Appendicular skeleton Flashcards
Appendicular skeleton
= bones of upper limbs, lower limbs and pectoral and pelvic girdles
• Pectoral Girdle
scapula and clavicle
scapula
shoulder blade
dorsally located
clavicle
collar bone
ventrally located long bone with slight sigmoid (s-shaped) curve
o can be easily seen and felt
o sternal end articulates with manubrium
o acromial end – broader and flatter and articulates with acromion process of scapula
scapula : body
broad triangle with 3 borders: superior, medial (vertebral), and lateral (axillary
scapula : o subscapular fossa
deep anterior surface of scapula that overlies the ribs
scapula : o coracoid process
lateral and superior portion of anterior surface and projects anteriorly
• attachment site for short head of biceps brachii – muscle of the upper arm
scapula : o glenoid cavity (fossa)
cranially located on lateral surface – articulates with head of humerus
scapula : o scapular spine
extends across posterior surface of scapula
scapula : o acromion process
large flattened lateral portion of scapular spine
• forms protective cover for shoulder joint
• attachment site for clavicle
• attachment points for some shoulder muscles
o supraspinous fossa
above scapular spine
o infraspinous fossa
– below scapular spine
upper limb
humerus, ulna, radius, carpal bones, metacarpal bones, and phalanges
humerus
only bone of arm
head , humerus
proximal end of the bone that articulates with glenoid cavity of the scapula
greater tubercle of humerus
site of muscle attachment on lateral surface of proximal epiphysis
lesser tubercle of humerus
o - site of muscle attachment on anterior and medial surface of proximal epiphysis
♣ intertubercular sulcus (groove) – between two tubercles = contains tendon of biceps
deltoid tuberosity of humerus
o attachment site for deltoid muscle mid-way along lateral surface of shaft
articular condyle of humerus
o on distal epiphysis composed of two parts:
♣ capitulum – rounded lateral portion – articulates with head of radius
♣ trochlea – medial pulley-like area – articulates with ulna
• coronoid fossa – immediately superior to trochlea on anterior surface
• olecranon fossa – immediately superior to trochlea on posterior surface
medial and lateral epicondyles of humerus
o points of muscle attachment for forearm
Ulna
– on medial side of forearm
trochlear notch of ulna
o trochlear notch – c-shaped articular surface on proximal end that fits over trochlea of humerus
♣ olecranon process = superior and posterior portion of proximal epiphysis
• process easily felt – point forms “elbow”
♣ coronoid process = anterior process
radial notch of ulna
lateral to coronoid process – articulates with head of radius
head of ulna
o on distal end - articulates with radius and wrist bones
♣ styloid process – posteriomedial side – attachment site for ligaments of wrist
radius
on lateral side (thumb-side) of forearm
head of radius
o disc-shaped proximal end – articulates with capitulum of humerus
♣ lateral surface rotates against ulna
radial tuberosity
attachment point for biceps brachii
styloid process –
lateral side of the expanded distal end
Carpals bones
o carpus (wrist) = two rows of four carpal bones
proximal row for carpal bone
o lateral to medial: scaphoid, lunate, triquetrum, pisiform (located on palmar surface of triquetrum)
♣ scaphoid = most frequently fractured carpal bone – usually resulting from fall onto outstretched hand (clinical note p. 184)
distal row for carpal bone
o lateral to medial: trapezium, trapezoid, capitate, hamate (has hook process on palmar surface),
mnemonic for carpal bone
o mnemonic for above order using the first letter for each carpal bone: Sam Likes To Push The Toy Car Hard
o carpal bones as group are convex posteriorly and concave anteriorly
manus
metacarpals and phalanges
Metacarpals (5)
o form the framework for the hand
♣ numbered by Roman numerals I-V from lateral (thumb side) to medial
♣ bones curve so palmer surface of hand in concave
wide proximal base articulate with distal row of carpals and distal heads with proximal phalanges
Phalanges (14)
o bones that make up the digits – 1 thumb and 4 fingers
♣ pollex (thumb) – has two phalanges – proximal and distal
♣ fingers – have three phalanges – proximal, middle and distal
Pelvic Girdle and Lower Limb
• bones generally thicker, longer and heavier than upper limb
Pelvic Girdle
• right and left coxal bones of appendicular skeleton and sacrum and coccyx of axial skeleton (Fig 7.11)
Hip (Coxal) bones
right and left halves join anteriorly to each other at the pubis and posteriorly with sacrum
o formed from the fusion of three bones: ilium, ischium and pubis
acetabulum (hip bone)
o fossa on lateral surface of pelvis formed by fusion of ilium, ischium and pubis
♣ articular surface is crescent shaped where head of the femur articulates
ilium –
o broad, flat and curved dish-like portion
♣ iliac crest – on superior surface easily seen and palpated (Fig 7.10)
• anterior and posterior superior iliac spine = continuation of crest anteriorly and posteriorly
bony landmarks for gluteal injections
(hip bone )
iliac fossa (hip bone )
large depression on medial side of ilium
greater sciatic notch (hip bone)
♣ on posterior and inferior portion of ilium – sciatic nerve passes through it
auricular surface (hip bone)
♣ joins with sacrum to form sacroiliac joint
• receives most of the weight of the upper body and strongly supported by ligaments
ischium (hip bone)
♣ posterior, inferior and lateral positioning
• ischial spine – posterior to acetabulum superior to lesser sciatic notch
• ischial tuberosity – heavy posterolateral bony prominence that person sits on and where posterior thigh muscles attach
pubis (hip bone)
o anterior and medial positioning
♣ pubic crest – roughened ridge located medially
• where abdominal muscles attach
♣ pubis symphysis – just inferior to pubic crest = junction between right and left coxal bones
obturator foramen (hip bone)
o large opening enclosed by pubic and ischial rami
♣ in life – space closed by collagenous connective tissue that act as firm base for attachment of hip muscles
Pelvis
ing of bone with hips forming anterior and lateral parts and sacrum and coccyx forming posterior part
greater pelvis
o false pelvis formed by bladelike extensions of ilium
♣ encloses organs within the inferior portion of abdominal cavity
lesser pelvis
o true pelvis – bony edge = pelvic brim
♣ pelvic inlet = superior opening into the true pelvis
♣ pelvic outlet = inferior opening of the pelvis
• in life, enclosed by perineum with pelvic muscles forming floor of pelvic cavity
male pevis
o male – heavier (most robust) with prominent markings
♣ pelvic inlet and outlet smaller and heart shaped
♣ iliac fossa deeper
♣ sub-public angle <90%
♣ ischial spines closed together and point medially
♣ coccyx more concave
female pelvis
o broader, shorter superior to inferior
♣ smoother and lighter
♣ larger oval-shaped pelvic inlet and outlet
♣ iliac fossa shallower
♣ sub-pubic angle >100%
♣ ischial spines further apart and point posteriorly
♣ coccyx straighter (less concave)
