The Upper Limb

diaphysis

shaft of a long bone, inside space called medullary cavity which is filled w yellow bone marrow

has spongy bone lining the medullary cavity

nutrient foramen

holds blood vessels along diaphysis

proximal and distal epiphysis

ends of bone, can be more than one, has red bone marrow

epiphyseal line/plate

separates epiphysis from shaft

metaphysis

portion between shaft and epiphysis (shaft widening)

periosteum

CT around bone

endosteum

CT lining medullary cavity

circumferential lamellae

surround entire bone in layers (have outer and inner)

endochondral ossificiation

all upper limbs but clavicle

cartilage is calcified to make bone at primary center of ossification that is fed by blood vessels

epiphysis usually ossified by second center of ossification

articular cartilage

hyaline cartilage on ends of bone that reduces friction when bones meet

epiphyseal plate ossification

cartilage plate where bone grows length wise, side closest to epiphysis grows cartilage, side closet to shaft becomes bone

rate changes around puberty and the cartilage isn’t made fast enough so everything becomes bone

clavicle

s shaped bone between the sternum and scapula

the sternal end is the rounded end connected to the sternum

the acromial end is the flat end attached to the scapula

^the only connection between upper limbs and trunk—transmits force between upper limb and axial skeleton

acts as support holding upper limbs from trunk

also acts as a site of muscle attachment

scapula

triangular shaped bone

the acromion process is an extension of the spine that attaches to the clavicle

supraspinous fossa is above the spine, infraspinous fossa below the spine, supscapular fossa is on the front

glenoid fossa is the joint surface with the humerus and forms glenohumeral joint

supraglenoid tubercle is bump above glenoid fossa, infraglenoid tubercle is bump below glenoid fossa

coracoid process is on the ventral side and attaches to pectoralis minor

humerus

only bone in arm from shoulder to elbow, can do every movement at the glenohumeral joint

the head is the proximal end that articulates with the glenoid fossa, the neck is right after, the surgical head is the part on metaphysis that is fractured easily

greater tubercle is a bump on the lateral side, lesser tubercle is a smaller ventral bump

intertubecular groove is between the greater and lesser tubercles

the deltoid tuberosity is a anterolateral roughened area of bone that is an attachment site for the deltoid musle

capitulum is the lateral condyle that articulates with the radius and is ball shaped

the trochlea is the medial condyle that articulates with the ulna and is spool shaped

there are medial epicondyles above each ^

olecranon fossa is a pit on the distal side for the proximal ulna extension

ulna

medial forearm bone

olecranon process is the part articulating with the olecranon fossa and is medially wrench shaped

the trochlear notch is the joint surface articulating with the trochlea of the humerus between the olecranon and coronoid

coronoid process is at the bottom of the wrench

radial notch articulates with the head of the radius

the ulnar tuberosity is a bump for anterior muscle attachment

the interosseus border is on the lateral side that is sharp and attaches to the interroseous ligament

the head is the distal portion, and the styloid process is the most distal part of the ulna

radius

lateral forearm bone

the head is the proximal end and the neck is after the head

radial tuberosity is the anterior bump for muscle attachment

interrosseous border is the entire medial side and is sharp for attachment

the styloid process is on the distal end and provides wrist stability

the ulnar notch articulates with the ulna to form a joint

elbow joint

is comprised of the humeroulnar joint, humeroradial joint and proximal radioulnar joint

can flex, extend, supinate and pronate (radius moves but not ulna)

carpus (carpal bones)

ulna does not articulate with them

8 bones total in two rows

can flex, extend, abduct, adduct, and circumduct

proximal row at base- Scaphoid, Lunate, Triquetrum, Pisiform

distal row close to palm- trapezium trapezoid, capitate, hamate

^articulate with metacarpals-carpometacarpal joints

metacarpus (metacarpals 1-5)

palm bones

thumb side is #1, pink side is #5 (M1-M5)

(proximal to distal) have a base shaft and head- forms joints with proximal phalanges (metacarpophalangeal joints)

manual phalanges

14 bones, every digit has three but the thumb is missing a middle phalanx

has base, shaft, and head like the metacarpals

interphalangeal joints are between phalanges

innervation of the upper limb

innervated by the brachial plexus (C5-T1) that runs between the clavicle and first rib that comes from ventral rami

roots are made of 5 ventral rami, trunks are upper middle and lower, divisions split into anterior and posterior, cords are lateral medial and posterior

5 major nerves innervating the upper limb

musculocutaneous, median, ulnar, radial, axillary