Bones of the Appendicular Skeleton

Page 1

Bones of the Upper Extremity

Pectoral

Girdle

Clavicle

Sternal end articulates with

sternum medially

Acromial end articulates with

scapula laterally

Conoid

tubercle -

located inferoposterior on the acromial end of the clavicle

Trapezoid

line - located

inferoposterior on the acromial end of the clavicle, more lateral than

conoid tubercle

Scapula

Large, flat triangular bone

Three borders: superior,

lateral, medial

Three processes: spine,

acromion, coracoid process

Three angles: lateral,

superior, inferior

Spine - prominent posterior ridge

Acromion - lateral projection that

articulates with acromial end of the clavicle to form the

acromioclavicular joint

Coracoid

process -

anterior projection that anchors the bicep muscle of the arm

Supraspinous

fossa - posterior

fossa, superior to spine

Infraspinous

fossa -

posterior fossa, inferior to spine

Glenoid

fossa - lateral

fossa, site of articulation with humerus

Subscapular

fossa - anterior

fossa, medial to glenoid fossa

Infraglenoid

tubercle -

lateral tubercle, inferior end of glenoid fossa

Supraglenoid

tubercle -

lateral tubercle, superior end of glenoid fossa

The

arm

Portion of the upper limb

between shoulder and elbow

Only one bone - the humerus

which articulates proximally with the scapula and distally with the radius

and ulna

Proximal

end of Humerus

Head - spherical shape, projects

medially and articulates with scapula

Anatomical

neck -

constriction below head

Surgical

neck - proximal

end of diaphysis

Greater

tubercle -

large, lateral bulge

Lesser

tubercle -

small, medial bulge

Radial

groove -

impression on the posterior surface, a pathway for the radial nerve and

blood vessels

Deltoid

tuberosity -

lateral ridge that lies midway along the diaphysis

Distal

end of Humerus

Condyles - articular surfaces of the

humerus

Capitulum - anterior lateral condyle,

articulates with radius

Trochlea - anterior medial condyle,

articulates with ulna

Epicondyles

- important

sites for surface anatomy, muscle attachments and the formation of the

elbow

Medial

epicondyle -

located medially

Lateral

epicondyle -

located posteriolaterally

Radial

fossa - located

superior to capitulum

Coronoid

fossa - Located

superior to trochlea

Olecranon

fossa - located

posteriorly superior to trochlea

The

Forearm

Portion of the upper limb

between the elbow and the wrist

Proximal

Radius

Head - articular surface that

contacts the capitulum of the humerus and the radial notch of the ulna

Radial

tuberosity - medial projection, site of muscle

attachment

Interosseus

border - sharp

medial surface, site of interosseus membrane attachment

Distal

Radius

Radial

styloid process

- distal, lateral projection, attaches ligaments from the wrist

Ulnar notch

- articular

surface in contact with ulna

Distal

articular surface -articulation

site with wrist bones

Proximal

Ulna

Olecranon - posterior, proximal

projection that contributes to articular surfaces

Coronoid

process -

anterior proximal projection that contributes to articular surfaces (like

a small hook)

Trochlear

notch - inner

surface of olecranon and coronoid processes that articulates with humerus

Radial

notch - lateral

articulating surface, articulates with head of radius

Tuberosity

of ulna - medial

site of muscle attachment

Interosseus

border - sharp,

medial line, site of interosseus membrane attachment

Distal

Ulna

Posterior

border - sharp,

palpable surface on medial posterior surface

Ulnar

styloid process

- medial projection, attaches ligaments from wrist

Wrist

Two rows of small, short

bones, the carpal bones

Distal row articulates with

metacarpal bones

Proximal row articulates with

the distal end of the radius

Proximal

row (lateral to medial)

Scaphoid

Lunate

Triquetrum

Pisiform

Distal

row (lateral to medial)

Trapezium

Trapezoid

Capitate

Hamate

Hand

5 metacarpals

Long bones with shaft, head

and base

Base articulates with carpal

bones

Head articulates with

phalanges

14 phalanges

Long bones with shaft, head

and base

Proximal phalanges

articulate with metacarpals

Page 2

Bones of the Lower Extremity

Pelvic

Girdle

Connects the lower limb to

axial skeleton

Supports the weight of the

upper body

Contains strongest ligaments

in the body

Made up of 3 bones, the

ilium, the ischium and the pubis

Technically also the sacrum

though it is part of the axial skeleton

Pelvic

bones

3 distinct bones

separated by cartilage at birth that fuse around the ages of 16-18 to form a

single bone

Ilium - superior region of the

hip bone

Ischium - posterior inferior part

of the hip bone

Pubis - anterior portion of the hip

bone, joins at the pubic symphysis joint

Bony Landmarks

Medial

Iliac

crest -

superior margin of hips, site of attachment for many muscles

Iliac

spines - both

anterior and posterior superior iliac spines and anterior and posterior

inferior spines, attachment for muscles of hip, trunk and thigh

Articular

surface -

L-shaped facet for articulation with the sacrum

Sciatic

notches - both

greater and lesser, greater sciatic nerve houses the thick sciatic nerve

Pubic

tubercle -

rounded pubic crest, articular surface for pubic symphysis

Obturator

foramen - passageway from pelvis to lower limb

Lateral

view

Acetabulum

- large articular surface formed by all

three pelvic bones, forms the ball and socket hip joint with the head of

the femur

Ischial

spine - bony

protuberance of ischium, separates greater and lesser sciatic notches

Ischial

tuberosity -

'sit bones' attachment of lower limb muscles (hamstrings)

Sexual

dimorphism of the Pelvic Bones

Structure reflects function

Female pelvis is more

shallow and better equipped for childbearing

Male

pelvis

Better adapted to support a

heavier body

Pelvic cavity is narrow and

deep and consists of heavier, thicker bones with more prominent markings

Angle of pubic arch is acute

50-60°

Female

pelvis

Tilted anteriorly

Pelvis cavity is broad and

shallow and has a greater capacity than the male pelvis does

Bones are lighter, thinner

and smoother

The pubic arch is more

rounded, and the angle is obtuse

Sacrum

Formed by 5 fused vertebra

Articulates superiorly with

L5 bone at the sacral promontory

Inferiorly articulates with

the coccyx

Transverse ridges on concave

anterior aspect mark the sites of vertebral fusion fo sacral vertebrae

Foramina are present for the

passage of spinal nerves

Bony

markings

Alae - lateral wing shaped

projections for articulation with the pelvic bones (synovial joints

Median

sacral crest - midline

roughened surface

Posterior

sacral foramina - transmit sacral spine nerves

Sacral

canal - for the passage of spinal nerves

within vertebral column

The

Femur

Contributes

proximally to the hip joint and distally to the knee joint. The head fits into

the acetabulum and the distal end sits on the tibia but does not contact the

fibula. It sits at an angle of 7° so the distal end is closer to the midline

than the proximal end (the angle is larger in females). This brings the knee

closer to the centre of gravity allowing for more effective bipedalism

Proximal

Femur

Head - smooth, spherical

articular surface that contacts the acetabulum

Neck - cylindrical shaft of bone that extends anteriorly to increase

the range of motion available to the hip

Greater

trochanter -

large, lateral projection

Lesser

trochanter -

moderately sized medial projection

Fovea - small depression in the head

of the femur's head, a site of attachment for ligament of the hip joint

Intertrochanteric

crest - ridge

passing between the greater and lesser trochanters

Gluteal

tuberosity -

medial ridge on the shaft of the bone

Linea

aspera -

thinner continuation of the gluteal tuberosity

Distal

Femur

Medial and

lateral condyles - articulate with the tibia as

the femur does not contact the fibula

Medial and

lateral epicondyles - sites of muscle attachment

Adductor

tubercle - bump of superior part of medial

epicondyle

Patella

surface -

between the condyles on the anterior surface, articulates with the patella

Intercondylar

fossa - facet

for articulation of the cruciate ligaments

Patella

Technically not a part of

the leg or the thigh

Sesamoid bone enclosed in

the quadriceps tendon

Offers the knee protection

anteriorly

Improves the leverage of the

thigh muscles acting across the knee

The

Leg

Proximal

Tibia

medial and

lateral condyles - articular surfaces separated by

intercondylar eminence. There is an articular surface for the fibula on

the lateral condyle to form the superior tibiofibular joint

Tibial

tuberosity - large roughening on anterior surface,

site of attachment for the patella ligament

Proximal

Fibula

Articular surface - articulates with

lateral aspect of tibia and does not bear weight

Styloid

process -

superior apex on lateral side

Distal

Tibia and Fibula

Malleolus - medial (tibia) lateral

(fibula)

Inferior

tibiofibular joint

- fibular notch on lateral surface of tibia

Shafts

of Tibia and Fibula

Both shafts are triangular

The anterior medial surface

of tibia is completely palpable

The

Foot

Superior surface called the

dorsum, inferior surface called the plantar

Provides a stable platform

for weight-bearing

Tarsal

bones

Talus - most superior, articulates

with the tibia and fibula

Calcaneus - heel bone, carries the talus on its

superior surface,

calcaneal

tuberosity

touches the ground

sustentaculum

tali - shelf

like projection that supports the talus

Navicular

Cuboid

Cuneiforms

(medial, intermediate, lateral)

Metatarsals

and Phalanges

Numbered I - V started

medially at the hallux

Ball of foot is formed by

enlarged head of metatarsal I

14 phalanges (proximal,

medial, distal)

3 phalanges per digit

except hallux (proximal and distal only)