-C4) picks up additional C5 roots
- Descend down obliquely with IVJ cross the anterior scalene and passes into thorax
what are the 4 parts of the anterior triangle
submandibular, carotid, muscular and submental
describe the 4 parts of the anterior triangle
a. Submandibular (digastric) -submandibular gland fills most of triangle, hypoglossal nerve, parts of facial artery and vein
b. Carotid – anatomically important with a lot of structures
c. Muscular – sternohyoid, thyrohyoid and sternothyroid (infrahyoid muscles). Thyroid and parathyroid glands
d. Submental – floor of mouth – mylohyoid
what is the hyoid bone
– attachment point for infrahyloid muslces and muscles that are supporting the jaw of the mouth
what are the boundaries of the carotid triangle
- Posterior belly of digastric
- Superior belly of omohyoid
- Anterior border of SCM
what goes through the carotid triangle
Blood vessels
- Common carotid artery
- Internal and external carotid arteries
- Intenral jugular vein
Nerves • Glossopharyngeal • Vagus • Spinal accessory • Hypoglossal • Cervical sympathetic trunk • Ansa cervicalis
what are the carotid carotid triangle contents
- Common carotid – at anterior border of SCM at level of the thyroid cartilage
- Carotid bifurcation – superior border thyroid cartilage
- Carotid sinus (IX) baroreceptors
- Carotid body (IX X) chemoreceptors – carry the information via glossophargenal and vagus to measure carbon dioxide and oxygen content of the blood
the internal carotid has..
no branches until it enters the skull
what does the external carotid supply
blood supply to the face, neck and skull, inside of the skull and the dura