ALL TOGETHER

upper extremity innervation

upper extremity is innervated by spinal nerves originating from the cervical spine

brachial plexus

nerve plexus formed from nerves of the cervical spine (C5-T1)

nerve plexus

a network of interweaving anterior rami of spinal nerves

spinal nerve functions

- helps with reflexes - innervates myotome and dermatome

meninges

three protective membranes that surround the brain and spinal cord

dura mater

- "tough mother"

- strongest of meninges

- outermost layer

pia mater

- "delicate mother"

- innermost of the meninges

- tightly adheres to spinal cord

arachnoid mater

- "spider, cobweb"

- lies external to pia mater

- space for blood vessels and cerebrospinal fluid

8

number of cervical nerves

12

number of thoracic nerves

5

number of lumbar and sacral/coccygeal nerves

posterior ramus

branch of spinal nerve that innervates deep muscles of back

anterior ramus

- branch of spinal nerve that innervates anterior and lateral portions of the trunk, upper limbs, and lower limbs

- creates the brachial plexus

principal plexuses

cervical, brachial, lumbar, sacral

brachial plexus mnemonic

Rowdy Tom Drinks Cold Beer

brachial plexus roots

C5-T1

brachial plexus trunks

- superior (C5 + C6)

- middle (C7)

- inferior (C8 + T1)

brachial plexus divisions

- superior anterior

- superior posterior

- middle anterior

- middle posterior

- inferior anterior

- inferior posterior

brachial plexus cords

- lateral (musculocutaneous and median)

- posterior (axillary and radial)

- medial (median and ulnar)

brachial plexus branches

musculocutaneous, median, axillary, radial, ulnar

axillary nerve

- myotome: innervates teres minor and deltoid

- dermatome: lateral upper arm

radial nerve

- myotome: posterior arm and forearm muscles, extensors

- dermatome: triceps area, back of fingers 1-3

musculocutaneous nerve

- myotome: biceps brachii, brachialis, coracobrachialis

- dermatome: radial side of forearm

median nerve

- myotome: innervates anterior forearm muscles

- dermatome: fingers 1-4

ulnar nerve

- myotome: anterior forearm muscles, intrinsic hand muscles

- dermatome: fingers 4-5

brachial plexus injuries

- thoracic outlet complex (TOC)

- cervical burner

sternoclavicular joint

- joint between manubrium of sternum and sternal end of clavicle

- saddle joint

functions of clavicle

holds the upper limb away from the trunk

sternoclavicular joint movements

depression, elevation, and circumduction of the clavicle

ligament

attaches bone to bone

sternoclavicular joint ligaments

sternoclavicular, interclavicular, costoclavicular

sternoclavicular ligaments

go between sternum and clavicle and reinforce the joint capsule

interclavicular ligament

- connects clavicles

- superiorly

costoclavicular ligament

- attaches the clavicle to the first rib

- inferior

acromioclavicular joint

- joint between acromial end of clavicle and acromion of scapula

- planar joint

acromioclavicular joint movement

gliding of scapula on clavicle

acromioclavicular ligaments

acromioclavicular and coracoclavicular

acromioclavicular ligament

stabilizes the acromioclavicular joint by strengthening the articular capsule

coracoclavicular ligament

binds the clavicle to the coracoid process of the scapula

glenohumeral joint

- joint between glenoid fossa of scapula and head of humerus

- ball-and-socket joint

glenohumeral joint restraints

fibrous capsule and rotator cuff muscles

glenohumeral joint ligaments

coracoacromial and glenohumeral

coracoacromial ligament

connects the coracoid process to the acromion process of the scapula

glenohumeral ligaments

- three thickenings of the anterior portion of the articular capsule

- superior, middle, inferior

bursa

fluid-filled sac that allows for easy movement of one part of a joint over another

rotator cuff muscles

- work together to hold the head of the humerus in the glenoid cavity

- supraspinatus, infraspinatus, subscapularis, teres minor

dislocation

a joint injury in which the articulating bones have separated

shoulder separation

acromioclavicular joint dislocation

sprain

ligament injury

strain

muscle or tendon injury

glenohumeral joint dislocation

occurs when the head of the humerus dislocates from the glenoid fossa

pulled elbow

occurs when the radial head is pulled out of the annular ligament

dislocated elbow

separation of ulna from humerus

elbow joint

- consists of joints between humerus, radius, and ulna

- enclosed by a fibrous capsule

humeroulnar joint

hinge joint between trochlea of humerus and trochlear notch of ulna

humeroradial joint

hinge joint between capitulum of humerus and head of radius

proximal radioulnar joint

pivot joint between head of radius and radial notch of ulna

radial collateral ligament of elbow

stabilizes the elbow joint at its lateral surface

ulnar collateral ligament of elbow

stabilizes the elbow joint at its medial surface

annular ligament

- surrounds neck of radius and connects proximal head of radius to ulna

- allows for pronation and supination

distal radioulnar joint

pivot joint between distal end of ulna and ulnar notch of radius

radiocarpal joint

condyloid joint between radius and three proximal carpal bones (scaphoid, lunate, and triquetrum)

radial collateral ligament of wrist

ligament connecting radius to carpal bones

ulnar collateral ligament of wrist

ligament connecting ulna to carpal bones

intercarpal joints

- planar joints between individual carpal bones

- movement: gliding of carpals

carpometacarpal joints

joints between carpal and metacarpal bones

thumb joint

saddle joint between trapezium and first metacarpal

carpometacarpal joints of fingers II-V

planar joints between carpals and metacarpals II-V

metacarpophalangeal (MP) joints

condyloid joints between metacarpals and proximal phalanges

interphalangeal (IP) joints

- hinge joints between phalanges

- 9 on each hand

proximal interphalangeal (PIP) joint

joint between proximal and middle phalanx

distal interphalangeal (DIP) joint

joint between middle and distal phalanx

axial muscles

have origin and insertion on parts of axial skeleton

axial muscles functions

- support and move head and spinal column

- facial expressions

- aid in mastication and deglutition processes

- support and protect abdominal and pelvic organs

pectoral girdle

clavicle and scapula

pelvic girdle

right and left os coxae bones

muscles of head and neck

- separated into specific groups

- origin: skull or hyoid bone

muscles of facial expression

contort the skin, causing it to move and form expressions based on mood

epicranius/occipitofrontalis

composed of frontal belly, occipital belly, and epicranial aponeurosis

epicranial aponeurosis

tendinous sheet connecting frontal and occipital bellies

frontal belly of occipitofrontalis

superficial to frontal bone; moves scalp, eyebrows, and wrinkles skin of forehead

occipital belly of occipitofrontalis

superficial to occipital bone; retracts scalp

procerus

- continuous with frontal belly of occipitofrontalis muscle

- runs over bridge of nose and causes nose to wrinkle

orbicularis oculi

- circular muscle fibers around the eye

- cause eyes to close (blinking, winking, squinting)

nasalis

causes nostrils to flare

levator labii superioris

pulls upper lip superiorly

levator anguli oris

- pulls corners of mouth superiorly and laterally

- smile muscle

zygomaticus major and minor

- work with levator anguli oris muscle

- elevate corner of mouth

- produce an open-mouth smile

buccinator

- compresses the cheek

- holds food between teeth during mastication

risorious

- pulls corners of lips laterally

- produces a closed-mouth smile

depressor anguli oris

- pulls corners of the mouth inferiorly and laterally

- frown muscle

depressor labii inferioris

pulls lower lip inferiorly

orbicularis oris

- muscle fibers surrounding the opening of the mouth

- compresses and purses lips

mentalis

- attaches to lower lip

- protrudes lower lip

platysma

tenses skin of neck and pulls lower lip inferiorly

muscles of mastication

- four paired muscles that

- move the mandible at the temporomandibular joint

- innervated by CN V (trigeminal nerve)

temporomandibular joint

connection between temporal bone and mandible

temporalis

- fan-shaped muscle that attaches to mandible

- elevates and retracts mandible

masseter

- elevates and protracts mandible

- superficial to temporalis muscle

lateral pterygoids

- originate in sphenoid bone and insert on mandible

- protract and produce side-to-side movement of mandible