week 10: upper extremity bones and joints

function of pectoral girdle

• attach upper limb to axial skeleton

• provide attachment points for muscles of UE

• very light, allowing for most mobility

composition of pectoral girdle

• clavicle (anteriorly)

  • attaches to sternum medially

  • attaches to scapula laterally

• scapula (posteriorly)

  • attaches to thorax and vertebral column by muscles

clavicle

• collarbone

• palpated horizontally along superior thorax

• slender, doubly curved (medial 2/3 convex anteriorly, lateral 1/3 concave anteriorly)

• smooth superior surface and ridged and grooved inferior surface

acromial end of clavicle

• lateral end

• flat

• attaches to acromion process of scapula

sternal end of clavicle

• medial

• cone shaped

• attaches to manubrium

conoid tubercle

bump on inferior posterior side of clavicle that attaches to ligament of scapula

function of clavicle

• braces arm laterally away from thorax

• transmits compression forces from UE to axial skeleton

• become alrger in those using arms for labor/athletics

clavicle fractures

• usually anterior due to curves

• posterior fracture could sever subclavian artery

• typically from bicycle falls, hits, falls on shoulder, arm, or hand

• ossiefies at 20 so childrem break it more

scapula

• thin triangular flat bones on dorsal surface of ribcage ribs 2-7

• anterior costal side is concave and featureless

• spade or shovel

acromion

• lateral end of spine (point of shoulder)

• rough enlarged triangle porjection

• articulates with clavicle

suprascapular notch

superior border just medial to coracoid process for nerve passage

superior border of scapula

short and sharp border

superior angle of scapula

connects superior and medial border

subscapular fossa

fossa on anterior scapula

medial border of scapula

vertebral side and parallels vertebral column

inferior angle of scapula

connects lateral and medial border

lateral border of scapula

axillary side, thick and near armpit

lateral angle of scapula

connects lateral and superior border

glenoid cavity

pit-shaped lateral part of scapular that articulates with humerus to form shoulder joint

coracoid process

• beaklike bent finger projection on anterior superior scapular border

• anchors biceps of arm

subscapular muscle

covers entire anterior surface of scapula

scapular spine

line projection on posterior side of scapula (palpated through skin)

humerus

• largest and longest bone of UE

• articulates with scapula and radius and ulna

greater and lesser tubercle

• inferior to neck of humerus

• attachment for rotator cuff muscles

intertubercular groove

• bicipital groove

• guides tendon of biceps to attachment point at rim of glenoid cavity

head of humerus

• proximal end is smooth

• fits in glenoid cavity of scapula

deltoid tuberosity

• projection midway down lateral side of humerus

• v-shaped rough attachment for deltoid muscle of shoulder

coronoid fossa

• space on bottom of humerus

• superior to trochlea on anterior surface

trochlea

• pulley looking structure on bottom of humerus

• medial sude looks like an hourglass on its side

• articulates with ulna

radial groove

• runs obliquely down posterior shaft

• course of radial nerve

medial and lateral supracondylar ridge

ridges above condyles of humerus

radial fossa

• lateral to coronoid fossa on humerus

• head of radius when elbow is flexed

capitulum

ball like projection that articulates with radius on lateral side of humerus

surgical neck of humerus

most frequently fractured part

head of radius

• shaped like head of nail

• superior surface is concavae

• superiorly articulates with capitulum of humerus

• medially articulates with radial notch of ulna

radial tuberosity

bump inferior to head of radius that anchors to biceps muscle

styloid process of radius

bump medial to head of radius on the distal side that connects to ligaments of wrist

radius

• one of arm bones

• thin at proximal end and wide distally

ulna

• one of arm bones (longer)

• wide at proximal end and thin distally

• forms elbow joint w/ humerus

• proximal end looks like a monkey wrench

olecranon process

• projection on proximal side of ulna that locks into olecranon fossa when elbow fully extended to prevent hyperextension

• forms angle of elbow when flexed

• portion that rests on table

trochlear notch

deep cavity between olecranon and coronoid process on ulna

coronoid process

anterior process on ulna that is more distal than olecranon process

interosseus membrane

flat flexible ligament that runs entire length connecting radius and ulna

wrist articulation

happens between ulnar notch and styloid process

ulnar notch

• notch on distal side of radius

• articulates w/ ulna medially

head of ulna

distal part of ulna

styloid process of ulna

• lateral edge of ulna that is medially palpated

• anchoring site for ligaments to wrist

orientatino of radius and ulna

• radius lies laterally (thumb side)

• ulna is pinky side

• during pronation the distal end of radius crosses over to ulna to form x

colles fracture

• distal radial fracture

• bone breaks on lower end close to where it connects to bones of hand on thumb side of wrist

• most common break in arm

carpals

• 2 rows of 4 marble sized short bones in hand

• glide for flexibility

proximal row

• scaphoid

• lunate

• triquetrum

• pisiform

distal row

• trapezium

• trapezoid

• capitate

• hamate

pisiform

one of the carpals that is a sesamoid bone embedded in tendon of flexor carpi ulna’s

thumb

• aka pollux

• no middle phalange

metacarpals

• small long bones

• #1 is shorter and more anterior to be more mobile

• base articulates w/ carpal proximally and each other medially/laterally

• head articulates w/ phalanges and forms knuckles in fist

articular capsule

thickened periostium around synovial joint

plane joint

• intercarpal

• intertasrsal

• vertebral facet

hinge joint

• elbow

• interphalangeal

pivot joint

• C1-C2

• proximal radioulnar joint

condyloid

• radiocarpal

• MCP (knuckles)

saddle

CMC of thumb (twiddle thumbs)

ball and socket joint

shoulder joint

glenohumeral joint (shoulder)

• most free moving joint in body

• ball and socket allowing movement in all directions and planes

• synovial

• large head of humerus fits into glenoid cavity

• secured by articular capsule and rotator cuff muscles (SITS) and tendon of long head of biceps

glenoid labrum

cavity slightly increased by rim of fibrocartilage (1/3 of head)

shoulder dislocation

anterior is most common

subacromial and subscapular bursa

fluid filled sacs that provide cushion around joints in between ligaments and tendons

transverse humeral ligament

ligament that wraps around the biceps tendon in glenohumeral joint

subacromial impingement

• entrapment of bursa or tendon when raising arm overhead

• causes bone spur and torn supraspinatus causing humeral head to no longer depress when raising arm

elbow joint

• hinge joint formed w/ trochlea and notch

• allows one plane (flex/ext)

• synovial w/ loose capsule

medial ulnar colalteral ligament

• has anterior, posterior, and transverse part

• anterior is primary stabilizer against valgus force (away from midline) due to carrying angle of elbow

lateral radial collateral ligament

• reinforces humeral radial articulation and protects against distraction of joint

• fan shaped and extends from lateral epicondyle of humerus to annular ligament

• encircle head of radius and olecranon process

• weaker than medial ligament

• some protection against varus (towards midline) force

forearm supination and pronation

• pivot joint where spinning of radius on ulna

• distal radius goes along for the ride

annular ligament

• closely binds radial head to ulna so they move together

• encircles head of radius

oblique cord

• runs just inferior to radial arch of ulna to inferior portion of bicipital tuberosity on radius

• fibers are perpendicular to interosseus membrane

radiocarpal joint

favors flexion and ulnar deviation (proximal)

midcarpal joint

favors extension and radial deviation (distal)

flexor and extensor retinaculum

• all muscles pass beneath flexor retinaculum along w/ median nerve except for PL

• prevents bowstringing (muscles coming away from arm)

cross section of wrist

carpals form a tunnel for nerves and vessels in wrist

intrinsic musculature

• 18 intrinsic muscles that begin and end in hand

• divided into dorsal and volar muscles

• serve to balance finger flexors in grasp and release

extrinsic musculature

• 18 more tendons from extrinsic muscles that end in hand

• origins are proximal to wrist

• muscle bellies are in forearm

• most of htem cross 4 joints

carpometacarpal joint (CMC)

• articulation between distal carpal row and bases of metacarpal bones

metacarpophalangeal joint (MCP or MP)

articulation between metacarpal and phalanx

oblique palmar arch

thumb across palm at diagonal to base of 5th digit, important for splints

transverse arches

run across palm at both distal and proximal ends (radial to ulnar)

longitudinal pallmar arch

• traverses length of digits (wrist to fingertips)

• 90 degrees perpendicular to transverse arch