W6: Blood supply

Question 1

What are the main arteries supplying blood supply to the head and neck?

Answer 1

Arterial supply to the headand neck is via the carotid (internal and external) and vertebral arteries

Question 2

Describe the pathway of the carotid arteries, including the where the divison occurs.

Answer 2

Common carotid arteries ascend through the neck, lateral to the oesophagus and trachea in the carotid sheath. They divide into the external and internal carotid arteries near the upper border of the thyroid cartilage.
Internal carotid- ascends upwards to the base of the skull and enters through the carotid canal in the petrous temporal bone. It gives off no branches in the neck
External carotid artery- begins giving off branches immediately after bifurcation - 8 branches

Question 3

*Know the eight branches of the ext. carotid

Answer 3

S: superior thyroid artery.
A: ascending pharyngeal artery.
L: lingual artery.
F: facial artery.
O: occipital artery.
P: posterior auricular artery.
M: maxillary artery.
S: superficial temporal artery.

Question 4

Describe the pathway of the lingual artery and what it supplies

Answer 4

Lingual artery arises at about the level of the hyoid bone. Supplies suprahyoid muscles, muscles of the tongue and floor of the mouth. Also sublingual salivary gland and mucous membranes of the floor of the mouth.

Question 5

The ____ artery is the largest terminal branch of the ext.carotid and the most important for dentists.

Answer 5

The maxillary artery is the largest terminal branch of the ext.carotid and the most important for dentists.

Question 6

Describe the pathway of the Maxillary artery and what it supplies

Generally

Answer 6

It arises within the the parotid gland. It is the major source of blood supply for the nasal cavity, the lateral wall and roof of the oral cavity, all teeth and dura mater in cranial cavity
Its branches usually follow the same pathways as the nerves

Question 7

Describe the pathway of the facial artery and what it supplies

Answer 7

Facial artery has a tortuous course, running medially to the mandible, around the inferior border the upwards towards the medial canthus of the eye. Supplies face in oral, buccal, zygomatic, nasal, infraorbital and orbital regions. Essentially, tissues in the face from the inferior border of the mandible, anterior to masseter to the medial corner of the eye ,including muscles of the soft palate and submandibular salivary gland

Question 8

Describe the pathway of the superficial temporal artery and what it supplies

Answer 8

Question 9

List the first of the three parts/branches of the Mx artery and what it supplies

Answer 9

Mandibular: 1st part before the lateral pterygoid. Branches enter bone.
Middle meningeal to dura through through foramen spinosum.
Inferior alveolar- mandibular foramen, branch to mylohoid runs in the mylohyoid groove

Question 10

List the second of the three parts/branches of the Mx artery and what it supplies

Answer 10

Not associated with teeth, but supplies muscles of mastication
The branches of the second (pterygoid) part provide blood to the four pairs of muscles of mastication

Question 11

Describe the blood supply to the 3 glands

Answer 11

Parotid: Posterior auriscular, External carotid, Mx artery, Superficial temporal, Transverse facial
SubMd: Lingual, Facial
Sublingual: Sublingual + Submental

Question 12

List the thrid of the three parts/branches of the Mx artery and what it supplies

Answer 12

Maxillary teeth are supplied by the third (pterygopalatine) part of the maxillary artery. The posterior superior alveolar aa supplies the molars. Whilst in thein infraorbital foramen the infraobital artery gives off the middle and anterior superior arteries that supply the premolars and anterior teeth respectively
Descending palatine artery supplies some nasal mucosa before emerging onto the palate as greater palatine artery (through greater palatineforamen).
Sphenopalatine artery is an end branch of the maxillary, and supplies nasal cavity

Question 13

List the structures the Occipital and Post. Auricular arteries supply

Answer 13

Question 14

Describe the innervation of the Salivary glands

Answer 14

Secretomotor, parasympathetic submandibular gland (from VII)-forsublingual and submandibular glands. Parotid innervated by fibres from IX (NB cranial outflow: III, VII, IX, X)

Question 15

Describe the blood supply to the teeth

Answer 15

The first and third parts of the Mx artery (mandibular and pterygopalatine) are involved with blood supply to the mandibular and maxillary teeth respectively.

Question 16

List the veins contributing tot he venous drainage of head and neck especially around orofacial region.

Answer 16

These include (but are not limited to) maxillary vein, pterygoid plexus, retromandibular and facial veins, ext. and int. jugular

Question 17

Describe the venous drainage from the scalp, orbits and muscles of facial expression including mouth
Describe the clinical implications

Answer 17

Second major vein of interest to dentists is the facial vein. This drains into the internal jugular vein and begins at the medial corner of the eye
there is an anastomosis with the ophthalmic veins which connect with intracranial structures, especially the cavernous sinus

Question 18

Describe the venous drainage from the teeth and adjacent tissues (lips and muscles around the mouth, lips, post nasal cavity and palate).
Describe the clinical implications

Answer 18

into the pterygoid plexus of veins- located between lateral and medial pterygoid muscles. These veins drain into the maxillary vein which joins the superficial temporal vein within the parotid to form the retromandibular vein-> external jugular -> subclavian (some into internal jugular -> braciocephalic)

Pterygoid plexus has numerous small emmissary veins which pass though F. ovale, spinosum, cartilage of lacerum etc. This is a potential route of infection, also LA injected into veins in the plexus can back flow into the cranial cavity

Question 19

Veins usually travel with arteries. There are no valves in facial veins- therefore infection can travel in either direction. Which two veins are the exception to this?

Answer 19

Angular and inferior ophthalmic