Upper Limb Anatomy

Question 1

What are the roots of the brachial plexus?

Answer 1

C5 - T1

Question 2

What nerve roots make up the inferior trunk of the brachial plexus?

Answer 2

C8 - T1

Question 3

What nerve root makes up the middle trunk of the brachial plexus?

Answer 3

C7

Question 4

What nerve roots make up the upper trunk of the brachial plexus?

Answer 4

C5 - C6

Question 5

Where are the nerve roots of the brachial plexus found?

Answer 5

Posterior triangle

Between scalenus anterior and scalenus medius

Question 6

Where are the trunks of the brachial plexus found?

Answer 6

Found at the base of the posterior triangle behind the 3rd part of the subclavian artery

Question 7

Where are the divisions of the brachial plexus found?

Answer 7

Behind the middle 1/3 of the clavicle

Question 8

Where would you find the beginning of the cords of the brachial plexus on a subject?

Answer 8

Apex of the axilla

Question 9

What makes up the lateral cord of the brachial plexus?

Answer 9

Upper and Middle trunk (anterior aspect)

Question 10

What makes up the posterior cord?

Answer 10

Posterior divisions of all trunks

Question 11

What are the 3 nerve branches that come off the roots of the brachial plexus?

Answer 11

• Dorsal scapular nerve
• C5 contribution to phrenic nerve
• Long thoracic nerve (supplies serrates anterior)

Question 12

Where does the sub scapular nerve branch from and what does it supply?

Answer 12

Branches from superior trunk (C5-C6)

Supplies Supraspinatus and Infraspinatus muscle

Question 13

What are the 5 branches of the medial cord?

MEDIAL

Answer 13

• Medial pectoral nerve
• Medial cutaneous nerve of arm
• Medial cutaneous nerve of forearm
• Medial branch of median nerve
• Ulnar nerve (most medial nerve in the arm)

Question 14

What are the branches of the posterior cord?

Answer 14

STARS

• Subscapular (upper) nerve
• Thoracodorsal nerve
• Axillary nerve
• Radial nerve
• Subscapular nerve (lower)

Question 15

What are the 3 branches of the lateral cord?

Answer 15

• Lateral pectoral nerve
• Musculocutaenous nerve
• Lateral part of medial nerve

Question 16

What nerve roots are damaged in Erbs Palsy and what are the motor and sensory affections?

Answer 16

C5 - C6

Sensory: loss of sensation of radial side of arm and forearm

Motor:
- Paralysis of abductors (supraspinatus + deltoid
- Paralysis of arm external rotators (infraspinatus + tires minor)
- Paralysis of forearm flexors and supinators (biceps + brachialis + brachioradialis)

Arm will be ADDUCTED and INTERNALLY ROTATED and forearm EXTENDED AND PRONATED (waiters tip position

Question 17

Which nerve roots are damaged in Klumpke’s palsy and what are the motor and sensory affections?

Answer 17

C8 - T1

Sensory: loss of sensation over ulnar border of forearm and hand

Motor:
- Paralysis of all intrinsic muscles of hand
- Paralysis of wrist flexors (except flexor carpi radialis)
- Hyperextension of MCP joints with flexion of IP joints (claw hand)

Question 18

What does the acromion articulate with?

Answer 18

Clavicle

Question 19

Where does the the supraspinatus muscle originate?

Answer 19

Supraspinous fossa (of scapula)

Question 20

Where does the infraspinatus muscle originate?

Answer 20

Infraspinous fossa (of scapula)

Question 21

Where does the subscapularis muscle originate?

Answer 21

Subscapular fossa (of scapula)

Question 22

Where does the Teres minor originate from?

Answer 22

Lateral border of scapula

Question 23

Where is the subclavian groove found?

Answer 23

Underside of clavicle

Question 24

What is the origin of the long head of biceps?

Answer 24

Supraglenoid tubercle

Question 25

Where does the short head of the biceps originate from?

Answer 25

Coracoid process

Question 26

What is the origin of the triceps?

Answer 26

Infraglenoid tubercle

Question 27

What are the attachments of the rotator cuff muscles?

Answer 27

SITS SIT (supraspinatus, infraspinatus, teres minor) - Greater tuberosity S (Subscapularis) - Lesser tuberosity

Question 28

What is the nerve supply of the Subscapularis muscle?

Answer 28

Upper + Lower sub scapular nerves (Posterior trunk of brachial plexus)

Question 29

What innervates the supraspinatus and infraspinatus muscle?

Answer 29

Suprascapular nerve (Upper trunk)

Question 30

Which rotator cuff muscle does the axillary nerve supply?

Answer 30

Teres minor

Question 31

What is the origin and insertion of the deltoid muscle?

Answer 31

Origin: Lateral clavicle + scapula Insertion: Deltoid tuberosity (on humerus)

Question 32

What are the 3 fibres of the deltoid and their actions?

Answer 32

Anterior fibres: Flexion + medial rotation Posterior fibres: Extension + lateral rotation Middle fibres: Abductor of arm AFTER 15 degrees

Question 33

What are the 2 points of origin of Pectoralis major?

Answer 33

- Clavicular head (medial half of anterior surface) - Sternocal-costal head (anterior surface of sternum + upper 6 costal cartilages + EOA)

Question 34

Where does the pectolaris major insert?

Answer 34

Lateral lip of bicipital groove

Question 35

What are the actions of the pectolaris major?

Answer 35

Overall: adduction and medial rotation of arm Clavicular head: flexion of arm Sternocostal head: extends flexed arm Also acts as accessory respiratory muscle by elevating ribs

Question 36

What are nerve innervations of pectoralis major and their roots?

Answer 36

Medial (C8-T1) and Lateral (C5-C&) pectoral nerves

Question 37

What are the origins of the trapezius?

Answer 37

- Spinal processes C7 - T12 - Occipital protuberance Action: rotating of scapula

Question 38

What are the origins and insertions of the serratus anterior and what is its action?

Answer 38

Origins: Ribs 1-9 Insertion: ventral medial scapula Prevents winging of scapula

Question 39

What supplies the serratus anterior and its roots?

Answer 39

Long thoracic nerve (C5-C7)

Question 40

What are the borders of the Triangular space and what structure passes through it?

Answer 40

Superior: Teres Minor Inferior: Teres Major Laterally: Long head of triceps Circumflex scapular artery passes through

Question 41

What are the borders of the quadrangular space and what structures pass through it?

Answer 41

Superiorly: Teres Minor Inferiorly: Teres Major Medially: Long head of triceps Laterally: Humerus Structures passing through: - Axillary nerve - Humeral artery - Posterior circumflex artery

Question 42

Which muscle divides the axillary artery and which muscle marks the termination of the axillary artery?

Answer 42

Pectolaris minor divides the artery into 3 parts Pectoralis major is the landmark of the termination of the axillary artery where it becomes the brachial artery

Question 43

What are the branches of axillary artery that make up the 3 parts of it?

Answer 43

Screw The Lawyer, Save A Patient Part 1: - Superior thoracic artery Part 2: - Thoracoacromial artery (branches into deltoid, acromial, pectoralis, clavicular) - Lateral thoracic artery Part 3: - Subscapular artery (thoracodorsal and circumflex artery) - Anterior humeral circumflex artery (supplies humeral head) - Posterior humeral circumflex artery

Question 44

What 3 ligaments and 3 muscles attach to the coracoid process?

Answer 44

Ligaments: - Coracoclavicular - Coracoacromial - Coracohumeral Muscles: - Pec minor (inserts) - Coracobrachialis (origin) - Short head of biceps (origin)

Question 45

What muscles insert into the bicipital groove? Lady between 2 majors

Answer 45

- Teres major (medial lip) - Latissimus dorsi (floor) - Pectoralis major (lateral lip)

Question 46

What are 3 factors that decrease the stability of the shoulder joint?

Answer 46

- Shallow glenoid cavity - Lax capsule with few ligaments - Inferior aspect not supported due to presence of quadrangular space

Question 47

What additional movement of the humerus is required to achieve complete abduction of the humerus?

Answer 47

External rotation (alongside upward rotation of scapula)

Question 48

What factors contribute to the stability of the shoulder joint?

Answer 48

- Bony surfaces covered in hyaline articular cartilage - Fibrous capsule - Internal and external accessory ligaments - Rotator cuff muscles and tendons

Question 49

Which nerve is mainly affected in shoulder dislocations and how can it be tested?

Answer 49

Axillary nerve Motor: assess middle, anterior and posterior fibres (abduction, flexion, extension) Sensory: skin overlying deltoid