The appendicular skeleton

Appendicular skelton + skeletal muscles= movement

Bones of the appendicular skeleton

• 2 pectoral girdles– Clavicles, scapulae

• 2 upper extremities

• Pelvic girdle– Coxae (hip bones)

• 2 lower extremities

Some important external features of bones

• Processes where tendons and ligaments attach– Trochanter, tuberosity- large and small– Tubercle- rounded– Crest- ridge– Spine- pointed

• Processes formed at articulations– Head, condyle, facet

• Depressions and openings– Fossa, sulcus, foramen, sinus

Pectoral girdle

The clavicle

• Joint between clavicle and sternum is only direct connection between axial skeleton, shoulder girdle

• Easily fractured

Scapula (shoulder blade)

• Glenoid cavity articulates with head of humerus to form shoulder joint

• Acromion forms tip of shoulder; articulates with clavice

• Coracoid process is an attachment site

Upper limb

• Arm (humerus)– Glenohumeral joint– Distal end articulates

with radius and ulna

• Forearm– Radius (lateral), ulna

(medial)– Fibrous membrane

connects the two

Wrist and hand

• 8 carpals, 5 metacarpals, 14 phalanges

• Carpal tunnel formed by space between hamate and pisiform; scaphoid and trapezium– Median nerve and

flexor tendons pass through it

Pelvic girdle is much more massive than pectoral girdle

• Pelvis: two coxae, sacrum, coccyx

• Coxa formed by ileum, ischium and pubis

• Obturator foramen is largest in skeleton

Male and female pelves

Female pelvis is lighter and shallowerwider

Wider outlet

Pectoral vs pelvic girdle

• Pectoral does not articulate directly with vertebrae

• Pectoral girdle provides more mobility than strength

• Pelvic girdle provides more strength than mobility

Lower limb

• Femur is longest, strongest, heaviest bone– Articulates with pelvis at

acetabulum– Articulates with tibia and

fibula at distal end

• Tibia and fibula form lower leg– Fibula is attachment site;

does not bear weight or help form knee joint

– Fibrous membrane between the two

Bones of ankle and foot

• Seven tarsals; talus articulates with tibia and fibula

• Standing, most weight is supported by calcaneus

• Muscles attached to calcaneus by Achilles tendon

• Metatarsal bones carry the rest

Arches of the foot

• Longitudinal arch– Begins at calcaneus,

extends to heads of metatarsals

• Transverse arch– Formed by tarsals and

bases of metatarsals

• Normally ball of foot carries 40% of weight and heel 60%

Bone and joint disorders

• Bone structure and remodeling is affected by:– Age (osteopoenia)– Physical stress– Hormone levels– Rates of calcium and phosphate absorption

and excretion– Genetic and environmental factors

Diagnosing skeletal disorders

• Limitation of movement

• Joint involvement (mono-or polyarthritic?)

• Inflammation

• Sounds (bony crepitus)- grating sounds

• Abnormal bone deposits around fractures or joints

• Abnormal posture

Congenital disorders

• Osteogenesis imperfecta- lack of bone collagen fibers

• Marfan’s syndrome- connective tissue disorder affects heart as well

• Achondroplasia-epiphyseal plates are replaced by bone

• Clubfoot(congenital talipes equinovarus) abnormal muscle development

• Cleft palate• Spina bifida

infections

• Osteomyelitis usually caused by S. aureus

• Paget’s disease apparently caused by virus

Malnutrition and bone disorders

scurvy

rickets

Secondary disorders can also affect skeleton

• Endocrine (giantism)

• Autoimmune (rheumatoid arthitis)

• Gout (digestive)

• How do joints faciliate bone movement?