Bones – Test Review

5 functions of bones:

• Protection – examples: skull, ribs• Support – for internal organs• Storage – of minerals (esp. Ca, P)• Movement – by muscles pulling on bones• Hematopoiesis – blood cell formation (RBC)

2 subdivisions of the skeletal system

• Axial skeleton – skull, thorax, vertebrae

• Appendicular skeleton – limbs, girdles

4 Classifications of bones• Long– Ex. Upper and lower limbs

• Short– Ex. Carpals and tarsals

• Flat– Ex. Ribs, sternum, skull, scapulae

• Irregular– Ex. Vertebrae, facial

Parts of a Long Bone

• Epiphysis – ends of long bones

• Diaphysis – shaft part of bone for length

• Periosteum – wraps around diaphysis

• Sharpey’s fibers – used to secure periosteum to diaphysis

Spongy vs. Compact Bone

• Spongy bone – found on epiphysis

· Small needle-like pieces of bone

· Many open spaces

• Compact bone - Dense and smooth

Microanatomy of Bone

• Osteons (Haversian system)

• Central (Haversian) Canals

• Lamellae – Rings around the central canal

• Canaliculi – Tiny canals• Lacunae - Cavities

containing bone cells

Bone Formation, Growth, Remodeling

Bone Formation

· In embryos, the skeleton is primarily hyaline cartilage

· During development, much of this cartilage is replaced by bone

· Cartilage remains in isolated areas

· Bridge of the nose

· Parts of ribs

· Joints

Bone Growth and Remodeling Cartilage is broken down, bone

replaces cartilage, epiphyseal plates allow for growth of long bones during childhood

· Bones are remodeled and lengthened until growth stops

· Bones change shape somewhat

· Bones grow in width

PTH / Calcitonin

Bone Cells

• Osteocytes – mature bone cells

• Osteoclasts – breakdown bone

• Osteoblasts – build bone

• Hyaline cartilage is most abundant cartilage

Bones of the Cranium (skull)

Cranium bones• Frontal bone• Temporal bone• Occipital bone• Parietal bone

Diagram

Bones of the skull – facial bones

Facial bones• Zygomatic• Nasal• Maxilla• Lacrimal • Sphenoid• Mandible

Diagram

Bone Markings (skull)

• Foramen magnum – on occipital bone

• Styloid process – temporal bone

• Mastoid process – temporal bone

• Zygomatic process – temporal bone

Sutures of the skull

• Sagittal suture• Coronal suture• Squamous suture• Lambdoid suture

Fractures• Treatment is reduction

open or closed• Types of fractures:• Simple• Compound• Comminuted• Impacted• Epiphyseal• Greenstick• Osteomyelitis (problem)

Fracture Healing Process

• Healing– Hematoma– Fibrocartilaginous callus– Bony calllus– Remodeling by

osteoclasts/osteoblasts

Pectoral Girdle (bones, joints)

• Clavicle, Scapula make up the girdle• Joints: S/C (sternoclavicular)

A/C (acromioclavicluar) - separation

Glenohumeral joint - dislocation• Glenoid of the scapula• Coracoid process

Bone of the Arm

• HumerusHead of the humerus (proximal) articulates with the glenoid of the scapulaDistal: condyle, trochlea, capitulum to help form the elbow joint

• Fossa – Ant. Coronoid fossaPost. Olecranon fossa

• Deltoid tuberosity – for the deltoid muscle

Bones of the Forearm

• Radius • Ulna

Humerus

• Anatomical Neck – site of fractures

Interosseous membrane

• Surgical neck

Carpals, Metacarpals, Phalanges

• Carpals – 8 bones of the wrist

• Metacarpals – 5 bones of the hand (knuckles)

• Phalanges – 14 bones of the fingers

Pelvic Girdle

• Bones – fusion of ilium, ischium, and pubis

• Together they make the coxal (hip) bone

• They all meet together at the acetabulum

• Locate the pubic symphysis and the obturator foramen

Bones of the Thigh and Leg

• Thigh – head of the femur articulates with the acetabulum superiorly and inferiorly at the knee with the tibia/fibula

• Longest, strongest bone in the body

• Bones of the leg - Tibia/fibula

• Tibia bears the weight of the leg; fibula is non-weight bearing

• Distal end of tibia is medial malleolus and lateral malleolus is the distal end of the fibula

Arches of the Foot