Bones Of Skull-trunk-ruan-2015.ppt

• Skull • Vertebral column • Bony thorax

The Skull • The body’s most complex bony structure • Formed by the cranium and facial bones

Crania bones

Facial bones

I. Cranium (8) – Paired bones • Temporal bones • Parietal bones

– Unpaired bones • • • •

Frontal bone Occipital bone Sphenoid bone Ethmoid bone

Functions of Cranium 1. protects the brain 2. Provide the site of attachment for head and neck muscles 3. Provide openings for important structures 1) Spinal cord 2) Blood vessels serving the brain 3) 12 pairs of cranial nerves

II. Facial bones(15) – – – –

Maxillae (2) Zygomatic bones (2) Lacrimal bones(2) Nasal bones(2)

– – – – –

Inferior nasal conchae(2) Palatine bones (2) Vomer(1) Mandible(1) Hyoid bone (1)

II. Facial bones –Hyoid bone

Functions of facial bones • Supply the framework of the face and the teeth. • House and protect the sense organs of smell, sight, and taste • Provide the site of attachment for the facial muscles

of expression and mastication muscles, which can act to facilitate eating, facial expression, breathing,

and speech.

Sutures of the skull 1. 2. 3. 4.

Sagittal Coronal Lambdoidal Squamosal

I. Cranium Eight cranial bones – one frontal, two parietal, two temporal, one occipital, one sphenoid, and ethmoid.

PARIETAL (2)

FRONTAL (1)

SPHENOID (1) OCCIPITAL (1) TEMPORAL (2)

Pterion –exterior view • Pterion is the area that marks

the junction between four bones: – parietal – temporal – sphenoid bone

– frontal bones pterion

Pterion –interior view

Middle MENINGEAL ARTERIES

Clinical significance • the weakest part of the

skull • the middle meningeal artery runs beneath it on

the inner side of the skull. • A blow to the pterion may rupture the artery causing an epidural haematoma.

pterion

1. Frontal Bone Two parts: •

a vertical portion (the squama frontalis) corresponding with the region of the forehead.

•

an orbital (horizontal) portion,

which forms the roofs of the orbital and nasal cavities.

1. Frontal Bone • Articulates posteriorly with the parietal bones via the coronal suture • Major markings : • anterior cranial fossa • supraorbital margins • frontal sinuses

2. Parietal Bones Four sutures mark the articulations of the parietal bones 1. Coronal suture – articulation between parietal bones and frontal bone anteriorly 2. Lambdoid suture – where parietal bones meet the occipital bone posteriorly 3. Sagittal suture – where right and left parietal bones meet superiorly 4. Squamosal or squamous suture – where parietal and temporal bones meet

2. Parietal Bones - Lateral View

2. Parietal Bones – interior view Grooves for ant. Mid. And post. Meningeal a. Middle and posterior meninging arteries

3. Occipital Bone • Forms most of skull’s posterior wall and base • Major markings: • foramen magnum • posterior cranial fossa • occipital condyles • hypoglossal canal

posterior cranial fossa

Superior nuchal line

Inferior nuchal line

3. Occipital Bone - Posterior View

3. Occipital Bone -interior view

4. Temporal Bones • Form the inferolateral aspects of the skull and parts of the cranial floor • Divided into four major parts: 1. squamous 2. Tympanic 3. Mastoid 4. petrous

4. Temporal Bones – interior view

4. Temporal Bones Major structures: • Zygomatic process • Styloid process • Mastoid process • Mandibular fossa • Middle cranial fossa

Mastoid part

4. Temporal Bones Major openings: • • • • •

Stylomastoid foramen External auditory meatus Internal auditory meatus Jugular foramen carotid canal

4. Temporal Bones

4. Temporal Bones - interior view

5. Sphenoid Bone • Forms the central wedge that articulates with all other cranial bones and covers the width of the middle cranial fossa. • Butterfly-shaped bone that consists of a central body, greater wings, lesser wings, and pterygoid processes

5. Sphenoid Bone Major makings: • sella turcica • hypophyseal fossa • pterygoid processes

Major openings • foramen rotundum • foramen ovale

• foramen spinosum • optic canals • superior orbital fissure

5. Sphenoid Bone- superior view

6. The Ethmoid Bone • Most deep of the skull; lies between the sphenoid and nasal bones • Forms most of the bony area between the nasal cavity and the orbits 5:Sphenoid bone 13: Ethmoid bone

6. Ethmoid Bone Major markings: • Crista galli • Cribriform plate • Perpendicular plate • Superior nasal conchea

• Middle nasal conchae • Ethmoid sinuses

6. Ethmoid Bone-Superior view

6. Ethmoid Bone- posterior view

crista galli cribriform plate

6. Ethmoid Bone –medial view

II. Facial Bones • Paired bones: – maxillae – Zygomatics – Nasals – lacrimals – palatines – inferior conchae • Unpaired bones – mandible – vomer – hyoid bones

1. Maxillary Bones • Medially fused bones that make up the upper jaw and the central portion of the facial skeleton • Facial keystone bones that articulate with all other facial bones except the mandible

1. Maxillary Bones The major markings: • Frontal zygomatic processes

• palatine processes • orbital surface • inferior orbital foramen

• alveolar margins • maxillary sinuses

1. Maxillary Bones

2. Mandible • The mandible (lower jaw bone) is the largest, strongest bone of the face

• major markings: – coronoid process – mandibular condyle – mandibular notch – mandibular angle – ramus – mandibular mental foramen – alveolar margin

2. Mandible

3. Zygomatic Bones • Irregularly shaped bones • Forms cheeks (prominences of the cheeks) • Forms lower outer margin of orbits

3. Zygomatic Bones • Articulates with – Frontal – Temporal – Sphenoid

– maxillae

4. Palatine bones • L-shaped bones • Horizontal portion forms posterior hard palate • Vertical portion extends between the maxillae and the pterygoid plate of sphenoid bone

4. Palatine bones • Articulates with 2 cranial bones (sphenoid and ethmoid) and 3 facial bones (maxillae, inf. conchae, vermer)

4. Palatine bones

5. hyoid bone • A horseshoe shaped bone • situated in the anterior midline of the neck between the chin and the thyroid cartilage.

6. Nasal bones – thin medially fused bones that form the bridge of the nose

7. Lacrimal bones • contribute to the

medial walls of the orbit and contain a deep groove called the lacrimal fossa that houses the

lacrimal sac

8. Vomer • plow-shaped bone that forms part of the nasal septum

9. Inferior nasal conchae • paired, curved bones in the nasal cavity that form part of the lateral walls of the nasal cavity

III. Skull at Birth Fontanelles Fontanelles are soft spots on a baby's head which, during birth, enable the bony plates of the skull to flex, allowing the child's head to pass through the birth canal. At birth there are 4 fontanelles 1. Anterior fontanell - bregma 2. Posterior fontanelle - lambda 3. Sphenoid fontanelle - pterion 4. Mastoid fontanelle

Closure of fontanelles In humans, the sequence of fontanelle closure is as follows: • The posterior fontanelle generally closes 1-3 months after birth; • The sphenoidal fontanelle is the next to close around 6 months after birth; • The mastoid fontanelle closes next from 6 to 18 months after birth; and • The anterior fontanelle is generally the last to close between 719 months.

IV Bones of the trank Cervical Thoracic

1. vertebrae

Lumbar Sacrum

2. rib

3. sternum

Coccyx

The number of Vertebrae Number Child Cervical vertebrae 7 Thoracic vertebrae 12 Lumbar vertebrae 5 Sacral vertebrae 5 Coccygeal vertebrae 4

Adult 7 12 5 1 1

1. General Features of Vertebrae Body

vertebral foramen (canal)

vertebrae

pedicle Arch

laminae

process (7)

spinous process (1)

transverse process (2) articular process (4)

2. Characteristics of Vertebrae in Each Region (1) Cervical vertebrae ① Small body ② Transverse a.&v.)

foramen(vertebral

③ Bifucated transverse processes ④ Bifid spines （except C1,C7）

⑤ Horizontal articular facets ⑥ C1 (atlas), C2 (axis), C7 – with vertebra prominence.

Cervical vertebrae

(2) Thoracic vertebrae ① Heart-shaped body of the vertebrae ② Costal facets (2 on each side of their bodies and 1 on their transverse processes ) ③ Sloping spines ④ Vertical articular facets

Thoracic vertebrae

(3) Lumbar vertebrae ① ② ③

Large body Horizontal quadrilateral spines vertical articular facets

(4 ) The sacrum ①Formed by 5 fused vertebrae ②Apex-downward ③Base- upward ④3 surfaces (ant.post. & lat.) ⑤Promontory ⑥ Anterior sacral foramina

Anterior view

The sacrum 1) Median sacral crest

2) Intermedial sacral crest 3) Lateral sacral crest 4) Posterior sacral foramina 5) Sacral canal 6) Sacral hiatus 7) Sacral cornu (horns)

8) Auricular surface

Posterior view

(5 ) The coccyx is the final segment of the ape vertebral column (tailbone). Comprising three to five separate or fused vertebrae (the coccygeal vertebrae) below the sacrum

3. Ribs (Costae) • The long curved bones which

form the rib cage. • In most vertebrates, ribs surround the chest, enabling the lungs to expand and thus facilitate breathing by expanding the chest cavity. • Protect the lungs, heart, and other internal organs of the

thorax.

The Thoracic Cage

• A bony and cartilaginous structure which surrounds the thoracic (chest) cavity • Consists of 24 ribs, the sternum, costal cartilages, and the 12 thoracic vertebrae.

True Ribs (7)

False Ribs (8-10)

Floating Ribs (11-12)

Structures of ribs

Posterior view

Anterior view

Two sulcus for subclavian v.& a. in 1st rib.

4. The Sternum • • • • •

Manubrium Jugular notch Sternal angle Body Xiphoid process