Posterior Triangle of the Neck

Question 1

What is the anterior border of the triangle?

Answer 1

The posterior border of the

sternocleidomastoid.

Question 2

What is the posterior border of the triangle?

Answer 2

The anterior border of the trapezius.

Question 3

What is the base of the triangle?

Answer 3

The clavicle.

Question 4

What is the contents of the posterior triangle of the neck?

Answer 4

The external jugular vein,
The roots of the brachial plexus,
accessory nerve,
cervical and supracervical lymph nodes.

Question 5

What are the cutaneous nerves of the posterior triangle?

Answer 5

The lesser occipital (C2),
The greater auricular C2,3),
The lateral supraclavicular (C3,4),
The intermediate supraclavicular (C3,4)
The medial Supraclavicular (C3,4).

Question 6

What is the major vein present in the posterior triangle?

Answer 6

The External Jugular.

Question 7

what is the origin and attachment of the Sternocleidomastoid (SCM)?

Answer 7

Origin - The mastoid process, and partially to nuchal line.

Attachment - Sternum and clavicle.

Question 8

What is the innervation of the SCM?

Answer 8

Motor - Spinal accessory nerve (CNXI)

pain and proprioception - cervical plexus (C2,C3).

Question 9

What are the functions of the SCM?

Answer 9

Lateral flexion ( by rotation),
Extension (at atlanto-occipital joint),
Flexion of the cervical vertebrae.

Question 10

What are the three “parts” of the trapezius muscle?

Answer 10

The ascending part,
The transverse part,
The descending part,

Question 11

What is the function of the ascending part of the trapezuis?

Answer 11

To depress the scapula.

Question 12

What is the function of the transverse part of the trapezuis?

Answer 12

To retract the scapula.

Question 13

What is the function of the descending part of the trapezuis?

Answer 13

To elevate the scapula and rotate the glenoid cavity.

Question 14

What is the innervation of the trapezuis?

Answer 14

Motor - spinal accessory nerve CNXI,

Proprioception - cervical plexus C3,C4.

Question 15

What is the overall function of the trapezuis muscle group?

Answer 15

To hold the scapula in position whilst the body is weight bearing.

Question 16

What are the muscles of the floor of the posterior triangle of the neck?

Answer 16

The Omohyoid muscle,

Splenius capitis.

Question 17

What is the function and innervation of the omohyoid muscle?

Answer 17

Function - to depress the hyoid bone.

Innervation - the ansa cervicalis.

Question 18

What is the function and innervation of the Splenius capitis?

Answer 18

Function - to extend and rotate the neck.

Innervation - dorsal rami of middle cervical.

Question 19

What are the muscles of the posterior triangle excluding the muscles of the floor, SCM and Trapezius?

Answer 19

Anterior scalene,
Middle scalene,
levator scapulae,
posterior scalene.

Question 20

What is the origin and attachment of the levator scapulae?

Answer 20

Origin - the transverse processes of the atlas, axis, 3rd and 4th cervical vertebrae.
Attachment - the medial scapular bone between superior angle and medial end of scapular spine.

Question 21

What is the function of the levator scapulae muscle?

Answer 21

help control the scapular position, elevate the shoulder and when the shoulder is fixed can help laterally flex neck to the same side.

Question 22

What is the innervation of the levator scapulae?

Answer 22

Direct branches of C3,C4 and C5 via dorsal scapular nerve.

Question 23

What is the origin and attachment of anterior scalene?

Answer 23

Origin - the transverse processes of C3-6.

Attachment - The scalene tubercle on the first rib.

Question 24

What is the origin and attachment of the middle scalene?

Answer 24

Origin - the transverse processes of C2-7.

Attachment - The subclavian artery grove on the first rib.

Question 25

What is the origin and attachment of the posterior scalene?

Answer 25

Origin - the transverse processes of C4-6.

Attachment - to the second rib.

Question 26

What is the innervation the Scalenes?

Answer 26

direct branches from the anterior rami;
Anterior - C4 too C7,
Middle - C3 too C7,
Posterior - C5 too C7.

Question 27

What is the functions of the Scalenes?

Answer 27

To flex the neck (bilaterally), Tilt the head to the same side (unilaterally) and elevate the upper ribs.