cervical and brachial phlexus

Question 1

Main roots(ventral rami) of cervical plexus:

Answer 1

C1 to C4, C5 not a major root
The plexus is formed in front of the Levator scapula and Scalenus medius, and covered by the Sterno-cleido-mastoid.

Each nerve, except the first, divides into an
upper and a lower branch, and the branches
unite to form three loops.

Question 2

Cervical plexus is sandwiched between the

Answer 2

scalene muscles posteriorly and SCM anteriorly.

Question 3

middle post. border of SCM, a point where nerves wrap around the border of SCM.

Answer 3

Punctum nervousum-Is formed by the anterior divisions of the upper four cervical nerves. (4 branches go to the punctum nervousum)

Question 4

cervical plexus- branches are divided into

Answer 4

two (superficial & deep) groups

Question 5

which supplies the skin of the upper and back part of the auricle.

Answer 5

lesser occipital(C2) (superficial sensory)

Question 6

is distributed to the skin of the face over the parotid gland, and the skin over the mastoid process and on the back of the auricle.

Answer 6

Great auricular(C2,3)(superficial sensory)

Question 7

distributed to the antero-lateral parts of the neck.

Answer 7

Transverse cervical(C2,3) (superficial sensory) which formed by the midline,scm and the lower border of mandible

Question 8

branches that are divided into three major groups (anterior, middle, and posterior) supplying the skin from the middle line to the skin over the Pectoralis major and Deltoid and also the skin of the upper and posterior parts of the shoulder.

Answer 8

Supraclavicular(C3,4) (superficial sensory)-above the clavicle

Question 9

(deep branches of cervical)

Deep Internal communicating With:

Answer 9

Hypoglossal (C1) cranial nerve 12 communicate with c1

vagus (C1,2), cranial nerve 10 communicates with c1 ,c2

sympathetic (C1-4).

Question 10

deep branches of cervical

Muscular branches to:

Answer 10

Rectus capitis lateralis (C1),

Rectus capitis anterior (C1,2),

Longus capitis (C1-3).

Question 11

deep branches of cervical

Deep External communicating with:

Answer 11

Accessory (C2-4).

Question 12

deep branches of cervical

Muscular branches to:

Answer 12

Sternocleidomastoid (C2),

Trapezius (C3,4),

Levator scapula (C3,4),

Scalenus medius (C3,4).

Question 13

contains motor and sensory fibers in the proportion of about two to one. It arises chiefly from the fourth cervical nerve, but receives a branch from the third and another from the fifth.
It’s motor fibers supply the diaphragm, and the sensory fibers will supply parts of pleura and peritoneum lining the diaphragm.

Answer 13

Phrenic Nerve roots C 3, 4, 5

NOTE: If asked in exam phrenic nerve is a pure motor!

Question 14

sandwiched between ant scalene and middle scalene

Answer 14

Brachial Plexus

SCM not touching the brachial plexus
Is formed by the anterior ram (roots of plexus)i of spinal nerves C5-T1.

Question 15

C5 and C6 will join to form the upper trunk

C7 will make the middle trunk by itself

C8 and T1 also unite to form the lower trunk.

Answer 15

Each trunk will divide into anterior and posterior divisions.

Question 16

_____ of the upper and middle trunk will unite to form the lateral cord.

Answer 16

Anterior divisions

Question 17

The medial cord is just made by the anterior division of the lower trunk.

Answer 17

The posterior cord is formed by the union of all posterior divisions.

Question 18

The branches derived from the roots or trunks of the plexus are called supraclavicular branches

Answer 18

those derived from the cords are called infraclavicular branches.

Question 19

(brachial)The main branches derived from the cords include:

Lat. Cord:

Answer 19

Lat. Pectoral [C5 – C7] (motor) -pec major and pec minor*more important for pec major

Musculocutaneous [C5 – C7] (Mixed)

Lat. Root of median nerve [C5– C7]

Question 20

(brachial)The main branches derived from the cords include: Med. Cord:

Answer 20

Med. Pectoral [C8 – T1] (motor) pec major and pec minor *pec minor

Med. Cutaneous n. of arm [T1] (sensory)

Med. Cutaneous n. Of forearm [C8 – T1] (sensory)

Ulnar [C7 – T1]mixed nerve

Med. Root of median nerve [C8 – T1] - combine with lateral root of median nerve to become median nerve

Question 21

(brachial)The main branches derived from the cords include: Post. Cord:

Answer 21

Upper subscapular [C5 – C6]-pure motor,supplies half of subscapularis

Thoracodorsal [C6 – C8], lats

Lower subscapular [C5 – C6],-pure motor nerve that reaches the lower part of subscapularis,supplies also teres major

Axillary [C5 – C6]-mixed nerve with motor and sensory

Radial [C5 – T1] -largest and more important branch

Question 22

The major nerves in supra-clavicular group include:

Answer 22

Nerve to scaleni and longus coli root[C5 – C8]

Long thoracic root[C5 – C7] to serratus anterior

Dorsal scapular [rootC5] to rhomboidei and levator scapula

Suprascapular [C5 – C6] to supraspinatus and infraspinatus
upper trunk
Nerve to subclavius upper trunk [C5 – C6]

Question 23

This nerve is one of the branches of the lateral cord.

It enters the arm by piercing the coracobrachialis muscle and then lies between biceps and brachialis. Here it supplies all the muscles in the anterior compartment.

Answer 23

Musculo-cutaneous

After leaving the arm the remaining part of the musculo-cutaneous is called “lateral cutaneous nerve of forearm”, which supplies the skin of the lateral aspect of the forearm.

Question 24

sympathetic/visceral motor branch

This nerve is formed by the union of medial and lateral roots derived from medial and lateral cords respectively.

After entering the arm, this nerve descends on the medial bicipital groove and leaves the arm with only giving off one sympathetic (vasomotor) branch to the artery (brachial branch).

The median nerve enters the forearm region deep to the pronator teres and flexor digitorum superficialis. Here it gives branches to most of the muscles of the anterior compartment (except FCU and medial half of FDP). The deep muscles of this area are supplied by the anterior interosseous branch of median nerve.

Just above the wrist the palmar cutaneous branch is derived from the median nerve. This branch innervates the skin of the lateral 2/3 of the palmar surface of the hand.

After passing through the carpal tunnel, the nerve enters the hand and just inferior to flexor retinaculum it gives off the recurrent branch that supplies the thenar muscles (except half of the FPB).

Finally after supplying the lumbricals (1-2), the terminal branches of the nerve (common palmar digital nerves) will supply the lateral 3 ½ fingers.

Answer 24

median nerve

Question 25

When a nerve reaches an artery ie brachial nerve its sympathetic nerve activates the smooth mm. Of the artery

Answer 25

(tunica media)

Question 26

The recurrent branch of the median nerve (small nerve in the end of OP) supplies the

Answer 26

OP, ABP, superficial head of FPB and the first and second lumbricals

Question 27

overactivity of the median nerve branch (mid point in the medial side of the arm)

Answer 27

Raynauds syndrome

In a real Carpal Tunnel syndrome the sense of the lateral 3 fingers will be lost

When a nerve is compressed only the branches in the distal part is affected

Question 28

It passes the arm through the medial bicipital groove, without giving any branches.

Then it passes behind the medial epicondyle of humerus, to enter the forearm region. Here it supplies FCU and medial half of FDP. Also well above the level of wrist joint, the ulnar nerve gives off two cutaneous (palmar & dorsal) branches.

These palmar and dorsal cutaneous nerves will innervate the skin of the medial 1/3 of both surfaces of the hand.

Answer 28

Ulnar N.

Ulnar nerve is derived from medial cord.

Question 29

The ulnar nerve enters the hand after passing in front of the flexor retinaculum (through Guyenne tunnel). Here it divides into superficial and deep branches.

Answer 29

The superficial branch supplies palmaris brevis muscle and also the skin of the medial 1 ½ fingers (common / proper palmar digitals).

The deep branch supplies all remaining muscles in the hand including Abd. DM, FDMB, Opp DM, 3rd and 4th lumbricals, palmar & dorsal interossei, add. Pollicis, and half of FPB.

Question 30

Arises from posterior cord

Wraps around the surgical neck of humerus (4 inches below the acromial process of scapula) while passing through quadrangular space.

Divides into superior and inferior branches.

Superior branch supplies deltoid muscle.

Inferior branch also supplies deltoid and teres minor and has a sensory branch to upper lateral part of the arm.

Upper lateral cutaneous nerve of the arm

Answer 30

Axillary N.

Question 31

This nerve is derived from the posterior cord.

It follows the deep brachial artery through triangular interval to enter the radial (spiral) groove.

Here it supplies triceps brachii and anconeus and also gives off 3 sensory branches for the posterior and lower lateral aspects of the arm and posterior surface of the forearm.

Then the nerve passes in front of lateral epicondyle of humerus to enter the cubital fossa. Here it supplies BR and ECRL .

Answer 31

Radial N.

Question 32

The radial nerve then divides into deep and superficial branches.

Answer 32

The deep branch innervates ECRB and supinator and after piercing the supinator muscle enters the posterior compartment of the forearm. At this point the name of the nerve changes to posterior interosseous nerve and supplies the rest of the muscles in the posterior compartment of the forearm.

The superficial branch descends deep to brachioradialis muscle and innervates the skin of the lateral 2/3 of the dorsal surface of the hand and the proximal phalanges of the corresponding fingers.

Saturday Night Palsy: superficial part of the radial nerve in the axillary is compressed

Question 33

Dorsal Rami of cervical Segments

Answer 33

üThe dorsal ramus of C1 , the suboccipital N., is a motor nerve that supplies the suboccipital muscles.

üThe dorsal rami of C2 and C3 are known as greater occipital and third occipital respectively.
Both of these two are sensory nerves and supply back of the head & neck.

üThe rest of the dorsal rami are numbered and
supply the muscles and skin of the back.

Question 34

affects the nerves within the neck that control the motions of the arm. The condition turns muscles inward toward the body, disrupting mobility. It can occur during delivery if a baby’s neck is stretched unnaturally as the head and shoulders pass through the birth canal.

Answer 34

Erb’s Palsy - damage to the muscles lateral rotation pulling shoulder medial rotation
damage to flexor ,extend elbow wrist=extensor damage

waiter’s tip position

Question 35

is a form of paralysis involving the muscles of the forearm and hand, resulting from a brachial plexus injury in which the eighth cervical (C8) and first thoracic (T1) nerves are injured either before or after they have joined to form the lower trunk

Answer 35

Klumpke’s paralysis

• won’t be able to opposition hands
• lower trunk of phlexus are at risk roots or trunk can be injured

Question 36

(median nerve)

supplies the muscles in the deep layer of the ant.compartment of foreamr lateral side of fdp,fpl,pq

Answer 36

anterior interosseous nerve

Question 37

(median nerve)
sensory
lateral 2/3 of palm of the hand is innervated bt palmar cutaneous does not extend to finger
this branch doesn’t pass through carpal tunnel

Answer 37

palmar branch of median nerve

Question 38

recurrent branch of median nerve in the end of opponens pollicis supplies op,abpb and superficial head of fpb, 1 and 2 lumbricals

Answer 38

opponens pollicis-thenar muscle

Question 39

sensory branches of median nerve

Answer 39

2 branches supplying the skin of the fingers

Question 40

loop of the neck-it’s roots are c1,c2,c3

it branches supply your infrahyoid

Answer 40

ansa cervicalis

Question 41

surface anatomy of musculo-cutaneous nerve

Answer 41

For nerve entrapment (releasing nerve from scar tissue)

1. One inch below the coracoid process. (below lateral ⅓ of clavicle)
2. Medial bicipital (muscular) groove. (between brachiallis and biceps) (seperation)
3. Anterior to lateral epicondyle of humerus
4. Styloid process of radius
   * Most common area for musculo-cuteneou nerve entrapment is lateral epicondyle

For best visual on the path of musculo cutaneous have the individual abduct arm to 90 degrees

Question 42

Surface Anatomy of median nerve

Answer 42

1. Two inches below the coracoid process
2. Medial bicipital (muscular) groove.
3. Medial to biceps tendon in cubital fossa.
4. Deep to palmaris longus tendon above the wrist. (PL covering nerve) (15 % pop PL is absent in one hand, 7% Pop PL is absent in both hands)
5. Medial to the base of thenar eminence

Question 43

Surface Anatomy of ulnar nerve

Answer 43

1. Two inches below the coracoid process
2. Medial bicipital (muscular) groove.
3. behind the medial epiconyle of humerus (most common entrapment area)
4. Junction of the proximal and middle thirds of the medial surface of forearm
5. Lateral to pisiform

Question 44

Surface Anatomy of radial nerve

Answer 44

Surface Anatomy

1. Two inches below the coracoid process
2. Spiral groove of humerus.
3. Anterior to lateral epicondyle
4. Styloid process of radius
5. Anatomical snuff box
6. Junction of proximal and middle thirds of posterior surface of forearm.
7. Midpoint between ulnar and radial styloid processes