AXIAL SKELETON HUMAN SKELETON
Puzzle Piece 5: Axial Skeleton Human Skeleton
Adult human skeleton has 206 bones.
Children have more bones since some fuse during childhood and adolescence.
Skeleton divided into two main parts:
Axial Skeleton:
Bones in the vertical central axis of the body.
Includes:
Cranial bones (encase the brain):
Paired bones: parietal bones, temporal bones.
Unpaired bones: sphenoid bone, ethmoid bone, occipital bone, frontal bone.
Facial bones.
Ear ossicles.
Hyoid bone.
Vertebral column (spine).
Thoracic cage (rib cage).
Appendicular Skeleton:
Bones in the upper and lower limbs.
Includes bones that connect limbs to the axial skeleton.
Witty Tip:
Axial skeleton = main axis bones of the body.
Appendicular skeleton = all limb bones + connection bones.
Bone Function and Structure
Each bone has a specific function determined by its size, shape, and strength.
Bones in lower back and limbs are thicker and stronger to support body weight.
Surface markings (bone features) provide clues about function:
Prominent attachment points indicate areas for strong muscle attachment.
Smaller markings suggest attachment for weaker muscles.
Witty Tip 1:
Strong muscles need larger gripping areas to hold on during contraction.
Witty Tip 2:
Learn bone names and features; understand bone structure vs. function for better skeletal anatomy comprehension.
Axial Skeleton
Composed of 80 bones.
Includes:
Cranial bones.
Facial bones.
Ear ossicles.
Hyoid bone.
Vertebral column.
Thoracic cage.
Cranial Bones
Encases the brain.
8 cranial bones:
Paired bones: parietal bones, temporal bones.
Unpaired bones: sphenoid bone, ethmoid bone, occipital bone, frontal bone.
Witty Tip 1:
Cranial bones = PEST OF 211:
2 Parietal bones.
1 Ethmoid bone.
1 Sphenoid bone.
2 Temporal bones.
1 Occipital bone.
1 Frontal bone.
Witty Tip 2:
Paired means right and left (like shoes).
Unpaired means singular; no pair.
Sutures: narrow bands of dense irregular connective tissue between cranial bones:
Coronal suture: separates frontal bone from parietal bones.
Sagittal suture: separates right and left parietal bones.
Lambdoid suture: separates occipital bone from parietal bones.
Squamous suture: separates temporal bone from adjacent bones.
Witty Tip 1: Coronal suture is like a crown on Miss Universe's head.
Witty Tip 2: Lambdoid suture resembles the Greek letter lambda.
Witty Tip 3: Squamous suture is flat like a scale.
Witty Tip 4: Sutures are fibrous joints comprised of dense irregular connective tissue, providing strength in multiple directions.
Bone Features and Associations
Critical to associate bone features with their respective bones to avoid confusion.
Witty Tip:
Use full names like "infraorbital foramen of maxilla" when studying bone features for automatic recall.
Frontal Bone
Forms the forehead (anterior aspect of cranium) and part of bony orbits.
Bone features:
Supraorbital foramen: hole above each orbit allowing passage of nerves and vessels.
Frontal sinus: air pocket space; inflammation leads to frontal sinusitis.
Classified as pneumatized bone due to the frontal sinus.
Witty Tip:
“Foramen” means hole; “supra” means superior; “orbital” means bone orbit. Therefore, supraorbital foramen = hole above bony orbit.
Categorized as a flat bone and pneumatized bone.
Parietal Bones
Found posterior to the frontal bone and anterior to the occipital bone.
Right and left parietal bones form sides (lateral) and roof (superior) of the cranium.
Separated by the sagittal suture.
Occipital Bone
Forms back (posterior) and base of cranium.
Classified as flat bone.
Bone features:
Foramen magnum: large hole for brainstem passage.
Occipital condyle: smooth rounded surface articulating with C1 (atlas).
Hypoglossal canal: below the tongue, pathway for structures reaching underneath.
Located superior to occipital condyle.
Jugular foramen: shared with temporal bone, passageway for internal jugular artery and cranial nerves IX, X, XI.
Witty Tip: The jugular foramen is at the cranium's base between occipital and temporal bones.
Temporal Bone
Forms sides (lateral) and base of cranium.
Described as irregular bone.
Distinct features:
Mastoid process: bump behind ear.
Styloid process: sharp pointy process.
Zygomatic process: connects with zygomatic bone.
Mandibular fossa: articulates with mandible's smooth rounded surface.
External acoustic meatus: canal facing external for hearing.
Internal acoustic meatus: canal related to hearing and equilibrium within cranium.
Carotid canal: base of cranium for internal carotid artery.
Jugular foramen: features shared with occipital bone, behind carotid canal.
Witty Tip: Arteries and veins often run parallel, e.g., carotid artery parallels the jugular vein.
Modern Example:
The mandibular fossa articulates with mandibular condyle of mandible, forming temporomandibular joint (TMJ) crucial for jaw movement.
Sphenoid Bone
An irregular bone that touches all other cranial bones (nickname: “Keystone”).
Comprises superior and posterior parts of bony orbit.
Bone features:
Sella turcica: houses the pituitary gland.
Foramina (Rotundum, Ovale, Spinosum): passageways for branches of CN V (trigeminal nerve).
Optic canal: passageway for CN II (optic nerve).
Superior orbital fissure.
Inferior orbital fissure.
Witty Tip: Don’t confuse foramen (short) with fissure (elongated).
Foramina are holes; fissures are long openings.
Ethmoid Bone
An irregular and pneumatized bone with ethmoid air cells.
Contributes to bony orbit and superior/middle nasal conchae.
Forms nasal septum with vomer bone.
Bone features:
Crista galli: anchors brain anteriorly (resembles rooster crest).
Cribriform plate: for passage of CN I (olfactory nerve).
Superior and middle nasal conchae: aid in air swirling in nasal cavity.
Perpendicular plate: upper nasal septum aspect (with vomer below).
Ethmoid sinus: air pocket leading to potential inflammation (ethmoid sinusitis).
Facial Bones
14 facial bones in total:
Unpaired bones: mandible, vomer.
Paired bones: inferior nasal concha, maxilla, palatine, zygomatic, nasal, lacrimal.
Mandible Bone
Unpaired, irregular bone; only movable bone in face.
Forms the lower jaw and houses lower teeth.
Bone features:
Mental foramen: passage for CN V (trigeminal nerve) branch.
Mandibular foramen: another branch of CN V.
Mandibular condyle: articulates with mandibular fossa of temporal bone (TMJ).
Inferior Nasal Concha
Paired, irregular bone forming a bump in the nasal cavity.
Not part of the ethmoid bone.
Vomer Bone
Unpaired, flat bone forming inferior nasal septum.
Triangular shape with a small anterior view area.
Perpendicular plate of ethmoid forms majority of anterior nasal septum.
Maxilla Bone
Paired, irregular and pneumatized bone with maxillary sinuses.
Forms part of the bony orbit and floor of nasal cavity;
Houses upper teeth and makes largest part of hard palate.
Bone feature:
Infraorbital foramen: hole below bony orbit for CN V passage.
Palatine Bone
Paired, irregular bone forming tiny part of bony orbit.
Forms posterior hard palate (roof of mouth).
Transverse palatine suture lies between maxilla and palatine bones.
Zygomatic Bone
Paired, irregular bone (cheekbone) forming part of bony orbit.
Bone feature:
Temporal process: connects zygomatic bone with temporal bone, forming zygomatic arch.
Lacrimal Bone
Paired, flat bone forming medial bony orbit.
Provides lacrimal fossa and nasolacrimal canal for tears.
Witty Tip:
"Lacrima" means tears, positioned where tears flow.
Nasal Bone
Paired, flat bone forming the bridge of the nose.
Witty Tip:
Glasses rest on nasal bones.
Hyoid Bone
Unpaired, irregular, U-shaped bone in the upper neck.
Features: greater and lesser horns.
Unique: Only bone not connected to any other bone.
Supports movement controlled by muscles used in talking and swallowing; suspended by muscles attached above (suprahyoid) and below (infrahyoid).
Ear Ossicles
Paired, irregular bones found in the middle ear (smallest bones in the body).
Include: malleus, incus, stapes.
Responsible for amplifying sound waves.
Witty Tip: As ear ossicles are in the middle ear, they are part of the axial skeleton.
Anatomy of the Vertebral Column
Composed of vertebrae:
Cervical vertebrae: 7 vertebrae.
Thoracic vertebrae: 12 vertebrae.
Lumbar vertebrae: 5 vertebrae.
Sacrum: 5 fused sacral vertebrae.
Coccyx: 3-5 fused coccygeal vertebrae.
Witty Tip:
Understand vertebrae order with mnemonic; 7 cervical = “ce,” 12 thoracic = “th,” 5 lumbar = “five.”
Curves:
Four natural curves: cervical, thoracic, lumbar, sacral/coccygeal.
Purpose: Increase flexibility, strength, shock absorption.
Abnormal curvatures:
Scoliosis: abnormal lateral curve.
Kyphosis: excessive upper thoracic bend.
Lordosis: excessive lumbar curvature.
Common Features of Cervical, Thoracic, and Lumbar Vertebrae
Specific vertebrae features include:
Spinous process: always posterior.
Body (centrum): always anterior.
Transverse process: sticks out to sides.
Vertebral foramen: hole in vertebra center.
Articular facets: used in vertebrae articulation.
Witty Tip:
Spinous processes are smooth when feeling the back.
The body faces anteriorly, making it close to the body center.
Witty Tip: A process that sticks out is termed a "process"; 'transverse' means horizontal. Thus, transverse process sticks out horizontally.
Vertebra alignment: formed by the vertebral column; intervertebral disks between adjacent bodies.
Aligned vertebral foramina create the vertebral canal for the spinal cord.
Spinal nerves emerge from the cord through holes between two vertebrae (intervertebral foramen).
Cervical Vertebrae
7 cervical vertebrae (C1 to C7): located in cervical (neck) region.
Unique features include:
C1 (atlas): No spinous process/body. Articulates with occipital condyles at the atlanto-occipital joint allowing for “yes” head motion.
C2 (axis): has odontoid process (dens) articulating with C1 for “no” movement.
No intervertebral disc between C1 and C2.
Specific features of cervical vertebrae:
Bifid spinous process (all except C7).
Transverse foramen for vertebral blood vessels.
Witty Tips:
Bifid spinous process: "bi" means two.
C7 has the largest spinous process, significant for landmarking.
Thoracic Vertebrae
12 thoracic vertebrae (T1 to T12): located at thorax level.
Forms thoracic cage with ribs/sternum, featuring indentations for rib articulation.
Features include:
Superior costal facet, inferior costal facet, transverse costal facet for rib connections.
Witty Tip: Ribs articulate with thoracic vertebrae having heads and tubercles.
Bone Features of Thoracic Vertebrae
Head of rib articulates with body of thoracic vertebra via costal facets.
Tubercle of rib articulates with transverse process via transverse costal facet.
T9 to T12 have variations in coastal facets' position.
Lumbar Vertebrae
5 lumbar vertebrae (L1 to L5): located in lumbar region.
Characterized by large bodies to support upper body weight.
Exhibit common features: spinous processes, superior/inferior articular facets, transverse processes.
Sacrum
Triangular bone fusing five sacral vertebrae.
Articulation: superior articular facets with inferior articular facets of L5 vertebra.
Sacral canal: formed by aligned fused sacral vertebral foramina.
Median sacral crest: fusion result from spinous processes.
Sacral hiatus: located at sacral canal end; passageway for spinal nerves.
Sacral foramina: holes for spinal nerve passageways.
Sacral ala: articulates with hip bone, forming superior part of sacroiliac joint.
Coccyx
Formed by fusion of three to five coccygeal vertebrae.
Articulates with sacrum; may bear weight when sitting.
Thoracic Cage
Composed of ribs, sternum, and costal cartilages.
Each rib has a head, neck, and tubercle at its sternal end.
Includes 12 pairs of ribs attached to thoracic vertebrae.
Witty Tip: 12 thoracic vertebrae = 12 pairs of ribs (6 on each side).
Ribs Types
Vertebrosternal ribs (7 pairs):
Ribs 1-7 connect directly to sternum (true ribs).
Vertebrochondral ribs (3 pairs):
Ribs 8-10 connect to sternum via additional cartilage (false ribs).
Vertebral ribs (2 pairs):
Ribs 11-12 don’t connect to sternum (floating ribs).
Witty Tip 1: Rib names indicate their connections; vertebrosternal at vertebra/sternum; which is true, and vertebrochondral (false) have extra cartilage.
Witty Tip 2: Remembering only 2 pairs of floating ribs leads to understanding the total distribution of ribs.
Sternum (Breastbone)
Comprised of three parts:
Manubrium: top part, resembles “M.”
Body: longest part.
Xiphoid process: inferior aspect, resembles “X.”
Notches and articulations:
Clavicular notch: articulate with clavicle.
Suprasternal notch (Jugular notch): top part between clavicular notches.
Sternal angle: junction of manubrium with body.
Witty Tip: Suprasternal notch and sternal angle serve as valuable landmarks for medical examinations.
Suprasternal notch aids in neck/thorax locating for procedures (e.g., tracheostomy).
Sternal angle identifies second ribs and provides positioning reference for the heart's base.
Please be aware: All 'Witty Tips' sections and any associated visual cues (such as emojis/smiley faces) are considered examinable material.
Adult human skeleton has 206 bones.
Children have more bones since some fuse during childhood and adolescence.
Skeleton divided into two main parts:
Axial Skeleton:
Bones in the vertical central axis of the body.
Includes:- Cranial bones (encase the brain):
Paired bones: parietal bones, temporal bones.
Unpaired bones: sphenoid bone, ethmoid bone, occipital bone, frontal bone.
Facial bones.
Ear ossicles.
Hyoid bone.
Vertebral column (spine).
Thoracic cage (rib cage).
Appendicular Skeleton:
Bones in the upper and lower limbs.
Includes bones that connect limbs to the axial skeleton.
Witty Tip:
Axial skeleton = main axis bones of the body.
Appendicular skeleton = all limb bones + connection bones.
Bone Function and Structure
Each bone has a specific function determined by its size, shape, and strength.
Bones in lower back and limbs are thicker and stronger to support body weight.
Surface markings (bone features) provide clues about function:
Prominent attachment points indicate areas for strong muscle attachment.
Smaller markings suggest attachment for weaker muscles.
Witty Tip 1:
Strong muscles need larger gripping areas to hold on during contraction.
Witty Tip 2:
Learn bone names and features; understand bone structure vs. function for better skeletal anatomy comprehension.
Axial Skeleton
Composed of 80 bones.- Includes:
Cranial bones.
Facial bones.
Ear ossicles.
Hyoid bone.
Vertebral column.
Thoracic cage.
Cranial Bones
Encases the brain.
8 cranial bones:
Paired bones: parietal bones, temporal bones.
Unpaired bones: sphenoid bone, ethmoid bone, occipital bone, frontal bone.
Witty Tip 1:
Cranial bones = PEST OF 211:
2 Parietal bones.
1 Ethmoid bone.
1 Sphenoid bone.
2 Temporal bones.
1 Occipital bone.
1 Frontal bone.
Witty Tip 2:
Paired means right and left (like shoes).
Unpaired means singular; no pair.
Sutures: narrow bands of dense irregular connective tissue between cranial bones:
Coronal suture: separates frontal bone from parietal bones.
Sagittal suture: separates right and left parietal bones.
Lambdoid suture: separates occipital bone from parietal bones.
Squamous suture: separates temporal bone from adjacent bones.
Witty Tip 1: Coronal suture is like a crown on Miss Universe's head.
Witty Tip 2: Lambdoid suture resembles the Greek letter lambda.
Witty Tip 3: Squamous suture is flat like a scale.
Witty Tip 4: Sutures are fibrous joints comprised of dense irregular connective tissue, providing strength in multiple directions.
Bone Features and Associations
Critical to associate bone features with their respective bones to avoid confusion.
Witty Tip: - Use full names like "infraorbital foramen of maxilla" when studying bone features for automatic recall.
Frontal Bone
Forms the forehead (anterior aspect of cranium) and part of bony orbits.
Bone features:
Supraorbital foramen: hole above each orbit allowing passage of nerves and vessels.
Frontal sinus: air pocket space; inflammation leads to frontal sinusitis.
Classified as pneumatized bone due to the frontal sinus.
Witty Tip:
“Foramen” means hole; “supra” means superior; “orbital” means bone orbit. Therefore, supraorbital foramen = hole above bony orbit.
Categorized as a flat bone and pneumatized bone.
Parietal Bones
Found posterior to the frontal bone and anterior to the occipital bone.
Right and left parietal bones form sides (lateral) and roof (superior) of the cranium.
Separated by the sagittal suture.
Occipital Bone
Forms back (posterior) and base of cranium.
Classified as flat bone.
Bone features:
Foramen magnum: large hole for brainstem passage.
Occipital condyle: smooth rounded surface articulating with C1 (atlas).
Hypoglossal canal: below the tongue, pathway for structures reaching underneath.
Located superior to occipital condyle.
Jugular foramen: shared with temporal bone, passageway for internal jugular artery and cranial nerves IX, X, XI.
Witty Tip: The jugular foramen is at the cranium's base between occipital and temporal bones.
Temporal Bone
Forms sides (lateral) and base of cranium.
Described as irregular bone.
Distinct features:
Mastoid process: bump behind ear.
Styloid process: sharp pointy process.
Zygomatic process: connects with zygomatic bone.
Mandibular fossa: articulates with mandible's smooth rounded surface.
External acoustic meatus: canal facing external for hearing.
Internal acoustic meatus: canal related to hearing and equilibrium within cranium.
Carotid canal: base of cranium for internal carotid artery.
Jugular foramen: features shared with occipital bone, behind carotid canal.
Witty Tip: Arteries and veins often run parallel, e.g., carotid artery parallels the jugular vein.
Modern Example:
The mandibular fossa articulates with mandibular condyle of mandible, forming temporomandibular joint (TMJ) crucial for jaw movement.
Sphenoid Bone
An irregular bone that touches all other cranial bones (nickname: “Keystone”).
Comprises superior and posterior parts of bony orbit.
Bone features:
Sella turcica: houses the pituitary gland.
Foramina (Rotundum, Ovale, Spinosum): passageways for branches of CN V (trigeminal nerve).
Optic canal: passageway for CN II (optic nerve).
Superior orbital fissure.
Inferior orbital fissure.
Witty Tip: Don’t confuse foramen (short) with fissure (elongated).
Foramina are holes; fissures are long openings.
Ethmoid Bone
An irregular and pneumatized bone with ethmoid air cells.
Contributes to bony orbit and superior/middle nasal conchae.
Forms nasal septum with vomer bone.
Bone features: - Crista galli: anchors brain anteriorly (resembles rooster crest).
Cribriform plate: for passage of CN I (olfactory nerve).
Superior and middle nasal conchae: aid in air swirling in nasal cavity.
Perpendicular plate: upper nasal septum aspect (with vomer below).
Ethmoid sinus: air pocket leading to potential inflammation (ethmoid sinusitis).
Facial Bones
14 facial bones in total: - Unpaired bones: mandible, vomer.
Paired bones: inferior nasal concha, maxilla, palatine, zygomatic, nasal, lacrimal.
Mandible Bone
Unpaired, irregular bone; only movable bone in face.
Forms the lower jaw and houses lower teeth.
Bone features: - Mental foramen: passage for CN V (trigeminal nerve) branch.
Mandibular foramen: another branch of CN V.
Mandibular condyle: articulates with mandibular fossa of temporal bone (TMJ).
Inferior Nasal Concha
Paired, irregular bone forming a bump in the nasal cavity.
Not part of the ethmoid bone.
Vomer Bone
Unpaired, flat bone forming inferior nasal septum.- Triangular shape with a small anterior view area.
Perpendicular plate of ethmoid forms majority of anterior nasal septum.
Maxilla Bone
Paired, irregular and pneumatized bone with maxillary sinuses.
Forms part of the bony orbit and floor of nasal cavity;- Houses upper teeth and makes largest part of hard palate.
Bone feature:
Infraorbital foramen: hole below bony orbit for CN V passage.
Palatine Bone
Paired, irregular bone forming tiny part of bony orbit.- Forms posterior hard palate (roof of mouth).
Transverse palatine suture lies between maxilla and palatine bones.
Zygomatic Bone
Paired, irregular bone (cheekbone) forming part of bony orbit.- Bone feature:
Temporal process: connects zygomatic bone with temporal bone, forming zygomatic arch.
Lacrimal Bone
Paired, flat bone forming medial bony orbit.- Provides lacrimal fossa and nasolacrimal canal for tears.
Witty Tip:
"Lacrima" means tears, positioned where tears flow.
Nasal Bone
Paired, flat bone forming the bridge of the nose.- Witty Tip:
Glasses rest on nasal bones.
Hyoid Bone
Unpaired, irregular, U-shaped bone in the upper neck.
Features: greater and lesser horns.- Unique: Only bone not connected to any other bone.
Supports movement controlled by muscles used in talking and swallowing; suspended by muscles attached above (suprahyoid) and below (infrahyoid).
Ear Ossicles
Paired, irregular bones found in the middle ear (smallest bones in the body).
Include: malleus, incus, stapes.
Responsible for amplifying sound waves.
Witty Tip: As ear ossicles are in the middle ear, they are part of the axial skeleton.
Anatomy of the Vertebral Column
Composed of vertebrae:
Cervical vertebrae: 7 vertebrae.
Thoracic vertebrae: 12 vertebrae.
Lumbar vertebrae: 5 vertebrae.
Sacrum: 5 fused sacral vertebrae.
Coccyx: 3-5 fused coccygeal vertebrae.
Witty Tip:
Understand vertebrae order with mnemonic; 7 cervical = “ce,” 12 thoracic = “th,” 5 lumbar = “five.”
Curves:
Four natural curves: cervical, thoracic, lumbar, sacral/coccygeal.
Purpose: Increase flexibility, strength, shock absorption.
Abnormal curvatures:
Scoliosis: abnormal lateral curve.
Kyphosis: excessive upper thoracic bend.
Lordosis: excessive lumbar curvature.
Common Features of Cervical, Thoracic, and Lumbar Vertebrae
Specific vertebrae features include:
Spinous process: always posterior.
Body (centrum): always anterior.
Transverse process: sticks out to sides.
Vertebral foramen: hole in vertebra center.
Articular facets: used in vertebrae articulation.
Witty Tip:
Spinous processes are smooth when feeling the back.
The body faces anteriorly, making it close to the body center.
Witty Tip: A process that sticks out is termed a "process"; 'transverse' means horizontal. Thus, transverse process sticks out horizontally.
Vertebra alignment: formed by the vertebral column; intervertebral disks between adjacent bodies.
Aligned vertebral foramina create the vertebral canal for the spinal cord.
Spinal nerves emerge from the cord through holes between two vertebrae (intervertebral foramen).
Cervical Vertebrae
7 cervical vertebrae (C1 to C7): located in cervical (neck) region.
Unique features include:
C1 (atlas): No spinous process/body. Articulates with occipital condyles at the atlanto-occipital joint allowing for “yes” head motion.
C2 (axis): has odontoid process (dens) articulating with C1 for “no” movement.
No intervertebral disc between C1 and C2.
Specific features of cervical vertebrae:
Bifid spinous process (all except C7).
Transverse foramen for vertebral blood vessels.
Witty Tips:
Bifid spinous process: "bi" means two.
C7 has the largest spinous process, significant for landmarking.
Thoracic Vertebrae
12 thoracic vertebrae (T1 to T12): located at thorax level.
Forms thoracic cage with ribs/sternum, featuring indentations for rib articulation.
Features include:
Superior costal facet, inferior costal facet, transverse costal facet for rib connections.
Witty Tip: Ribs articulate with thoracic vertebrae having heads and tubercles.
Bone Features of Thoracic Vertebrae
Head of rib articulates with body of thoracic vertebra via costal facets.
Tubercle of rib articulates with transverse process via transverse costal facet.
T9 to T12 have variations in coastal facets' position.
Lumbar Vertebrae
5 lumbar vertebrae (L1 to L5): located in lumbar region.
Characterized by large bodies to support upper body weight.
Exhibit common features: spinous processes, superior/inferior articular facets, transverse processes.
Sacrum
Triangular bone fusing five sacral vertebrae.
Articulation: superior articular facets with inferior articular facets of L5 vertebra.
Sacral canal: formed by aligned fused sacral vertebral foramina.
Median sacral crest: fusion result from spinous processes.
Sacral hiatus: located at sacral canal end; passageway for spinal nerves.
Sacral foramina: holes for spinal nerve passageways.
Sacral ala: articulates with hip bone, forming superior part of sacroiliac joint.
Coccyx
Formed by fusion of three to five coccygeal vertebrae.
Articulates with sacrum; may bear weight when sitting.
Thoracic Cage
Composed of ribs, sternum, and costal cartilages.
Each rib has a head, neck, and tubercle at its sternal end.
Includes 12 pairs of ribs attached to thoracic vertebrae.
Witty Tip: 12 thoracic vertebrae = 12 pairs of ribs (6 on each side).
Ribs Types
Vertebrosternal ribs (7 pairs):
Ribs 1-7 connect directly to sternum (true ribs).
Vertebrochondral ribs (3 pairs):
Ribs 8-10 connect to sternum via additional cartilage (false ribs).
Vertebral ribs (2 pairs):
Ribs 11-12 don’t connect to sternum (floating ribs).
Witty Tip 1: Rib names indicate their connections; vertebrosternal at vertebra/sternum; which is true, and vertebrochondral (false) have extra cartilage.
Witty Tip 2: Remembering only 2 pairs of floating ribs leads to understanding the total distribution of ribs.
Sternum (Breastbone)
Comprised of three parts:
Manubrium: top part, resembles “M.”
Body: longest part.
Xiphoid process: inferior aspect, resembles “X.”
Notches and articulations:
Clavicular notch: articulate with clavicle.
Suprasternal notch (Jugular notch): top part between clavicular notches.
Sternal angle: junction of manubrium with body.
Witty Tip: Suprasternal notch and sternal angle serve as valuable landmarks for medical examinations.
Suprasternal notch aids in neck/thorax locating for procedures (e.g., tracheostomy).
Sternal angle identifies second ribs and provides positioning reference for the heart's base.