The Appendicular Skeleton - harcoboe.com · Shoulder Girdle •Only forms one joint with the axial skeleton •Clavicle –Sternoclavicular joint •Where the sternum meets the clavicle

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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