Bones and Joints

Long bones

• Greater in length that width

• ex: bones of arm, forearm, metacarpal bones, phalanges

Short bones

• length nearly equal to width

• ex: bones of wrist

Bones are

the primary organ of the skeletal system

Skeletal system consists of

Bones, cartilage, and ligament

Flat bones

• flat, thin surfaces, may be slightly curves

• ex: some cranial bones and scapula

Irregular bones

• complex shapes

• ex: vertebrae

Axial skeleton

Bones along central body axis, provides support and protection

Appendicular skeleton

Bones of upper and lower limbs, facilitates movement and mobility

Most complex structure of the skeleton and how many bones it’s made of

Skull, make of 22 bones

Neurocranium bones

• 8 bones of this type

• form the rounded cranium and surround the brain

Frontal bone, 3 parts

• squamous part (flat)= forehead

• orbital part= roof of orbits (where eyes are)

• nasal parts= articulation for nasal bones and maxilla (arrow shaped)

Parietal bone

• quadrilateral in shape on the top and sides of skull

Frontal bone

Parietal bone

What key structure does the occipital bone contain

Foramen magnum

Occipital bone

What are the 3 sections in the occipital bone?

Squamous, condylar, basilar (yellow, red, green resp)

Describe the locations of the occipital squamous, condylar, and basilar parts

• squamous= posterior to magnum foramen

• condylar= lateral to magnum foramen

• basilar= anterior to magnum foramen

Ethmoid

Ethmoid is

Roof and nasal septum of nasal cavity

Describe the cribriform and perpendicular plates

Cribriform plate= horizontal part, roof of nasal cavity

Perpendicular plate= vertical part, superior 2/3 of nasal septum

Name the red, green, and gray side structures

Red= cribriform plate

Green= perpendicular plate

Gray side structures= ethmoidal labyrinth

What is the spenoid

Base and side of skull

Describe the 2 greater and lesser wings, and the 2 pterygoid processes

• 2 greater wings= large, flat projection that extend laterally from the body

• 2 lesser wings= smaller, upward projection from the body

• 2 pterygoid processes= downward projections from the junction of body and greater wings

What is the temporal bone

Sides of skull

Name the red part

Squamous (mandibular fossa)

Name the blue part

Zygomatic process (articulates with zygomatic bone)

Name the green part

Tympanic part (surrounds the external opening of the external auditory meatus)

Name the purple part

Petromastoid

Name the yellow part

Styloid process

Describe the petrous part of temporal bone

• can only be viewed internally

• pyramid shapes

• internal auditory meatus

Viscerocranium, how many bones and function

• made of 14 bones

• Forms the face, oral cavity (supports teeth), and parts of nasal cavities

• attachment sites for muscles of facial expression and chewing

Zygomatic: prominence of cheeks and lateral wayys of orbits

Lacrimal bone: medial wall of orbits (smallest bone in face)

Vomer: forms the hinder and lower part of the nasal septum

Palatine: between left and right maxilla, forms lateral wall and floor of nasal cavity, and roof of oral cavity

Nasal bones

Inferior nasal conchae (inferolateral wall of nasal cavity)

4 processes of maxilla

Frontal, alveolar, palatine (anterior part of hard palate), zygomatic process

Upper= frontal process

Lower= alveolar process

(black lines)

Upper= Palatine process

Lower= Alveolar process

Body of mandible

Body=horizontal portion

Left and right ramus

2 processes of mandible

Coronoid process and condylar process (articulates with mandibular fossa of temporal bone)

Condylar and coronoid process (resp, L-R)

Hyoid function

Attachment site for anterior neck muscles

Green= greater horn

Yellow= lesser horn

Red= body

Which articulation processes form the zygomatic arch

Temporal process of zygomatic bone and zygomatic process of temporal bone

Zygomatic bone

Foramen magnum

Cervical vertebrae

• bones of neck

• C1-C7

• C2 articulates with occipital condyles

Thoracic vertebrae

• Forms upper back region

• Each articulates laterally with 1-2 pairs of ribs

• T1-T12

Lumbar vertebrae

• Form lower back region

• L1-L5

Sacrum vertebrae region

• 5 fused vertebrae, S1-S5

• Fused by late 20s

• laterally articulates 2 hip bone

Coccyx (tailbone)

• formed by 4 coccygeal vertebrae, Co1-Co4

• start uniting during puberty, does not bear upper body weight

• provides attachment points for muscles

4 spinal curvatures

• Cervical= forward convex

• Thoracic= backward convex

• Lumbar= forward convex

• Sacral= backward convex

Spinal curvature function

• gives column some flexibility

• supports weight of body and acts as natural shock absorber

Atlas (C1) functions and characteristics

• supports the head, allows for nodding motion

• lacks body and spinous process

• anterior and posterior arches connect lateral masses

Articular facet for dens

On inner side of C1 anterior arch

Articular facet for dens

Axis (C2) functions and characteristics

• produces dens

• acts as atlas pivot, allows shaking head (‘no‘)

Dens

Vertebra prominens (C7) features

• transition from cervical to thoracic region

• longer spinous process (easily palpated)

Key features of cervical vertebrae

• have transverse foramen

• have bifurcated spinous processes (except for C7)

Thoracic vertebrae key features

• Heart shaped bodies

• Costal facet on lateral side of body and on sides of transverse processes (except T11, T12)

Costal facet

Thoracis spinous process (longer, angled downwards)

Lumbar vertebrae key characeristics

• largest vertebrae

• thicker, oval body

• shorter spinous body that is perpendicular to body

• bears most of the upper body weight

Spinous process of lumbar vertebra (perpendicular to body)

What is the sacrum

• Anteriorly curved, triangular bone

• forms posterior wall of pelvic cavity

Ala (wing of sacrum)

Superior articular process

Base of sacrum

Apex of sacrum

Auricular surface of sacrum (ear shaped on upper-lateral part of sacrum)

Anterior and posterior sacral foramina (8 total)

Transverse ridges of sacrum

Medial crest of sacrum

Sacral canal:

• Whose ending is bound by sacral hiatus

• Has bony projections called sacral cornua

Sacral cornu= left (landmark for epidural injection)

Sacral hiatus= upper

C1

Manubrium

• Widest and most superior portion of sternum

• has 2 clavicular notches

Jugular notch (shallow superior depression between clavicular notches)

Costal notches (articulation points for ribs)

Sternum body characteristics

• longest portion of sternum

• Costal notches for ribs 2-7

Sternal angle

• Where manubrium and body meet

• where cartilage of rib 2 attaches

• key landmark in palpitation and counting ribs

Xiphoid process (projection at sternum tip)

True ribs

• ribs 1-7

• connect individually to costal cartilages

False ribs

• ribs 8-12

• not directly attached to sternum

Costal cartilage of ribs 8-10

• fused to costal cartilage of rib 7

• indirectly attached to sternum

Floating ribs

• Ribs 11-12

• without connection

• Costal groove of rib

• marks path of nerves and blood vessels

Angle of rib

Where shaft begins to curve

Tubercle of rib (small knot-like projection below neck)

Neck of rib

Head of rib

Pectoral girdle consists of, and functions to

• clavicles and scapulae

• supports upper limbs

Clavicle functions and structure

Stabilizes shoulder joint

• sternal end: roughly pyramidal

• Acromial end: broad and flattened

Spine of scapula

Acromion of scapula

Supraspinous fossa of scapula