7.8: Alternate Text Descriptions

Figure 7.1: Facial Skull Bones

This image is a exploded front view of the facial bones of the skull with labeled, color-coded structures. The mandible forms the lower jaw at the bottom. The paired maxillae form the upper jaw on either side of the nasal opening. The zygomatic bones are positioned laterally as the cheekbones. Above the nasal opening are the paired nasal bones, with the lacrimal bones located beside them. The palatine bones are shown deeper within the skull, the vomer is centered in the midline, and the inferior nasal conchae are positioned below the nasal cavity. Labels identify each bone and show their relative positions in the facial skeleton.

Figure 7.1.1: Axial and Appendicular Skeleton

This image is of a human skeleton shown in anterior (front) and posterior (back) views. The skeleton is divided into the axial skeleton and the appendicular skeleton. The axial skeleton forms the central axis of the body and includes the skull, vertebral column, and thoracic cage. The skull includes a cranial portion, which encloses the brain, and a facial portion, which forms the face. The vertebral column extends from the skull through the trunk and supports posture while protecting the spinal cord. The thoracic cage, consisting of the ribs and sternum, protects the heart and lungs.

The appendicular skeleton includes the pectoral girdle, upper limbs, pelvic girdle, and lower limbs. The pectoral girdle consists of the clavicle and scapula and attaches the upper limbs to the axial skeleton. The upper limbs include the humerus, radius, ulna, carpals, metacarpals, and phalanges. The pelvic girdle is formed by the hip bones and connects the lower limbs to the trunk. The lower limbs include the femur, patella, tibia, fibula, tarsals, metatarsals, and phalanges. Together, these bones support body weight and enable movement.

Labels identify the cranial portion, facial portion, vertebral column, ribs, sternum, clavicle, scapula, humerus, radius, ulna, carpals, metacarpals, phalanges, hip bones, femur, patella, tibia, fibula, tarsals, and metatarsals.

Figure 7.2.1: Lateral Skull

This image illustrates a left-side view of a human skull with the cranial bones. Each bone is labeled, including the frontal, parietal, temporal, occipital, sphenoid, and ethmoid bones, with numbers indicating how many of each are present. Facial bones are shown in white for contrast, while the focus remains on identifying and distinguishing the eight cranial bones that form the protective case around the brain.

• The frontal bone forms the superior part of the orbits (eye sockets) and extends upward to meet the parietal bones at the coronal suture.
• While primarily visible from the lateral and superior views, the parietal bones are located posteriorly to the frontal bone and contribute to the cranial vault. They play a crucial role in the overall shape and protection of the brain.
• Temporal bones, also more prominent in the lateral view, are located on the sides of the skull and contribute to the structure behind the orbits.
• Sphenoid bone is partially visible in the anterior view at the lateral walls of the orbits. It spans the skull laterally, contributing to the cranial base.
• Ethmoid bone forms part of the medial wall of the orbits and the superior part of the nasal cavity. It is located posterior to the nasal bones and is partially visible in the anterior view.
• Occipital bone is the single bone that forms the posterior skull and posterior base of the cranial cavity.

This image depicts a front-facing of a human skull used for anatomical study. The skull is shown in an upright position, with the eye sockets, nasal opening, and teeth clearly visible. Labels with thin lines point to each bone and name it.

At the top of the skull, the frontal bone forms the forehead. On either side, the parietal and temporal bones contribute to the upper and side portions of the skull. Around the eye sockets, smaller bones such as the sphenoid, ethmoid, lacrimal, and zygomatic bones are identified, showing how multiple bones come together to form the orbits. The nasal bones sit at the bridge of the nose, while the maxilla forms the upper jaw and holds the upper teeth. The mandible, shown at the bottom, is the lower jaw and the only movable skull bone.

Several small openings called foramina are also labeled, including the supraorbital foramen above the eye sockets, the infraorbital foramen below them, and the mental foramen on the front of the lower jaw. These openings indicate pathways for nerves and blood vessels. Overall, the image emphasizes how facial and cranial bones are arranged and interconnected in the anterior view of the skull.

Figure 7.2.3: Right Lateral View

This image of the human skull with major cranial bones, facial bones, sutures, and anatomical landmarks labeled. The cranial bones shown are the frontal bone, parietal bone, temporal bone, occipital bone, and greater wing of the sphenoid bone. The facial bones shown are the zygomatic bone, maxilla, mandible, nasal bone, lacrimal bone, and ethmoid bone.

Major sutures include the coronal suture between the frontal and parietal bones, the squamous suture between the parietal and temporal bones, and the lambdoid suture between the parietal and occipital bones.

Additional labeled landmarks include the zygomatic arch, pterion, external acoustic meatus, mastoid process, styloid process, articular tubercle, mandibular fossa, lacrimal fossa, temporal process, zygomatic process, and mental protuberance of the mandible. The diagram shows the arrangement and relationships of bones and landmarks visible from the right side of the skull.

Figure 7.2.4: Cranial Fossae

Figure 7.2.5: Temporal Bone

Important landmarks of the temporal bone, as shown in the image include the following:

• External acoustic meatus (ear canal)—This is the large opening on the lateral side of the skull that is associated with the ear.
• Internal acoustic meatus—This opening is located inside the cranial cavity, on the medial side of the petrous ridge. It connects to the middle and inner ear cavities of the temporal bone.
• Mandibular fossa—This is the deep, oval-shaped depression located on the external base of the skull, just in front of the external acoustic meatus. The mandible (lower jaw) joins with the skull at this site as part of the temporomandibular joint, which allows for movements of the mandible during opening and closing of the mouth.
• Articular tubercle—The smooth ridge located immediately anterior to the mandibular fossa. Both the articular tubercle and mandibular fossa contribute to the temporomandibular joint, the joint that provides for movements between the temporal bone of the skull and the mandible.
• Styloid process—Posterior to the mandibular fossa on the external base of the skull is an elongated, downward bony projection called the styloid process, so named because of its resemblance to a stylus (a pen or writing tool). This structure serves as an attachment site for several small muscles and for a ligament that supports the hyoid bone of the neck.
• Zygomatic process - rises from the lower part of the squamous portion of the temporal bone and projects anteriorly. This forms the posterior, longer portion of the zygomatic arch. It articulates with the temporal process of the zygomatic bone to complete the zygomatic arch, functioning like "the two ends of a drawbridge.".
• Carotid canal—The carotid canal is a zig-zag shaped tunnel that provides passage through the base of the skull for one of the major arteries that supplies the brain. Its entrance is located on the outside base of the skull, anteromedial to the styloid process. The canal then runs anteromedially within the bony base of the skull, and then turns upward to its exit in the floor of the middle cranial cavity, above the foramen lacerum.

Figure 7.2.6: Anatomy of the Cranial Base

This image shows two labeled diagrams of the base of the human skull, presented from two perspectives: an inferior view on the top and a superior view on the bottom.

• The inferior view shows the underside of the skull, as if looking upward from below.
• The superior view shows the internal base of the skull from above, after the top portion has been removed.
• A small reference skull above each diagram indicates the viewing direction.

Inferior View (Underside of Skull) - The underside of the skull includes several key bones and openings:

• The maxilla forms the front portion of the hard palate, including the palatine process.
• Behind it, the palatine bone contributes to the posterior hard palate.
• The vomer is located along the midline, forming part of the nasal septum.
• On each side, the zygomatic arch and zygomatic bone contribute to the cheek structure.
• The sphenoid bone is centrally located and contains multiple openings:
  • Foramen ovale
  • Foramen spinosum
• Nearby openings include:
  • Foramen lacerum
  • Jugular foramen
  • Stylomastoid foramen
• The temporal bone contains important structures such as:
  • External auditory meatus (ear canal opening)
  • Mastoid process and styloid process
  • Mandibular fossa, where the lower jaw articulates
• At the center toward the back is the foramen magnum, a large opening for the spinal cord.
• Surrounding this are the occipital bone, occipital condyles, and external occipital protuberance.
• The entrance to the carotid canal is also labeled, indicating where major arteries enter the skull.

Superior View (Internal Skull Base) - The superior view shows the internal floor of the cranial cavity:

• The frontal bone forms the anterior portion.
• The ethmoid bone lies between the eye sockets and includes:
  • Crista galli
  • Cribriform plate
• The sphenoid bone is centrally located and features:
  • Lesser wings
  • Hypophyseal fossa (location of the pituitary gland)
  • Sella turcica (a depression housing the pituitary gland)
• Openings in this region include:
  • Optic canal (not explicitly labeled but implied near the sphenoid region)
  • Superior orbital fissure
  • Foramen rotundum
  • Foramen ovale
  • Foramen spinosum
  • Foramen lacerum
• The temporal bone forms the lateral regions and includes:
  • Petrous portion (petrous ridge)
  • Internal acoustic meatus
• The posterior region includes:
  • Occipital bone
  • Foramen magnum
  • Hypoglossal canal
  • Jugular foramen
• The parietal bones form the upper sides of the skull.

Figure 7.2.7: Posterior Skull Anatomy

This image shows a posterior view of the human skull, emphasizing the major cranial bones, sutures, and anatomical landmarks associated with brain protection, neck muscle attachment, and the connection between the skull and vertebral column.

The overall organization presents the skull from the posterior aspect, or back view. The labels in the image include parietal bones, occipital bone, temporal bones, zygomatic bone, sagittal suture, lambdoid suture, external occipital protuberance, mastoid process, superior nuchal line, foramen magnum, and occipital condyles.

The parietal bones are a paired set of bones that form the upper posterior portion of the skull. Their functions are to protect the upper regions of the brain and contribute to the overall shape and strength of the skull.

The occipital bone is located at the lower back portion of the skull. Its functions are to protect the posterior part of the brain and form the base of the skull where it connects to the spine.

The temporal bones are located on both sides of the skull near the lower regions. Their functions are to house structures related to hearing and balance and provide attachment points for muscles of the head and neck.

The zygomatic bone, shown as partially visible, is a facial bone extending toward the side of the skull. Its function is to contribute to facial structure and support the cheek region.

The labeled sutures include the sagittal suture and the lambdoid suture. The sagittal suture runs along the midline between the two parietal bones. Its function is to hold these bones together while allowing slight flexibility during development. The lambdoid suture lies between the parietal bones and the occipital bone. Its function is to connect the cranial bones and contribute to overall skull integrity.

The labeled surface landmarks and projections include the external occipital protuberance, mastoid process, and superior nuchal line. The external occipital protuberance is a raised area on the midline of the occipital bone and serves as an attachment site for ligaments and neck muscles. The mastoid process is a projection behind the ear region on each side and provides attachment for neck muscles involved in head movement. The superior nuchal line is a horizontal ridge extending across the occipital bone and serves as an attachment site for neck and upper back muscles.

The labeled opening and articulation points include the foramen magnum and occipital condyles. The foramen magnum is a large opening at the base of the occipital bone. Its function is to allow passage of the spinal cord, connecting the brain to the body. The occipital condyles are paired rounded surfaces located on either side of the foramen magnum. Their functions are to articulate with the first vertebra, the atlas, and to enable head movement, such as nodding.

Figure 7.2.9: Sagittal Section of Skull

This image shows a right lateral section of the human skull with portions of the skull removed to reveal internal cranial and nasal structures. The image combines external skull anatomy with internal features visible in a sagittal view.

Major cranial bones labeled include the frontal, parietal, temporal, occipital, and sphenoid bones. Facial bones and related structures include the nasal bone, maxilla, palatine bone, mandible, and hyoid bone.

Internal cranial landmarks include the sella turcica (hypophyseal fossa), crista galli, cribriform plate, internal acoustic meatus, and hypoglossal canal. The sphenoid sinus is shown within the sphenoid bone.

Structures associated with the nasal cavity include the perpendicular plate, vomer, and inferior nasal concha. Together, the perpendicular plate and vomer form the nasal septum.

The mandible is labeled with the mandibular foramen, lingula, and mylohyoid line. Additional landmarks include the styloid process and the medial and lateral pterygoid plates.

The figure illustrates the spatial relationships among the cranial cavity, nasal cavity, facial skeleton, mandible, and associated anatomical landmarks as viewed from the right side.

Figure 7.2.10: Ethmoid Bone Anatomy

Figure 7.2.11: Nasal Cavity

This image shows a medial view of the nasal cavity within the skull, highlighting internal nasal structures and air spaces. A small inset indicates the location of this region within the full skull.

The overall organization includes a main diagram showing a side view of the skull focused on the nasal cavity and a smaller inset that shows where this region is located in the skull. The labels in the image include ethmoid bone, superior nasal concha, middle nasal concha, inferior nasal concha, and sphenoidal sinus.

The ethmoid bone is located in the upper central region of the nasal cavity, between the eyes. It forms part of the medial walls and roof of the nasal cavity and gives rise to the superior and middle nasal conchae. Its functions are to support the structure of the nasal cavity, separate the nasal cavity from the cranial cavity, and contribute to airflow organization within the nose.

The diagram shows three curved bony structures projecting into the nasal cavity, called the nasal conchae, or turbinates. The superior nasal concha is the smallest and highest concha, located near the roof of the nasal cavity. Its functions are to help regulate airflow and contribute to the warming and humidifying of inhaled air. The middle nasal concha is located below the superior concha and is larger and more prominent. Its functions are to direct airflow toward the middle nasal region and enhance filtration and conditioning of air. The inferior nasal concha is the largest concha, located at the lower part of the nasal cavity and extending along the lateral nasal wall. Its functions are to play a major role in air filtering, warming, and humidification and to increase surface area for efficient air processing.

The sphenoidal sinus is located at the posterior portion of the nasal cavity within the sphenoid bone. Its functions are to reduce skull weight, contribute to air circulation and resonance of the voice, and produce mucus that helps protect the respiratory system.

Figure 7.2.12: Maxilla

This image shows a right lateral view of the maxilla, which is the upper jaw bone, with labeled features related to the orbit, facial structure, and tooth support.

The overall organization focuses on a single maxilla bone viewed from the right side. A small inset shows the location of the maxilla within the skull, while the main image identifies labeled structural features. The labels in the image include maxilla, floor of the orbit or orbital surface, infraorbital foramen, alveolar process, frontal bone, and zygomatic process (cut).

As a whole, the maxilla forms the upper jaw and contributes to the floor of the orbit, the side of the nasal cavity, and the upper dental arch. Its functions are to provide structural support for the midface, anchor the upper teeth, and form part of the eye socket and nasal cavity.

The floor of the orbit, also described as the orbital surface, is a broad surface on the superior portion of the maxilla. It forms the lower boundary of the eye socket. Its functions are to support the eye from below and help maintain the shape and stability of the orbit.

The infraorbital foramen is a small opening located on the anterior surface of the maxilla. Its function is to allow passage of the infraorbital nerve and blood vessels, which supply sensation and circulation to the cheek, upper lip, and part of the face.

The alveolar process is the lower margin of the maxilla that contains the sockets for the upper teeth. Its functions are to hold and stabilize the teeth and to support chewing and biting forces.

The superior portion of the maxilla articulates with the frontal bone. This connection helps form the upper boundary of the nasal region and orbit and contributes to the stability of the facial skeleton.

The zygomatic process, labeled as cut in the diagram, is a projection that normally connects the maxilla to the zygomatic bone, or cheekbone. It is shown as cut to reveal internal structures. Its functions are to contribute to the lateral facial structure and help transfer forces during chewing.

Figure 7.2.13: Mandible

This image shows the right lateral view of the mandible, which is the lower jaw, with labeled structures involved in jaw movement, muscle attachment, and nerve passage.

The overall organization presents the mandible as a single bone of the lower jaw. A small inset at the top shows the mandible in relation to the skull, while the main image focuses on the detailed anatomy of the mandible from a side view. The labels in the image include body of the mandible, alveolar process, ramus of the mandible, mandibular angle, condylar process, mandibular condyle, coronoid process, mandibular notch, mylohyoid line, lingula, mandibular foramen, mental foramen, and mental protuberance.

The body of the mandible is the horizontal portion that holds the lower teeth. It includes the alveolar process, which contains the tooth sockets. Its functions are to support the teeth for chewing, also called mastication, and to provide structural shape to the lower face.

The ramus of the mandible is the vertical portion extending upward from the body. Its functions are to serve as an attachment site for muscles involved in jaw movement and to connect the body to the upper processes of the mandible.

The mandibular angle is the region where the body meets the ramus. Its function is to provide leverage for muscles that elevate and depress the jaw.

The condylar process, also labeled mandibular condyle, is the rounded projection at the upper posterior part of the ramus. Its function is to form a joint with the temporal bone of the skull and enable movement of the jaw, including opening, closing, and side-to-side motion.

The coronoid process is the anterior projection located in front of the condylar process. It serves as an attachment site for the temporalis muscle, which helps elevate the jaw.

The mandibular notch is the curved depression between the condylar process and the coronoid process. It provides separation between these two structures and serves as a passage region.

The mylohyoid line is a ridge on the inner surface of the mandible. Its function is to serve as an attachment site for the mylohyoid muscle, which supports the floor of the mouth.

The lingula is a small projection near the mandibular foramen. Its function is to serve as an attachment point for ligaments associated with jaw movement.

The mandibular foramen is an opening on the inner surface of the ramus. It allows passage of the inferior alveolar nerve and blood vessels into the mandible.

The mental foramen is an opening on the front portion of the mandible. It allows nerves and blood vessels to exit and supply the chin and lower lip.

The mental protuberance is the anterior projection of the mandible that forms the chin. Its function is to provide the shape and prominence of the chin.

Figure 7.2.14: Eye Socket

This image shows a magnified view of the bony orbit, or eye socket, identifying the bones that form the orbit and several important openings for nerves and blood vessels.

The overall organization focuses on a single eye orbit within the skull. The labels in the image include frontal bone, supraorbital margin, sphenoid bone, zygomatic bone, maxilla, ethmoid bone, lacrimal bone, nasal bone, palatine bone, supraorbital foramen, optic canal, superior orbital fissure, infraorbital foramen, and lacrimal fossa. The image shows that the orbit is a composite structure formed by several bones working together, rather than a cavity formed by one bone alone.

The frontal bone is located at the upper portion of the orbit, forming the roof. It includes the supraorbital margin along the upper edge. Its functions are to protect the eye from above, provide attachment points for structures around the eye, and support the forehead and upper orbit structure.

The sphenoid bone is located deeper within the orbit toward the back. It forms part of the posterior wall of the orbit and provides structural support. It also contains openings that serve as pathways for nerves.

The zygomatic bone forms the lateral, or outer, wall of the orbit. Its functions are to provide protection to the eye from the side and contribute to facial structure and cheek prominence.

The maxilla forms much of the floor of the orbit. Its functions are to support the eye from below, contribute to facial structure, and house the upper teeth.

The ethmoid bone forms part of the medial, or inner, wall of the orbit. It helps separate the orbit from the nasal cavity and provides structural support to delicate inner orbital structures.

The lacrimal bone is located near the inner corner of the orbit. It contains the lacrimal fossa, which houses structures involved in tear drainage.

The nasal bone is located at the bridge of the nose, near the orbit. Its function is to provide structural support to the nasal bridge.

The palatine bone contributes a small portion to the posterior floor of the orbit. Its function is to support the rear portion of the orbital floor.

The labeled openings and features include the supraorbital foramen, optic canal, superior orbital fissure, infraorbital foramen, and lacrimal fossa. The supraorbital foramen is located on the upper margin of the orbit and allows passage of nerves and blood vessels to the forehead region. The optic canal is located toward the back of the orbit and transmits the optic nerve, which carries visual information from the eye to the brain. The superior orbital fissure is a gap in the posterior orbit that allows multiple nerves and blood vessels to pass between the brain and the eye. The infraorbital foramen is located below the orbit in the maxilla and provides a passage for nerves and blood vessels supplying the face. The lacrimal fossa is a depression near the medial orbit that houses structures involved in tear collection and drainage.

Figure 7.2.15: Nasal Cavity

This image shows a sagittal section, or side-view cut, of the nasal cavity and surrounding skull structures, with labeled bones, sinuses, and components of the nasal septum.

The overall organization presents a side view of the head focused on the nasal cavity. The labels in the image include nasal septum, perpendicular plate of the ethmoid bone, vomer bone, septal cartilage, frontal bone, frontal sinus, sphenoid bone, sphenoid sinus, ethmoid bone, crista galli, nasal bone, palatine process of the maxilla, horizontal plate of the palatine bone, and the maxillary sinus region.

The nasal septum forms the midline partition inside the nasal cavity. Its labeled components are the perpendicular plate of the ethmoid bone in the superior portion, the vomer bone in the posterior-inferior portion, and the septal cartilage in the anterior portion. The nasal septum divides the nasal cavity into left and right passages, helps regulate and direct airflow, and provides structural support for the nose.

In the frontal region, the labeled structures are the frontal bone and the frontal sinus. The frontal bone is located above the nasal cavity, and the frontal sinus is a hollow space within this bone. The frontal bone helps protect the brain. The frontal sinus reduces skull weight and contributes to air conditioning and voice resonance.

In the sphenoid region, the labeled structures are the sphenoid bone and the sphenoid sinus. The sphenoid bone is located deeper in the skull behind the nasal cavity, and the sphenoid sinus is a cavity within it. The sphenoid bone provides structural support at the base of the skull. The sphenoid sinus helps lighten the skull and supports airflow.

In the ethmoid region, the labeled structures are the ethmoid bone and the crista galli. The ethmoid bone lies between the eyes and contributes to the superior part of the nasal septum. The crista galli is a vertical projection of the ethmoid bone. The ethmoid region supports structures of the nasal cavity and brain, and the crista galli provides attachment for membranes that help stabilize the brain.

The nasal bone is located at the upper part of the nose. Its function is to provide structural support and shape to the nasal bridge.

The palate is formed by the palatine process of the maxilla and the horizontal plate of the palatine bone. These structures form the roof of the mouth and the floor of the nasal cavity. Their function is to separate the nasal cavity from the oral cavity, which allows breathing and eating to occur simultaneously.

In the maxillary sinus region, the maxillary bone forms part of the lateral nasal wall and contains adjacent sinus space. Its functions are to support the upper teeth and facial structure and to contribute to sinus functions such as air filtration and moisture regulation.

Figure 7.2.16: Paranasal Sinuses

This image presents the paranasal sinuses of the skull using two perspectives: an anterior view on the left and a lateral view on the right. Each view labels the same four sinus regions.

The overall organization is divided into two panels. The left panel shows the anterior view of the face, and the right panel shows the lateral view of the head. The labels in both panels are frontal sinus, sphenoid sinus, ethmoid air cells, and maxillary sinuses.

The frontal sinus is located in the upper region of the face above the eyes, within the frontal bone. Its functions are to reduce the weight of the skull, contribute to voice resonance, and produce mucus that helps protect and moisten the nasal cavity.

The sphenoid sinus is located deep within the skull, behind the nasal cavity and below the brain. Its functions are to help lighten the skull, support air circulation within the sinus system, and contribute to sound resonance.

The ethmoid air cells are a cluster of small air-filled spaces located between the eyes, between the nasal cavity and the orbit, or eye socket. Their functions are to help filter and condition inhaled air, produce mucus to trap particles and pathogens, and contribute to overall sinus ventilation.

The maxillary sinuses are located in the cheek region on both sides of the nose and are the largest of the paranasal sinuses. Their functions are to reduce skull mass, warm and humidify inhaled air, and produce mucus for respiratory protection.

Figure 7.2.17: Hyoid Bone

This image shows the hyoid bone, including its position in the neck and detailed views of its structure. The diagram is divided into three sections: the anatomical location in the body, an anterior view, and a right lateral view.

The overall organization includes a top image showing the location of the hyoid bone in the neck and two lower images showing the bone itself. The labels in the figure include body, greater horns, lesser horns, mandible, and larynx. The lower portion includes an anterior (front) view and a right lateral (side) view of the hyoid bone.

In the top image, the hyoid bone is positioned in the upper neck region. It is located below the mandible, which is the lower jaw, and above the larynx, which is the voice box. The hyoid bone functions as a support structure for the tongue and upper airway. It also serves as an attachment site for muscles involved in speech and swallowing.

In the anterior view, the hyoid bone has a central region labeled the body. Extending outward from each side are the greater horns, which curve laterally. Smaller projections near the upper region are labeled the lesser horns. The body provides a central anchoring point for muscles. The greater horns provide attachment for muscles that move the tongue, larynx, and pharynx. The lesser horns serve as additional attachment points for ligaments and muscles.

In the right lateral view, the curved three-dimensional shape of the hyoid bone is shown from the side. The body appears as a central mass, and the horns extend backward. This shape allows for flexible movement, which supports coordinated actions involved in swallowing, breathing, and speech production.

Figure 7.3.1: Anatomy of the Vertebral Column

This image shows the vertebral column, or spine, in two views: a posterior view of the full body on the left and a lateral view of the body on the right. The diagram labels the major spinal regions, the number of vertebrae in each region, and the natural curves of the spine.

The overall organization shows the vertebral column extending from the base of the skull to the pelvis. The labels in the image include the cervical region, thoracic region, lumbar region, sacrum, coccyx, intervertebral discs, cervical curve, thoracic curve, lumbar curve, and sacrococcygeal curve. The left image shows the spine from the back, and the right image emphasizes the spine’s natural curves from the side.

The cervical region is located in the neck and contains 7 cervical vertebrae, C1 through C7. Its functions are to support and allow movement of the head and to form the cervical curve, which bends forward.

The thoracic region is located in the upper back and contains 12 thoracic vertebrae, T1 through T12. Its functions are to provide attachment points for the ribs, form the thoracic curve, which bends backward, and help protect organs in the chest cavity.

The lumbar region is located in the lower back and contains 5 lumbar vertebrae, L1 through L5. These vertebrae are larger and thicker than those in other regions. Their functions are to support a large portion of body weight, allow bending and movement of the lower torso, and form the lumbar curve, which bends forward.

The sacrum is composed of fused vertebrae that form a triangular structure at the base of the spine. Its functions are to connect the vertebral column to the pelvis and help transfer body weight to the lower limbs.

The coccyx is a small structure made of fused vertebrae located below the sacrum. Its functions are to serve as an attachment site for ligaments and muscles and provide minor support when sitting.

The intervertebral discs are located between adjacent vertebrae. Their functions are to act as shock absorbers and allow flexibility and movement of the spine.

The lateral view labels the natural spinal curves. These include the cervical curve, which bends forward, the thoracic curve, which bends backward, the lumbar curve, which bends forward, and the sacrococcygeal curve, which bends backward. Together, these curves help distribute body weight, absorb shock, and maintain balance and posture.

Figure 7.3.2: Abnormal curvatures of Spine

This image shows abnormal curvatures of the vertebral column shown in three panels. The left panel shows scoliosis in a rear-view illustration of a person with an abnormal lateral curvature of the vertebral column, accompanied by an X-ray showing a pronounced side-to-side spinal curve. The middle panel shows kyphosis in a side-view illustration and a photograph of a person bending forward, demonstrating an exaggerated posterior curvature of the thoracic vertebral column. The right panel shows lordosis in a side-view illustration with an exaggerated inward curvature of the lumbar region, accompanied by a silhouette of a woman in late pregnancy pressing against her lower back for support, illustrating increased lumbar curvature. Together, the panels show scoliosis as an abnormal lateral curvature, kyphosis as an excessive thoracic curvature, and lordosis as an excessive lumbar curvature.

Figure 7.3.3: Normal and Compressed Vertebrae

This image presents two detailed line drawings of vertebrae positioned side by side for comparison. The drawing on the left shows a set of healthy, normal vertebrae. These vertebrae appear evenly shaped, with consistent thickness in the bone structure and well‑defined intervertebral spaces. The alignment is straight, indicating typical curvature and proper structural support. The drawing on the right depicts vertebrae affected by bone loss. In this illustration, the bones appear thinner and more irregular, with noticeable collapse or compression along their front edges. This change in shape causes the vertebrae to tilt forward, producing an exaggerated spinal curvature. The comparison highlights how reduced bone density weakens the vertebral bodies and contributes to increased spinal bending over time.

Figure 7.3.4: The Structure of a Typical Vertebra

This image shows the structure of a typical vertebra and articulated vertebrae. The left panel shows a superior view of a single vertebra. Labels identify the vertebral body, vertebral arch, pedicle, lamina, vertebral foramen, spinous process, transverse processes, facet of the superior articular process, facet for head of rib, and spinal cord. The vertebral body forms the anterior portion of the vertebra, while the vertebral arch surrounds the vertebral foramen, which contains the spinal cord. The spinous and transverse processes project from the vertebra, and articular facets mark the locations where vertebrae articulate with adjacent vertebrae and, in the thoracic region, with ribs.

The right panel shows a left posterolateral view of several articulated vertebrae. The vertebrae are stacked and separated by intervertebral discs located between adjacent vertebral bodies. Labels identify the vertebral body, vertebral arch, lamina, pedicle, spinous process, superior and inferior articular processes, facet for head of rib, intervertebral disc, spinal cord, spinal nerve, and intervertebral foramen. The intervertebral foramina are openings formed between adjacent vertebrae through which spinal nerves exit the vertebral column. The figure shows the anatomical relationships among adjacent vertebrae, intervertebral discs, the spinal cord, and emerging spinal nerves.

Figure 7.3.5: The Structure of an Intervertebral Disc

This image shows the structure of an intervertebral disc positioned between adjacent vertebrae, presented in two views: a lateral view on the left and a superior view on the right. The figure explains how the disc connects vertebral bodies and supports movement and shock absorption.

The overall organization includes two panels. The left panel shows two stacked vertebrae with an intervertebral disc between them. The right panel shows a superior view of a vertebra and disc, emphasizing the internal parts of the disc. The labels in the image include vertebral body, intervertebral disc, intervertebral foramen, spinal nerves, annulus fibrosus, nucleus pulposus, and surrounding vertebral structures, including the vertebral arch and processes.

In the left panel, the vertebral body is the large solid portion of each vertebra located anteriorly. Its functions are to support body weight and provide a stable surface for the intervertebral disc. The intervertebral disc lies between adjacent vertebral bodies and appears as a thick, flexible layer separating the bones. Its functions are to act as a shock absorber between vertebrae and allow movement and flexibility of the spine. The intervertebral foramen is the opening between adjacent vertebrae. Its function is to allow spinal nerves to exit the vertebral column and provide a pathway for communication between the spinal cord and the body.

In the right panel, the annulus fibrosus is the outer ring of the intervertebral disc. It is made of multiple layers arranged in concentric patterns. Its functions are to provide strength and support, contain the nucleus pulposus, and resist compressive and twisting forces. The nucleus pulposus is the central core of the disc. Its functions are to act as a compressible cushion, distribute pressure evenly across the disc, and help absorb shock during movement. The surrounding vertebral structures show that the disc sits between vertebral bodies, while the posterior region includes the vertebral arch and processes. Together, these structures protect the spinal cord and allow controlled movement of the spine.

Figure 7.3.6: The Structure of Cervical Vertebrae

This image presents multiple views and comparisons of cervical vertebrae, including a typical cervical vertebra, the atlas (C1), the axis (C2), and a short sequence of cervical vertebrae in order.

The overall organization is divided into several labeled sections. The labels in the figure include typical cervical vertebra, C1 (atlas), C2 (axis), C3–C6, C7 (vertebra prominens), vertebral body, vertebral foramen, vertebral arch, pedicle, lamina, spinous process, bifid spinous process, transverse processes, transverse foramen, superior articular process, groove for spinal nerve, anterior arch, posterior arch, superior articular facets, dens (odontoid process), inferior articular processes, and transverse ligament. The figure compares the structure of a typical cervical vertebra with the specialized forms of the atlas and axis and shows how the cervical vertebrae are arranged in sequence from C1 through C7.

In the section showing a typical cervical vertebra in superior view, the vertebral body is a relatively small anterior portion of the vertebra. Its function is to support the weight of the head and neck. The vertebral foramen is a large central opening that allows passage of the spinal cord. The vertebral arch, made of the pedicle and lamina, forms the curved portion behind the vertebral body. Its functions are to protect the spinal cord and provide structural integrity. The spinous process is a posterior projection, and in most cervical vertebrae it is bifid, meaning split into two parts. Its functions are to provide attachment for muscles and ligaments and support neck movement. The transverse processes project laterally and serve as attachment points for muscles. Each contains a transverse foramen, which allows passage of blood vessels supplying the brain. The superior articular process provides a joint surface for controlled movement with adjacent vertebrae. The groove for spinal nerve is a small channel that allows spinal nerves to pass safely.

The section showing the cervical vertebrae in column labels C1 (atlas), C2 (axis), C3–C6 as typical cervical vertebrae, and C7 (vertebra prominens). Together, these seven vertebrae form the flexible neck region, support head movement, and help maintain posture.

The atlas (C1) is shown in superior view. It is a ring-shaped vertebra without a body. The labeled structures include the anterior arch, posterior arch, superior articular facets, transverse foramina, and the transverse ligament that holds the dens in place. The atlas functions to support the skull and allow nodding movements, including flexion and extension of the head.

The axis (C2) is shown in both superior and anterior views. Its key feature is the dens, also called the odontoid process, which is a vertical projection extending upward from the body of the axis. The dens acts as a pivot point for the atlas and enables rotation of the head, such as turning side to side. In the superior view of the axis, the labeled structures include the dens, superior articular facets, spinous process, and transverse foramen. These structures support articulation with the atlas and allow combined rotational and stabilizing movements. In the anterior view, the axis shows the dens projecting upward, the body of the vertebra, and the inferior articular processes. These structures contribute to stability of the cervical spine and allow connections with lower vertebrae.

The figure also highlights special features of cervical vertebrae. The bifid spinous processes of most cervical vertebrae provide increased surface area for muscle attachment. The transverse ligament is a band that holds the dens against the atlas. Its function is to stabilize the joint between C1 and C2 and prevent displacement that could affect the spinal cord.

Figure 7.3.7: Structure of Thoracic Vertebrae

This image shows a lateral view of several thoracic vertebrae and identifies structures that distinguish thoracic vertebrae from other vertebral regions. A small inset highlights the thoracic region within the vertebral column.

Several thoracic vertebrae are stacked vertically, with intervertebral discs located between adjacent vertebral bodies. The vertebral bodies form the anterior portion of the vertebral column and are connected by the discs.

Projecting posteriorly from each vertebral body is the vertebral arch, formed by the pedicle and lamina. Extending from the vertebral arch are the transverse processes, spinous processes, and articular processes.

The spinous processes are long and slope downward toward the inferior vertebrae, which is a characteristic feature of the thoracic region. The transverse processes extend laterally from each vertebra.

The superior articular processes project upward, and the inferior articular processes project downward, forming joints between adjacent vertebrae.

The figure highlights three surfaces associated with rib attachment:

• Superior costal facet: located on the upper portion of the vertebral body
• Inferior costal facet: located on the lower portion of the vertebral body
• Articular facet for the tubercle of the rib: located on the transverse process

The superior and inferior costal facets articulate with the head of a rib, while the articular facet on the transverse process articulates with the tubercle of a rib.

Intervertebral discs are shown between neighboring vertebral bodies throughout the thoracic region.

The figure demonstrates how thoracic vertebrae are specialized to support and articulate with the rib cage. The superior and inferior costal facets on the vertebral bodies, together with the articular facet on the transverse process, form joints with the ribs. These articulations help stabilize the thoracic cage while still permitting the limited movements necessary for breathing and trunk motion. The downward-projecting spinous processes and interconnected articular processes provide additional support and stability to the thoracic region of the vertebral column.

Figure 7.3.8: Articulation of a Thoracic Vertebra and Rib

This image shows a lateral view of several thoracic vertebrae with an attached rib, illustrating the anatomical relationship between the vertebral column and the rib cage.

Several thoracic vertebrae are stacked vertically and separated by intervertebral discs. Each vertebra includes a large anterior vertebral body and a posterior vertebral arch formed by the pedicle and lamina. Extending from the vertebra are the spinous process, transverse process, and superior and inferior articular processes.

The rib attaches to the vertebra at two locations:

• Head of the rib: articulates with the superior costal facet and inferior costal facet on adjacent vertebral bodies
• Tubercle of the rib: articulates with the facet for the tubercle of the rib on the transverse process

The neck of the rib is the narrow region between the head and the tubercle. Lateral to the tubercle, the rib bends at the angle of the rib before continuing around the thoracic cage.

The superior articular facets are located on the upper portion of the vertebra and form joints with the vertebra above. The inferior articular process projects downward and forms a joint with the vertebra below. The spinous process extends posteriorly and inferiorly, which is characteristic of thoracic vertebrae.

The figure highlights three structures involved in rib articulation:

• Superior costal facet: on the upper portion of the vertebral body
• Inferior costal facet: on the lower portion of the vertebral body
• Facet for the tubercle of the rib: on the transverse process

Together, these facets form joints between the rib and the vertebrae.

The figure demonstrates how thoracic vertebrae are specialized to support and articulate with the ribs. The head of the rib articulates with costal facets on the vertebral bodies, while the tubercle articulates with a facet on the transverse process. These joints anchor the ribs to the vertebral column and provide the stability and limited mobility necessary for movements of the thoracic cage during breathing. The articular processes connect adjacent vertebrae and help guide movement while maintaining alignment of the thoracic spine.

Figure 7.3.9: Structure of Lumbar Vertebrae

This image shows a lateral view of several lumbar vertebrae stacked vertically. A small inset identifies the lumbar region within the vertebral column.

The vertebrae are separated by intervertebral discs, which lie between adjacent vertebral bodies. The vertebral body forms the large anterior portion of each vertebra and is noticeably larger than the vertebral bodies in the cervical and thoracic regions, reflecting the greater weight-bearing role of the lumbar spine.

Projecting posteriorly from each vertebra are the spinous processes, which are broad and relatively short compared with the long, downward-sloping spinous processes of thoracic vertebrae. Extending laterally from each vertebra are the transverse processes.

The figure also labels the superior articular processes and inferior articular processes, which project upward and downward from adjacent vertebrae. These processes form joints between neighboring lumbar vertebrae and help maintain alignment of the vertebral column.

The labeled structures include:

• Vertebral body: located anteriorly and separated from adjacent vertebral bodies by intervertebral discs
• Intervertebral disc: located between neighboring vertebral bodies
• Transverse process: extending laterally from the vertebral arch
• Superior articular process: projecting upward to articulate with the vertebra above
• Inferior articular process: projecting downward to articulate with the vertebra below
• Spinous process: projecting posteriorly from the vertebral arch

The figure demonstrates structural features that enable the lumbar vertebrae to support the greatest amount of body weight while maintaining flexibility in the lower back. The large vertebral bodies and intervertebral discs help bear compressive forces, while the superior and inferior articular processes form joints that stabilize the lumbar spine and guide movement. Together, these structures allow flexion, extension, and limited rotation of the lower back while supporting the upper body.

Figure 7.3.10: The Sacrum and Coccyx

This image shows the sacrum and coccyx in two views: an anterior view on the left and a posterior view on the right. A small inset shows the location of the sacrum within the vertebral column.

The overall organization presents the sacrum as a triangular bone formed by fused vertebrae at the base of the vertebral column, with the coccyx attached to its inferior end. The labels in the figure include body of first sacral vertebra, sacral promontory, transverse ridges, anterior sacral foramina, apex of sacrum, coccyx, sacral canal, median sacral crest, posterior sacral foramina, lateral sacral crest, sacral hiatus, auricular surface, and superior articular facet. The figure emphasizes structures related to nerve passage, muscle and ligament attachment, and connection to the pelvis.

In the anterior view, the body of the first sacral vertebra forms the upper portion of the sacrum. Its function is to support weight transferred from the lumbar spine and contribute to the load-bearing surface. The sacral promontory is a projecting edge at the superior part of the sacrum. Its functions are to mark the boundary between the lumbar spine and sacrum and serve as an anatomical landmark in the pelvis. The transverse ridges are horizontal ridges across the anterior surface. Their function is to represent the fusion lines of the original sacral vertebrae, showing the developmental history of the bone. The anterior sacral foramina are openings on the anterior surface that allow passage of spinal nerves and blood vessels. The apex of the sacrum is the inferior tip that connects to the coccyx. The coccyx is a small fused bone extending below the sacrum. Its functions are to serve as an attachment site for ligaments and muscles and provide support when sitting.

In the posterior view, the sacral canal is a continuation of the vertebral canal running through the sacrum. Its function is to house and protect the lower portion of the spinal nerves. The median sacral crest is a vertical ridge along the midline. Its functions are to represent fused spinous processes and serve as an attachment site for ligaments. The posterior sacral foramina are openings on the posterior surface that allow passage of spinal nerves exiting the sacrum. The lateral sacral crest consists of ridges lateral to the median crest and provides attachment points for muscles and ligaments. The sacral hiatus is an opening at the lower end of the sacral canal. Its functions are to allow access to the sacral canal and provide passage for nerve structures. The auricular surface lies on the lateral side of the sacrum and articulates with the ilium, forming part of the sacroiliac joint, which transfers weight to the lower limbs. The superior articular facet is located on the upper part of the sacrum and joins with the last lumbar vertebra, L5, helping provide movement and stability between the lumbar spine and sacrum.

Figure 7.3.11: Anterior and Posterior Views of the Sacrum and Coccyx

This image shows two detailed anatomical views of the sacrum and coccyx. On the left is the anterior view, where the broad upper surface forms the sacral promontory. The fused sacral vertebrae are visible as transverse ridges running horizontally across the bone. Four pairs of anterior sacral foramina line each side, providing passage for spinal nerves. The sacrum narrows toward the bottom, ending at the apex, which connects to the small triangular coccyx. On the right is the posterior view, which displays the irregular contours and ridges formed by fused vertebral elements. The median sacral crest, created by fused spinous processes, runs down the center. Lateral sacral crests lie to each side, and the posterior sacral foramina appear as a set of openings similar to those on the anterior surface. The sacral canal extends downward through the bone and ends at the sacral hiatus near the lower end. The auricular surfaces, shaped for articulation with the hip bones, are labeled along the sides. The coccyx appears at the bottom in both views.

Figure 7.3.12: Ligaments of the Cervical Vertebral Column

This image shows a side view of the skull and cervical portion of the vertebral column with several ligaments labeled. At the back of the skull, the external occipital protuberance is identified as the attachment site for the nuchal ligament, which extends downward along the cervical spinous processes. The supraspinous ligament continues this line of connection inferiorly. Each cervical vertebra is drawn with its spinous process visible. Along the front of the vertebral bodies, the anterior longitudinal ligament is labeled, illustrating its role in stabilizing the vertebral column from the anterior side. The diagram provides a clear overview of how these ligaments connect the skull to the cervical spine and help maintain posture and spinal alignment.

Figure 7.4.1: The Thoracic Cage

Two anterior views of the thoracic skeleton. Panel (a) shows the sternum alone. The superior manubrium contains the jugular notch at the midline and clavicular notches on either side. The manubrium joins the body of the sternum at the sternal angle. The xiphoid process forms the small inferior tip of the sternum.

Panel (b) shows the thoracic cage. The sternum is located at the midline and consists of the manubrium, body, and xiphoid process. Twelve pairs of ribs curve from the thoracic vertebrae toward the anterior chest wall. Costal cartilages connect the anterior ends of many ribs to the sternum. Intercostal spaces are visible between adjacent ribs. The clavicles and portions of the scapulae are shown as adjacent skeletal structures. Thoracic vertebrae T1 through T12 are visible posterior to the ribs. Labels identify the jugular notch, clavicular notches, clavicles, scapulae, sternal angle, costal cartilages, intercostal spaces, and ribs 1 through 12. Orientation is indicated with superior at the top and inferior at the bottom.

Figure 7.4.2: Anatomy of a Rib

This image shows a single rib, identifying its major anatomical regions and the surfaces involved in articulation and support within the thoracic cage.

The overall organization presents the rib as a curved, elongated bone. One end connects to the vertebral column, and the opposite end connects toward the sternum through costal cartilage. The labels in the image include head of rib, neck of rib, tubercle of rib, articular facet, shaft (body) of rib, angle of rib, and anterior end of rib.

At the posterior, or vertebral, end of the rib, the head of the rib is the rounded end. Its functions are to articulate with the vertebral bodies at the costal facets and to form part of the joint between the rib and the spine. The neck of the rib is the narrowed segment between the head and the shaft. Its functions are to connect the head to the rest of the rib and provide stability and alignment between articulation points. The tubercle of the rib is a projection near the junction of the neck and shaft. Its functions are to articulate with the transverse process of a thoracic vertebra and help stabilize rib movement. The articular facet is the smooth surface on the tubercle. Its functions are to form a joint with the vertebra and allow controlled movement of the rib.

The shaft, or body, of the rib is the long curved portion extending from the posterior end. Its functions are to provide structural support for the thoracic cage and contribute to the shape and expansion of the chest. The angle of the rib is the point where the rib begins to curve forward. Its functions are to enhance the shape of the thoracic cage and allow flexibility during breathing movements.

The anterior end of the rib is the flattened end opposite the head. Its function is to connect to the costal cartilage, which then connects toward the sternum, allowing flexibility in the rib cage during breathing.

Figure 7.4.3: Rib Classifications

This image is an oblique anterior view of the thoracic cage shows the ribs color-coded by classification. Ribs 1–7 are colored red and represent the true ribs, which attach directly to the sternum through their own costal cartilages. Ribs 8–10 are colored green and represent the false ribs, whose costal cartilages join the cartilage of the rib above, creating an indirect connection to the sternum. Ribs 11–12 are colored blue and represent the floating ribs, which have no anterior attachment to the sternum. The sternum, thoracic vertebrae, and other skeletal structures are shown in gray to provide anatomical context.