Superficial Back

Question 1

What are the main shoulder joints?

Answer 1

1. Glenohumeral Joint
2. Acromioclavicular Joint
3. Sternoclavicular Joint

Question 2

Glenohumeral Joint

Answer 2

Ball-in-socket joint, multiaxial
Movement of the arm
Extremely mobile, weak and not very stable

Question 3

Acromioclavicular Joint

Answer 3

Relatively weak planar joint with limited mobility
Some rotation occurs with scapular movements

Question 4

Sternoclavicular Joint

Answer 4

Mobile, saddle joint surrounded by strong ligaments
Movement occurs with all scapular motions

Question 5

What are the three types of fascia?

Answer 5

Superficial fascia
Deep fascia
Investing fascia

Question 6

Superficial fascia

Answer 6

Deep to skin, primarily adipose
Varies in thickness, often very thick in lower back

Question 7

Deep Fascia

Answer 7

Dense connective tissue lying deep to superficial fascia

Question 8

Investing Fascia

Answer 8

Extensions of deep fascia that surround muscles and neurovascular bundles

Question 9

What does the extrinsic back muscles act on?

Answer 9

Primary action is on the upper limb and rib cage

Question 10

What are the different movements of the scapula?

Answer 10

Elevation/Depression
Protraction/Retraction
Superior/Inferior Rotation

Question 11

What are the superficial extrinsic back muscles?

Answer 11

1. Trapezius
2. Latissimus dorsi
3. Levator scapulae
4. Rhomboid major
5. Rhomboid minor

Question 12

What is the origin, insertion, and innervation of the trapezius muscle?

Answer 12

Origin - external occipital protuberance, nuchal ligament, spinous processes of lower cervical and thoracic vertebrae (C7-T12)

Insertion - Lateral 1/3 of clavicle, scapular spine, acromion process

Innervation - Accessory nerve (CN XI)

Question 13

What are the actions of the trapezius muscle?

Answer 13

Descending fibers - elevate scapula (extend and laterally flex neck when shoulders are fixed)

Middle fibers - Retracts scapula

Ascending fibers - Depress scapula

Ascending and descending fibers - work together to superiorly rotate the scapula

Question 14

Clinical correlate - Injury to Spinal Accessory Nerve (CN XI)

Answer 14

CN XI prone to injury and can cause paralysis of the trapezius and possibly sternocleidomastoid. Shoulder will noticeable lower at rest due to unresisted pull of gravity. Pt will be unable to abduct upper limb above shoulder due to weakened superior scapular rotation

Question 15

What is the origin, insertion, action, and innervation of the latissimus dorsi?

Answer 15

Origin - Spinous processes of lower thoracic vertebrae (T7-T12), thoracolumbar fascia

Insertion - Anterior humerus (floor of intertubercular sulcus), sometimes angle of scapula

Action - Adducts, extends, and medially rotates humerus

Innervation - Thoracodorsal nerve

Question 16

What is the origin, insertion, actions, and innervation of the levator scapulae?

Answer 16

Origin - Transverse processes of cervical vertebrae (C1-C4)

Insertion - Medial border of the scapula superior to scapular spine

Action - Elevates and inferiorly rotates scapula, assists in extension of neck

Innervation - Dorsal scapular nerve

Question 17

What is the origin, insertion, action, and innervation of the rhomboid major?

Answer 17

Origin - Spinous processes of upper thoracic vertebrae (T2-T5)

Insertion - Medial border of scapula inferior to scapular spine

Action - Retract and elevate scapula, inferior rotation

Innervation - Dorsal scapular nerve

Question 18

What is the origin, insertion, action, and innervation of the rhomboid minor?

Answer 18

Origin - Spinous processes of lower cervical and upper thoracic vertebrae (C7-T1)

Insertion - Medial border of scapula at root of scapular spine

Action - Retract and elevate scapula, inferior rotation

Innervation - Dorsal scapular nerve

Question 19

What are the deep extrinsic muscles?

Answer 19

Serratus posterior superior
Serratus posterior inferior

Question 20

What is the origin, insertion, action, and innervation of the serratus posterior superior?

Answer 20

Origin - Spinous processes of lower cervical and upper thoracic vertebrae (C7-T3)

Insertion - Super borders of upper ribs (ribs 2-5)

Actions - Elevate ribs (superior), proprioception

Innervation - Local intercostal nerves (ventral primary rami)

Question 21

What is the origin, insertion, action, and innervation of the serratus posterior inferior?

Answer 21

Origin - Spinous processes of lower thoracic and upper lumbar vertebrae (T11-L2)

Insertion - Inferior border of lower ribs (ribs 8-12)

Actions - Depress ribs (inferior), proprioception

Innervation - Local intercostal nerves (ventral primary rami)

Question 22

Clinical correlate: Triangle of Auscultation

Answer 22

Triangular space deep to which is devoid of large muscles making it an ideal place to listen to posterior lungs. Borders: Inferior is latissimus dorsi, medial is trapezius, and lateral is medial border of scapula

Question 23

Clinical correlate: Lumbar Triangle

Answer 23

Triangular space between latissimus dorsi and external abdominal oblique, lacks muscular reinforcement making it prone to lumbar hernias

Question 24

What innervates the superficial extrinsic back muscles (except trapezius)?

Answer 24

Brachial plexus - supplies the upper limb. Dorsal scapular and thoracodorsal nerves are branches of this plexus.

Question 25

What kind of nerve innervates the trapezius?

Answer 25

Cranial Nerve - accessory nerve

Question 26

What innervates the deep extrinsic back muscles?

Answer 26

Local intercostal nerves from ventral primary rami of spinal nerves

Question 27

What innervates the skin of the back?

Answer 27

Posterior cutaneous branches of dorsal rami of spinal nerves - developed from dermatomes

Question 28

What is the primary blood supply to the extrinsic back muscles?

Answer 28

From branches of subclavian and axillary arteries.

Transverse cervical and dorsal scapular are from subclavian

Blood also supplies by regional intercostal arteries