ANAPHY 100 MT LEC - Skeletal System

Support, Protection, Movement, Mineral storage, Hematopoiesis

Enumerate the functions of the Sekeltal System

Compact and Spongy/Cancellous Bone

The two classifications of Bones according to TEXTURE

Compact bone

dense and looks smooth and homogenous; it forms the hard outer layer

Spongy/cancellous bone:

composed of small needlelike pieces of bone and lots of open space; honeycomb-like structure made of trabeculae and contains red marrow

Long Bones, Short Bones, Flat Bones, Irregular Bones

Classification of Bones according to SHAPE

Long Bones

have shaft with heads at both ends, mostly compact bone

Short Bones

generally cube shaped, mostly spongy bone

Sesamoid Bones

A short bone that is formed within tendons,

Flat bones:

thin, flattened, usually curved, 2 thin layers of compact bone sandwiching a layer of spongy bone between them

Irregular bones

bones that do not fit any of the above bones

Diaphysis, Epiphysis, Medullary Cavity, Periosteum, Endosteum, Articular Cartilage

Enumerate the Anatomy of a Long Bone

Diaphysis

shaft, composed mainly of compact bone

Epiphysis

containing spongy bone and red marrow

Medullary Cavity

central cavity, contains yellow marrow

Periosteum

tough outer membrane covering the

bone surface

Endosteum

lines the medullary cavity

Articular Cartilage

smooth hyaline cartilage that covers joint surfaces

Osteon Haversian System, Central Haversian Canal, Lamellae, Lacunae with osteocytes, Canaliculi

Enumerate the parts of a Microscopic Bone Structure

Osteon Haversian System

structural unit of the bone

Central Haversian Canal

contains blood vessels and nerves

Lamellae

concentric rings of calcified matrix

Lacunae with osteocytes

spaces with osteocytes

Canaliculi

tiny canals connecting lacunae, enabling nutrient and waste exchange

Osteoblasts, Osteocytes, Osteoclasts

Enumerate the Bone Cells

Osteoblasts

bone forming cells, responsible for secreting bone matrix

Osteocytes

mature bone cells that maintain bone matrix

Osteoclasts

bone resorbing cells, break down bone to release calcium

Projection

sites on the bone where muscles or ligaments are attached

Tuberosity, Crest, Trochanter, Line, Tubercle, Epicondyle, Spine, Process

Enumerate the Projections of a Bone

Tuberosity

A substantial, rounded prominence that can have a rough surface.

Crest

A distinct, narrow ridge extending along a bone.

Trochanter

An exceptionally large, irregular prominence (found exclusively on the femur).

Line

A narrow bony ridge, though less prominent than a crest

Tubercle

A small, rounded process or projection.

Epicondyle

An elevated surface situated above or upon a condyle.

Spine

A slender, sharp, and frequently pointed projection.

Process

A general term referring to any bony projection or prominence.

Head, Facet, Condyle, Ramus

Enumerate the Projections that help to form joints

Head

An expanded, rounded end of a bone supported by a narrowed neck region.

Facet

A flat, smooth surface where two bones meet to articulate.

Condyle

A smooth, rounded protrusion involved in joint articulation.

Ramus

A bridge-like or arm-like extension projecting from a main bony mass.

Groove, Fissure, Foramen, Notch

Enumerate the Depressions and Openings of a bone

Groove

A shallow trough or linear channel running along the surface of a bone.

Fissure

A narrow, slit-like gap or slit passing through bone.

Foramen

A circular or oval hole through which structures pass.

Notch

A distinct indentation or cutout along the margin of a bone.

Meatus

A canal/tube-shaped passageway traversing through bone.

Sinus

An internal, air-filled cavity enclosed within a bone and lined with a mucous membrane.

Fossa

A shallow, basin-shaped depression that often accommodates another bone in a joint.

ossification

process of bone formation

Intramembranous Ossification, Endochondral Ossification

the 2 processes of bone formation

Intramembranous Ossification

directly from mesenchyme forming flat bones like the skull

Endochondral Ossification

replacement of cartilage with bone, responsible for most bones

epiphyseal plates

Growth occurs at the _____ during childhood

1. Cartiage grows on the articular cartilage

2. Bone replaces cartilage

3. Cartilage grows on the epiphyseal plate

4. bone replaces cartilage

Bone Growth Process:

1. Bone is resorbed in the epiphyseal plate

2. Bone is added by appositional growth

3. Bone is resorbed

Bone Remodelling Process

Simple/Closed (clean break, skin intact)

Compound/Open (bone penetrates the skin)

the two types of bone fractures:

hematoma, fibrocartilage callus, bony callus, remodeling

healing stage of bone fractures:

Comminuted, Compression,

Depressed, Impacted, Spiral, Greenstick

Enumerate the common types of fractures

Comminuted

Bone shatters into multiple fragments; common in older adults with brittle bones.

Compression

Bone is crushed; typically affects porous or osteoporotic bones in older individuals.

Depressed

Broken portion of bone is pressed inward; characteristic of skull fractures.

Impacted

Broken bone ends jam directly into each other; often caused by trying to break a fall.

Spiral

Ragged break resulting from excessive twisting; common sports injury.

Greenstick

Incomplete break (bends and splinters like a twig); common in children with flexible bones.

Foramen magnum

large opening where the spinal cord passes

Coronal

suture formed where the paired parietal bones meet the frontal bone

Sagittal

suture formed at the midline where two parietal bones meet

Lambdoid

suture where occipital bone joins the parietal bones anteriorly

Squamous

suture where temporal bone and parietal bone meet

Sinuses:

air-filled spaces that lighten the skull and resonate voice (frontal, maxillary, sphenoidal, ethmoidal)

Hyoid bone

- U-shaped bone in the neck

- not connected to other bones

- Located above the larynx, suspended by ligaments

- Supports the tongue and helps with swallowing and speech

Vertebral Column (26 bones)

- Protects the spinal cord

- Supports the head

- Provides attachment for ribs and back muscles

- separated by flexible fibrocartilage pads called intervertebral discs.

Body (centrum)

anterior, weight-bearing portion of the vertebrae

Vertebral arch

formed by pedicles and laminae

Vertebral foramen

opening through which the spinal cord passes in the evrtebrae

Transverse processes

two lateral projections of the vertebrae

Spinous processes

posterior projection from the vertebral arch

Superior and inferior articular processes

form joints with adjacent vertebrae

Cervical Vertebrae (C1-C7)

-7 vertebrae in the neck

- Smallest and lightest vertebrae

- Have transverse foramina for vertebral arteries

- Usually have short, bifid (split) spinous processes

- Include the special vertebrae: Atlas (C1) and Axis (C2).

ATLAS (C1)

• No body

• Articulates with the occipital condyles of the skull

• Allows the "yes" (nodding) movement

AXIS (C2)

• Contains the dens (odontoid process)

• Acts as a pivot for the atlas and skull

• Allows the "no" (rotation) movement

Thoracic Vertebrae (T1-T12)

• 12 vertebrae

• Larger than cervical vertebrae

• Only vertebrae that articulate with ribs

• Have costal facets on the body for rib articulation

• Transverse processes articulate with rib tubercles

• Long spinous processes that slope downward

Lumbar Vertebrae (L1-L5)

• 5 vertebrae

• Largest and strongest vertebrae

• Massive, kidney bean-shaped bodies

• Short, thick, hatchet-shaped spinous processes

• Bear most of the body's weight and stress

Sacrum

-Formed by fusion of 5 sacral vertebrae

- Articulates with: L5 (superiorly); Coccyx (inferiorly); Hip bones at the sacroiliac joints (laterally)

- Forms the posterior wall of the pelvis

Contains:

Median sacral crest

Posterior sacral foramina

Sacral canal

Sacral hiatus

Coccyx

• Formed by fusion of 3-5 small vertebrae

• Commonly called the tailbone

• Remnant of the embryonic tail

True RIbs (1-7)

False Ribs (8-12)

Floating Ribs (11-12)

intercoastal spaces

The ribs consists of:

True ribs (1-7)

attach directly to the sternum by costal cartilages

False ribs (8-12)

either attach indirectly to the sternum or are not attached to the sternum at all

Floating ribs (11-12)

lack sternal attachments

Intercostal spaces

are filled with intercosal muscles, which aid in breathing

Clavicle

• Attaches to the manubrium of the sternum medially and to the scapula laterally

• Acts as a brace to hold the arm away from the top of the thorax

• Helps prevent shoulder dislocation

sternoclavicular joint

Each shoulder girdle attaches to the axial skeleton at only one point:

Ilium, Ischium, Pubis

Coxal bones are made of:

ilium

large, flaring bone that forms most of the hip bone

ischium

forms the most inferior part of the coxal bone

pubis

most anterior and inferior part of the coxal bone

Pelvic Girdle

Articulates with sacrum at sacroiliac joint

Plane joint:

short slipping or gliding movements, nonaxial, e.g. intercarpal joints of the wrist