The Appendicular Skeleton

The Pectoral Girdle and Upper Limbs

The Appendicular Skeleton

• Upper and lower limbs

• Pectoral and pelvic girdle

Pectoral girdle (shoulder girdle)

• Articulates the upper limbs with the trunk

• Consists of clavicle and scapula

Clavicle and scapula

• Position the shoulder joint

• Help move the upper limb

• Provide a base for muscle attachment

Scapula markings are attachment sites for tendons/ligaments of shoulder joint

The upper limbs

• Scapula articulates with the humerus at the glenohumoral joint

• Greater and lesser tubercles are muscle attachment sites

Humerus

Carpal bones and hand

• Carpus forms wrist

• Two rows of short bones

• Distal row articulates with metacarpals

• Four fingers have three phalanges

• Pollex (thumb) has two

The pelvic girdle and lower limbs

• More massive than the pectoral girdle

• Consists of two os coxae

• Fusion of ilium, ischium and pubis

Ilium

• Largest hip bone

• Within acetabulum, fused to the ischium (posteriorly) and the pubis (anteriorly)

• Pubic symphysis limits left to right

Pelvis

• Composed of the hipbones, sacrum and coccyx

• Subdivided into the false (greater) and true (lesser) pelvis

The lower limbs

• Femur is the longest bone in the body

• Articulates with the tibia at the knee

• Patella is a large sesamoid bone

• Fibula parallels tibia laterally

Tarsus

• Has seven tarsal bones

• Pattern of metatarsal bones and phalanges parallels that of the hand

• All toes have three phalanges except the hallux (two phalanges)

Ankle and arches

• When standing, most of the weight of the body is transferred from the talus to the calcaneous

• Rest is passed on to metatarsals

• Weight transfer occurs along longitudinal arch

• Transverse arch

Individual Variation in the Skeletal System

Important Variation in the Skeletal System

• Medical history

• Weight

• Gender

• Body size

• Muscle mass

• Age

Age related changes in skeletal system

• Begin about age one

• Continue throughout life