BIOL171A Module 2: Support and Movement

Paired bones

bone that occurs in symmetrical copies

what are the paired bones of the skull

Parietal, temporal, maxilla, zygomatic, nasal, lacrimal

Unpaired bones

bone that occurs in single bone located along the midline

what are the unpaired bones of the skull

Frontal, occipital, sphenoid, ethmoid, mandible, vomer

Centrum (vertebral body)

anterior portion of vertebra that bears primary weight of body

Vertebral arch (neural arch)

forms protective enclosure for spinal cord

what consists of vertebral arch

Consists of two pedicles and 2 laminae

Vertebral foramen

large opening created by vertebral body and vertebral arch

what is function of vertebral foramen

Houses and protects spinal cord

Spinous process

posterior projection pointing backward

Transverse processes

lateral projections extending from sides of vertebral arch

what is function of transverse processes

Attachment sites for muscles and ligaments

Articular processes

projections that form joins with vertebrae directly above and below them

Cervical vertebrae (C1-C7)

neck, top 7 vertebrae

what is the function of cervical vertebrae

Small, supports weight of head

Thoracic vertebrae (T1-T12)

mid back, attached to ribs

what is the function of thoracic vertebrae

Medium sized, get larger downward

Lumbar vertebrae (L1-L5)

lower back

what are functions of lumbar vertebrae

Largest and heaviest, bear most body weight

what are functions of appendicular skeleton

Designed for high mobility, dexterity, and strength

what are bones of pectoral girdle

clavicle and scapula

Clavicle

horizontal bone located above first rib

what are functions of clavicle

keeps shoulder away from thorax; transmits forces from arm to axial skeleton

Scapula

large, flat bone on posterior rib cage

what are functions of scapula

Attachment point for numerous muscles to move arm and shoulder

what are bones of upper limb

arm, forearm, hand, wrist

Humerus

long bone of upper arm

what are functions of humerus

Fits into scapula’s glenoid cavity

what are bones of arm

humerus

what are bones of forearm

radius and ulna

Radius

lateral side of forearm (thumb)

what are functions of radius

Pivots around ulna when forearm rotated

Ulna

medial side of forearm (pinky)

what are functions of ulna

forms point of elbow; locks tightly with humerus

what are bones of hands and wrists

carpals, metacarpals, phalanges

Carpals (wrist)

 irregularly shaped bones

what are functions of carpals

Allow for flexible wrist movement

Metacarpals

form framework of palm

Phalanges

finger bones

Pelvic girdle

 connects lower limbs to axial skeleton and provide sturdy, stable foundation for supporting the upper body

what are bones of pelvic girdle

hip bone, lower limb,

what consists of the hip bone

ilium, ischium, pubis

Ilium

flaring upper portion

Ischium

supports weight when sitting

Pubis

joins with opposite pubis

what consists of lower limbs

femur, patella, leg, foot and ankle

Femur

bone of thigh; Longest, heaviest, strongest bone

patella

Protects knee joint and improves leverage

Tibia

medial side of leg; larger, weight bearing bone of lower leg

Fibula

lateral side of leg; thin stick like; stabilizes ankle joint and serves as muscle attachment site

Tarsals

posterior half of foot

Metatarsals

bones that form framework of sole

Phalanges

toe bones

what are axial skeleton adaptations associated with bipedalism

Central foramen magnum, S-shaped vertebral column, Increasing vertebral size

Central foramen magnum

positions head over spine for balance

S-shaped vertebral column

balances head and trunk over pelvis; absorbs shock during walking; Pronounced lumbar curve brings center of gravity back over hips and feet

Increasing vertebral size

Increased proportion of total body weight on lower back

what are appendicular skeleton adaptations associated with bipedalism

Pelvic girdle, Lower limb and knee, Foot and ankle, Upper limb and pectoral girdle

Pelvic girdle

supports abdominal organs; stabilizes trunk in upright posture; Iliac blades shorter, wider, and wrap laterally instead of flat along the back; Gluteus medius and gluteus minimus act as hip abductors instead of hip extensors

Lower limb and knee

bring knee under body’s center of gravity for stability & efficient gait; Female angles inward from hip joint down to knee; Large joint surfaces and joint heads

Foot and ankle

Big toe aligns parallel to other digits; Foot arches Shock absorbers and levers; Heel bone Heel strike shock absorption

Upper limb and pectoral girdle

enables manipulation, tool use, throwing; Arms shortened; Phalanges become straighter and shorter

Arms shortened

Liberated from movement responsibilities

Phalanges become straighter and shorter

Fine motor manipulation tools 

Fibrous joints

bones connected by dense, fibrous connective tissue; no joint cavity

Fibrous joints Movement

immoveable or extremely limited movement

Fibrous joints example

sutures

Cartilaginous joints

bones connected by connective tissue and cartilage; no joint cavity

Cartilaginous joints Movement

rigid to slight movement

Cartilaginous joints examples

 pubic symphysis, discs in spine

Synovial joints

bones connected by connective tissue and cartilage; bone ends covered by articular cartilage; joint enclosed by articular capsule

Synovial joints Movement

freely moveable

Synovial joints example

elbow, knee, shoulder

Synarthrotic

provides high stability and protection

Synarthrotic Movement

immoveable joint

Synarthrotic example

cranial sutures

Amphiarthrotic

provides balance between stability and flexibility

Amphiarthrotic Movement

slightly moveable joint

Amphiarthrotic example

intervertebral discs, pubic symphysis

Diarthrotic

provide high mobility

Diarthrotic Movement

freely moveable joint

Diarthrotic example

 any synovial joint

Types of diarthrotic

ball and socket, hinge, pivot, saddle

Ball and socket

move along different directions; most moveable

ball and socket example

shoulder, hip

Hinge

 move along one axis

Hinge example

elbow, knee

pivot

move along one axis, rotation only

pivot example

C1 & C2

Saddle

modes in two planes

saddle example

thumb

Articular cartilage

thin layer of cartilage covering articulating surfaces of bone

Articular cartilage function

Cushion bone ends, absorbs impact, facilitates smooth movement

Joint cavity

 fluid-filled space between two articulating bones

Joint cavity function

Allows bone to glide past each other without direct physical contact; Has lubricating synovial fluid

Articular capsule

layer that encloses joint cavity and brings together articulating bones

Outer fibrous layer

Made of dense irregular connective tissue

Outer fibrous layer function

adds structural strength and prevents bones from pulling apart

Inner synovial membrane

Connective tissue membrane that lines interior of capsule

Inner synovial membrane function

secretes synovial fluid