MSK 2

Question 1

Terminal branches of the brachial plexus

State whether they arise from anterior or posterior division

Answer 1

Musculocutaneous - anterior
Median - anterior
Ulnar - anterior
Axillary - posterior
Radial - posterior

Question 2

State the root values of Musculocutaneous nerve and its sensory and motor function.

Answer 2

Musculocutaneous - C5 C6 C7
Motor - innervates Brachialis, Biceps Brachii and Coracobrachialis
Sensory - gives lateral cutaneous branch of the forearm
- innervates the skin of the lateral surface of the forearm

Question 3

State the root values of Axillary nerve and its sensory and motor function.

Answer 3

C5 C6 (as is nerve to subclavius) 
Motor - deltoids, teres minor and long head of triceps 
Sensory - superior lateral cutaneous nerve of the arm (regimental patch)

Question 4

State the root values of Median nerve and its sensory and motor function.

Answer 4

C6-T1
Motor - most of the flexors of forearm (minus medial half of FDP), thenar muscles and 2 lateral lumbricals.

Sensory - palmar cutaneous branch that innervates lateral part of the Palm and digital cutaneous branch that innervates the lateral 3.5 digits on the palmar aspect.

Question 5

Beneath which muscle in the pectoral region do structures passing into the upper limb travel beneath?

Answer 5

Pec minor

Question 6

State the root values of Radial nerve and its sensory and motor function.

Answer 6

C5-T1
Motor - triceps brachii, brachioradialis and extensors in the posterior compartment of forearm
Sensory - posterior aspect of arm and forearm and posterior lateral aspect of the hand.

Question 7

State the root values of Ulnar nerve and its sensory and motor function.

Answer 7

C8-T1
Motor - medial half of FDP, FCU, muscles of the hand ( including interrosei) except lateral 2 lumbricals
Sensory - anterior and posterior medial 1.5 fingers and Palm.

Question 8

When are the contents of the Axilla most at risk?

Answer 8

When the arm is fully abducted as this compresses the structures in the Axilla the most

Question 9

Borders of the Axilla

Answer 9

Lateral - intertubercular sulcus
Anterior - pectoralis major, minor and subclavius
Medial - serratous anterior and thoracic wall
Posterior - latissimus Dorsi, teres major and subscapularis
Floor - fascia
Apex - posterior border of clavicle and superior border of scapula

Question 10

Contents of Axilla

Answer 10

Axillary artery
Axillary vein
Brachial plexus
Tendons of Coracobrachialis and short head of biceps brachii
Lymph nodes - drain UL and pectoral region (care in women!!)

Question 11

Consequences of Axillary clearance

Answer 11

Lymphoedema
Damage to long thoracic nerve (C5-7)
- winging of scapula

Question 12

Nerve to Subclavius
Long thoracic nerve
Medial pectoral nerve

These are all branches off the brachial plexus. State their nerve roots and the structures they innervate.

Answer 12

Nerve to subclavius

• C5+C6
• innervates subclavius

Long thoracic nerve

• C5-7
• innervates serratous anterior

Medial pectoral nerve

• C8-T1
• innervates pec minor

Question 13

Insertion, neurovascular and action of Coracobrachialis

Answer 13

Inserts into Coracoid process
Brachial artery and musculocutaneous nerve (c5-7)
Action is flex, internally rotate and fine adduction of the arm.

Question 14

Name all the movements of the scapula and the muscles that produce them

Answer 14

Protraction - serratous anterior
Retraction- middle fibres of trapezius and rhomboid
Elevation - upper fibres of trapezius and levator scapulae
Depress - relaxation of the elevator muscles
Lateral rotation - upper and lower fibres of trapezius
Medial rotation - levator scapulae, rhomboid and latissimus Dorsi