Upper Appendicular Skeleton Midterm 2

Appendicular skeleton consists of

126 bones

Upper limb

arm, forearm, and hand bones

Lower limb

thigh, leg, and foot bones

Pectoral Girdle

bones attach upper limb to axial skeleton

Arm

between shoulder and elbow, consists of humerus

Forearm

between elbow and wrist, comprises radius and ulna

Hand

contains carpal & metacarpal bones and phalanges

Humerus Bone (Arm)

Longest and largest bone of upper limb

Head (humerus proximal end)

smooth rounded surface that faces medially to articulate with glenoid fossa of scapula, forms glenohumeral joint (shoulder joint)

Anatomical neck (humerus proximal end)

located below the head of humerus

Surgical neck (humerus proximal end)

common site for fractures

Greater and lesser tubercles (humerus proximal end)

muscle attachment site, greater is lateral, lesser is medial

Intertubercular/bicipital groove (humerus proximal end)

passage for tendon of biceps brachii muscle, found between tubercles

Deltoid tuberosity (humerus shaft)

located laterally on humerus, attachment site for deltoid muscle

*Tuberosity is a rough spot in a bone. We typically receive vaccines on deltoid muscle

Trochlea (humerus distal end)

condyle (smooth, rounded surface) articulates with ulna (trochlear notch of ulna), it’s medial to the capitulum

Capitulum (humerus distal end)

condyle that articulates with radius (head of radius), it’s lateral to trochlea

Medial epicondyle (humerus distal end)

site for muscle attachment on medial aspect of humerus, bump on medial side and is more pronounced than lateral epicondyle

Lateral epicondyle (humerus distal end)

site for muscle attachment on lateral aspect of humerus

Olecranon fossa (humerus distal end)

posterior big indentation, receives olecranon process of ulna during forearm extension

*Olecranon = elbow

Coronoid fossa (humerus distal end)

indentation found above trochlea, received coronoid process of ulna during forearm flexion

Radial fossa (humerus distal end)

indentation above capitulum, receives head of radius during forearm flexion

Radius bone (forearm)

most lateral bone in forearm

*thumb is the “antenna” for the “radio”

Head (radius proximal end)

smooth rounded surface articulates with capitulum of humerus

*For radio to work you need to “capture” the signal

Radial tuberosity (radius shaft)

attachment site for biceps brachii muscle

Styloid process (radius distal end)

prominent bony projection, bump that we feel on our wrist

Ulnar notch (radius distal end)

small indentation that articulates with head of ulna, receives head of ulna

Ulna Bone (forearm)

most medial bone

*Proximal end: OTC (Over The Counter medication)

Olecranon process/olecranon (ulna proximal end)

bony protuberance that moves into olecranon fossa of humerus in extension and moves out of fossa in flexion

Trochlear notch (ulna proximal end)

indentation in ulna bone (the inside of the U of ulna) articulates with trochlea of humerus bone

Coronoid process (ulna proximal end)

bony protuberance that moves coronoid fossa of humerus during flexion and moves out of fossa during extension

Radial notch (ulna proximal end)

small indentation that articulates with head of radius, receives head of ulna

Head (ulna distal end)

smooth rounded surface that articulates with ulnar notch of radius

Styloid process (ulna distal end)

prominent bony projection, bump that we feel on our wrist

Radius and ulna bones articulation

allow pronation and supination of forearm

Interosseous membrane

between shafts of radius and ulna bones

Proximal and Distal Radio-Ulnar joints

Proximal: head of radius articulates with radial notch of ulna

Distal: head of ulna articulates with ulnar notch of radius

Humerus, radius, and ulna bone articulation

form elbow joint, allow flexion and extension of forearm

During flexion and extension (at all times!)

head of radius articulates with capitulum of humerus, trochlear notch articulates with trochlea of humerus

Flexion

head of radius goes into radial fossa of humerus, coronoid process of ulna goes in coronoid fossa of humerus, olecranon process exits olecranon fossa of humerus

Extension

head of radius exits radial fossa of humerus, coronoid process of ulna exits coronoid fossa of humerus, as olecranon process into olecranon fossa of humerus

Hand bones

Carpals: 8 short bones in wrist, organized into 2 rows

Metacarpals: 5 long bones in palm

Phalanges: 14 long bones in fingers and thumb

Carpals

bones that form our wrist

Proximal row: Some (scaphoid) Lovers (lunate) Try (triquetrum) Positions (pisiform)

Distal row: That (trapezium) They (trapezoid) Can’t (capitate) Handle (hamate)

*Trapezium is beneath thumb, triquetrum comes before pisiform, capitate is beneath middle finger

Metacarpals

bones that form palm of hand, numbered 1-5 starting at thumb (pollex)

I: under thumb

II: under index

III: under middle finger

IV: under ring finger

V: under pinky

Phalanges

bones that form our fingers (& toes), each hand has 14 phalanges, 2 in thumb and 3 in each of other fingers

*Phalanges: plural, phalanx: singular

Distal phalanx

most distant from torso, it’s at tip of fingers

Proximal phalanx

most proximal to torso, phalanx closest to metacarpal

Middle phalanx

in the middle, between distal and proximal phalanges

*pollex does NOT have middle phalanx

Pectoral Girdle

Attaches upper limbs to axial skeleton, consists of scapula and clavicle (move as a unit). Clavicle: only bone attaching to axial skeleton, sternoclavicular joint is the only bony articulation between pectoral girdle and axial skeleton. The single point of attachment allows extensive mobility in shoulder joint (great mobility for upper limbs)

Scapula (shoulder blade)

flat bone with triangular shape, articulates with humerus via glenoid fossa and clavicle via acromion process

Spine (of scapula)

ridge in posterior aspect of scapula

*you can feel the scapular spine by passing your fingers on top of shoulder blade

Acromion process

bony protuberance in lateral aspect of scapula, articulates with acromial end of clavicle

*imagine spine “extending” laterally and sticking out, that is the acromion process (or acromion)

Supraspinous fossa

fossa superior to spine

Infraspinous fossa

fossa inferior to spine

Subscapular fossa

fossa anterior aspect of scapula

Suprascapular notch

notch at superior border of scapula

Coracoid process

attachment point for coracobrachialis muscle

Glenoid fossa

shallow, smooth indentation facing laterally and articulates with head of humerus, forms glenohumeral joint (shoulder joint)

Clavicle (collarbone)

long bone, S-shaped, with medial and lateral ends and a shaft

Sternal end

medial end of clavicle, articulates with sternum forming the sternoclavicular joint

Acromial end

lateral end of clavicle, articulates with acromion of scapula forming acromioclavicular joint

Articulations of Pectoral Girdle

Gelnohumeral joint (shoulder joint) is between head of humerus and glenoid fossa of scapula. Acromioclavicular joint is between acromial end of clavicle and acromion process of scapula. Sternoclavicular joint is between sternal end of clavicle and sternum (the ONLY bony articulation between pectoral girdle and axial skeleton)

Which of the following bones is found in the arm?

Humerus

The pectoral girdle attaches the upper limb to the:

axial skeleton

Which condyle of the humerus articulates with the ulna?

Trochlea (medial condyle)

The olecranon fossa receives the olecranon process of the:

Ulna (prevents hyperextension)

Which bone is the most lateral in the forearm?

Radius

The __________ of the ulna articulates with the head of the radius

radial notch

The _________ of the radius is located just below the head and serves as a muscle attachment site

radial tuberosity

The ________ of the ulna is a C-shaped structure that articulates with the trochlea of the humerus

trochlear notch

The _______ process is found at the distal ends of both the ulna and the radius and can be felt at the wrist

styloid

At the distal radioulnar joint, the head of the ulna articulates with the:

ulnar notch of the radius

During elbow flexion, which structure of the ulna fits into the coronoid fossa of the humerus?

coronoid process

What part of the radius articulates with the capitulum of the humerus?

head

Which carpal bone articulates with the radius?

Scaphoid

How many phalanges are found in one human hand?

14

Which of the following is part of the distal row of carpal bones?

Trapezium

The thumb (pollex) lacks which phalanx?

middle

Which bone(s) does not make up the pectoral girdle?

Humerus

*Pectoral girdle: only clavicle and scapula

What structure of the scapula articulates with the clavicle

acromion

Which of the following is NOT a function of the pectoral girdle?

Attach the lower limb to axial skeleton

The _______ end of the clavicle articulates with the sternum

sternal

The _______ is a bony ridge on the posterior scapula that separates the supraspinous and infraspinous fossae

spine