Muscles of the back

Question 1

What is the sole connection of the scapula with the axial skeleton?

Answer 1

The clavicle

Question 2

3 functions of the pectoral girdle?

Answer 2

1) The strut formed by the clavicle transmits the forces applied to the upper limb to the trunk
2) Clavicle holds arm clear of the trunk and the scapula is very mobile allowing a great range of movement at the glenohumeral joint
3) Provides attachments for muscles which produce the wide range of movement of the arm

Question 3

Is the clavicle concave or convex?

Answer 3

Concave in lateral third

Convex in medial 2/3

Question 4

Why are the medial 2/3 of the clavicle convex?

Answer 4

To allow the passage of the neurovascular bundle supplying the upper limb

Question 5

What are the medial and lateral ends of the clavicle called?

Answer 5

Medial = sternal
Lateral = acromial

Question 6

Which ribs does the scapula lie between?

Answer 6

Ribs 2-7

Question 7

In which direction do the acromion and coracoid process of the scapula project?

Answer 7

They both project anteriorly but the acromion lies superiorly to the coracoid process

Question 8

What are the 2 condyles of the distal end of the humerus, which lies more laterally?

Answer 8

The capitulum and trochlea

Capitulum lies more laterally

Question 9

What is the nerve supply to the trapezius?

Answer 9

Motor - spinal part of accessory nerve

Sensory (proprioception) - anterior rami of C3 and C4`

Question 10

Why are teres major and deltoid not considered rotator cuff muscles?

Answer 10

All rotator cuff muscles insert into the head of the humerus

Teres major and deltoid do not, they attach to the intertubercular fossa and deltoid tuberosity respectively

Question 11

What is the difference between the actions of the muscles that attach to the greater tuberosity and those that attach to the lesser tuberosity of the humerus?

Answer 11

1) Attached at greater tuberosity - lateral rotators

2) Attached at lesser tuberosity - medial rotators

Question 12

Which muscle tendon crosses teres major and minor at right angles?

Answer 12

The long head of triceps brachii

Question 13

What are the 4 borders of the quadrangular space?

Answer 13

Superiorly - teres minor
Inferiorly - teres major
Medially - long head triceps brachii
Laterally - humerus

Question 14

Which artery and nerve are located within the quadrangular space?

Answer 14

Axillary nerve

Posterior circumflex artery and vein

Question 15

What are the 4 structures that help stabilise the glenohumeral joint?

Answer 15

1) Glenoid labrum
2) Ligaments
3) Biceps tendon
4) Rotator cuff muscles

Question 16

Contraction of which muscles produces protraction of the scapula? 3

Answer 16

Pectoralis major and minor

Serratus anterior

Question 17

Contraction of which muscles produces retraction of the scapula? 3

Answer 17

Rhomboid major and minor

Middle fibres of the trapezius

Question 18

Contraction of which muscles leads to elevation of the scapula? 4

Answer 18

Upper fibres of the trapezius
Levator scapulae
Rhomboid major and minor

Question 19

Contraction of which muscles leads to depression of the scapula? 3

Answer 19

Lower fibres of trapezius
Pectoralis minor
Latissimus dorsi

Question 20

In which direction can the inferior angle of the scapula be moved from its anatomical position and how does this allow the arm to be lifted above the head?

Answer 20

Inferior angle can be moved laterally and cranially from the anatomical position
This movement brings the face of the glenoid cavity upwards and allows the arm to be lifted above the head

Question 21

What are the attachements and innervations of the latissimus dorsi muscle?

Answer 21

Origins - spinous processes T7-L5, iliac crest, thoracolumbar fascia, inferior angle of scapula, ribs 9-12
Insertions - floor of intertubercular groove of humerus
Innervation - Thoracodorsal nerve C6-8

Question 22

Which 4 muscles act in elevation of the pectoral girdle?

Answer 22

1) Trapezius
2) Levator scapulae
3) Rhomboids

Question 23

Which 5 muscles act in depression of the pectoral girdle, what also plays a role?

Answer 23

1) Pectoralis major
2) Pectoralis minor
3) Latissimus dorsi
4) Serratus anterior
5) Inferior fibres of trapezius
Gravity also plays a role

Question 24

Which 3 muscles act in protraction of the pectoral girdle?

Answer 24

1) Pectoralis minor
2) Pectoralis major
3) Serratus anterior

Question 25

Which 4 muscles act in retraction of the pectoral girdle?

Answer 25

1) Rhomboids
2) Latissimus dorsi
3) Middle fibres of trapezius

Question 26

Which 3 muscles act in upward (lateral) rotation of the pectoral girdle?

Answer 26

1) Superior fibres of trapezius
2) Serratus anterior
3) Inferior fibres of trapezius

Question 27

Which 6 muscles act in downward (medial) rotation of the pectoral girdle, what also plays a role?

Answer 27

1) Levator scapulae
2) Rhomboids
3) Pectoralis major
4) Pectoralis minor
5) Latissimus dorsi
Gravity also plays a role

Question 28

Sensory (proprioception) fibres from the trapezius are carried in what nerve?

Answer 28

Anterior rami of C3 and C4