2. Blood, Lymph, and Osteology of the Head and Neck Flashcards
(138 cards)
1
Q
What is the main blood supply to the head and neck through?
A
Common carotid arteries and vertebral arteries.
2
Q
What is the main venous drainage of the head and neck via?
A
Internal jugular vein. External jugular vein and anterior jugular vein draining superficial structures.
3
Q
What do the major blood vessels supplying and draining the head and neck make up?
A
The upper systemic vascular loop.
4
Q
What is the carotid sheath?
A
A fascial envelope of areaolar tissue.
5
Q
What does the carotid sheath enclose?
A
Common carotid artery, internal jugular vein, vagus nerve (CN X).
6
Q
Where is the carotid sheath found?
A
Deep to the sternocleidomastoid muscle.
7
Q
What is the carotid sheath derived from?
A
Fusion of: the prevertebral layer of cervical fascia posteriorly + the pretracheal layer of cervical fascia anteromedially + the superficial layer of cervical fascia anterolaterally.
8
Q
What do the common carotid artery, internal jugular vein, and vagus nerve lie within the carotid sheath?
A
Artery is medial, vein is layer, and nerve is between and posterior to the two vessels.
9
Q
What lies outside the carotid sheath, medially and posterior to it?
A
Sympathetic trunk.
10
Q
Where does the right common carotid artery originate from?
A
Bifurcation of the brachiocephalic trunk behind the right sternoclavicular joint.
11
Q
What does the left common carotid artery originate from?
A
The arch of the aorta, it courses for 2cm in superior mediastinum before entering the neck.
12
Q
Where do the common carotids terminate?
A
Midway between the angle of the mandible and the mastoid process of the temporal bone - upper border of the thyroid cartilage.
13
Q
Where is the carotid sinus given rise to?
A
Where the common carotids dilate and then bifurcate into internal and external carotid arteries at C4.
14
Q
Where are the baroreceptors?
A
The carotid sinus, detects changes in blood pressure.
15
Q
What is a carotid massage?
A
Gentle rubbing of the carotid sinus that alleviate supra-ventricular tachycardia.
16
Q
What is the location of the peripheral chemoreceptors?
A
The carotid body, detects arterial O2 concentrations.
17
Q
Why is the carotid artery bifurcation a common site for atheroma formation?
A
Narrowing/stenosis of the artery.
18
Q
What is a potential sequelae of carotid artery atheroma?
A
Rupture of the clot causing the embolus to travel to the brain in transient ischaemic attack or stroke.
19
Q
How can the internal carotid artery be distinguished from the external?
A
Internal has no branches in the neck and enters the skull through the carotid canal. The external has 8 branches to the extra-cranial structures of the head and neck.
20
Q
What are the eight branches of the external carotid artery?
A
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Superior thyroid, ascending pharyngeal, lingual, facial, occipital, posterior auricular, maxillary, superficial temporal.
21
Q
What happens to the external carotid artery in the parotid gland?
A
It divides into the maxillary and superficial temporal arteries, accompanied by the facial nerve (CN VII) and retromandibular vein.
22
Q
Where do the vertebral arteries arise from?
A
The subclavian arteries on the left and right, ascend through the transverse foramen in cervical vertebrae 6 to 1.
23
Q
What do the vertebral arteries supply?
A
The brain along with the internal carotid arteries.
24
Q
What is the carotid triangle a subdivision of?
A
The anterior triangle of the neck.
25
What are the boundaries of the carotid triangle?
Superiorly - posterior belly of the digastric.
Laterally - sternocleidomastiod.
Medially - superior belly of omohyoid.
26
What are the contents of the carotid triangle?
Carotid sheath with common carotid artery, internal jugular vein, vagus nerve, and deep cervical lymph nodes; thyroid gland; larynx; pharynx; external carotid artery and some branches; hypoglossal and spinal accessory nerve; branches of cervical plexus.
27
What are the layers of the scalp?
SCALP: skin, connective tissue (dense), aponeurosis, loose connective tissue (with blood vessels), periosteum.
28
What is the blood supply to the scalp?
Rich with many anastomoses. From branches of external carotid arteries (superficial temporal, posterior auricular, occipital), supratrochlear and suborbital arteries (branches of opthalmic arteries, arise from internal carotid arteries).
29
Why does the scalp bleed profusely?
It has numerous anastomoses and walls of arteries are closely attached to connective tissue, limiting their constriction.
30
Why do deep laceration involving the epicranial aponeurosis cause profuse bleeding?
Opposing pull of occipitofrontalis.
31
Why does loss of blood to the scalp not lead to underlying bone necrosis?
The skull has a different blood supply, mostly from the middle meningeal artery.
32
What is the venous drainage of the scalp?
Superficial temporal veins, occipital veins, posterior auricular veins. Some deep parts drain into the pterygoid venous plexus.
33
Where do supraorbital and supratrochlear veins drain?
Untie at medial angle of eye to form angular vein then drains into facial vein.
34
How do the veins of the scalp connect to veins of the skull?
Connect to diploic veins of skull via valve-less emissary veins so connect to dural venous sinuses.
35
How can infection spread from scalp to meninges?
Through the dural venous sinuses, there is a relationship between scalp to skull then to cranial cavity.
36
What is the arterial supply of the dura and skull?
Anterior and posterior branches of the middle meningeal artery, branch of maxillary artery, which is a branch of external carotid artery.
37
How can extradural haemorrhage occur?
From fracture at the pterion of the skull as the middle meningeal artery runs close to here and this would cause bleeding deep to the cranium but superficial to the dura.
38
What are craniotomies?
Bone and skin flap are reflected inferiorly to preserve blood supply but gain access into the cranial cavity.
39
What are the dural venous sinuses?
Endothelium-lined space between the periosteal and meningeal layers of the dura which form at the dural septae and receive blood from large veins that drain the brain.
40
What are the veins that drain the brain and form dural venous sinuses?
Superior sagittal sinus, inferior sagittal sinus, cavernous sinus, sigmoid sinus (continues as internal jugular veins and exits skull through jugular foramen), and transverse sinus.
41
What is the arterial supply to the face?
All superficial arteries arise from external carotid artery, except supraorbital and supratrochlear (from internal carotid via opthalmic artery). Facial, superior and inferior labial, maxillary, lateral nasal, angular, transverse facial.
42
What is the distribution of supply of the facial artery?
Muscles of facial expression and face.
43
What is the distribution of supply of the superior and inferior labial artery?
Upper lip, side and septum of nose, lower lip.
44
What is the distribution of supply of the maxillary artery?
Deep structure of the face.
45
What is the distribution of supply of the lateral nasal artery?
Skin on ala and dorsum of nose.
46
What is the distribution of supply of the angular artery?
Superior cheek and lower eyelid.
47
What is the distribution of supply of the transverse facial artery?
Facial muscles and skin of temporal frontal and temporal regions.
48
What is the distribution of supply of the supratrochlear artery?
Muscles and skin of forehead and scalp, superior conjunctiva.
49
What is the distribution of supply of the supraorbital artery?
Muscles and skin of forehead and scalp, superior conjunctiva.
50
What is the venous drainage of the face?
Veins accompanying the arteries of the face. They drain into the facial vein, drains into internal jugular vein.
51
What is the cavernous sinus?
Plexus of extremely thin-walled veins on the upper surface of the sphenoid bone.
52
What is in the cavernous sinus?
Veins, internal carotid artery, oculomotor nerve CNIII, trochlear nerve CNIV, abducens CNVI, trigeminal CNV (1 opthalmic and 2 maxillary).
53
Do the veins of the face have valves?
No.
54
Which veins communicate at the medial angle of the eye?
Facial vein and superior opthalmic vein, drain into cavernous sinus.
55
Where does the deep facial vein drain?
Into the pterygoid plexus.
56
What is the clinical relevance of the deep facial vein draining into the pterygoid plexus?
Infection can travel from facial vein to dural venous sinuses. Thrombophlebitis of facial vein (infected clot can travel to intracranial system).
57
Where does the internal jugular vein lie?
Under the sternocleidomastoid.
58
What is a good indicator of the pressure in the right atrium and how can this be assessed?
The internal jugular vein. View pulsations of vein through sternocleidomastoid muscle. Use right IJV and lie patient at 45 degree angle with head turned to the left. Observe from 5cm height from sternal angle.
59
What are the regional groups of the lymph nodes of the head?
Occipital, retroauricular, parotid, buccal, submandibular, submental, anterior, cervical, superficial cervical, retropharyngeal, laryngeal, tracheal.
60
What is the terminal group of lymph nodes of the head?
Deep cervical nodes which receive all afferent lymph vessels of the head and neck directly or indirectly via one of the regional groups.
61
What are the four lymph nodes of the deep cervical nodes terminal group, their position and what they drain?
Jugulo-digastric/tonsillar node - below and behind angle of the mandible, drain tonsil and tongue.
Jugulo-omohyoid/tongue node - drain tongue, oral cavity, trachea, oesophagus, and thyroid gland.
Posterior triangle - along course of accessory nerve.
Supraclavicular nodes - root of neck, drain thorax and abdomen.
62
What are Virchow's nodes?
Enlarged supraclavicular nodes associated with gastric carcinoma.
63
What do the efferent lymph vessels from deep cervical nodes join to form?
The jugular lymph trunks.
64
What happens on the left side of the jugular lymph trunk?
Joins the thoracic duct, enters left brachiocephalic vein at junction between subclavian and internal jugular veins.
65
What happens on the right side of the jugular lymph trunk?
It enters the venous system at the junction between the subclavian and internal jugular veins via right lymphatic duct.
66
What is the thoracic duct?
Body's main duct for return of lymph to venous blood.
67
Where does the thoracic duct run from and to?
Abdomen at cisterna chyli L2, it runs for 38-45cm long. Extends vertically in chest and curves posteriorly to left common carotid artery and left internal jugular vein.
68
Where does the thoracic duct empty?
Into the left brachiocephalic vein at the junction between the subclavian and internal jugular veins at left venous angle.
69
What does the right lymphatic duct drain?
Upper right side of the body - right side of head and neck, right upper limb, right thorax.
70
What does the right lymphatic duct drain into?
Junction of subclavian vein and internal jugular vein at right venous angle.
71
What is lymphadenopathy?
Enlargement of lymph nodes due to infection or malignancy.
72
How can the cause of lymphadenopathy be distinguished?
Infection - tender, smooth.
| Malignancy - non-tender, craggy.
73
What is glandular fever?
Epstein Barr Virus (EBC) where viral infiltrate produces atypical lymphocytes.
74
What are the symptoms of glandular fever?
Swollen, painful lymph nodes, sore throat, fatigue, fever.
75
What is lymphoma?
Solid tumour of lymphoid cells - B or T cells, originating in lymph node (primary).
76
What are the most common head and neck cancers?
Squamous cell carcinomas, 90%.
77
What are squamous cell carcinomas associated with?
Alcohol, smoking, HPV.
78
What is the presentation of squamous cell carcinomas?
Lymphadenopathy/mass in the neck, sore throat, dysphagia, hoarseness.
79
How is squamous cell carcinoma of the head and neck diagnosed?
Fine needle aspiration cytology/biopsy.
80
How is cervical metastases managed?
Surgical block dissection of the cervical nodes - removal of internal jugular vein, fascia, lymph nodes, and submandibular salivary gland.
81
What are the two main functions of lymph nodes?
Phagocytic cells act as filter for particular matter and micro-organisms, antigens present to immune system.
82
What is the structure of a lymph node?
Fibrous capsule with trabecular extending to centre forming a framework. Node is made of lymphatic sinuses, blood vessels, parenchyma (cortex, paracortex, medulla).
83
What happens with B cells in the cortex of lymph nodes?
B cells enter the lymph node via post-capillary venules with high endothelial venules (HEV) and pass to follicles. They either pass out rapidly and return to circulation with lymph if unstimulated of proliferate and stay in node if activated by antigenic stimulation.
84
What are follicle centre cells?
Activated B cells within the lymphoid follicles.
85
What is the structure of follicle centre cells?
Cleaved nuclei or more open/several nuclei. Pale staining central area of secondary follicle - germinal centre, surrounded by mantle zone of small, naive B cells and a few T cells.
86
What happens to stimulated B cells?
They proliferate and undergo somatic hypermutation and are selected for high affinity antibodies to the antigen displaced by follicular dendritic cells. They take up antigen, process, and present to T cells.
87
How do T cells respond to antigen presentation by B cells?
They promote development of B cells by releasing cytokines IL-4.
88
How do B cells respond to IL-4 from T cells?
They become centrocytes then centroblasts. Centroblasts leave the follicle and pass to the paracortex and medullary sinuses -> immunoblasts -> give rise to plasma cells or memory B cells.
89
What does the paracortex of lymph nodes contain?
Lymphocytes, accessory cells, supporting cells.
90
What is the paracortex of lymph nodes the predominant site for?
T-lymphocytes in the lymph nodes.
91
What is the medulla rich in and comprised of?
Rich in macrophages.
Comprises: large blood vessels, medullary cords (rich in plasma cells, produced antibodies pass out of node via efferent lymphatic), and medullary sinuses.
92
What are the cranial bones?
Calvaria - frontal, two parietal, occipital, ethmoid.
| Cranial base - sphenoid, two temporal.
93
What is the calvaria?
The vault of the skull.
94
What do the bones of the calvarai consist of?
Two layers of compact bone separated by a layer of bone marrow - diploe.
95
What do the bones of the cranial base articulate wth?
1st cervical vertebrae (atlas), facial skeleton, and mandible.
96
What are the sutures joining the bones of the cranium?
Coronal (frontal and parietal), sagittal (parietal), lamboidal (parietal and occipital).
97
Where is the skull prone to fracture?
Squamous temporal bone and parietal bone over temples and sphenoid air sinus.
Foramen magnum and inner parts of sphenoid wing at skull base.
Anterior cranial fossa - cribriform plate of ethmoid and roof of orbits.
Middle cranial fossa - weakest, thin bones and multiple foramina.
Posterior cranial fossa - areas between mastoid and dural sinuses.
98
What are the symptoms of skull fractures?
Bleeding from the wound, ear, nose or around eyes; bruising; draining of CSF from ears or nose; swelling; confusion; convulsions; difficulties with balance; drowsiness; headache; loss of consciousness; nausea; vomiting; visual disturbance; stuff neck; slurred speech.
99
What is a depressed skull fracture?
Severe, localised blow causing local indentation, in which a fragment of bone may compress of injure the underlying brain.
100
What is a linear calvarial skull fracture?
Trauma to calvaria leading to radiating linear fractures.
101
What is a comminuted skull fracture?
Bone broken into several pieces.
102
What is a contrecoup/counterblow skull fracture?
No fracture at sight of impact but on opposite side of cranium.
103
What is a simple fracture of the skull?
Break in bone but no damage to skin.
104
What is a compound skull fracture?
Break in, or loss of, skin and splintering of the bone + brain injury and bleeding.
105
How does a basal skull fracture present?
With Battle's sign.
106
What is the pterion?
H-shaped junction of 4 bones (frontal, parietal, sphenoidal, temporal) which lies on the lateral aspect of the skull and is the thinnest part of the calveria.
107
What is the result of pterion fracture?
Bone fragments rupture middle meningeal artery -> extradural haemorrhage.
108
What is a route of infection from scalp to skull bones?
Emissary veins of scalp connect with diploic veins of skull bones and with intracranial venous sinuses.
109
What is the result of infection spread from scalp to skull bones?
Osteomyelitis.
110
What are the foramen of the calvaria?
Foramen magnum, foramen ovale, foramen spinosum, foramen lacerum, carotid canal, jugular forament.
111
What is the facial skeleton?
Bones that enclose the orbits, nasal cavity, oral cavity, paranasal sinuses.
112
What are the bones of the facial skeleton?
Frontal, zygomatic x 2, maxilla x 2, palatine x 2, nasal x 2, lacrimal x 2, inferior concha x 2, vomer, mandible.
113
What does the frontal bone form?
The skeleton of the forehead, flood of the cranial cavity, roof of the orbit.
114
What is the supraciliary arch?
The sharp bony ridge just above the orbital margin.
115
What does the frontal bone articulate with?
Nasal bone, zygomatic bones, lacrimal bones, ethmoid bone, sphenoid bone.
116
Where are the zygomatic bones?
Cheek bones, lie on inferolateral sides of the orbit.
117
What do the zygomatic bones articulate with?
Frontal bone, sphenoid bone, temporal bones, maxillae.
118
What does the maxillae make up?
Large part of the upper facial skeleton and the upper jaw.
119
What does the mandible form?
The temporomandibular joint with the cranial base.
120
What is the most common bone for facial fractures?
Nasal bones due to prominence of the nose.
121
When do maxillofacial fractures occur?
As a result of massive facial trauma.
122
What is black eye?
Skin bruising around the orbit -> tissue fluid and blood accumulation in surrounding connective tissue.
123
What is malar flush?
Redness of skin covering zygomatic bones in mitral stenosis.
124
What projections do the transverse processes end in?
Anterior and posterior tubercles.
125
What is the C1 bone?
The atlas, ring shaped and supports the skull at atlanto-occipital joint.
126
What is the C2 bone?
The axis, strongest cervical vertebrae. Dens projects superiorly.
127
What are the spinous processes of C3-C6 like?
Short and bifid.
128
What are the carotid tubercles?
The anterior tubercles of C6 where the common carotid arteries can be compressed against for control of bleeding.
129
What characterises C7?
Long spinous process which is not bifid. It has a small transverse foramen but vertebral arteries don't pass through it.
130
How do cervical spine fractures happen and what is the risk?
With force, severe dislocation can cause severe injury.
131
What is fracture of the dens from and what is it?
From falling on head, displacement of fractured dens may injure spinal cord -> quadriplegia, displacement of fractured dens may injure medulla of brainstem -> death.
132
What is hyperflexion of cervical region from and what can result?
From head on collisions in care. Rupture of lower intervertebral discs -> compression of spinal roots C6/C7. Pain in neck, shoulder, arm, and hand.
133
What is hyperextension of cervical region from and what can result?
Whiplash injury from rear-end car collisions. Tearing of anterior and posterior longitudinal ligaments, fracture of cervical spinous processes, disc rupture, neck muscle injury, blood vessel injury.
134
What happens in osteoarthritis of the cervical region?
Osteophyte form and compress related spinal nerve -> pain along dermatomes and muscle spasms along myotomes.
135
What is a broken neck?
Compression of cervical spine against shoulder normally at C2, C6, and C7.
136
What can result from a broken neck?
Partial or complete paralysis or death.
137
What causes a burst/Jefferson fracture?
Head first fall from a heigh.
138
What causes a Hangman's fracture?
Hyperextension of the head on the neck.
