THE BONES OF THE APPENDICULAR SKELETON

the appendicular skeleton = 126 bones of the pectoral girdle, upper limbs, pelvic girdle, lower limbs

SKELETAL ORGANIZATION pectoral girdle = scapula + clavicles upper limbs = humerus, radius, ulna, carpals, metacarpals, phalanges pelvic girdle = 2 os coxae or coxal bones lower limbs = femur, tibia, fibula, patella, tarsals, metatarsals, phalanges

THE PECTORAL GIRDLE 2 clavicles + 2 scapula supports the upper limbs, provides a place for muscle attachment arrangement of bones is good for mobility, but bad for stability

THE PECTORAL GIRDLE clavicles = “collarbones” “S” shape not very strong; easily fractured

THE PECTORAL GIRDLE scapulae = “spade” shoulder blades broad, triangular bones

THE PECTORAL GIRDLE glenoid cavity = a depression where the head of the humerus fits

THE UPPER LIMBS humerus: location = upper arm extends from the scapula to the elbow head fits into the glenoid cavity of the scapula

THE UPPER LIMBS radius: location = forearm on the thumb side between the elbow & wrist

THE UPPER LIMBS ulna = forearm longer than the radius, overlaps the humerus

THE UPPER LIMBS carpals = wrist 8 bones – 2 rows of four short bones

THE UPPER LIMBS 5 metacarpals = palm distal ends form the knuckles numbered 1-5 starting with the thumb

THE UPPER LIMBS 14 phalanges = fingers / digits 3 in each finger (proximal, middle, distal), 2 in the thumb / pollex (proximal, distal)

THE PELVIC GIRDLE made of 2 os coxae or coxal bones which articulate with each other & the sacrum

THE PELVIC GIRDLE functions include support for the trunk, attachments for the lower limbs, protection for the bladder, large intestine, & reproductive organs has a cup-shaped acetabulum which receives the head of the femur

THE PELVIC GIRDLE each coxal bone has 3 parts: ilium: the largest portion, upper prominence called the iliac crest ischium: the lowest portion, you sit on the ischial tuberosities pubis: the anterior portion, fuses at the pubic symphysis

THE PELVIC GIRDLE the obturator foramen is a large opening where nerves & blood vessels pass from the spinal cord to the lower limbs

THE LOWER LIMBS

THE LOWER LIMBS femur = “thigh bone” longest, strongest bone in the body extends from the hip to the knee head of femur fits into the acetabulum of the coxae

articulates with the femur Patella = kneecap, a sesamoid bone articulates with the femur

THE LOWER LIMBS tibia = larger bone of the lower leg, “shin” on the medial side of the leg

THE LOWER LIMBS fibula = smaller bone of the lower leg on the lateral lower leg bears no weight

THE LOWER LIMBS tarsals = ankle 7 tarsal bones the talus is the only free moving bone of the ankle the calcaneus / heel is the largest tarsal bone

THE LOWER LIMBS metatarsals = soles / arch numbered 1-5 starting with the big toe longitudinal arch + transverse arch when arches weaken you may get flat feet

THE LOWER LIMBS phalanges = toes 14 total, 3 in each except the big toe

JOINTS 230 in the body = functional junctions between bones bind parts of the skeletal system make bone growth possible allow the skeleton to change shape during birth enable movement

JOINTS classified according to their degree of movement = functional classification immovable slightly movable freely movable

JOINTS also classified according to the type of tissue binding bone = structural classification fibrous cartilaginous synovial

FIBROUS JOINTS: bones are tightly joined by a layer of dense connective tissue allow little or no movement ex. sutures of the skull, tibia-fibula

CARTILAGINOUS JOINTS: bones are connected by fibrocartilage allow limited movement ex. intervertebral discs, pubic symphysis, 1st rib to sternum

SYNOVIAL JOINTS: bones are covered with articular cartilage & held together by a fibrous joint capsule (outer layer of ligaments + inner layer of synovial membrane)

SYNOVIAL JOINTS: some have menisci (shock-absorbing pads), some have bursae (fluid-filled sacs located between the skin & bony prominences such as knees & elbows)

SYNOVIAL JOINTS: types of synovial joints: gliding hinge Pivot ellipsoidal saddle ball-and-socket

TYPES OF JOINT MOVEMENTS: flexion / extension abduction / adduction Circumduction hyperextension Refer to handouts! retraction / protraction elevation / depression Rotation pronation / supination opposition dorsiflexion / plantar flexion eversion / inversion