Case 19- Neck anatomy Flashcards

1
Q

Triangles in the neck

A

• Anterior triangle- two anterior triangles on both the left and right
• Posterior triangle- two triangles on both the left and right
The Sternocleidomastoid muscle splits it into the anterior and posterior triangle.

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2
Q

Borders of the anterior triangle

A
  • Inferior border of the mandible
  • Anterior border of the Sternocleidomastoid muscle
  • An imaginary line from the mental protuberance (chin) to the Manubrium
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3
Q

Contents of the anterior triangle

A
  • Suprahyoid and infrahyoid muscles
  • Submandibular and Sublingual glands
  • Vasculature- common carotid artery, internal jugular vein
  • Nerves- cranial nerves and branches of the cervical plexus
  • Oesophagus, trachea, pharynx, larynx, thyroid gland
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4
Q

Divisions of the anterior triangle

A

Submandibular triangle, submental triangle, carotid triangle, muscular triangle.

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5
Q

Borders of the posterior triangle

A
  • The posterior border of the Sternocleidomastoid muscle
  • Middle 1/3 of the Clavicle
  • Anterior border of the Trapezius
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6
Q

Contents of the posterior triangle

A
  • Muscular floor
  • Vasculature- external jugular vein, arteries
  • Cervical plexus
  • Spinal accessory nerve
  • Roots of brachial plexus
  • Root of the neck
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7
Q

Subdivision of the posterior triangle

A

Occipital triangle (superiorly), Omoclavicular/Subclavian triangle. The inferior belly of the Omohyoid muscle splits the posterior triangle into the two zones

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8
Q

Cervical fascia

A

Fascia is a band/sheet of connective tissue deep to the skin.
Cervical- relating to the neck
Around the C6 level

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9
Q

Layers of the cervical fascia

A
  • Superficial fascia
  • 3 layers of deep fascia- investing, prevertebral, pretracheal
  • Carotid sheath
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10
Q

Layers of the cervical fascia- Investing layer

A
  • Surrounds the neck like a collar
  • It envelopes to surround the SCM (Sternocleidomastoid), infrahyoid muscle and trapezius
  • Attaches to the zygomatic arch (bone in the check) and down to the sternum and clavicle
  • Attaches posteriorly to the superior nuchal line
  • Forms the roof of the posterior triangle
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11
Q

Layers of the Cervical fascia- Prevertebral layer

A
  • Covers the cervical vertebrae and associated muscles (prevertebral muscles)
  • Anteriorly it splits into the alar fascia- the alar fascia fuses with the pre-tracheal fascia, important for infection spread. The fusion is at T4
  • Attaches to the base of the skull and extends down to the mediastinum
  • Covers the muscles that form the floor of the posterior triangle
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12
Q

Layers of the cervical fascia- Pretracheal fascia

A
  • Surrounds the trachea, thyroid and pharynx/oesophagus
  • Superiorly its known as the buccopharyngeal fascia- this is the area which fuses with the alar fascia
  • Its deep to the infrahyoid muscles
  • Attaches to the Hyoid bone and fuses with the fibrous pericardium which covers the aorta. Extends into the pharynx
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13
Q

Layers of the cervical fascia- carotid sheath

A

Surrounds the internal jugular vein, the common and internal carotid arteries and the vagus nerve

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14
Q

Fascial spaces and spread of infection

A

There are potential spaces between the layers of fascia. Within them infection can spread. The fascia are not fused together but they are closely related

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15
Q

Spaces within the cervical fascia

A

Retropharyngeal space- between the alar fascia and pretracheal layer (buccopharyngeal fascia). Its limited inferiorly at T4, so infections cant spread past then
Prevertebral space/ Danger space- between the alar fascia and the prevertebral fascia (between the two layers of the prevertebral fascia). A continuous space from the base of the skull to the posterior mediastinum. Posterior to the retropharyngeal space

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16
Q

Muscles in the neck- Plastysma

A

Broad, thin sheet of muscle which covers the anterior portion of the neck. It sits within the superficial fascia of the neck and covers the anterior and posterior triangle. It functions to tense the skin, depress the mandible and draw the corners of the mouth inferiorly

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17
Q

Muscles of the neck- Sternocleidomastoid

A

Splits the neck into an anterior and posterior triangle. Has two heads: the sternal head which attaches to the anterior surface of the manubrium and the clavicular head which attaches to the superior surface of the medial 1/3 of the clavicle. Its superior attachment it to the mastoid process and superior nuchal line. Function is to rotate the head when the left sternocleidomastoid muscle contracts are head moves to the right. Helps flex our neck

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18
Q

Suprahyoid muscles

A
Superior to hyoid bone, paired muscle. Within the anterior triangle
• Stylohyoid
• Digastric
• Mylohyoid
• Geniohyoid
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19
Q

Infrahyoid muscles

A
Inferior to the hyoid bone, paired muscle
• Omohyoid
• Sternohyoid
• Thyrohyoid
• Sternothyroid
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20
Q

Suprahyoid muscle- Digastric muscles

A

It originates at two belly’s. The anterior belly is at the Digastric fossa (mandible) and the posterior belly is at the Mastoid notch. Both bellies insert on a piece of tendon which attaches to the hyoid bone

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21
Q

Suprahyoid muscles- Stylohyoid / Mylohyoid / Geniohyoid

A

1) Stylohyoid muscle- originates at the styloid process and inserts on the body of the hyoid bone
2) Mylohyoid muscle- originates on the Mylohyoid line of the mandible, inserts on the body of the hyoid bone and the fibres of the opposite muscle. Forms the floor of the oral cavity.
3) Geniohyoid muscle- originates on the inferior mental spine of the mandible, inserts on the body of the hyoid bone. Forms part of the floor of the oral cavity

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22
Q

Infrahyoid muscles- Omohyoid

A

Originates on the superior border of the scapula and inserts on the lower border of the body if the hyoid bone. Has two bellies. The inferior belly sits in the posterior triangle, it is only the superior belly which sits in the anterior belly

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23
Q

Infrahyoid muscles- Sternohyoid / Sternothyroid / Thyrohyoid

A

Sternohyoid muscle- originates on the posterior aspect on the sternoclavicular joint and manubrium and inserts on the body of the hyoid bone
Sternothyroid muscle- originates on the posterior surface of the manubrium of the sternum, inserts on the oblique line of the thyroid cartilage.
Thyrohyoid muscle- originates on the oblique line of the thyroid cartilage, inserts on the greater horn an body of the hyoid bone

24
Q

Muscles of the posterior triangle of the neck

A
  • Anterior scalene
  • Splenius capitis
  • Levator scapulae
  • Posterior scalene
  • Middle scalene
  • Inferior body of the omohyoid
  • Trapezius
25
Q

Trapezius muscle

A

Originates on the superior nuchal line and spinous processes of vertebrae C7-T12. It inserts on the lateral 1/3 of the clavicle and the scapula. Has a large attachment area. Functions to support our head and elevate the shoulders.

26
Q

Splenius capitis

A

Originates on the skull and the spinous processes of vertebrae C7 to T4. It inserts on the mastoid process and the lateral 1/3 of the superior nuchal line.

27
Q

Levator scapulae

A

Originates on the transverse processes of C1 to C4. It inserts on the scapula

28
Q

The Scalene muscle

A

Anterior scalene- originates on the transvers process of C3 to C6 and inserts on the 1st rib. Functions to lift the ribs in breathing
Middle scalene- originates on the transverse process C2 to C7 and inserts on the first rib
Posterior scalene- originates on the transverse processes of C4 to C6 and inserts on the 2nd rib

29
Q

Arch of the Aorta

A
  • Brachiocephalic trunk- splits into the right subclavian artery and the right common carotid
  • Left common carotid artery
  • Left subclavian artery
30
Q

Divisions of the common carotid artery

A

1) At the level of the superior margin of the thyroid cartilage (C4) the common carotid artery splits into the external and internal carotid arteries.
2) The internal carotid supplies the brain.
3) The bulging of the internal carotid artery is the carotid sinus which senses changes in blood pressure.
4) The carotid body sits between the internal and external carotid artery, chemoreceptor which monitors the pH of the blood.

31
Q

The branches of the external carotid artery

A
  1. Superior thyroid artery- supplies the thyroid gland
  2. Ascending pharyngeal artery- supplies the pharynx
  3. Lingual artery- supplies the tongue
  4. Facial artery- supplies structures of the face
  5. Occipital artery- goes towards the occipital bone of the skull
  6. Posterior auricular artery- posterior to the ear
  7. Maxillary artery- near the Maxillar bone of the skull
  8. Superficial temporal bone- superior to the temporal bone
32
Q

Branches of the Thyrocervical trunk

A

The left and right subclavian arteries give rise to the thyrocervical trunk. Branches of the thyrocervical trunk supply the neck:
• Inferior thyroid artery- supplies the thyroid gland
• Ascending cervical artery- goes up the neck
• Transverse cervical artery- across the neck
• Supracapular artery- superior to the capular, moves posteriorly
The vertebral arteries are a branch of the subclavian artery. The travel in the transverse foramina of the cervical vertebrae towards the posterior brain. Sits within the neck.

33
Q

External jugular vein

A

Formed by the union of the posterior division of the retromandibular vein and the posterior auricular vein. Its superficial to the sternocleidomastoid muscle.

34
Q

Tributaries of the external jugular vein

A
  • Posterior external jugular vein
  • Transverse cervical vein
  • Suprascapular vein
  • Anterior jugular vein- paired venous channels on either side of the midline. They drain the anterior aspect of the neck. The left and right communicate via the jugular venous arch. Drain into the external jugular vein, varies from person to person
35
Q

The internal jugular vein

A

The internal jugular vein drains blood from the brain, anterior face, cervical viscera and deep muscles of the neck. First part is the superior bulb which is an expanded part of the vein at the jugular foramin.

36
Q

Tributaries of the internal jugular vein

A
  • Inferior petrosal sinus
  • Facial vein
  • Lingual vein
  • Pharyngeal vein
  • Occipital vein
  • Superior thyroid vein
  • Middle thyroid vein
37
Q

Nerves in the neck

A
  • Anterior triangle- cranial nerve, branches from the cervical plexus
  • Posterior triangle- spinal accessory nerve (CNXI), cervical plexus, sympathetic chain, brachial plexus
38
Q

The cranial nerves in the neck

A
  • CNXI spinal accessory- anterior and posterior triangle
  • CNVII Facial- anterior triangle. Provides motor innervation to the posterior belly of the digastric, stylohyoid and plastysma
  • CNIX Glossopharyngeal- anterior triangle, emerge through the jugular foramin. Descends between the internal carotid artery and the internal jugular vein Goes towards the tongue and pharynx
  • CNX Vagus- anterior triangle, emerge through the jugular foramin descends between the internal jugular vein and the internal carotid artery
  • CNXII Hypoglossal- anterior triangle, supplies the muscles of the tongue. Leaves the skull medial to the internal jugular vein. Enters the oral cavity towards the tongue. Fibres from C1 travel with the Hypoglossal nerve. C1 fibres give motor supply to the geniohyoid and thyrohyoid muscles
39
Q

Cervical plexus

A

Anterior rami C1-C4, a network of nerves. Formed in the muscles of the floor of the posterior triangle.
• Muscular/deep branches= Motor- strap muscles (infrahyoid muscles). Phrenic nerve, inferior root of ansa cervicalis, superior root of ansa cervicalis
• Cutaneous/superficial branches- sensory nerves. Supraclavicular nerve, transverse cervical nerve, great auricular nerve, lesser occipital nerve
The cervical plexus travels between the anterior and middle scalene muscles

40
Q

Nerves in the anterior triangle

A

Cranial nerves, branches from the cervical plexus, brachial plexus

41
Q

Cervical plexus branches

A
  • Transverse cervical nerve- cutaneous, emerges from underneath the Sternocleidomastoid muscle in between the anterior and posterior scalene muscles. Extends within the anterior triangle. On top of the fascia
  • Ansa cervicalis- motor, within the muscles of the floor of the posterior triangle. A loop of nerve fibres. Mostly supplies the strap muscles (infrahyoid). C1-C3. Has a superior (C1) and inferior root (C2,C3)
42
Q

Nerves in the posterior triangle

A

Spinal accessory nerve (CNXI), Cervical plexus, Sympathetic chain, Brachial plexus

43
Q

Spinal accessory nerve (CNXI)

A

Sits in both the anterior and posterior triangle, runs deep to the SCM. Travels obliquely over the posterior triangle (on top of the levator scapulae). Provides motor innervation to SCM and trapezius. Sits within the investing layer of the deep cervical fascia, damage to this nerve within the posterior triangle can cause paralysis to the trapezius muscle. Forms the roof of the posterior triangle. Susceptible to damage in the posterior triangle.

44
Q

Cutaneous branches of the cervical plexus

A

Lesser occipital, greater auricular, Transverse cervical and Supraclavicular. Provides the skin, sensory nerves which sit on top of muscles
• Greater auricular- travels superiorly towards the ear
• Lesser occipital- travel towards the occipital bone of the skull
• Supraclavicular- few branches, superior to the clavicle
• Transverse cervical- travels towards the anterior triangle

45
Q

Nerve point of the neck (Herbs point)

A

Where all the nerves emerge underneath the posterior border of the Sternocleidomastoid, around hallway down. Useful in nerve blocks in surgery

46
Q

Phrenic nerve / Brachial plexus / Sympathetic trunk

A

Phrenic nerve- travels anteriorly and inferiorly along the anterior scalene muscle. Provides the diaphragm
Brachial plexus- emerging from the posterior triangle and provides motor and sensory supply to the upper limb.
Sympathetic trunk- cervical part of the sympathetic trunk, deep in the neck. Within the posterior triangle

47
Q

Roots of the neck

A

Key area where structures pass between thorax/neck/upper limb. Relates to the anterior scalenes:
• Anterior to anterior scalene- subclavian vein
• Posterior to anterior scalene- subclavian artery, roots of brachial plexus, apex of lungs
• Crossing the anterior scalene- phrenic nerve, branches of thyrocervical trunk (suprascapular and transverse cervical arteries)

48
Q

Basal ganglia, Cerebellum, Brainstem, Spinal reflexes

A
  • Basal ganglia- organises programs of movement, selection and initiation
  • Cerebellum- fine tuning and motor learning
  • Brainstem- control of posture
  • Spinal reflexes- feedback on movement
49
Q

Layers of the Cerebral cortex

A

There are 6 layers of the cerebral cortex. The cortex contains lots of cell bodies and the white matter contains axons and connections

50
Q

The first layer of the cerebral cortex

A

Layer 1- molecular (plexiform. Composed of the apical dendrites of pyramidal cells. Has a large number of synapses with lots of axons and connections

51
Q

The second layer of the Cerebral cortex

A

Layer 2- outer (external) granular layer. Composed mostly of stellate cells, it receives inputs from the cortex and small pyramidal cells which have local connections which can project to other cortical areas. The outputs mainly go to the cortex but there are lots of local connections

52
Q

The third layer of the Cerebral cortex

A

Layer 3- outer (external) pyramidal cell layer. Contains small/medium pyramidal cells which connect to the molecular layer. There are association and commissural fibres which are sometimes known as cortico-cortical fibres. Receives inputs from a wide area of the cortex

53
Q

The 4th layer of the Cerebral cortex

A

Layer 4- inner (internal) granular cell layer. Composed of closely packed stellate cells, the main input (afferent) layer from the thalamus and cortex

54
Q

The 5th layer of the Cerebral cortex

A

Layer 5- the inner (internal) pyramidal cell layer. Its composed of large pyramidal cells particularly in the motor area. It’s the main output layer i.e. the corticospinal tract

55
Q

The 6th layer of the Cerebral Cortex

A

Layer 6- Multiform layer, contains lots of cell types. Outputs to thalamus and other cortical areas. Below this is the white matter