Upper limbs anatomy exam 2

what regions of the spinal cord has enlargements

cervical and lumbar

what do the enlargements signify

number of spinal nerve fibers in those areas

what does the posterior (dorsal) rami innervate

skin and muscles of posterior neck/trunk

what rami contributes to the plexus

anterior (ventral) rami

what innervates the skin and muscles of the lateral trunk

the thoracic region of anterior ventral rami

C1-C7 spinal nerves exits….

above the vertebrae for what they are named

where does C8 spinal nerve exit

between C7 and T1

T1 and below exit….

below the vertebrae for what they are named

how many cervical vertebrae are there vs cervical spinal nerves

7 cervical vertebrae and 8 spinal nerves

where do the spinal nerves exit

intervertebral foramen

Nemonic for plexus

relax, talk, drink, cold, beer

where is the location of the plexus

neck and axilla region, goes under clavicle and into axilla

O of this muscle

anterior TP of C3-C6 vertebrae

I of this muscle

1st rib

N of the all scalene muscles

C 3-8

A of this muscle

Uni: lat flex head and neck ipsilaterally, rot to contralateral side

Bi: flex head, elevate rib

O of posterior and middle scalene

posterior TP of C2-C7

I of this muscle

2nd rib

I of this muscle

1st rib

A of middle and posterior scalene

Uni: lat flex head and neck ipsilaterally, rot to contralateral side

Bi: elevate rib

how do the plexus and scalene muscles work together

create a pathway in the lateral neck

Where does the plexus pass through in the scalene muscles

through the gap between the anterior and middle scalene

How can scalene muscles affect the plexus

Spasms in the muscles can compress the nerves, causing TOS

How many trunks are in the plexus

three

what composes the superior trunk

C5-C6

what composes the middle trunk

C7 it stands alone

What composes inferior trunk

C8 and T1

where is the location of the trunks of the plexus

superomedial to the clavicle, at the level of the lateral border of anterior scalene muscle

how many divisions are there

six

how many anterior

3, one from each trunk

the anterior divisions contributes to

flexor compartment (median and ulnar)

how many posterior divisons

1 from each trunk

the posterior divisions contributes to

extensor compartments

where are the divisions located

deep to the clavicle

how many cords are there

three

what is the lateral cord composed of

anterior divisions of upper and middle trunks join together

what is the medial cord composed of

anterior division of lower trunk

what is the posterior cord composed of

posterior divisions of all three trunks join

where are the cords located

named in position in relation to the axillary artery

how many terminal branches are there

five

what branch does the lateral cord form

musculocutaneous nerve and contributes to median nerve (flexors)

what branch does the medial cord form

ulnar nerve and contributes to median nerve (flexors)

what branch comes from the posterior cord

axillary nerve and radial nerve (extensors)

location of terminal branches

in the axilla, lateral to pectoralis minor

What components form the M

muscolocutaneous, ulnar and median nerve (MMU)

what is the sensory distribution of musculocutaneous nerve

lateral spect of forearm

what is the sensory distribution of median nerve

elbow joint, lateral palm, thener eminence, palmer surface of digits 1-4 1/2, dorsal surface of ends (2nd and 3rd phalanges) of those digits

what is the sensory distribution of ulnar nerve

medial side of palm, dorsum of hand, palmar and dorsal surface of digit 5 and medial half of digit 4

what are the motor flexors

muschulocutaneous, median and ulnar

what are the anterior terminal branches

muschulocutaneous, median and ulnar

what are the posterior terminal branches

radial and axillary nerves

what is the sensory distribution of axillary nerve

back of upper arm

what is the sensory distribution radial nerve

back of arm and forearm, lateral half of dorsum of hand, dorsum of lateral 31/2 digits

the ulnar nerve crosses elbow joint…

posterior to medial epicondyle

the radial nerve crosses elbow joint…

anterior to lateral epicondyle

how many supraclavicular branches are there

4 branches arise from the roots and trunks

how many infraclavicular branches are there

7 branches arise from the cords

what are the supraclav branches

dorsal scapular nerve, suprascapular nerve, nerve to subclavius, long thoracic nerve

N for rhomboids

dorsal scapular nerve

N for supraspinatus and infraspinatus

suprascapular nerve

N for subclavius

nerve to subclavius

N for serratus anterior

long thoracic nerve

medial cord infra nerves

medial pectoral nerve, medial brachial cutaneous nerve, medial antebrachial cutaneous

N for pec minor and parts of pec major

medial pectoral nerve

N for sensation of the arm

medial brachial cutaneous nerve

N for sensation of forearm

medial antebrachial cutaneous nerve

lat cord for infra branches

lateral pectoral nerve

N for pec major and branches

lat pectoral nerve

posterior cord of infra branches

upper and lower subscapular nerve, thoracodorsal nerve

N for subscapularsis

upper subscapular nerve

N for subscapularis and teres major

lower subscapular n

N for lats

thoracodorsal n

what is a symptom

any subjective evidence of a disease, phenomenon that is experienced by the individual affected by the disease

what is a sign

Any objective evidence of disease, phenomenon that can be detected by someone other than the individual affected by the disease

sensory ex

lost or diminishes sensation, pain, tingling

motor ex

weakness or paralysis, loss of reflexes

autonomic ex

changes in circulation, sweating, skin tone

What depends on an injury or disorder

the pattern of signs and symptoms we see depends on the location

Injury to spinal nerves, roots or spinal nerves in trunk or divisions…

affects the distribution of sensory impairment (dermatone)

what is a dermatome

A section of skin innervated by a single spinal nerve, multiple dermatomes can be involved

injury to specific branches

then the distribution of sensory impairment fits a branch pattern or map

sensory impairment signs

burning or shooting, tingling, reduced or absent sensation

motor impairment signs

weakness or paralysis, reduced or absent reflexes, abnormal posturing of extremities, distribution signs and symptoms depends on location of injury

Myotome

a group of muscles innervated by a single spinal nerve

what is traction

pulling or stretching of nerves, surgical complications, sports injury, fall from heigh onto shoulders

what is compression

a squeezing force that reduces the space between two structures

what cause thoracic outlet syndrome

compression of neural or vascular structures

neurologic TOS

95%, compression of brachial plexus by soft tissue or bone abnormalities between anterior and middle scalene muscles

Vascular TOS

compression of veins or arteries, Venous 3-4%, Arterial 1-2%

Tracking nerve healing

observation of UE appearance and use, sensory evaluation, MMT, nerve conduction studies, ability to perform

Nerve healing is affected by

age, health, etiology, extend, nutritional health, personal habits, fitness

Location of injury

upper, lower, whole plexus or branches and nerves

Upper plexus lesion

occurs with traction, when arm is pulled down forcefully or head is pushed to opposite side

Erbs palsy

superior trunk, birth injury, motorcycle accident, etc (axillary, suprascap and musculocut)

lower plexus injury

occurs when arm is pulled up forcefully

klumpkeys paralysis

inferior trunk, traction from birth injury or fall, mechanical compression (radial and ulnar)

whole plexus lesion

loss of motor function in UE, loss sensation, flaccid limb, poor prognosis

function of musculocutaneous

elbow flexors

function of axillary

shoulder movement (anterior, middle and posterior deltoid and teres minor)

function of radial

extensors of elbow, wrist and fingers