Root of the Neck

Question 1

boundaries of root of the neck

Answer 1

posterior: Body of T1 (anterior surfaces), head and neck of first rib
Lateral: body first rib
anterior: distal portion first rib, articulation of first rib with manubrium

Question 2

Anterior Scalene

Answer 2

O: anterior tubercles of transverse processes of CV3-CV6
I: scalene tubercle 1st rib
A: elevates 1st rib, side bends and rotates cervical column to opposite side, both sides acting flexes vertebral column
N: ventral rami, spinal nerves C5-7

Question 3

middle scalene

Answer 3

O: posterior tubercles of transverse processes of CV2-CV7
I: superior surface of 1st rib posterior to the groove for the subclavian artery
A: elevates 1st rib; side bends and rotates cervical column; both sides acting flexes the vertebral column
N: ventral rami of spinal nerves

Question 4

posterior scalene

Answer 4

O: posterior tubercles of tansverse processes CV5-CV7
I: outer surface of 2nd rib
A: elevates 2nd rib; side bends and rotates cervical columns, both sides acting flexes vertebral column
n: ventral rami from brachial plexus (C7-8)

Note; the posterior scalene may be partially or totally fused with the middle scalene muscle.

Question 5

scalenius minimus

Answer 5

in approx. 4-5% of individuals, a scalenius minimus (sibson’s muscle) exists which courses from the lower cervical spinous processes, usually CV7, to the 1st rib between the anterior and middle scalenes compressing the inferior trunk of the brachial plexus.

Question 6

thoracic outlet syndrome

Answer 6

Clinical note: the brachial plexus and the subclavian artery pass between the anterior and middle scalene muscles (scalene triangle) and can be compressed between the two when the scalene muscles undergo tonic contraction or in the presence of a cervical rib resulting in thoracic outlet syndrome: pain, numbness and tingling in the neck, medial forearm and 4th and 5th fingers, paresis of the intrinsic muscles of the hand, and poor circulation (cold fingers, swollen upper limb.)

Also, brachial plexus nerve block to anesthetize the upper limb is conducted by injecting an anesthetic agent around the supraclavicular portion of the brachial plexus in the region superior to the middle third of the clavicle.

Question 7

Longus capitis

Answer 7

O: anterior tubercles of transverse processes C3-CV6
I: inferior surface, basilar portion of occipital bone
a: flexes head and neck
N: ventral rami spinal n C1-4

Question 8

longus colli

Answer 8

O and I: upper portion: extends from the anterior surface of vertebral bodies above to transverse processes of vertebrae below
lower portion: extends from teh anterior surfaces of vertebral bodies below to transverse proccesses of vertebrae above.

Tie vertebrae together much like the erector spinae muscles do posteriorly.

A: flexes neck and assists in its rotation (upper fibers rotate to the same side whiel lower fibers rotate to the side opposite)
N: ventral rami, spinal nerves C2-C7

Question 9

Rectus capitis anterior

Answer 9

O: anterior surface of lateral mass of atlast (CV1)
I: basilar portion of occipital anterior to foramen magnum
A: flexes and rotates skull to same side
N: ventral rami of spinal nn. C1 (C2)

Question 10

rectus capitis lateralis

Answer 10

O: superior surface transverse process of atlas (CV1)
I: inferior surface, jugular process of occipital (directly posterior to jugular foramen)
A: lateral flexion (side bending) of skull.
N: ventral rami of spinal nn. C1

Question 11

general info re: arteries

Answer 11

the brachiocephalic artery on the right bifurcates posterior to the sternoclavicular joint into RIGHT SUBCLAVIAN and RIGHT COMMON CAROTID arteries.

On the left, these arteries arise directly from the arch of the aorta

Common carotid (in the neck) ascends within carotid sheath.

Question 12

dysphagia lusoria

Answer 12

is a condition where the right subclavian artery arises from the left side of the aorta distal to the origin of the left subclavian a. It crosses posterior to the esophagus and trachea to course over the 1st rib in the root of the neck. This condition, often undiagnosed until death, has the potential to compress both the trachea and esophagus thereby leading to difficulty swallowing. 1% occurrence.

Question 13

Subclavian artery

Answer 13

1. Courses through the root of the neck from its origin laterally over the cupola of the lung to the lateral border of the 1st rib.
2. divisible into 3 parts by the passage of the anterior scalene muscle anteriorly.

Question 14

Part 1 of the subclavian artery

Answer 14

medial to the anterior scalene
a. Vertebral a.
Thyrocervical trunk
- inferior thyroid a.
- transverse cervical a.
- suprascapular a.
- ascending cervical a.
b. internal thoracic

Question 15

Vertebral a.

Answer 15

branches superiorly and ascends between the longus colli and anterior scalene muscles to enter the transverse cervical foramen of CV6. It ascends through all remaining cervical vertebrae, courses posteriorly over the atlas, grooving the posterior arch, pierces the atlanto-occipital membrane posteriorly and ascends through the foramen magnum where it fuses with its opposite counterpart inferior to the pons to form the basilar artery. In the neck, it supplies muscular branches and spinal branches to vertebrae and the spinal cord and anastomoses with the ascending cervical a.

Question 16

Thyrocervical trunk

Answer 16

arises from the anterior-superior surface of the subclavian artery medial to the anterior scalene and opposite the internal thoracic artery. It runs a short course and provides the following branches:

• inferior thyroid a.
• transverse cervical a.
• suprascapular a.
• (ascending cervical a.)

Question 17

inferior thyroid a.

Answer 17

branches from the thyrocervical trunk medially to ascend the medial border of the anterior scalene.
passes behind the carotid sheath and sympathetic trunk at the level of the thyroid cartilage
provides branches to the pharynx, larynx, trachea and esophagus before providing glandular branches to the posterior inferior portion of the thyroid gland.
anastomoses with posterior branches of the superior thyroid artery.

Question 18

transverse cervical a.

Answer 18

branches from the thyrocervical trunk laterally
crosses the posterior triangle inferiorly, medial (deep) to the inferior belly of the omohyoid muscle.
Exits the posterior triangle by passing deep to the trapezius muscle which it supplies.

Question 19

suprascapular a.

Answer 19

branches from the thyrocervical trunk laterally just inferior to the origin of the transverse cervical a.
Crosses the posterio triangle inferiorly, medial (deep) to the inferior belly of the omohyoid muscle.
Paralleled by its accompanying vein, it is joined by the suprascapular n. as it passes out of hte posterior triangle laterally to enter the scapular region

Question 20

Ascending cervical a.

Answer 20

may arise as a branch of the thyrocervical trunk, but most often is a branch of hte inferior thyroid a. Ascends the anterior scalene muscle medial to the phrenic nerve to provide muscular and spinal branches. Anastomoses with the vertebral, ascending pharyngeal and occipital arteries.

Question 21

Internal thoracic a.

Answer 21

arises from the subclavian opposite the thyrocervical trunk to descend inferiorly into the thorax posterior to the sternal end of the clavicle and junction of the subclavian and internal jugular veins. It is crossed anteriorly by the phrenic n

Question 22

Part 2 of the Subclavian a.

Answer 22

Costocervical trunk

• deep cervical a.
• highest (posterior) intercostal a.

Question 23

Part 3 of the subclavian a.

Answer 23

Lateral to anterior scalene

- dorsal scapular a.

Question 24

Costocervical trunk

Answer 24

passes posteriorly from the subclavian a. over the cupola of the lung where it divides into:

• deep cervical a.
• highest (posterior) intercostal a.

Question 25

Deep cervical a.

Answer 25

ascends dorsal to the brachial plexus between the semispinalis cervicis and capitis muscles. Will anastomose with the descending branch of hte occipital artery.

Question 26

Highest (posterior) intercostal a.

Answer 26

descends anterior to the head of the 1st rib, provides the posterior intercostal a. to the first intercostal space and terminates by forming the 2nd posterior intercostal a.

Question 27

dorsal scapular a.

Answer 27

may arise from Part II or Part III. of the subclavian. When present (50-705) it passes dorsally through the brachial plexus near the middle trunk. After reaching the levator scapulae, it descends under the rhomboid muscles along the vertebral border of hte scapula where it accompanies the dorsal scapular n.; participates in the scapular anastomosis.

Question 28

Subclavian v.

Answer 28

direct continuation of the axillary v. medial to the lateral border of the 1st rib.

The subclavian and internal jugular veins join immediately posterior to the sternoclavicuar joint to form the right and left brachiocephalic veins.

The external jugular v. enters the subclavian v. superior to the clavicle after receiving the anterior jugular v. medially.

Tributatries to the major veins at the root of the neck are highly variable and include the following:

• transverse cervical v.
• dorsal scapular v.
• suprascapular v.
• vertebral v.
• inferior thyroid v.

Most often, the vertebral and inferior thyroid vv. empty into the brachiocephalic vv.

The transverse cervical, dorsal scapular, suprascapular vv. most often enter the external jugular v. but on occasion may enter the subclavian v. directly. Note that each possesses a bicuspid valve loated in close proximity to their joining hte next major vein.

Question 29

Clinical note: Central Venous Line placement

Answer 29

the subclavian vein is an often used point of entry for CVL placement. Used for the administration of parenteral fluids or drugs (patient controlled anesthetic- PCA), cardiac cathetrization, or as a means of measuring central venous pressure, improper needle placement can result in penumothorax or placement of the needle within the subclavian artery.

Recall: the union of the subclavian and internal jugular vv. forms the right and left jugulovenous angles which respectively receive the right lymphatic duct and thoracic duct.

Question 30

General info re; nerves

Answer 30

Neurons located within the lateral horn of hte spinal cord at the approximate levels of T1-T4 provide preganglionic fibers which traverse the ventral root, spinal nerve and white ramus communicans to enter the sympathetic chain and ascend to cervical sympathetic ganglia (superior, middle, vertebral, inferior). THESE GANGLIA will provide post-ganglionic innervation to the head, neck and a portion of hte thorax (heart).

Question 31

Superior cervical ganglion

Answer 31

Represents the fused cervical ganglia of C1-C4
located on the anterior surface of the longus capitis muscle
provides ALL post-ganglionic sympathetic fibers to the head; therefore, there are no pregangilionic sympathetic fibers in the head.

Question 32

Internal carotid nerve

Answer 32

forms a plexus on the internal carotid artery from which fibers leave to form:
caroticotympanic plexus on the promontory of the middle ear in conjunction with CNs VII and IX
Deep petrosal nerve
cavernous plexus