Head And Neck Anatomy - Last’s Anatomy Flashcards
(158 cards)
1
Q
What is the location of the first thoracic vertebra (T1)?
A
lies at the highest part of the sloping thoracic inlet.
2
Q
What supports the skull in the neck?
A
cervical spinal column
3
Q
What is the location of the cervical spinal column?
A
Rises from the upper border of T1
4
Q
What is the shape of the cervical spinal column?
A
Gently convex forwards
5
Q
What is the main function of the cervical spinal column?
A
Supports the skull
6
Q
What type of musculature lies behind the cervical vertebrae?
A
A mass of extensor musculature, supplied segmentally by posterior rami of cervical nerves that emerge from intervertebral foramina.
7
Q
What is the nerve supply of the extensor musculature that lies behind the cervical vertebrae?
A
supplied segmentally by posterior rami of cervical nerves that emerge from intervertebral foramina.
8
Q
What is the nerve supply of the extensor musculature that lies behind the cervical vertebrae?
A
supplied segmentally by posterior rami of cervical nerves that emerge from intervertebral foramina.
9
Q
What lies in front of the cervical vertebrae and behind the pharynx?
A
prevertebral flexor musculature,
(1) A much smaller amount
(2) covered by prevertebral fascia,
(3) supplied segmentally by anterior rami of cervical nerves.
10
Q
What are the features of the prevertebral flexor musculature that lies in front of the cervical vertebrae and behind the pharynx?
A
(1) A much smaller amount
(2) covered by prevertebral fascia,
(3) supplied segmentally by anterior rami of cervical nerves.
11
Q
What type of fascia covers the prevertebral flexor musculature that lies in front of the cervical vertebrae and behind the pharynx?
A
Prevertebral fascia
12
Q
What is the nerve supply of the prevertebral flexor musculature that lies in front of the cervical vertebrae and behind the pharynx?
A
supplied segmentally by anterior rami of cervical nerves.
13
Q
What is the location of the face in general?
A
projects forwards and backwards
(1) from the base of the skull
(2) in front of the upper part of the pharynx
+ At C1, base of the nose and the hard palate.
+ At C2, the teeth of a closed mouth.
+ At C3, the mandible and hyoid bone.
+ At C4, the common carotid artery bifurcates.
14
Q
What is the vertebral level of the hard palate?
A
anterior arch of the atlas (C1 vertebra).
15
Q
What is the vertebral level of the lower border of the mandible?
A
between C2 and 3 vertebrae
(C2-C3)
16
Q
Where does the pharynx extend to?
A
From the base of the skull to the level of the cricoid cartilage (C6), continuing as the oesophagus.
17
Q
What is the location of the larynx and trachea in relation to the pharynx and oesophagus?
A
The larynx and trachea are located in front of the lower pharynx and upper oesophagus
18
Q
What lies in front of the lower pharynx and upper oesophagus?
A
The larynx and trachea.
19
Q
At what vertebra level is the hyoid bone located?
A
(1) above the larynx
(2) at C3 vertebra level.
20
Q
What muscle connects the hyoid bone to the mandible?
A
the mylohyoid muscles which are:
(1) at the upper limit of the anterior part of the neck
(2) form the floor of the mouth
+ The hyoid bone is suspended by muscles from the skull and
+ The larynx is suspended from the hyoid by a membrane and muscles.
+ Inferiorly they are connected by muscles to the sternum and the scapula.
+ Deep to these muscles the thyroid gland, enclosed in the pretracheal
fascia, lies alongside the larynx and trachea.
21
Q
What encloses the thyroid gland?
A
pretracheal fascia.
22
Q
What is the location of the carotid sheath?
A
On each side of the pharynx
23
Q
What does the carotid sheath contain?
A
The common and internal carotid arteries and the internal jugular vein,
with the cervical sympathetic trunk behind it.
+The external carotid artery lies outside the sheath and gives several branches in the neck.
+ Descending into the neck are the ninth, tenth, eleventh and twelfth cranial nerves;
+ the ninth and twelfth pass forwards to the oropharynx and tongue,
+ the eleventh runs backwards to the sternocleidomastoid and trapezius muscles,
+ the vagus continues down in the carotid sheath.
+ Surrounding the whole neck is a collar of fascia, the investing layer of deep cervical fascia, which encloses the trapezius and sternocleidomastoid muscles; the fascia and the muscles are attached above to the base of the skull and below to the clavicle at the root of the neck.
24
Q
Which cranial nerves descend into the neck?
A
The ninth, tenth, eleventh, and twelfth cranial nerves.
25
What surrounds the whole neck?
A collar of fascia, the investing layer of deep cervical fascia.
26
What is the function of the neck or cervical fascia?
The neck fascia compartmentalises structures within the neck. These layers of tough fascia can limit the spread of infection (for example, a superficial skin abscess may be prevented from spreading deeper into the neck by the investing fascia).
However, infections that reach the potential spaces between the neck fascia have a well-defined spread
27
What is the platysma?
A sheet of muscle
(1) paper like
(2) broad
(3) flat
(4) lies superficial to the investing layer of deep cervical fascia.
28
What are the features of the platysma?
(1) paper like
(2) broad
(3) flat
29
What is the location of the platysma?
lies superficial to the investing layer of deep cervical fascia.
30
What is the origin of platysma muscle?
It has two heads, which originate from the fascia of the upper parts of:-
1) pectoralis major and
2) deltoid.
31
What is the insertion of platysma?
(1) Lower border of the mandible (Superiorly).
(2) some fibres continue on to the face, blending with the muscles of facial expression.
32
What is the nerve supply of the platysma?
(1) cervical branch of the facial nerve; the main nerve supply
(2) transverse cervical nerve; provides afferent (proprioceptive) or sensory fibres
(3) Marginal mandibular branch: This branch innervates the upper anterior portion of the platysma especially the part near the chin and mandible.
## Footnote
+ primarily by the cervical branch of the facial nerve (CNVII).
+ It also receives proprioceptive innervation from the transverse cervical nerve.
+ In addition, some parts of the muscle may be innervated by the marginal mandibular branch of the facial nerve.
Here's a more detailed explanation:
1) Cervical branch of the facial nerve: This is the main nerve supplying the platysma.
2) Transverse cervical nerve: This nerve provides sensory input to the platysma, allowing the brain to receive information about the muscle's position and activity.
3) Marginal mandibular branch: This branch innervates the upper anterior portion of the platysma, especially the part near the chin and mandible.
33
What is the course of the platysma muscle?
The fibres from the two heads:-
1) cross the clavicle, and
2) separated below
3) meet above
- in the midline,
- just beneath the chin,
- fusing with the muscles of the face.
34
What action does the platysma perform?
(1) It plays a part in facial expression and
(2) may assist in opening the mouth by depressing the mandible.
(3) wrinkles the skin of the neck
35
What is the relation of platysma muscle?
The muscle covers the external and anterior jugular veins.
36
What is the venous relation of platysma muscle?
The muscle covers the external and anterior jugular veins.
37
Where do the anterior jugular veins commence?
(1) Beneath the chin.
(2) near the hyoid bone
38
Discuss the course of the anterior jugular veins in the neck?
(1) The Rt and Lt anterior jugular veins pass downwards, to suprasternal region,i.e., above the sternum, in which on their descend they will be
- side by side
- close to the midline
- in the superficial fascia
- beneath the platysma,
(2) in the suprasternal region they
- pierce the deep fascia and
- come to lie in the suprasternal space, where they are often connected by a short anastomotic vein
- N.B: the Rt. & Lt. ant. jugular veins are connected by a transverse channel just above the sternum called the jugular venous arch
(3)Each now
- angles laterally backwards
- deep to sternocleidomastoid, but
- superficial to the
+ scalenus anterior and
+ strap muscles,
- open into the external jugular vein near its termination.
39
How do the anterior jugular veins terminate?
By joining the external jugular vein near its termination
40
Define the jugular venous arch or the jugular arch
A transverse channel
41
What is the location of the jugular venous arch or jugular arch?
Just above the sternum
42
What is the direction or shape of the jugular venous arch or jugular arch?
Transverse
43
What is the function of the jugular venous arch or jugular arch?
Connects between Rt and Lt anterior jugular veins
44
What is the location of the deep cervical fascia?
lies, as its name suggests, ‘deep’ to the superficial fascia and platysma muscle.
45
What are the four parts of the deep cervical fascia?
(1) investing layer,
(2) pretracheal fascia,
(3) prevertebral fascia,
(4) carotid sheath.
46
What is the location of the investing layer of deep cervical fascia?
The most superficial of the deep cervical fascia
47
What is the fascia in the body that can be compared to the investing layer of deep cervical fascia?
The investing layer of deep cervical fascia, is comparable in every way to the deep fascia that underlies the subcutaneous fat in the limbs and else where,
48
What is the function of the investing layer of deep cervical fascia?
surrounds all the structures in the neck like a collar
49
Discuss attachment of the investing layer of deep cervical fascia
+ It splits around sternocleidomastoid and trapezius
+ posteriorly
1- it blends with the ligamentum nuchae, which is attached to the spines of the cervical vertebrae (C1-C6).
2- it is attached to the spine of C7
+ Anteriorly
it is attached to the hyoid bone; and
+ Superiorly
at the base of the skull, to the :-
1) lower border of the mandible and
2) mastoid process,
3) superior nuchal line and
4) external occipital protuberance
+ Between the angle of the mandible and the tip of the mastoid process
1) the investing layer is strong and
2) splits to enclose the parotid gland.
+ Below, the investing layer is attached to the
1) spine and acromion of the scapula and the clavicle with the trapezius,
2) clavicle and the manubrium of the sternum with the sternocleidomastoid.
3) In the intervals between these muscles, it is attached to both clavicles and to the jugular (suprasternal) notch by two layers into which it splits a short distance above them. The layers are attached to the anterior and posterior borders of the jugular notch, enclosing between them the suprasternal space which contains the lower parts of the anterior jugular veins, an anastomotic arch between them, the sternal heads of the sternocleidomastoids and sometimes a lymph node. Of the two layers that adhere to the middle third of the clavicle, the deeper splits around the inferior belly of the omohyoid, forming a fascial sling which keeps this muscle belly low down in the neck
The two layers are pierced by the external jugular vein
50
To what type of fascia in the body the investing layer of deep cervical fascia is comparable ?
comparable in every way to the deep fascia that underlies the subcutaneous fat in the limbs and else-where
51
Where is the investing layer attached anteriorly?
hyoid bone
52
What does the investing layer enclose between the angle of the mandible and the tip of the mastoid process?
The investing layer is strong and splits to enclose the parotid gland.
53
What does the superficial part of the investing layer extend to?
The superficial part extends superiorly as the parotidomasseteric fascia and reaches up to the zygomatic arch.
54
Define parotidomassetric fascia
The superior extension of the superficial part of the investing layer of deep cervical fascia
55
What is the site of attachment of parotidomasseteric fascia?
Zygomatic arch
56
Define stylomandibular ligament
Thickened extension of the deep part of the investing layer of the deep cervical fascia (which is the parotid fascia in this area)
57
What is the site of attachment of the stylomandibular ligament?
extends to the base of the skull; between the
(1) styloid process and
(2) angle of the mandible
58
What is the prevertebral fascia?
a firm, tough membrane
59
What is the location of the prevertebral fascia?
In front of the prevertebral muscles
60
Discuss the sites of extension of the prevertebral fascia?
61
What is the function of the prevertebral fascia?
surrounds the
(1) vertebral column and its associated muscles;
(2) prevertebral muscles,
(3) scalene muscles,
(4) deep muscles of the back
62
Discuss sites of attachment of the prevertebral fascia?
1st/It has attachments along the anteroposterior and supero-inferior axes:
+ Superior attachment – base of the skull.
+ Anterior attachment – transverse processes and vertebral bodies of the
vertebral column.
+ Posterior attachment – along the nuchal ligament of the vertebral column
+Inferior attachment – fusion with the endothoracic fascia of the ribcage.
2nd/The anterolateral portion of prevertebral fascia forms the floor of the
posterior triangle of the neck.
3rd/It also surrounds the
(1) brachial plexus as it leaves the neck
(2) subclavian artery as it passes through the lower neck region – in doing so, it forms the axillary sheath.
63
What is the site of superior attachment of the prevertebral fascia?
Base of the skull
64
What does the prevertebral fascia cover?
It covers the muscles that form the floor of the posterior triangle of the neck and all the cervical nerve roots.
65
Discuss relations of the prevertebral fascia?
66
What does the pretracheal fascia lie deep to?
The pretracheal fascia lies deep to the infrahyoid strap muscles (sternothyroid, sternohyoid and omohyoid).
67
What does the pretracheal fascia enclose?
It splits to enclose the thyroid gland, to which it is not adherent except to the back of the isthmus.
68
What is the carotid sheath composed of?
The carotid sheath consists of a feltwork of areolar tissue that surrounds the common and internal carotid arteries, internal jugular vein, vagus nerve and some deep cervical structures.
69
What is the location of the pretrachial fascia?
(1) in the anterior neck
(2) deep to the infrahyoid strap muscles
(sternothyroid, sternohyoid and omohyoid) so that its
upward attachment is limited by the respective attach-
ments of those muscles, namely, the body of the hyoid
bone and the oblique line of the thyroid cartilage.
70
What is the feature of the pretrachial fascia?
Thin
71
Discuss parts of the pretrachial fascia
Anatomically, it can be divided into two parts:
+ Muscular part – encloses the infrahyoid strap muscles.
+ Visceral part – encloses the thyroid gland, trachea and oesophagus.
72
Discuss attachment of the pretrachial Fascia
(1) Superiorly — upward attachment is limited by the respective attachments of the infrahyoid strap muscles(sternothyroid, sternohyoisand omohyoid ), namely, the
+ body of the hyoid bone (so , thyroid gland moves up and down with deglutition) +oblique line of the thyroid cartilage.
(2) inferiorly — in the thorax, it passes behind the brachiocephalic veins to blend with the
+adventitia of the arch of the aorta
+ fibrous pericardium.
(3) Anterolaterally — it splits to form a capsule
around the thyroid gland that
+ encloses the thyroid gland, to which it is not adherent except to the back of the isthmus where it is also attached
to the second, third and fourth rings of the trachea.
+ is thicker anteriorly (that is why the gland enlarges posterior at first)
(4) Laterally — it fuses with the front of the carotid sheath on the
deep surface of the sternocleidomastoid
(5) Posteriorly —The pretracheal fascia is also described in some accounts as being part of a cervical visceral fascia
that surrounds the pharynx, oesophagus, larynx and trachea.
The posterior aspect of the cervical visceral fascia is formed by contributions from the buccopharyngeal fascia (a fascial covering of the pharynx).
73
What is the superior attachment of the pretrachial fascia?
upward attachment is limited by the respective attachments of the infrahyoid strap muscles(sternothyroid, sternohyoisand omohyoid ), namely, the
+ body of the hyoid bone (so , thyroid gland moves up and down with deglutition)
+oblique line of the thyroid cartilage.
74
What is the effect of the infra hyoid strap muscles on the superior attachment of the pretrachial fascia?
upward attachment is limited by the respective attachments of the infrahyoid strap muscles(sternothyroid, sternohyoisand omohyoid ), namely, the
+ body of the hyoid bone (so , thyroid gland moves up and down with deglutition)
+oblique line of the thyroid cartilage.
75
What is inferior attachment of the pretrachial attachment?
in the thorax, it passes behind the brachiocephalic veins to blend with the
+adventitia of the arch of the aorta
+ fibrous pericardium.
76
What is the anterolateral attachment of the pretrachial fascia?
it splits to form a capsule
around the thyroid gland that
+ encloses the thyroid gland, to which it is not adherent except to the back of the isthmus where it is also attached
to the second, third and fourth rings of the trachea.
+ is thicker anteriorly (that is why the gland enlarges posterior at first)
77
Does the pretrachial fascia adhere to the thyroid gland?
it is not adherent to the thyroid gland except to the back of the isthmus where it is also attached
to the second, third and fourth rings of the trachea.
78
Which part of the pretrachial fascia is adherent to thyroid gland?
it is not adherent to the thyroid gland except to the back of the isthmus where it is also attached
to the second, third and fourth rings of the trachea.
79
What is the direction of thyroid gland enlargement and why?
the thyroid gland enlarges posterior at first because the thyroid capsule ,formed by the pretrachial fascia, is thicker anteriorly
80
What is the lateral attachment of the pretrachial fascia?
it fuses with the front of the carotid sheath on the
deep surface of the sternocleidomastoid
81
Which part of the carotid sheath fuses with the pretrachial fascia ?
The pretrachial fascia fuses with the front of the carotid sheath on the
deep surface of the sternocleidomastoid
82
What is the site of fusion of the pretrachial fascia to the front of the carotid sheath?
on the deep surface of the sternocleidomastoid
83
What is the posterior attachment of the the pretrachial fascia?
The pretracheal fascia is also described in some accounts as being part of a cervical visceral fascia
that surrounds the pharynx, oesophagus, larynx and trachea.
The posterior aspect of the cervical visceral fascia is formed by contributions from the buccopharyngeal fascia (a fascial covering of the pharynx).
84
Enumerate contents of the pretrachial fascia that are mobile with deglutition
* Thyroid.
* Parathyroid.
* Pre-tracheal LNs (LN of Delphi).
* Pre-laryngeal LNs (LN of Poitier).
* Thyroglossal cyst & tract if found.
85
Enumerate structures mobile with deglutition
* Thyroid.
* Parathyroid.
* Pre-tracheal LNs (LN of Delphi).
* Pre-laryngeal LNs (LN of Poitier).
* Thyroglossal cyst & tract if found.
86
Is carotid sheath a fascia?
This is not a fascia in the sense of a demonstrable membranous layer, but consists of a feltwork of areolar tissue
87
How many carotid sheaths are there in the body?
Paired carotid sheaths on either side of the neck
88
Define the carotid sheath
A tube of deep fascia
89
What is the structure of carotid sheath?
A tubular sheath of dense fibrous tissue
90
What is the location of carotid sheath?
(1) on either side of the neck
(2) Deep to posterior border of sternocleidomastoid muscle
91
What is the other name of the fascia of the carotid sheath?
Carotid fascia
92
Discuss formation of the fascia of the carotid sheath (carotid fascia)
formed by contributions from the following fascia
(1) pretracheal fascia
(2) prevertebral fascia
(3) investing fascia
93
Enumerate contents of carotid sheath
94
What is the thickness of the carotid sheath?
It is thick over the artery (CCA and ICA) but thin where it overlies the internal jugular vein, allowing the vein to dilate during increased blood flow.
95
What is the site where the carotid sheath is the thinnest?
It is thick over the artery (CCA and ICA) but thin where it overlies the internal jugular vein, allowing the vein to dilate during increased blood flow.
96
Discuss attachment of carotid sheath
1st/Superiorly — base of the skull at the margins of the
+ carotid canal and
+ jugular fossa,
2nd/Inferiorly — adventitia of the aortic arch
continued downwards along the vessels to blend with the adventitia of the aortic arch.
3rd/Anteriorly — sternocleidomastoid+pretrachial fascia
+the lower part of the sheath fuses with the fascia on the deep surface of the sternocleidomastoid.
+Where they lie alongside, the sheath blends with the pretracheal fascia.
3rd/Posteriorly — prevertebral fascia
a minimum of loose areolar tissue between it and the prevertebral fascia; the cervical sympathetic trunk lies here in front of the prevertebral fascia.
97
What is reason behind organising the carotid sheath into a column extending between the base of the skull to the thoracic mediastinum?
This is of clinical importance as a pathway for the spread of infection.
98
Discuss relations of carotid sheath
1st/ superficial ( mostly anterolateral) relations
[I] generally
(1) skin
(2) superficial fascia
(3) deep fascia
(3) 2 limbs of ansa cervicalis and its roots
- is in the carotid sheath over the internal jugular vein
- embedded in the anterior wall
(4) deep cervical L.Ns
(5) infratemporal fossa
[II] below the upper border of thyroid cartilage (i.e, in the lower part of the carotid sheath)
(1) sternocleidomastoid muscle ( all through)
- the lower part of the carotid sheath fuses with the fascia on the deep surface of sternocleidomastoid muscle
- where they lie alongside(i.e., the pretrachial fascia and the carotid sheath),the carotid sheath blends with the pretrachial fascia and investing layer of deep fascia undercover of the sternocleidomastoid muscle
(2) infra hyoid strap muscles
- sternohyoid
- sternothyroid
- thyrohyoid
- omohyoid
(3) thyroid gland
[III] above the upper part of the thyroid cartilage (i.e.,in the upper part of the carotid sheath)
(1) styloid process and its attached structures and 3 muscles
(2) parotid gland — the deepest part of the parotid gland touches the sheath,partly separated by the styloid process and its attached structures and 3 muscles
(3) posterior belly of diagastric muscle
2nd/ deep (posterior) relations
(1) transverse processes of all cervical vertebrae
(2) covering prevertebral muscles
- longus capitis
- rectus capitis lateralis
- longus coli
(3) prevertebral fascia
- a minimum of loose areolar connective tissue is between the carotid sheath and the prevertebral fascia
- the cervical sympathetic trunk lies here in front of the prevertebral fascia
(4) lateral vertebral muscles
- scalenus anterior
- scalenus medius
- levator scapulae muscle
(5) cervical sympathetic trunk( or plexus)
- embedded in the posterior wall
- in front of the prevertebral fascia
(6) 1st part of subclavian artery
(7) inferior thyroid artery— crosses deep to the carotid sheath at C6 on both sides of the neck
(8) thoracic duct — crosses deep to the carotid sheath at C7 on the left side of the neck
3rd/ medial relations
Pharynx
4th/ superior relations
(1) base of the skull at the margins of the
- carotid canal — lies immediately in front of the jugular foramen which lies deep to the external acoustic meatus
- jugular fossa
(2) escaping from the upper sheath are
1- glossopharyngeal nerve (IX)
2- superior laryngeal nerve (X)
4- spinal root of accessory nerve (XI)
5- hypoglossal nerve (XII)
5th/ inferior relations — adventitia of the aortic arch
Continued downwards along the vessels to blend with the adventitia of the aortic arch
99
Discuss superficial (anterior) relations of the carotid sheath
[I] generally
(1) skin
(2) superficial fascia
(3) deep fascia
(3) 2 limbs of ansa cervicalis and its roots
- is in the carotid sheath over the internal jugular vein
- embedded in the anterior wall
(4) deep cervical L.Ns
(5) infratemporal fossa
[II] below the upper border of thyroid cartilage (i.e, in the lower part of the carotid sheath)
(1) sternocleidomastoid muscle ( all through)
- the lower part of the carotid sheath fuses with the fascia on the deep surface of sternocleidomastoid muscle
- where they lie alongside(i.e., the pretrachial fascia and the carotid sheath),the carotid sheath blends with the pretrachial fascia and investing layer of deep fascia undercover of the sternocleidomastoid muscle
(2) infra hyoid strap muscles
- sternohyoid
- sternothyroid
- thyrohyoid
- omohyoid
(3) thyroid gland
[III] above the upper part of the thyroid cartilage (i.e.,in the upper part of the carotid sheath)
(1) styloid process and its attached structures and 3 muscles
(2) parotid gland — the deepest part of the parotid gland touches the sheath,partly separated by the styloid process and its attached structures and 3 muscles
(3) posterior belly of diagastric muscle
100
Discuss deep (posterior) relations of carotid sheath
(1) transverse processes of all cervical vertebrae
(2) covering prevertebral muscles
- longus capitis
- rectus capitis lateralis
- longus coli
(3) prevertebral fascia
- a minimum of loose areolar connective tissue is between the carotid sheath and the prevertebral fascia
- the cervical sympathetic trunk lies here in front of the prevertebral fascia
(4) lateral vertebral muscles
- scalenus anterior
- scalenus medius
- levator scapulae muscle
(5) cervical sympathetic trunk( or plexus)
- embedded in the posterior wall
- in front of the prevertebral fascia
(6) 1st part of subclavian artery
(7) inferior thyroid artery— crosses deep to the carotid sheath at C6 on both sides of the neck
(8) thoracic duct — crosses deep to the carotid sheath at C7 on the left side of the neck
101
Discuss medial relations of the carotid sheath
Pharynx
102
Discuss superior relations of the carotid sheath
(1) base of the skull at the margins of the
- carotid canal — lies immediately in front of the jugular foramen which lies deep to the external acoustic meatus
- jugular fossa
(2) escaping from the upper sheath are
1- glossopharyngeal nerve (IX)
2- superior laryngeal nerve (X)
4- spinal root of accessory nerve (XI)
5- hypoglossal nerve (XII)
103
Discuss inferior relations of the carotid sheath
adventitia of the aortic arch:-
Continued downwards along the vessels to blend with the adventitia of the aortic arch
104
Enumerate the tissue spaces of the neck
1st/ spaces around the prevertebral fascia
(1) space behind the prevertebral fascia — prevertebral space
(2) space in front of the prevertebral fascia
2nd/ submandibular space
3rd/ visceral space
105
What is the reason behind dividing the neck into tissue spaces?
The neck fascia compartmentalises structures within the neck. These layers of tough fascia can limit the spread of infection (for example, a superficial skin abscess may be prevented from spreading deeper into the neck by the investing fascia).
However, infections that reach the potential spaces between the neck fascia have a well-defined spread
106
What is the location of the prevertebral space?
Behind the prevertebral fascia
107
What is the clinical significance of the prevertebral space?
(1) an anterior escape can only be made
by a perforation in the prevertebral fascia.
(2) Hence pus from an abscess
in a cervical vertebra can lift the prevertebral fascia as far down as the superior mediastinum.
108
What is the location of the space in front of the prevertebral fascia?
Immediately in front of the prevertebral fascia
109
What is the extension of the space in front of the prevertebral fascia?
from the base of the skull to the diaphragm
passing through the superior into the posterior mediastinum as it does so
110
What is the anatomical area from which the space in front of the prevertebral fascia passes?
passes through the superior into the posterior mediastinum
111
What are the parts of the space in front of the prevertebral fascia?
112
What is the other name of the upper part of the space in front of the prevertebral fascia?
Retropharyngeal space
113
What is the location of the upper part (retropharyngeal space) of the space in front of the prevertebral fascia?
(1) In the infratemporal fossa
(2) between the buccopharyngeal fascia (posterior aspect of the visceral pretracheal fascia) and the prevertebral fascia.
114
What are the lateral boundaries of the upper part (retropharyngeal space) of the space in front of the prevertebral fascia?
(1) Pterygoid muscle
(2) Parotid sheath
115
What are the extension of the upper part (retropharyngeal space) of the space in front of the prevertebral fascia?
Extends from the base of the skull to the posterior mediastinum.
116
Define the lateral part (parapharyngeal space) of the space in front of the prevertebral fascia?
Lateral extension of the upper part (retropharyngeal space) of the space in front of the prevertebral fascia
117
What is the location of the lateral part (parapharyngeal space) of the space in front of the prevertebral fascia?
At the side of the pharynx
118
What is the location of the submandibular space?
(1) In the upper part of the neck
(2) below the mylohyoid muscle
(3) deep to the investing layer of deep cervical fascia
(4) between the hyoid bone and the mandible.
119
What is the function of the submandibular space?
This space communicates around the posterior
border of mylohyoid with a sublingual space under the
mucous membrane of the floor of the mouth.
120
What is the clinical significance of the submandibular space?
Ludwig’s angina is a rare but severe form of cellulitis that involves these spaces and spreads backwards into the parapharyngeal space.
121
What is the fascia enclosing the visceral space?
visceral pretracheal fascia.
122
What is the extension of the visceral space?
Extends from the hyoid bone to the superior mediastinum
123
What is the number of submental lymph nodes?
Three or four small submental lymph nodes
124
What is the location of submental lymph nodes?
lie beneath the chin,
125
What is the types of submental lymph nodes?
(1) superficial to the investing layer of deep cervical fascia
(2) deep to the investing layer of deep cervical fascia
126
What is the function of submental lymph nodes?
They drain, across the midline, a wedge of tissue in the floor of the mouth opposite the four lower incisor teeth,including
those teeth, gums and lip, and the tip of the tongue
127
What is the site of drainage of submental lymph nodes?
(1) In their turn they drain to submandibular nodes or
(2) directly to the upper deep cervical group.
128
What is the number of the submandibular lymph nodes?
About half a dozen submandibular lymph nodes
129
What is the location of the submandibular lymph nodes?
(1) lie on the surface of the submandibular gland,
(2) some embedded within the gland
130
What organs are drained by the submandibular lymph nodes?
1st/mainly but not exclusively from their own side:-
(1) submental nodes,
(2) lateral parts of the lower lips,
(3) all the upper lip
(5) external nose,
6) anterior part of the tongue,
2nd/ They also receive lymph from the
(1) anterior half of the nasal walls
(2) paranasal sinuses that drain there
(frontal, anterior and middle ethmoidal, and maxillary),
(3) all the teeth (except lower incisors).
131
What is the reason behind dividing each side of the neck into anterior and posterior triangles by the obliquely placed sternocleidomastoid muscle?
To assist the description of the
(1) topographical anatomy of the neck
(2) location of pathological lesions
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What is the feature of sternocleidomastoid muscle ?
(1) prominent neck landmark
(2) oblique
133
What is the origin of sternocleidomastoid muscle?
has two heads of origin
below:
1st/Sternal head (that from the sternal manubrium)
is a rounded tendon,
The manubrial tendon is attached to the front of the bone below the jugular notch;
2nd/clavicular head (that from the clavicle)
a flat, fleshy mass
the clavicular head arises from the superior surface of the medial third of the clavicle.
The clavicular fibres spiral behind the sternal fibres with the deep aspect of which they blend
134
What is the clinical significance of the sternocleidomastoid muscle’s 2 heads origin?
An interval
+ shape = triangular
+ location = exists between the two heads
1- above the sternoclavicular joint, and
2- the lower end of the internal
jugular vein
+ significance = This interval can be entered by needle or catheter.
135
What is the insertion of the sternocleidomastoid muscle
The muscle is attached by
(1) The clavicular fibres
are directed by a tendon mainly to the lateral surface of the mastoid process,
(2) the sternal fibres
run more obliquely, as a thin aponeurosis ,chiefly to the lateral half of the superior nuchal line of the
occipital bone.
136
What is the nerve supply of the sternocleidomastoid muscle?
1st/ motor — spinal part of the accessory nerve
+ Origin in the muscle
from a branch which leaves the nerve proximal to its
point of entry into the muscle.
+ course in the muscle
(1) enters the muscle
- under cover of the lobule of the ear, - about 3 cm below the tip of the mastoid process,
- accompanied by a branch to the muscle from the occipital artery.
(2) It runs through the deep part of the muscle to emerge from between a third and a half of the way down the posterior border of the muscle.
2nd/ sensory (proprioception) — Branches from the cervical plexus (mostly C2 and 3) :-
+ The pathway for innervation by the cerebral cortex of the anterior horn cells of the segments concerned (mostly C2 and 3) is disputed;
+ projection to the muscle from either or both hemispheres has been described.
+ carrying proprioceptive fibres enter the muscle directly or by joining the accessory nerve.
137
What is the type of covering of the sternocleidomastoid muscle?
Sternocleidomastoid is enclosed within a sheath of the
investing layer of deep cervical fascia, which splits to surround it
138
Discuss relations of the sterncleidomastoid muscle?
1st/ superficial relations
(1) skin
(2) superficial fascia containing
+ platysma
+ in the order from above downwards,
the muscle is crossed superficially by
the
1- great auricular nerve,
2- external jugular vein and
3- transverse cervical nerve,
+ superficial cervical L.Ns
(3) deep fascia
(4) parotid gland covering the muscle partially at its insertion
2nd/ deep relations
(1) Deep to the upper half of the muscle lies the = cervical plexus; which is related to levator scapulae muscle
(2) deep to its lower part lies the = carotid sheath and its contents, overlying scalenus anterior.
(3) sternoclavicular joint
(4) infra hyoid strap muscles
- sternohyoid
- sternothyroid
- thyrohyoid
- omohyoid
(5) scalenus anterior and the structures in front of it
- phrenic nerve
- transverse cervical artery
- suprascapular artery
- anterior jugular vein
- subclavian vein
(6) scalenus medius & roots of brachial plexus
(7) levator scapulae & roots of cervical plexus
(8) lateral lobe of thyroid
(9) ansa cervicalis
(10) deep cervical L.Ns
3rd/ anterior border
forms the post. boundary of the ant.triangle of the neck.
4th/ The post. border:
+ forms the ant. boundary of the post. triangle
+ The following nerves appear from beneath this border:
(1) Lesser occipital n. (2) Great auricular n. (3) Tr. cutaneous n. of neck.
(4) Supraclavicular n. (5) Spinal accessory n.
5th/ the spinal accessory n.
pierces the upper part of the muscle.
139
What is the blood supply of the sternocleidomastoid muscle?
from branches of the
Upper third – Occipital artery
Middle third – Superior thyroid artery and external carotid artery
Lower third – Suprascapular artery
140
What is the action of the sternocleidomastoid muscle?
1st/ Contraction of
(1) one muscle
+ lateral flexion of the neck (i.e., tilts the head towards the ipsilateral shoulder), and
+ rotates the head and face to the opposite side.
(2) Both muscles acting together from below
Extension of the neck at the atlanto-occipital joints (i.e.,draw the head forwards)
2nd/ With the head fixed,
the muscles can assist in raising the roof of the thorax in forced inspiration.
141
How to test the sternocleidomastoid muscle?
The face is turned to the opposite side against
resistance and the muscle palpated.
142
What is the location of the posterior triangle?
is an anatomical area
(1) located at the posterolateral aspect of the neck.
(2) enclosed between the sternocleidomastoid and trapezius muscles.
143
Discuss boundaries of the posterior cervical triangle
Anterior – posterior border of the sternocleidomastoid.
Posterior – anterior border of the trapezius muscle.
Inferior(base) – middle 1/3 of the clavicle at the side of the root of the neck.
roof is formed by the
(1) skin
(2) superficial fascia containing
+ platysma
+ EJV
+ cutaneous branches of cervical plexus
(3) deep fascia = investing layer of deep cervical fascia, and
floor
+ consists of the prevertebral fascia lying on, from above downwards,
(1) splenius capitis ,
(2) levator scapulae and
(3) scalenus medius.
+ Depending on the size of the sternocleidomastoid and the degree
of depression of the shoulder, the following may contribute
to the floor,
(1) scalenus anterior and
(2) first digitation of serratus anterior
apex
+ lies high up at the back of the skull on the superior nuchal line, where there is a
small gap between the attachments of the sternocleidomastoid and trapezius muscles
+ at the apex of the triangle, splenius
may be low enough to expose a little of semispinalis capitis.
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Where is the apex of the posterior triangle located?
+ lies high up at the back of the skull on the superior nuchal line, where there is a
small gap between the attachments of the sternocleidomastoid and trapezius muscles
+ at the apex of the triangle, splenius
may be low enough to expose a little of semispinalis
capitis.
145
What forms the base of the posterior triangle?
middle third of the clavicle at the side of the root of the neck.
146
What forms the roof of the posterior triangle?
roof is formed by the
(1) skin
(2) superficial fascia containing
+ platysma
+ EJV
+ cutaneous branches of cervical plexus
(3) deep fascia = investing layer of deep cervical fascia
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What structures make up the floor of the posterior triangle?
+ consists of the prevertebral fascia lying on, from above downwards,
(1) splenius capitis ,
(2) levator scapulae and
(3) scalenus medius.
+ Depending on the size of the sternocleidomastoid and the degree
of depression of the shoulder, the following may contribute
to the floor,
(1) scalenus anterior and
(2) first digitation of serratus anterior
148
What additional muscles may contribute to the floor of the posterior triangle?
+ consists of the prevertebral fascia lying on, from above downwards,
(1) splenius capitis ,
(2) levator scapulae and
(3) scalenus medius.
+ Depending on the size of the sternocleidomastoid and the degree
of depression of the shoulder, the following may contribute
to the floor,
(1) scalenus anterior and
(2) first digitation of serratus anterior
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What are the contents of the posterior triangle?
1st/ muscles
inferior belly of omohyoid
+ crosses the lower medial part of the triangle
+ kept in place by its sling of investing fascia
+ divides the posterior cervical triangle into two smaller triangles
1. Occipital
2. Supraclavicular
2nd/ arteries
(1) subclavian artery,
- branches of the thyrocervical trunk of 1st part of subclavian artery
1. transverse cervical artery
2. suprascapular artery
- 3rd part of subclavian artery
The pulsation of the subclavian artery can be felt by pressing
1. downwards
2. behind the clavicle
3. at the posterior border of sternocleidomastoid.
(2) 3rd part of occipital artery
3rd/ veins
(1) subclavian vein
(2) transverse cervical vein
(3) suprascapular vein
* Deep to the omohyoid are the
transverse cervical and suprascapular vessels, just
above the clavicle.
(4) external jugular vein
pierces both split layers of the lower part of investing fascia to enter the posterior triangle on its way to the subclavian vein, which itself is too low to be a content of the triangle; the wall of the vein is adherent to the fascia as it passes through.
4th/ nerves
(1) accessory nerve
+ emerges from sternocleidomastoid, about a third of the way or a little lower down its posterior border.
+ It passes downwards and backwards, with a characteristic wavy course adherent to the inner surface of the fascia of the roof of the triangle,
+ disappears
1) beneath the anterior border of trapezius, about a
third of the way from its lower end and
2) 3–5 cm above the clavicle.
+ These points of reference to the borders of sternocleidomastoid and trapezius enable the surface
marking of the accessory nerve in the posterior triangle, where it is particularly liable to injury in operations involving the removal of lymph nodes, one or two of
which may lie in contact with the nerve.
+ More proximally, the nerve lies in front of the transverse process of the atlas (palpable between the mastoid process and mandibular ramus) and it enters the substance of sternocleidomastoid
between the upper two quarters of the muscle.
(2) muscular and cutaneous branches of the cervical plexus
+ pierce the investing fascia at the posterior border of
sternocleidomastoid.
+ The cervical branches to trapezius pass across the floor of the triangle deep to the prevertebral fasc
(3) roots and three trunks of the
brachial plexus and branches of the cervical plexus
are deep to the prevertebral fascia, they are listed as contents
of the posterior triangle; in operations on the triangle all
these structures are safe provided the prevertebral fascia
is left intact.
5th/ lymph nodes
+ Lying between the roof and floor
of the posterior triangle.
+ Two or three occipital nodes lie
in the subcutaneous tissue at the apex and
+ several supraclavicular nodes lie above the clavicle;
+ the latter are really outlying members of the lower group of deep cervical nodes .
.
150
How can the pulsation of the subclavian artery be felt?
By pressing downwards behind the clavicle at the posterior border of sternocleidomastoid.
151
Where do the cutaneous branches of the cervical plexus emerge?
They pierce the investing fascia at the posterior border of sternocleidomastoid.
152
Where are the lymph nodes of the posterior triangle located?
They lie between the roof and floor, with occipital nodes at the apex and supraclavicular nodes above the clavicle.
153
Where does the accessory nerve emerge?
It emerges from sternocleidomastoid about a third of the way down its posterior border.
154
What is the course of the accessory nerve?
It passes downwards and backwards, adhering to the inner surface of the fascia of the roof of the triangle.
155
What is the significance of the accessory nerve in the posterior triangle?
It is particularly liable to injury in operations involving the removal of lymph nodes.
156
What crosses the lower medial part of the posterior triangle?
The inferior belly of omohyoid crosses this area and is kept in place by its sling of investing fascia.
157
What vessels are located deep to the omohyoid?
The transverse cervical and suprascapular vessels are located just above the clavicle.
158
How does the external jugular vein enter the posterior triangle?
It pierces both split layers of the lower part of investing fascia on its way to the subclavian vein.
