The Appendicular Skeleton

THE UPPER EXTREMITY The Appendicular Skeleton

The Upper Extremity

• Bones of the shoulder girdle – Clavicle and scapula

• Upper arm – Humerus

• Lower arm – Radius

– Ulna

• Wrist – Carpal bones

• Hand – Metacarpals

– Phalanges

Shoulder Girdle

• Only forms one joint with the axial skeleton

• Clavicle

– Sternoclavicular joint • Where the sternum

meets the clavicle

Shoulder Girdle

• Scapula – Shoulder blade – 3 borders

• Superior (top) • Vertebral (by the spine) • Axillary (side near the armpit)

– Spine • Ridge along the posterior portion of the bone

– Acromion process • Articulates with clavicle • Process that is located at the end of the spine

– Coracoid process • Projection on the anterior portion of the scapula • Only 2 major projections

Shoulder Injuries

• Broken clavicle

• Separated shoulder - AC joint separation

Humerus

• Long bone that makes up the upper arm • Upper end (epiphysis)

– Head • Smooth rounded end that fits into glenoid fossa

– Anatomical neck • Groove immediately inferior to the head

– Greater and lesser tubercles • Greater is lateral to the head • Lesser is inferior (below) the greater

– Intertubercular groove • Groove b/t greater and lesser tubercles

– Surgical neck • Region below the tubercles that leads to the diaphysis • Common to fracture

Humerus

• Middle (diaphysis)

– Deltoid tuberosity • Protuberance midway

down shaft

• Deltoid attaches here

– Radial groove • Groove moving inferiorly

for radial nerve

Humerus • End (epiphysis)

– Eipicondyles • Medial and lateral projections

– Medial is larger of the two

– Capitulum • Rounded head below the lateral

epicondyle – Radius attaches

– Trochlea • Appears similar to a pully

• Deep depression in the epiphysis

• Articulates with the ulna

– Olecranon fossa • Depression on the posterior survace

• Olecranon process forms elbow here

– Coronoid fossa • Depression on the anterior portion

Forearm

• Radius – Thumb side

– Head • Proximal end

• Articulates with the capitulum

– Radial tuberosity • Projection just below the

head

– Styloid process • Located on the lateral,

distal end of the bone

Forearm

• Ulna – Pinky side – Longer than radius – Olecranon process

• Elbow

– Coronoid process • Opposite side of elbow

– Semilunar notch • Depression that articulates

with the trochlea

– Styloid process • Distal end

– Head • Distal end

Left Arm

Wrist

• 8 bones – 2 rows

– Proximal row • Pisiform

• Triquetrum

• Lunate

• Scapate

– Distal row • Hamate

• Capitate

• Trapezoid

• Trapezium

Hand

• Metacarpals

– “Middle” bones of the hand

– Distal end makes up the knuckles

– Numbered 1 – 5

• Phalanges

– Smaller bones that make up the fingers

– Separated into proximal, middle, and distal (finger tip)

THE LOWER EXTREMITY The Appendicular Skeleton

• Hip – Coxal bones (pelvis)

• Thigh – femur

• Lower leg – Tibia – Fibula

• Foot – Tarsal bones – Metatarsals – Phalanges

The Lower Extremity

Coxal Bones

• Pelvic girdle – Combination of the sacrum and the coxal bones

bound together by ligaments

– Supports the trunk of the body and allows for leg attachment

• Coxal bones – Each bone is made up of 3 fused bones

• Illium

• Ischium

• Pubis

• Ilium

– Most superior

– Largest

– Palpable

• Ischium

– Strongest

– Most inferior

• Pubus

– Anterior to the ischium

Coxal Bones

• Horizontally divided into 2 parts – Pelvic inlet

• a.k.a. pelvic brim

• Above the inlet – False pelvis

• Runs from the tip of the ilium to the pelvic inlet

• Below the inlet – True pelvis

• Boundary of the pelvic outlet

• Pubic symphysis – Where the coxal bones

meet

Thigh Bones

• Femur

– Upper end (epiphysis) • Head

• Greater/lesser trochanter

– Middle portion (diaphysis) • Linea apera

• Supracondylar ridges

Thigh Bones

• Distal end (epiphysis)

– Lateral/medial condyles

– Lateral/medial epicondyles

– Adductor tubercle

– Trochlea

– Intercondyloid fossa • notch

Patella

• Largest sesamoid bone in the body

• Knee cap

• Imbedded in the tendon from your quadrceps

Tibia

• Shin bone • Lateral/medial condyles

– Upper end of bone – Concave surface to articulate w/ femur

• Intercondylar eminence – Spine between condyles – Attachment for ACL and PCL

• Crest – Sharp ridge on the anterior – Part of the shin you can feel

Tibia

• Tibial tuberosity

– Protuberance just below condyles

– Palpable below the knee

• ½ “Ankle”

– Medial maleolus • Palpable on the inside of

the ankle

Fibula

• Smaller than tibia

• Deeper of the two bones – Always on the outside of

the lower leg

• Proximal end articulates with the tibia – @ lateral condyle

– Creates part of the knee joint

• Distal end (other ½ of the “ankle” – Articulates with the tibia

– Lateral malleolus

Foot

• Constructed similar to the hand

– Adapted to support weight

• Two way arch construction

– Longitudinal arch • Medial/lateral

longitudinal arches

– Transverse arch • Metatarsals & the distal

row of tarsals

Foot • Flat foot (fallen arches)

– Ligaments and muscles hold bones in place

– Keeps the arch intact

– Foot, knee, eventually back

• Very small number of individuals have a true “flat foot” – Usually over-pronation

• High arch – Charcot Marie Tooth

disorder (CMT)

Foot Bones

• Tarsal Bones – Talus

• Articulates w/ the tibia

– Calcaneus • Heel

– Navicular

• Distal row – Cuniform bones

• 1-3 starting at 1st metatarsal

– Cuboid

• Metatarsals – 1-5 (big toe out)

• Phalanges (1-5) – Proximal – Middle* – Distal

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2

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