Skeletal System

Right lower limb, anterior view A.) femur B.) Patella C.) tibia D.) fibula E.) tarsals F.) metatarsals G.) phalanges

the lower limb must withstand the stresses of locomotion and burying the bodies weight; for this reason, the bones are more massive than the bones of the upper limbs. The lower limbs are supported by the pelvis. The bones of the lower limbs include the femur, which articulates proximally with the pelvis at the acetabulum of the hip bone and distal with the tibia and patella. Lateral to the tibia is the fibula, but only the tibia articulates with the tarsals, or ankle bones. At the ankle, the foot turns 90 degrees compared to the leg bones to provide stability as the body's weight is transferred to the ground. The bones on the foot include the metatarsals and the phalanges, or toe bones.

Posterior view of the vertebrae A.) Cervical vertebrae B.) Thoracic vertebrae C.) Lumbar vertebrae D.) Sacrum E.) Coccyx

The adult human vertebral column consists of 26 bones - 7 cervical vertebrae (C1-C7, including the atlas [C1] and axis [C2]) form the neck, 12 thoracic vertebrae (T1-T12) support the upper back and articulate with ribs, 5 lumbar vertebrae (L1-L5) support the lower back, a sacrum consisting of 5 fused vertebrae articulates with the pelvis, and a coccyx resulting from the fusion of the final 4-6 vertebrae. Generally, 1 spinal nerve emerges at each vertebra; however, although there are only 7 cervical vertebrae, there are 8 cervical nerves. Each individual vertebra consists of a vertebral body or centrum that transfers weight to the next lower vertebra, a vertebral arch forming the posterior margin of the vertebral canal, and variable types of processes that either provide attachment points for muscles or articulate with ribs. The 5 sacral vertebrae begin fusing after puberty and are usually completely fused by age 25-30. The coccyx is not completely fused until late in adulthood.

Left clavicle and related bones, Superior View; left clavicle, inferior View A.) first thoracic vertebrae (T 1) B.) first rib C.) scapula D.) acromial end of clavicle E.) Conoid tubercle F.) sternal end of clavicle G.) sternum

Looking down from above the head and shoulders reveal the superior aspect of the pectoral girdle, including both the clavicle and scapula. The girdle is anchored to the axial skeleton by a single articulation anteriorly and is held in position posteriorly by many small muscles attached to the scapula; this provides Mobility but limited strength to the shoulders, which anchor the Motions of the arm. The s-shaped clavicle articulates medially with the manubrium of the sternum just above the first rib and laterally with the acromial process of the scapula. The acromial end of the clavicle is broader than the sternal end. At the posterior margin of the inferior surface near the acromial end is the conicoid tubercle; this is an attachment point for the coronoid ligament, which also attaches to the coracoid process of the scapula.

Skull, superior view A.) Frontal bone B.) Coronal suture C.) Parietal bones D.) Sagittal suture E.) Lambdoid suture F.) Occipital bone

Sutures are immovable joints between cranial bones where the bones are held together securely by dense fibrous tissue. The 2 parietal bones articulate at the sagittal suture. The frontal bone articulates with the 2 parietal bones at the coronal suture. The parietal bones meet the occipital bone at the lambdoid suture. However, at birth, an infant's skull is still growing and the bones do not completely meet; they are connected only by relatively large areas of fibrous tissue called fontanels. Most of the fontanels disappear within a few months after birth, although the largest may take a year or 2 before it closes completely.

Intervertebral discs, lateral and midsagittal views A.) Intervertebral disc B.) Superior articular process C.) Transverse process D.) Inferior articular process E.) Intervertebral foramen F.) Anterior longitudinal ligament G.) Supraspinous ligament H.) Interspinous ligament I.) Ligamentum flavum J.) Posterior longitudinal ligament

A lateral view of the vertebral column shows that adjacent bodies of the vertebrae are cushioned by the intervertebral discs, which permit some extension and flexion of the spine. Intervertebral discs are composed of fibrocartilage that resists compression but allows a little flexibility. The pedicles of adjacent vertebrae are separated by the intervertebral foramina, which allow the passage of nerves entering or exiting from the spinal cord. The spinal cord runs through the vertebral foramen within the vertebral arch formed in part by the pedicles. The lamina of adjacent vertebrae articulate through the facets on the superior and inferior articular processes, while the transverse processes project laterally. Ligaments connect and stabilize the vertebrae. Anterior and posterior longitudinal ligaments run along the bodies of the vertebrae, while supraspinous and interspinous ligaments connect the dorsal spinous processes, and the ligamentum flavum connects the adjacent laminae.

Skeleton, posterior view A.) Parietal bone B.) Mastoid process C.) Scapula D.) Humerus E.) Ulna F.) Radius G.) Carpals H.) Sacrum I.) Phalanges J.) Femur K.) Tibia L.) Tarsal M.) Calcaneus N.) Metatarsals O.) Fibula P.) Metacarpals Q.) Hip bone (os coxae) R.) Lumbar vertebra S.) Ribs T.) Thoracic vertebra U.) Acromion V.) Cervical vertebra W.) External occipital protuberance x.) Occipital bone

Bones of the cranium include the parietal and occipital; the external occipital protuberance is the bump obvious at the midsagittal point on the inferior margin of the cramium. The spinal cord is protected by vertebrae, including the cervical (7), thoracic (12), and lumbar (5), as well as the fused vertebrae that make up the sacrum. The upper limbs articulate with the scapula of the pectoral girdle; the acromion is a large process of the scapula that articulates with the clavicle, which in turn attaches to the sternum. Upper limb bones include the humerus, ulna, and radius; wrist bones are carpals; hand bones are metacarpals; and finger bones are phalanges. The pelvic girdle supports the weight of the torso, and the hip bone articulates with the lower limbs, which include the femur, tibia, and fibula; ankle bones are tarsals, the largest of which is the calcaneus or heel bone; foot bones are metatarsals; and toe bones are phalanges.

Cervical vertebra, superior and lateral views A.) Bifid spinous process B.) Vertebral foramen C.) Lamina of vertebral arch D.) Pedicle of vertebral arch E.) Superior articular process F.) Transverse process G.) Body H.) Uncus of vertebral body I.) Transverse foramen J.) Inferior articular process

Cervical vertebrae have a relatively large vertebral foramen, since the spinal cord still includes most of the axons that exit the brain, and the vertebral body only needs to support the weight of the head. The vertebral foramen is bounded by the body anteriorly, the pedicles laterally, and the laminae posteriorly. Where the laminae meet is a posteriorly projecting protrusion called the spinous process, which is notched, or bifid, for C2-C6. Articular processes lie at the junction between the pedicles and laminae; each has a relatively flat surface, the facet, which articulates with the articular process of the neighboring vertebra. The superior articular process articulates with the vertebra above, and the inferior articular process articulates with the vertebra below. The uncus is a ridge of bone around the superior edge of the body in cervical vertebrae, increasing the stability of the joint with the vertebra above it. Laterally, transverse processes provide attachment sites for neck muscles; a hole, the transverse foramen, allows passage of vertebral arteries and veins.

Thoracic vertebra, superior and lateral views A.) Spinous process B.) Vertebral foramen C.) Transverse process D.) Superior articular process E.) Superior costal facet F.) Body G.) Pedicle H.) Lamina I.) Costal facet of transverse process J.) Inferior articular process K.) Inferior costal facet

Each of the 12 thoracic vertebrae has a larger body and smaller vertebral foramen than those found in the cervical vertebrae. A long, slender dorsal spinous process projects inferiorly. The superior and inferior articular processes articulate with adjacent vertebrae. The thoracic vertebrae articulate with ribs; the superior and inferior costal facets arise at the junction between the vertebral body and pedicle for T2-T8, while a single costal facet is found for T1 and T9-T12. Two facets are needed for T2-T8 because each pair of ribs lies between 2 adjactent vertebrae, articulating with the inferior costal facet of the upper vertebra and the superior costal facet of the vertebra inferior to it. For T1 and T9-T12, a single pair of ribs articulates with a single vertebra. The ribs also articulate with the costal facet of the transverse process in vertebra T1-T10. The multiple articulations help the ribs to be mobile enough for the change in volume of the rib cage during breathing.

Right hand, anterior (Palmar) view a.) phalanges B.) metacarpal C.) trapezoid D.) trapezium E.) capitate F.) scaphoid G.) lunate H.) pisiform I.) hamate

Since the anatomical position is defined with the palms of the hands facing forward, the thumb is more lateral while the fingers are more medial. Among the proximal carpal Bones, the lateral scaphoid bone articulates with the styloid process of the radius; the lunate bone also articulates with the radius. The triquetrum articulates with the cartilaginous disc that separates the head of the ulna from the wrist. The small, anterior pea-shaped pisiform bone is seen primarily for the interior view and only articulates with the triquetrum. Among the distal carpal Bones, the lateral trapezium articulates with metacarpals 1 and 2; trapezoid bone articulates with metacarpal 2; the capitate articulates with metacarpals 2, 3, and 4; and the hamate articulates with metacarpals 4 and 5. The distal head of each metacarpal articulates with the more proximal of the phalanges in the finger. The phone has proximal and distal phalanges while each finger has proximal, media, and distal phalanges.

Atlas (C1) and axis (C2), superior view A.) Posterier tubercle B.) Vertebral foramen C.) Lateral mass D.) Transverse foramen E.) Superior articular process (facet) F.) Anterior arch G.) Anterior arch H.) Transverse process I.) Groove for vertebral artery J.) Posterior arch K.) Facet for odontoid process of axis L.) Bifid spinous process M.) Body of axis N.) odontoid process (dens) O.) Arch of axis (lamina) P.) Axis Q.) Atlas

The first cervical vertebra is called the atlas; its superior articular processes have facets that articulate with the occipital condyles of the skill in a type of joint that permits forward-backward motion of the head. The body of the second cervical vertebra, the axis, has a prominent odontoid process that extends superiorly and articulates with a facet on the atlas, providing a pivot point to allow rotational movement of the head. The facet of the superior articular process of the axis articulates with a similar flat surface on an interior articular process of the atlas. Like other individual vertebrae, the axis has a prominent dorsal spinous process, which is notched as it is in cervical vertebrae 3-6 and is referred to as bifid; the atlas has a smaller dorsal process known as the posterior tubercle. Laterally, a transverse process provides attachment sites for muscles, while the transverse foramen allows passage of vertebral arteries and veins.

Right temporal and sphenoid bones Temporal bone: A.) Squamous part B.) Zygomatic process C.) Mandibular fossa D.) External acoustic meatus E.) Styloid process F.) Mastoid process Sphenoid bone: G.) Hypophysial fossa (sella turcica, pituitary fossa) H.) Optic canal I.) Lesser wing J.) Superior orbital fissure K.) Great wing L.) Foramen spinosum M.) Pterygoid hamulus N.) Dorsum sallae O.) Foramen ovale P.) Foramen rotundum Q.) Anterior clinoid process

The large, flat surface of the temporal bone is the squamous region. The mandibular fossa is a depression that articulates with the mandible. The zygomatic process articulates with the zygomatic bone to form the cheekbone, while the mastoid process is an attachment site for muscles, and the styloid process is an attachment site for muscles and ligaments supporting the hyoid bone. The external acoustic meatus provides the opening for the auditory canal. The sphenoid bone is a butterfly-shaped bone that articulates with both cranial and facial bones and provides cross bracing that serves to strengthen the skull. The central region or body is composed of the dorsum sellae and the sella turcica, which contains a depression where the pituitary gland is located, the hypophysial fossa. The lesser wing of the sphenoid is located anterior to the sella turcica; it is penetrated by the optic canal carrying the optic nerve from the rear of the orbit toward the brain. The greater wing is lateral to the body. The superior orbital fissure, foramen spinosum, foramen ovale, and foramen rotundum are passages that carry blood vessels and nerves to the face, jaw, or eye region.

Right pectoral girdle & Upper Limb, anterior view A.) Clavicle B.) Acromion process C.) Coracoid process D.) Humerus E.) Radius F.) Sternum G.) Scapula H.) Ulna I.) Carpals J.) Metacarpals K.) Phalanges

The pectoral girdle is composed of 4 bones, 2 clavicles, and 2 scapulae. The acromion and coracoid processes of the scapulae are points of attachment for numerous ligaments and muscles. The clavicle articulates with the sternum of the axial skeleton immediately and with the scapula laterally. The primary function of the pectoral girdle is to provide an anchor for movements of the arm. Each Upper Limb consists of a humerus in the upper arm, an ulna and a radius in the forearm, 8 carpal bones in the wrist, 5 metacarpal bones in the hand, and 14 phalanges or finger bones. At the shoulder, the humerus articulates with the scapula to permit a wide range of arm movements; at the elbow, the humerus articulates with the radius and ulna to flex the forearm, while articulation between the radius and ulna allows pronation of the Forearm. B-Complex wrist joints provides for a wide range of movements, while the finger joint allows flexion and extension of the fingers.

Sacrum and coccyx, posterior view A.) Superior articular process B.) Articular surface C.) Lateral sacral crest D.) Median sacral crest E.) Posterior sacral foramina F.) Coccyx

The posterior surface of the sacrum is convex, allowing room within the pelvic region for internal organs and providing many surfaces for attachment of muscles and ligaments. Laterally, the auricular surfaces articulate with the pelvis at the iliac joints. The median sacral crest is a bumpy ridge produced from the fused spinal processes of the sacral vertebrae; deep to this ridge is the sacral canal, which is the continuation of the vertebral canal. The lateral sacral crest represents the fused transverse processes of the sacral vertebrae. Between the 2 ridges are the posterior sacral foramina, which serve as passageways for sacral nerves as well as arteries. Sexual differences exist - in the female, the sacrum is shorter and wider than in the male, with most of the curvature in the lower half, whereas curvature is more evenly distributed in the male.

Rib cage, anterior view A.) First thoracic vertebra B.) Clavicle C.) Scapula D.) Costal cartilage E.) Twelfth thoracic vertebra F.) First lumbar vertebra G.) Twelfth rib H.) Eleventh rib I.) Sternum J.) First rib

The rib cage consists of the sternum and the 12 pairs of ribs, which are attached posteriorly to the thoracic vertebrae. Ribs 1-7 articulate with the sternum through the costal cartilage. In ribs 8 - 10, the costal cartilage articulates only indirectly with the sternum; it fuses to the cartilage of rib 7 for support. Ribs 11-12 do not attach to the sternum at all; they are connected with other skeletal elements only at the vertebral end. The articulation between the axial skeleton and the pectoral girdle occurs where the clavicle, or collarbone, attaches to the sternum at the manubrium; in turn, the clavicle articulates with the scapula, or shoulder blade. The rib cage protects the heart, lungs, and other thoracic organs and also serves as an attachment point for muscles involved in movements of the pectoral girdle and the upper limbs. The rib cage also helps with adjustments to the position of the vertebral column and, most importantly, breathing.

Skull, anterior view. A.) Orbit B.) Frontal bone C.) Temporal bone D.) Sphenoid bone E.) Nasal bone F.) Zygomatic bone G.) Nasal septum H.) Maxilla I.) Mandible

The skull is composed of eight cranial bones and 14 facial bones. looking at the anterior surface, the facial bones include two nasal, two zygomatic, two maxillae, and one mandible. the maxillae and mandible form the upper and lower jaws. The maxillae and zygomatic form the interior surface of the orbits, or eye sockets. view Superior rim of the orbit consists of the frontal bone, and the back of the orbit is formed by the sphenoid, both cranial bones. The nasal bones and maxillae form the bridge and lateral rim of the nasal opening. the nasal cavity is subdivided by the nasal septum, formed from deeper facial bones including the vomer and one of the deep cranial bones-the ethmoid. cranial bones observed from this aspect include the frontal bone, which forms the forehead, and two temporal bones on the lateral surfaces.

Sternum, anterior view A.) Suprasternal notch B.) Clavicular notch C.) Manubrium D.) Sternal angle E.) Costal notches F.) Body G.) Xiphoid process

The sternum, part of the axial skeleton, functions to protect and support the internal organs of the thoracic cavity and to form an attachment point for ribs. It has 3 main portions - the superior section, which is the triangular manubrium that articulates with the clavicles; the main body; and the small xiphoid process located inferior to the body. The superior edge of the manubrium has 2 points of attachment for the clavicles, located laterally on either side of the medial depression known as the suprasternal notch. At the point of attachment between the manubrium and body of the sternum is the sternal angle, a convenient marker located at the level of the second rib. The anterior ends of ribs 1-7 articulate with the sternum; the first rib articulates with the manubrium at sites inferior to the clavicular notches, and ribs 2-7 have cartilage connections to the body of the sternum at the costal notches. RIbs 8-10 are attached by cartilage to the cartilage connections of rib 7. The xiphoid process forms an attachment point for some muscles, including the diaphragm.

Right hand, posterior (dorsal) view A.) phalanges B.) head of metacarpal C.) shaft of metacarpal D.) base of metacarpal E.) Hamate F.) capitate G.) triquetrum H.) Lunate I.) Metacarpal J.) trapezoid K.) trapezium L.) scaphoid

eight carpal bones make up the flexible wrist, articulating at individual joints that allow limited, gliding motion between the bone surfaces. The proximal row of carpals includes the scaphoid bone, lunate bone, triquetrum, and pisiform Bone; the distal row consists of the trapezium, trapezoid bone, capitate phone, and hamate Bone. Articulating with the distal carpal bones are the 5 metacarpal bones, forming the hand. The metacarpals are identified by Roman numerals; metacarpal one is most lateral, forming the base of the thumb, and articulates with the trapezium. The proximal base of each metacarpal articulates with the carpals. The metacarpal heads or distally with phalanges, or finger bones. The thumb has two phalanges; each of the other fingers has three, making a total of 14 phalanges on each hand. The Joint between metacarpal one and the trapezium at the base of the thumb is a saddle joint, which allows a greater range of motion than is found in the other metacarpals, permitting the abilities associated with having an opposable thumb.

Differences between male and female pelvis A.) Wing (KOA) of ilium B.) subpubic angle, mail (narrow we're) C.) true pelvis, male (narrower, heart. Shaped) D.) Subpubic angle, female (wider) E.) true pelvis, female(wider, oval)

sex-based differences between males and females are evident in the pelvis, due partly to the larger size and muscle mass of males and partly to adaptions in females for childbearing. Generally, The female pelvis has lighter bones with smoother surfaces; it is broader and shallower than the male pelvis. The broad surface of the ilium, known as the ala or wing, project farther laterally in females, but the superior iliac crest is comparatively closer to the level of the sacrum. The subpubic angle formed between the two pubic bones at the pubic symphysis is larger in females. The sacrum and coccyx are less curves in females at the inferior, anterior side, leading to a larger and more circular opening at the inferior side of the cavity known as the true pelvis. Overall, The true pelvis is wider, and moreover in females to allow for childbirth, while it is narrow we're in somewhat heart-shaped in males.

Right scapula, posterior View A.) acromion process B.) coracoid process C.) glenoid fossa D.) infraspinatus fossa E.) lateral border F.) inferior angle G.) medial border H.) supraspinatus fossa I.) Superior angle J.) spine

the basic triangular shape of the scapula is bound by the superior angle, the medial border, the inferior angle, and the lateral border. Muscles attached to these margins position the scapula; there is no direct articulation of the scapula with the vertebrae or rib cage. Located in the angle between the lateral and Superior borders, the glenoid fossa articulates with the humerus of the arm. The posterior surface is marked by The prominent Ridge called the scapular spine, which is continuous with the acromion process. The clavicle articulates with the acromion process at the medial surface of his interior projection. The spine divides the posterior face of the scapula into a smaller supraspinatus fossa in a larger infraspinatus fossa; both are sites of attachment for numerous muscles of the shoulder and back.

Left ulna and radius, lateral and interior views A.) olecranon process B.) trochlear notch C.) Coronoid process D.) radial Notch E.) tuberosity of the ulna F.) head of the radius G.) radial tuberosity H.) Interosseous margin I.) ulnar notch J.) styloid process of ulna K.) head of the ulna L.) styloid process of radius

the bones of the forearm are the ulna and radius. The more medial and longer ulna articulates with the trochlea of the humerus at the trochlear notch. The superior edge of the trochlear notch is the olecranon process, which fits into the olecranon fossa of the humerus when the form arm is extended, and the inferior edge of the trochlear notch is the coronoid process, which fits into the coronoid fossa of the humerus when the forearm is flexed. Lateral to the coronoid process, the radial notch of the ulna articulates with the head of the radius. Distal to the radial head. The radial tuberosity forms an attachment site for muscles. A chivalrous sheet called the interosseous margins connects the radius and ulna along the interosseous margins and serves as a site for muscle attachment. At their distal ends, the owner and radius articulate with each other, and the radius articulates with bones of the wrist. The lateral surface of the ulnar head articulates with the ulnar notch of the radius. A styloid process extends distally from each of the bones, providing many attachment sites for ligaments and muscles of the wrist.

Skeleton, anterior view A.) Frontal Bone B.) Maxilla C.) Mandible D.) Clavicle E.) Humerus F.) Costal cartilage G.) Thoracic vertebra H.) Ulna I.) Hip bone (os coxa) J.) Sacrum K.) Phalanges L.) Patella M.) Fibula N.) Metatarsals O.) Phalanges P.) Tarsals Q.) Tibia R.) Femur S.) Metacarpals T.) Carpals U.) Lumbar vertebra V.) Radius W.) Ribs X.) Sternum Y.) Cervical certebra Z.) Zygomatic bone

The axial skeleton has 80 bones, including the skull and associated bones, the rib cage and the vertebral column. Looking at the axial skeleton from the anterior aspect beginning with the head, one sees the frontal bones, which is part of the cranium; the maxilla, zygomatic, and mandible, which are all facial bones; the cervical, thoracic, and lumbar vertebrae; the sacrum and coccyx; as well as the ribs, which are connected to the sternum through the costal cartilage. The cramium and vertebral column protect the brain and spinal cord; the rib cage protects internal organs and facilitates breathing. The appendicular skeleton consists of 126 bones, including the pelvic and pectoral girdles and the limbs. Parts of the appendicular skeleton observed anteriorly include the clavicle of the pectoral girdle; the humerus, ulna, radius, carpals, metacarpals and phalanges of the upper limbs; the hip bone of the pelvic girdle; and the femus, patella, tibia fibula, tarsals, metatarals, and phalanges of the lower limbs. The pectoral and pelvic girdles connect the limbs to the axial skeleton; it is the appendicular skeleton that allows one to move about in the environment.

Hyoid bone A.) Lesser horn B.) Greater horn C.) Body

The small hyoid bone is located at the base of the tongue and immediately superior to the larynx. It is crucial to human speech as it braces the tongue and larynx to allow a wide range of movements. The body of the hyoid is an attachment site for muscles of the pharynx, larynx, and tongue. The greater horns support the larynx and provide attachment sites for muscles moving the tongue. The lesser horns are suspended from the styloid processes of the temporal bones via ligaments.

Bones of the Left Foot, lateral view A.) first (medial) cuneiform B.) second (intermediate) cuneiform C.) third (lateral) cuneiform D.) navicular E.) Talus F.) distal Phalanx G.) middle Phalanx H.) proximal Phalanx I.) head of metatarsal J.) shaft of metatarsal K.) base of metatarsal L.) cuboid M.) calcaneus

the large Tarsus called the talus articulates with the tibia to distribute the weight of the body evenly, both toward the distal end of the metatarsals and also toward the hill. Anteriorly, The talus articulates with the navicular bone, which in turn articulates with the medial, intermediate, and lateral cuneiform bones. These tarsals then articulate with metatarsals 1, 2, and 3. Additionally, The talus articulates with the calcaneus or heel bone. Anteriorly, The calcaneus articulates with the cuboid bone, which then articulates the metatarsals 4 and 5. Ligaments and tendons attached to tarsals and metatarsals to maintain an arch position that lifts the medial bones; this Arrangement spares blood vessels, nerves, and muscles from being squeezed beneath the bones and the ground. The elasticity of the art also helps to cushion the shock that arises as the weight shifts during walking or running. The head of each metatarsal articulates with the proximal phalanx of the toe.

Median sagittal section of the skull A.) Frontal bone B.) Frontal sinus C.) Crista galli D.) Nasal bone E.) Cribriform plate of the ethmoid bone F.) Perpendicular plate of the ethmoid bone G.) Vomer H.) Maxilla I.) Palatine bone J.) Mandible K.) Coronal suture L.) Squamosal suture M.) Parietal bone N.) Temporal bone O.) Sella turcica P.) Occipital bone Q.) Internal acoustic meatus R.) Sphenoid bone S.) Sphenoid sinus

A sagittal section of the skull shows the inner surface of the braincase, including the frontal, parietal, occipital, sphenoid, ethmoid, and temporal bones. The inner ear opens through the temporal bone at the internal acoustic meatus. The sella turcica is a saddlelike portion of the sphenoid that encloses the piruitary gland, which projects from the surface of the brain. Facial bones include the nasal, vomer, maxilla, palatine, and mandible. Several bones have hollow spaces known as sinuses to make the bones lighter and to provide a source of mucus; cross sections of these bones reveal the frontal sinus and the sphenoid sinus. The nasal cavity lies superior to the hard palate; its roof is formed by the cribriform plate of the ethmoid, while the perpendicular plate of the ethmoid forms part of the nasal septum. The crista galli is a ridge of the ethmoid that projects superiorly from the cribiform plate.

Sacrum and coccyx, anterior view A.) Sacral promontory B.) Superior articular process C.) Lateral mass (ala) D.) Transverse lines E.) Anterior sacral foramina F.) Coccyx

Five sacral vertebrae fuse to form the sacrum, while 3-5 coccygeal vertebrae fuse to form the coccyx. These vertebrae begin fusing after puberty; the sacrum is usually completely fused by the mid-20s, while the coccyx is not completely fused until late in adulthood. The coccyx is a vestigial remnant of the tail of evolutionary ancestors, but in humans it has no vertebral foramen and does not surround a part of the spinal cord. The regions of the sacrum include the sacral promontory, which articulates with the last lumbar vertebra (L5), the 2 broad lateral masses or ala on either side, and the central sacral body, corresponding to the fused vertebral bodies; the transverse lines mark the position of the intervertebral discs between the bodies of the fused vertebrae. The anterior sacral foramina provide passageways for sacral nerves as well as arteries.

Skull, Lateral view A.) Coronal structure B.) Parietal bone C.) Zygomatic process D.) Temporal bone E.) Squamous suture F.) Lambdoid suture G.) External occipital protuberance H.) Occipital bone I.) Mastoid process J.) External acoustic meatus K.) Styloid process L.) Mandible M.) Maxilla N.) Zygomatic bone O.) Nasal bone P.) Lacimal bone Q.) Sphenoid bone R.) Frontal bone S.) Coronoid process T.) Mandibular foramen U.) Mandibular notch V.) Mandibular condyle W.) Ramus of mandible X.) Angle of mandible Y.) Body of mandible Z.) Mental foramen

Observed from the lateral aspect, one can identify the large braincase formed by the cranial bones, including a single frontal, 2 parietal, 2 temporal, 1 occipital, 1 sphenoid, and 1 ethmoid (which is not seen in this view). The temporal bone has several processes, which articulate with bones or provide attachment sites for muscles and ligaments, and the external acoustic meatus or external ear. The temporal bone articulates with the parietal bone at the immovable joint, the squamous suture. The mandible forms the lower jaw; it articulates with the parietal bone at an immovable joint, the squamous structure. The mandible forms the lower jaw; it articulates with the temporalis muscle that closes the jaw attaches at the coronoid process. Openings in the mandible include the mental foramen for nerves and the mandibular foramen for blood vessels and nerves. Other facial bones visible from this aspect include the maxilla, zygomatic, nasal, and lacrimal bones.

Lumbar vertebra, superior and lateral views A.) Spinous process B.) Vertebral foramen C.) Superior articular process D.) Transverse process E.) Body of vertebra F.) Pedicle G.) Lamina (vertebral arch) H.) Inferior articular process

The 5 lumbar vertebrae are the most massive of the vertebral column since they support the most weight, and each has a thick oval body. Lumbar vertebrae have the smallest vertebral foramina because many of the axons from the brain have already branched out from the spinal cord into the torso or upper limbs. The spinous process is short and sturdy and projects dorsally; lower back muscles are attached here that adjust the lumbar curve of the vertebral column. The superior articular process faces medially while the inferior articular process faces laterally. Transverse processes are slender and project dorsalaterally.

External surface of the base of the skull A.) Palatine process of maxilla B.) Vomer C.) Greater wing of sphenoid bone D.) Medial pterygoid plate of sphenoid bone E.) Mandibular fossa F.) Carotid canal G.) Jugular foramen H.) Foramen magnum I.) External occipital protuberance J.) Occipital condyle K.) Mastoid process L.) Styloid process M.) Foramen lacerum N.) Foramen ovale O.) Zygomatic arch P.) Lateral plate of sphenoid bone Q.) Palatine bone R.) Incisive fossa

The hard palate is formed by the palatine process of the maxillae anteriorly and the palatine bones posteriorly; the incisive fossa forms a passageway for nerves and arteries. the vomer forms the bony part of the nasal septum. The pterygoid plates are extensions of the sphenoid bone that form attachment sites for muscles that move the lower jaw. The foramen magnum is the large hole in the occipital bone through which the spinal cord passes; on either side, the occipital condyles articulate with the first vertebra of the neck. Between the foramen magnum and the external occipital protuberance, a bony crest marks attachment sites for ligaments stabilizing the vertebrae of the neck. The mastoid process of the temporal bone provides an attachment site for muscles rotating the head; muscles attached to the styloid process control the hyoid, the pharynx, and the tongue. Holes for passage of blood vessels and nerves include the carotid canal and foramen lacerum in the temporal bone, the foramen ovale in the sphenoid bone, and the jugular foramen formed at the junction of the temporal and occipital bones. A depression in the temporal bone, the mandibular fossa, articulates with the mandible.

Rib and vertebra, articulated, superior view; rib, posterior view A.) Thoracic vertebra B.) Head of rib C.) Neck of rib D.) Tubercle of rib E.) Angle of rib F.) Costal groove G.) Sternal extremity

The ribs function to protect the organs of the thoracic cavity and to provide a flexible cavity for breathing. The thoracic vertebrae articulate with the ribs; the head of the rib attaches to the costal facets near the body of the vertebrae, while the tubercle of the rib is positioned at the costal facet of the transverse process. The shaft of the rib curves anteriorly at the angle of the rib. Along the inferior border of the internal surface of the ribbed lies a costal groove where nerves and blood vessels pass. Cartilage connected to ribs 1 - 7 at the sternal extremity articulate with the sternum at the costal notches. Cartilage attached to ribs 8-10, in turn, attaches to the cartilage from rib 7.

Right tibia and fibula, anterior and posterior views A.) lateral tibial condyle B.) intercondylar Eminence C.) medial tibial condyle D.) Apex of fibula E.) head of fibula F.) tibial tuberosity G.) soleal line H.) medial crest of fibula I.) anterior border of fibula J.) anterior border (Crest) of tibia K.) lateral surface of tibial shaft L.) posterior surface of tibia M.) medial surface of tibial shaft N.) interosseous borders O.) malleolar Groove P.) medial malleolus Q.) lateral malleolus R.) Inferior articular surface of tibia

The tibia, or shin bone, articulates with the lateral and medial condyles of the femur at the lateral and medial tibial condyle. Between the condyle of, the intercondylar eminence provides attachment for cruciate ligaments. Anteriorly, the tibial tuberosity is a site of attachment for the patellar ligament. The distal end of the tibia has an inferior articular surface that articulates with a proximal tarsal bone. Adjacent to this is the medial malleolus, a large process that lends stability to the ankle joint; the malleolar groove is a tendon passageway. The fibula, or calf bone, is a long slender bone. The head of the fibula articulates with the lateral tibial condyle, while the inferior end of the tibia also articulates with a flat region on the side of the fibula. The lateral malleolus has is a fibular process that continues inferior lie beyond the articulation within the tibia, providing lateral support for the ankle joint. Along the shaft of both phones, prominent crests, borders, and lines mark the attachment sites for muscles as well as the interosseous membrane, which helped stabilize the two bones and provides additional muscle attachment sites.

Right scapula, anterior and lateral views A.) Acromion process B.) Scapular notch C.) Superior border D.) Coracoid process E.) Glenoid fossa F.) Subscapular fossa G.) Lateral border H.) Medial border I.) Inferior angle J.) Supraglenoid tubercle K.) Infraglenoid tubercle

Viewed from the anterior perspective, the scapula has an obvious large, triangular surface that is roughly concave, forming the subscapular fossa; its edges are, observed in a clockwise direction from this aspect, the superior border, medial border, inferior angle, and lateral border. Between the superior and lateral borders, the scapula articulates with the humerus at the shoulder joint. The glenoid fossa is the concave socket within which the rounded head of the humerus rotates. Two processes also originated in this area and extend superiorly. The more anterior of the two is the coracoid process, which is an attachment point for ligaments and tendons. Posterior to this is the larger acromion process, which articulates with the clavicle and serves as the attachment point for additional ligaments and tendons of the shoulder joint. The scapular notch is located along the superior border near the coracoid process; it provides a passage for the suprascapular nerve. Along the medial border is the infraglenoid tubercle, the region where the triceps brachialis muscle originates. Along the lateral border is the supraglenoid tubercle, where the biceps brachialis muscle originates. The lateral view clearly shows the acromion and coracoid process is projecting from the thin plane of the scapula, with the acromion process forming the highest point of the shoulder; the rounded surface of the glenoid fossa also becomes more obvious

Bones of the left foot, dorsal view 1.) phalanges 2.) metatarsals 3.) tarsals A.) distal phalanges B.) middle phalanges C.) proximal phalanges D.) head of metatarsal E.) shaft of metatarsal F.) base of metatarsal G.) first (medial) cuneiform H.) second (intermediate) cuneiform I.) spurred (lateral) cuneiform J.) cuboid K.) navicular L.) Talus M.) calcaneus

the bones of the foot include 7 tarsal or ankle bones, 5 metatarsal or foot bones, and 14 phalanges or toe bones. Each toe has distal, middle, and proximal phalanges, with the exception of the most medial great toe, which (like the some) has only two phalanges, the distal and proximal. Each metatarsal has a head that articulates with the proximal phalanges, a shaft, and a base that articulates with the tarsals. The talus is a large tarsal that articulates with the tibia at the process that also articulates with the lateral malleolus of the fibula. The calcaneus, or heel bone, is the largest tarsal. The navicular bone is anterior to the talus and articulates with the medial, intermediate, and lateral cuneiform bones, which in turn articulates with metatarsal bones 1 - 3. Anterior to the calcaneous and lateral to the navicular and cuneiform is the cuboid bone, which articulates with metatarsals 4 and 5.

Right femur and patella, anterior and posterior views A.) greater trochanter B.) head of femur C.) neck of femur D.) intertrochanteric line E.) intertrochanteric Ridge F.) lesser trochanter G.) Linea aspera H.) lateral epicondyle I.) medial epicondyle J.) lateral condyle K.) medial condyle L.) base of patella M.) Apex of patella

the femur, or spy bone, is the largest and strongest bone in the human body. The head of the femur articulates with the pelvis of the acetabulum; the head is joined to the shaft of the femur through the neck at an angle of about 125 degrees. The rim of the articular capsule is marked anteriorly by the intertrochanteric line and posterior by the intertrochanteric ridge. Adjacent to the neck is the superior greater trochanter and the inferior lesser trochanter; large tendons attached to both sites. The linea aspera is a ridge running along the posterior side of the femur we're strong hip muscles attached. At the distal end, the femur widens out, forming the lateral and medial epicondyles. Inferior to the epicondyles are the lateral and medial condyles, the surfaces that articulate with the tibia at the knee. A deep groove, the intercondylar fossa, extends between the condyles on the posterior side. Between the condyles is a smooth surface over which the patella can glide. The Patella has an inferior Apex connected to the tibia by a ligament; a broad, Superior base; a smooth, convex anterior surface; and posterior faucets for articulating with the condyles of the femur.

Left hip bone, lateral view a.) iliac crest B.) posterior Superior iliac spine C.)Posterior inferior iliac spine D.) greater sciatic Notch .) ischial spine F.) lesser sciatic Notch G.) ischial tuberosity H.) ischial ramus I.) acetabulum J.) obturator foramen K.) inferior pubic ramus L.) Superior pubic ramus M anterior inferior iliac spine N.) anterior superior iliac spine O.) ilium P.) ischium Q.) pubis

the hip bone, or os coxa, is formed from the fusion of three bones - the ilium, ischium, and pubis. Diffusion lines are visible in the illustration of a child hip bone, showing how the three bones meet to form the acetabulum, the Cub ass shaped depression (seen clearly in the lateral view) that articulates with the head of the femur. Anterior to the acetabulum is the superior and inferior Rami of the pubis; posterior to the acetabulum is the ischium, extending from the ischial spine on the superior edge of the ischial ramus, which means the inferior pubic ramus. The ischial tuberosity is the rounded protrusion that bears one's weight when seated. Space immediately inferior to the acetabulum is the obturator Foreman, which house has a sheet is collagen fibers that provide sites for attachment of muscles. Superior to the acetabulum is the large broad ilium, which supports the weight of the internal Friends of the trunk. Muscles, tendons, And ligaments attached to the ilium at the iliac crest and various iliac spines. The greater sciatic notch allows passage of the sciatic nerve to the lower limbs, while blood vessels and nerve pass along the lesser sciatic notch.

pelvis, Interior view a.) iliac crest B.) sacroiliac joint C.) greater sciatic Notch D.) anterior superior iliac spine E.) anterior inferior iliac spine F.) acetabulum G.) obturator Foreman H.) symphysis pubis I.) false pelvis J.) true pelvis

the pelvis is formed from the to ossa coxae of the appendicular skeleton and the sacrum and coccyx of the axial skeleton. Because the pelvis supports the weight of the upper body and mediates the stresses of locomotion, the bones are larger and heavier than those of the pectoral girdle. The ilium of the OS coxa articulates with the sacrum of the sturdy sacroiliac joint. The iliac crest forms the superior, posterior edge of the pelvis, while the anterior superior iliac spines mark the lateral edges. The anterior and inferior limit of the pelvis is composed of the pubis bones, medial to the obturator Foreman; the pubis bones are connected by fibrocartilage at the symphysis pubis. The true pelvis (or lesser pelvis) is the cavity posterior to the pubic symphysis, anterior to the sacrum and coccyx, and found it to the medial surfaces of the ilia near the greater sciatic Notch. The false pelvis (or greater pelvis) is the larger, more Superior cavity bounded laterally by the anterior superior iliac spines.

Right humerus, anterior and posterior views A.) greater tubercle B.) lesser tubercle C.) intertubercular sulcus D.) head E.) anatomical neck F.) surgical neck G.) deltoid tuberosity H.) supracondylar ridges I.) lateral epicondyle J.) coronoid fossa K.) olecranon fossa L.) medial epicondyle M.) capitulum N.) trochlea

the rounded head of the humerus moves within the cup-shaped glenoid fossa of the scapula. Adjacent to the head or two projections of the lateral surface of the humerus - the greater tubercle is the most lateral point of the body at shoulder level, and the lesser tubercle lies on the anterior, medial surface and is separated from the Greater tubercle by a shallow Groove called the intertubercular sulcus. Muscles attached to both tubercles, while a large tendon passes along the length of the sulcus. The edge of the joint capsule is called the anatomical neck, while the narrower surgical neck marks the metaphysis of the growing bone. The deltoid muscle attaches to the shaft of the deltoid tuberosity. At the distal end of the humerus, the capitulum and the trochlea articulates with the radius and ulna, respectively. The radio, coronoid, and olectraon fossae are depressions that accommodate the radial head, ulnar coracoid process, the ulnar olecranon as they move. Laterally, the humerus widens out the medial and lateral epicondyles; supracondylar ridges provide attachment sites for muscles.

Vertebral column, lateral view A.) Cervical vertebrae (cervical curvature) B.) Thoracic vertebrae (thoracic curvature) C.) Lumbar vertebrae (lumbar curvature) D.) Sacrum (pelvic curvature) E.) Coccyx

the vertebral column is the part of the axial skeleton that surrounds and protects the spinal cord, which bearing the weight of the head, neck, and trunk. The vertebral column is not straight, as can be seen in this lateral view; its curves accommodate the thoracic and abdominopelvic viscera and also balance the weight of the trunk and head over the lower limbs. Regions of the vertebral column and their corresponding curves including 7 cervical vertebrae (the cervical curve is concave on the posterior surface), 12 thoracic vertebrae (the thoracic curve is convex on the posterior surface), 5 lumbar vertebrae (the lumbar curve is concave), a sacrum (pelvic or sacral curve is convex), and a coccyx.