Chapter 7: Skeletal system
Acetabulum
deep socket on the lateral side of the hipbone just above the obturator foramen
Incus
ear bone referred to as the anvil
Malleus
ear bone referred to as the hammer
Stapes
ear bone referred to as the stirrup
Atlas
first cervical vertebra that supports the head by articulation with the condyles of the occipital bone
Vomer bone
flat bone that makes up the lower posterior portion of the nasal septum
Temporal bones
form the lower sides and base of cranium
Palatine bones
form the posterior part of the roof of the mouth or part of the hard palate
Zygomatic or malar bones
form the prominence of the cheek
Parietal bones
form the upper sides and roof of the cranium
Pelvic girdle
formed by the two hip bones
Sphenoid bone
forms anterior portion of the base of the cranium
Tympanic plate
forms the floor and anterior wall of the external auditory meatus
A depression or cavity in or on a bone is called a(an) _____.
fossae
Coronal suture
found where the frontal bone joins the two parietal bones
The single bone that forms the forehead, the roof of the nasal cavity, and the orbits, which are the bony sockets that contain the eyes, is the:
frontal bone
The largest and longest bone of the upper arm is the:
humerus
The only bone in the body that does not articulate with any other bones but is suspended by ligaments from the styloid process of the temporal bone is the:
hyoid bone
Foramen magnum
inferior portion of the occipital bone through which the spinal cord connects with the brain
The strongest portion of the pelvis, the bone that bears the weight of the body in the sitting position, is known as the:
ischium
The largest of the sesamoid bones is the patella, commonly known as: the _____.
kneecap
Patella
kneecap. the largest of the sesamoid bones.
The two very small, thin bones that make up part of the orbit at the inner angle of the eye are the:
lacrimal bones
Tibia
larger of the two bones forming the lower leg
Humerus
largest and longest bone of the upper arm
Squamous portion
largest part of the temporal bone
Fibula
lateral calf bone
Sagittal suture
line where the two parietal bones join superiorly
Mastoid portion
located behind and below the auditory meatus or opening of the ear; part of the temporal bone
Wormian/sutural bones
located within the sutures of the cranial bones
Meatus/canal
long tube-like passage, like the auditory meatus or canal
Ulna
longer, medial bone of the forearm
Sacral vertebrae/sacrum
lower part of the vertebral column that form the sacrum
The largest and strongest vertebrae are those of the _____ section of the spine
lumbar
Hematopoiesis
blood cell formation. known as The function of the red bone marrow is the formation of red and white blood cells and blood platelets.
Osteoclasts
bone cells present in almost all cavities of bone responsible for reabsorbing bone during remodeling
Maxillary bones
make up the upper jaw
The freely movable bone of the face is the _____ _____.
mandible bone
Yellow bone marrow
connective tissue consisting of fat cells
The highest arch of the foot, formed by the calcaneus, talus, navicular, cuneiforms, and the medial metatarsal bones, is called the:
medial longitudinal arch
Crest
narrow ridge of bone, like the iliac crest of the hip bone
The spinal cord passes through a space called the _____ _____.
neural foramen
The _____ bone is a single bone that forms the posterior base of the cranium
occipital
Hamate
one of the bones of the wrist
Navicular/scaphoid
one of the bones of the wrist; also called the scaphoid bone
Scaphoid/navicular
one of the wrist bones; also called the navicular bone
Foramen
opening in a bone through which blood vessels, nerves and/or ligaments pass
The frontal bone forms the forehead, the roof of the nasal cavity, and the _____.
orbits
Large cells that are present in the cavities of bone that function in the reabsorption of bone are known as:
osteoclasts
Bone remodeling is made possible by _____ and _____.
osteocytes, osteoclasts
Supraorbital ridge
overlies the frontal sinus and can be felt in the middle of the forehead
Gladiolus
part of the sternum bone resembling the blade of a sword
Manubrium
part of the sternum resembling the handle of a sword
Petrous part
part of the temporal bone found deep within the base of the skull where it protects and surrounds the inner ear
The largest of the sesamoid bones is the kneecap, known as the:
patella
The fibrovascular membrane that covers a bone is called the:
periosteum
An obvious bony prominence is called a(an) _____.
process
Trochlea
process shaped like a pulley on a bone, as in the trochlea of the humerus
Osteoclasts are large cells that are present in the cavities of bone that function in the _____ of bone
reabsorption
The spaces within cancellous bone contain _____ _____ _____, which are responsible for hematopoiesis
red bone marrow
Diaphysis
shaft composed mainly of compact bone
Radius
shorter, lateral bone of the forearm
Scapula
shoulder blade
The anchor bone for the cranium is the _____ _____ _____.
single sphenoid bone
Canaliculi
small canals in compact bone that connect lacunae with one another
Tubercle
small round process on a bone, like the lesser tubercle of the humerus
Fontanelle
soft spot on top of a baby's head
Osteomalacia
softening of bone
Lamella
system of membranes that connect grana in a chloroplast; 2. layer of concentric rings surrounding the Haversian canals
Phalanges
the bones of the fingers and toes
Sternum
the breastbone. It develops in three parts: the manubrium, the gladiolus and the xiphoid (ZIFF-oyd) process. The sternum resembles a sword, with the manubrium resembling the handle of the sword, the gladiolus or body forming the blade and the xiphoid process forming the tip of the sword. No ribs are attached to the xiphoid, but the manubrium and gladiolus have notches on each side for attachment of the first seven costal (rib) cartilages. The manubrium articulates with the clavicle or collarbone. Between these two points of attachment is the suprasternal or jugular notch easily felt through the skin
Epiphysis
the extremity of a long bone. The extremities or the epiphyses of the long bone have a thin covering of compact tissue overlying a majority of cancellous tissue, which usually contains red marrow. The epiphyses are usually broad and expanded for articulation with other bones and to provide a large surface for muscle attachment
Lumbar vertebrae
the five vertebrae of the lower back
Endochondral ossification
the formation of bone in a cartilagenous environment
Calcaneus
the heel
Neck
the part of a bone that connects the head or terminal enlargement to the rest of a long bone
Ethmoid bone
the principal supporting structure of the nasal cavities; forms part of the orbits
Axis
the second vertebra
Cervical vertebrae
the seven smallest vertebrae found in the neck
Mandible bone
the strongest and longest bone of the face; forms the lower jaw
Ischium
the strongest portion of a hip bone
Cuneiforms
the tarsal bones of the forefoot
Xiphoid process
the terminal portion of the sternum
Ilium
the uppermost and largest portion of a hip bone
Coccygeal vertebrae/coccyx
the vertebrae of the tailbone
Femur
thigh bone. the largest and heaviest bone of the body.
Nasal bones
thin, delicate bones that join to form the bridge of the nose
Turbinates or nasal conchae bones
thin, fragile bones found on the lateral sides of the nostrils; nasal conchae
Lacunae
tiny cavities between the lamellae or rings of compact bone that contain bone cells
Osteoprogenitor cell
undifferentiated bone cell
The iliac crest is the expanded prominence of the _____ _____ _____.
upper hip bone
Trochanter
very large projection on a bone, like the greater and lesser trochanter of the femur.
The Foramina of the Skull
If one views the skull inferiorly and observes the floor of the cranial cavity, one can observe the largest foramen of the skull, the foramen magnum. One can also observe a number of much smaller foramina or openings that penetrate the individual bones of the skull. They all have names and are passageways for blood vessels and nerves entering and exiting the various organs of the skull
Hip Joint
On the lateral side of the hip just above the obturator foramen is the deep socket called the acetabulum (ass-eh-TAB-you-lum). All three parts of the pelvic bone meet and unite in this socket. It also receives the head of the femur to help form the hip joint
Lunate
a bone of the wrist
Pisiform
a bone of the wrist
Triquetral
a bone of the wrist
Trapezium
a bone of the wrist, also called the greater multiangular
Trapezoid
a bone of the wrist, also called the lesser multiangular
Fracture
a break in a bone
Orbital margin
a definite ridge above each orbit
Glenoid fossa
a depression in the scapula for articulation with the head of the humerus
Sulcus/groove
a furrow or groove
Obturator foramen
a large opening in the hip bone for passage of nerves, blood vessels and ligaments
Lambdoid suture
a line where the two parietal bones connect with the occipital bone
Pubis
a part of the hip bone found superior and slightly anterior to the ischium
Occipital condyle
a process for articulation with the first cervical vertebra
External occipital crest
a projection of the occipital bone for muscle attachment
External occipital protuberance
a projection of the occipital bone for muscle attachment
Olecranon process
a projection of the ulna known as the funny bone
Phalanx
a single bone of a finger or toe
Occipital bone
a single bone that forms the back and base of the cranium
Frontal bone
a single bone that forms the forehead and part of the roof of the nasal cavity
Alveolus
a socket for articulation with a tooth
Cuboid
a tarsal bone of the ankle
Head
a terminal enlargement like the head of the humerus and the head of the femur
Pelvic Girdle
actually made up of two hip or coxal bones that articulate with one another anteriorly at the pubic symphysis. Posteriorly, they articulate with the sacrum. This ring of bone is known as the pelvis. It consists of the paired hip bones or coxal bones. Each hipbone consists of three fused parts: 1.the ilium (ILL-ee-um), 2.the ischium (ISS-kee-um) 3.and the pubis (PYOO-bis).
Lordosis
an abnormal accentuated lumbar curvature
Scoliosis
an abnormal lateral curvature of the spine
Talus
ankle bone
Costae
another name for ribs
Auditory ossicles
another name for the ear bones
Fossae
any depression or cavity in or on a bone. specific examples of fossae: 1.Suture 2.Foramen 3.Meatus or canal 4.Sinus or antrum 5.Sulcus
Spine
any sharp, slender projection such as the spinous process of the vertebrae
The skeleton is divided into two main parts, the _____ (which consists of the extremities) and the _____.
appendicular, axial
The first cervical vertebra, which supports the head, is called:
atlas
Processes is a general term referring to any obvious bony prominence. The following is a list of specific examples of processes.
1.Spine 2.Condyle 3.Tubercle 4.Trochlea 5.Trochanter 6.Crest 7.Line 8.Head 9.Neck
The upper extremities include the bones of the:
1.shoulder girdle 2.arm 3.forearm 4.wrist 5.hand 6.fingers
Thoracic vertebrae
12 vertebrae that connect with the ribs
Typical Vertebra
A typical vertebra has the following parts or features: The body The neural arch The articular processes The vertebral arch
Tympanic
Finally, the tympanic plate forms the floor and anterior wall of the external auditory meatus. A long and slender styloid process can be seen extending from the under surface of this plate. Ligaments that hold the hyoid bone in place (which supports the tongue) attach to this styloid process of the tympanic plate of the temporal bone
Osteon
Haversian canal
The Facial Bones
Like the bones of the cranium, the facial bones are also united by immovable sutures, with one exception: the lower jawbone or mandible. This bone is capable of movement in a number of directions. It can be elevated and depressed as in talking, and it can protract and retract and move from side to side as in chewing
More Facial Bones
Other bones also include: 1.The orbits 2.Nasal cavities 3.Foramina of the Skull 4.Hyoid Bone
_____ are the bones of the fingers and toes
Phalanges
The Ribs
The 12 pairs of ribs are also referred to as the costae. They are named according to their anterior attachments. Because the upper seven pairs articulate directly with the sternum, they are called true ribs. The lower five pairs are called false ribs. The costal cartilages of the 8th, 9th, and 10th rib pairs are attached to the cartilage of the 7th rib so they join the sternum only indirectly. Because the 11th and 12th pairs of ribs have no cartilage and do not attach at all anteriorly, these "false" ribs have another name, floating ribs. Of course, all ribs attach posteriorly to the thoracic vertebrae
Alvelolar Process
The alveolar processes bear the teeth of the upper jaw, and each tooth is embedded in an alveolus or socket
Articular Processes and Vertebral Arch
The articular processes are used for articulating with the vertebra immediately above by the two superior articular processes and with the vertebra immediately below by the two inferior articular processes.
Body and Neural Arch
The body is a thick disk-shaped anterior portion pierced with numerous small holes for nerves and blood vessels that nurture the bone. The neural arch encloses a space, the neural foramen, for passage of the spinal cord. The arch has three processes for muscle attachment: the spinous process, quite large on the thoracic vertebrae, directed backward, and two transverse processes, one on each side of the vertebra
Cranial Bones
The bones of the cranium have a number of important functions. They protect and enclose the brain and special sense organs like the eyes and ears. Muscles for mastication or chewing and muscles for head movement attach to certain cranial bones. At certain locations, air sinuses or cavities are present that connect with the nasal cavities. All of the individual bones of the cranium are united by immovable junction lines called sutures
Arches of the Foot
The bones of the foot are arranged in a series of arches that enable the foot to bear weight while standing and to provide leverage while walking. There are two longitudinal arches and one transverse arch. The medial longitudinal arch is formed by the calcaneus, talus, navicular, the three cuneiforms and the three medial metatarsals. This is the highest arch of the foot and can easily be noted. The lateral longitudinal arch is much lower and is formed by the calcaneus, the cuboid and the two lateral metatarsals. The transverse arch is perpendicular to the longitudinal arches and is most pronounced at the base of the metatarsals
Appendicular Skeleton - Lower Extremities
The bones of the lower extremities include the pelvic girdle, which supports the trunk and provides attachment for the legs. Other bones of the lower extremity include the thigh, the kneecap, the shin, the calf, the ankle bones, the foot and the toes
Shoulder Girdle
The bones of the shoulder girdle are the clavicle and the scapula. The clavicle or collarbone is a long slim bone located at the root of the neck just below the skin and anterior to the first rib. The medial end articulates with the manubrium of the sternum and the lateral end with the acromial process of the scapula. The scapula or shoulder blade is a large, flat, triangular bone located on the dorsal portion of the thorax, covering the area from the second to the seventh rib
Wrist
The bones of the wrist are called carpals. They are arranged in two rows of four each. In the proximal row from medial to lateral they are the pisiform, triquetral, lunate and scaphoid, also known as the navicular. In the distal row from medial to lateral are the hamate, capitate, trapezoid, or lesser multiangular, and the trapezuim or greater multiangular
Cervical Vertebrae
The cervical vertebrae are the smallest vertebrae. The first two have been given special names . The first is called the atlas (named after Atlas in Greek mythology who held up the world); it supports the head by articulation with the condyles of the occipital bone.
Nasal Cavities
The framework of the nose surrounding the two nasal fossae is located in the middle of the face between the hard palate inferiorly and the frontal bone superiorly
Frontal Bone
The frontal bone is a single bone that forms the forehead, the roof of the nasal cavity and the orbits, which are the bony sockets that contain the eyes. Important bone markings are the orbital margin, a definite ridge above each orbit located where eyebrows are found, and the supraorbital ridge, which overlies the frontal sinus and can be felt in the middle of your forehead. The coronal suture is found where the frontal bone joins the two parietal bones
Frontal and Palatine Processes
The frontal process extends upward to the frontal bone or forehead. The palatine process extends posteriorly in a horizontal plane to join or articulate with the palatine bone and actually forms the greater anterior portion of the hard palate or roof of the mouth
Arm
The humerus is the largest and longest bone of the upper arm. Its head is rounded and joined to the rest of the bone by its anatomic neck. The upper part of the bone has two prominences, the greater and lesser tubercles, which function as insertions for many of the muscles of the upper extremity
The Body
The large body of the maxilla forms part of the floor and outer wall of the nasal cavity, the greater part of the floor of the orbit and much of the anterior face below the temple. The body is covered by a number of facial muscles and contains a large maxillary sinus located lateral to the nose
Lumbar Vertebrae
The lumbar vertebrae are the largest and the strongest. They are modified for the attachment of the powerful back muscles
Mastoid
The mastoid portion is located behind and below the auditory meatus or opening of the ear. The mastoid process is a rounded projection of the mastoid portion of the temporal bone easily felt behind the ear. Several muscles of the neck attach to this mastoid process and assist in moving your head
Occipital Bones
The occipital bone is a single bone that forms the back and base of the cranium and joins the parietal bones superiorly at the lambdoid suture. The inferior portion of this bone has a large opening called the foramen magnum through which the spinal cord connects with the brain. On each lower side of the occipital bone is a process called the occipital condyle. These processes are significant because they articulate with depressions in the first cervical vertebra (atlas), thus allowing the head to connect with and rest on the vertebrae. Other notable markings are the external occipital crest and the external occipital protuberance, which can be felt through the scalp at the base of the neck. Several ligaments and muscles attach to these regions
The Orbits
The orbits are the two deep cavities in the upper portion of the face that protect the eyes. A number of bones of the skull contribute to their formation.
Hand and Fingers
The palm of the hand is made up of the five metacarpal bones. These are small, long bones, each with a base, shaft and a head. They radiate out from the wrist bones like the spokes of a wheel rather than being parallel. They each articulate with a proximal phalanx of a finger. Each finger, except the thumb, has three phalanges: a proximal, a middle and a terminal, or distal, phalanx. The thumb has only a proximal and distal phalanx.
Petrous
The petrous part is found deep within the base of the skull where it protects and surrounds the inner ear
Toes
The phalanges of the toes are classified as long bones despite their short length because again they have a base, shaft and head. They have the same arrangement as the phalanges of the fingers. There are two phalanges in the great toe, proximal and distal. The proximal one is large due to its weight-bearing function when walking. The other four toes have three each, proximal, middle and distal phalanges
Forefoot Bones
The rest of the forefoot bones are the metatarsals and phalanges. There are five metatarsal bones in the forefoot. Each is classified as a long bone based on shape and each has a base, shaft and a head. The heads formed at the distal ends of the metatarsals form what we call the ball of the foot. The bases of the first, second and third metatarsals articulate with the three cuneiforms; the fourth and fifth metatarsals articulate with the cuboid. The intrinsic muscles of the toes are attached to the shafts of the metatarsals. The first metatarsal is the largest due to its weight-bearing function during walking
Sacrum and Cocyx
The sacrum is a triangular and slightly curved bone. The curving coccyx can move slightly to increase the size of the birth canal during delivery in the female
Thoracic Vertebrae
The second vertebra is the axis; it acts as the pivot on which the atlas and head rotate. The thoracic vertebrae have two distinguishing characteristics: the long spinous process pointing downward and six facets, three on each side for articulation with a rib.
Ethmoid Bone
The single ethmoid bone is the principal supporting structure of the nasal cavities and helps form part of the orbits. It is the lightest of the cranial bones
Mandible Bone
The single mandible bone develops in two parts. The intervening cartilage ossifies in early childhood, and the bone becomes fused into a single continuous structure. It is the strongest and longest bone of the face. It consists of a U-shaped body with alveolar processes to bear the teeth of the lower jaw (just like the maxillary bone's alveolar processes that bear the teeth of the upper jaw). On each side of the body are the rami that extend perpendicularly upward. Each ramus has a condyle for articulation with the mandibular fossa of the temporal bone, thus allowing for the wide range of movement of the lower jawbone
Sphenoid Bone
The single sphenoid bone forms the anterior portion of the base of the cranium. When viewed from below it looks like a butterfly. It acts as an anchor binding all of the cranial bones together
Vomer Bone
The single vomer bone is a flat bone that makes up the lower posterior portion of the nasal septum
Auditory Ossicles
The six auditory ossicles are the three bones found in each ear (see Figure 7-7B): the malleus or hammer, the stapes (STAY-peez) or stirrup and the incus or anvil. These tiny bones are highly specialized in both structure and function and are involved in exciting the hearing receptors
Divisions of the Skeleton
The skeleton typically has 206 named bones. The axial part consists of the skull (28 bones, including the cranial and facial bones), the hyoid bone, the vertebrae (26 bones), the ribs (24 bones) and the sternum. The appendicular part of the skeleton consists of the bones of the upper extremities or arms (64 bones, including the shoulder girdle bones) and the bones of the lower extremities or legs (62 bones, including the bones of the pelvic girdle).
Axial Skeleton
The skull, in the correct use of the term, includes the cranial and the facial bones. We will discuss the cranial bones first
Spinal Column
The spinal column is formed from a series of 26 irregular bones called vertebrae, separated and cushioned by the intervertebral disks of cartilage
Squamous and Zygomatic Arch
The squamous portion is the largest and most superior of the four parts. It is a thin flat plate of bone that forms the temple. Projecting from its lower part is the zygomatic process that forms the lateral part of the zygomatic arch or cheek bone
The Torso or Trunk
The sternum, ribs and vertebrae make up the trunk or torso of the axial skeleton. The vertebrae are rigid and provide support for the body but the fibrocartilaginous disks between the vertebrae allow for a high degree of flexibility. The disks and vertebrae protect the delicate spinal cord contained within their articulated channels formed from successive foramina
The Thorax
The thorax or the rib cage of the body is made up of the sternum, the costal cartilages, the ribs and the bodies of the thoracic vertebrae. This bony cage encloses and protects the heart and lungs. It also supports the bones of the shoulder girdle and the bones of the upper extremities
Lacrimal Bones
The two lacrimal (LAK-rim-al) bones make up part of the orbit at the inner angle of the eye. These very small and thin bones lie directly behind the frontal process of the maxilla. Their lateral surface has a depression or fossa that holds the lacrimal sac or tear sac and provides a canal for the lacrimal duct. Tears are directed from this point to the inferior meatus of the nasal cavity after they have cleansed and lubricated the eye.
Maxillary Bones
The two maxillary bones make up the upper jaw. Each maxillary bone consists of five parts: a body, a zygomatic process, a frontal process, a palatine process and an alveolar process. The two maxillary bones join at the intermaxillary suture. This fusion is usually completed just before birth. If the two bones do not unite to form a continuous structure, the resulting defect is called a cleft palate and is usually associated with a cleft lip. With today's surgical techniques, the defect can be repaired early in the development of the child
Nasal Bones
The two nasal bones are thin and delicate bones that join in a suture to form the bridge of the nose
Palatine Bones
The two palatine bones form the posterior part of the roof of your mouth or part of the hard palate. This region is the same as the floor of the nasal cavity. Upward extensions of the palatine bones help form the outer walls of the nasal cavity
Parietal Bones
The two parietal (pah-RYE-eh-tal) bones form the upper sides and roof of the cranium. They are joined at the sagittal suture in the midline
Temporal Bones
The two temporal bones help form the lower sides and base of the cranium. Each temporal bone encloses an ear and bears a fossa for articulation with the lower jaw or mandible. The temporal bones are irregular in shape and each consists of four parts: the squamous, petrous, mastoid and tympanic parts
Turbinates (Nasal Conchae Bones
The two turbinates or nasal conchae bones are very thin and fragile. There is one in each nostril on the lateral side. They extend to but do not quite reach the bony portion of the nasal septum. They help form a series of shelves in the nasal cavity where air is moistened, warmed and filtered
Zygomatic Bones (Malar Bones)
The two zygomatic bones, also known as the malar bones, form the prominence of the cheek and rest on the maxillae. Its maxillary process joins the maxillary bone by connecting with the maxillary bone's zygomatic process. Each zygomatic bone has a frontal process extending upward to articulate with the frontal bone and a smaller temporal process that joins laterally with the temporal bone, thus forming the easily identified zygomatic arch
Forearm
The ulna is the longer, medial bone of the forearm. Its shaft is triangular, and the distal, or lower, end is called the head. At its proximal end is the olecranon (oh-LEK-rah-non) process or elbow. When banged, nerves are pressed causing the tingling sensation, which gives it the common name of "funny bone." The radius is the shorter, lateral bone of the forearm. It is joined to the ulna by an interosseus membrane traversing the area between the shafts of the two bones. They move as one. The styloid process of the radius articulates with some of the bones of the wrist
Sutural Bones
The wormian bones or sutural bones are located within the sutures of the cranial bones. They vary in number, are small and irregular in shape and are never included in the total number of bones in the body. They form as a result of intramembranous ossification of the cranial bones
Zygomatic Process
The zygomatic process extends laterally to participate in the formation of the cheek. (Processes are named according to the bone they go to; thus, the zygomatic process of the maxillary bone goes toward and joins the zygomatic or cheekbone
Structure of the Vertebral Column
There are 7 cervical vertebrae, 12 thoracic vertebrae and 5 lumbar vertebrae. These all remain separate throughout life and are referred to as movable. In addition there are five sacral vertebrae that become fused by adult life and form the single sacrum
Hyoid bone
bone that supports the tongue. The single hyoid bone is a unique component of the axial skeleton because it has no articulations with other bones. It is rarely seen as part of an articulated skeleton in a lab. Rather, it is suspended from the styloid process of the temporal bone by two styloid ligaments. Externally, you can detect its position in the neck just above the larynx or voice box a fair distance from the mandible. It is shaped like a horseshoe consisting of a central body with two lateral projections. The larger projections are the greater cornu, and the smaller lateral projections are the lesser cornu. The hyoid bone acts as a support for the tongue and its associated muscles. It also helps elevate the larynx during swallowing and speech
Sesamoid
bones enclosed in a tendon and fascial tissue, located adjacent to joints
Tarsal bones
bones of the ankle
Metacarpal bones
bones of the palm of the hand
Metatarsals
bones of the sole of the foot; form the arch of the foot
Carpals
bones of the wrist
Lacrimal bones
bones that make up part of the orbit at the inner angle of the eye; contain the tear sac
Coracoid process
bony projection on the scapula that functions as an attachment for muscles that move the arm
Acromial process
bony prominence on the scapula
When the palatine processes of the maxillary bones do not fuse properly, resulting in an opening between the oral and nasal cavities, the condition is known as:
cleft palate
Clavicle
collar bone
Kyphosis
condition commonly referred to as hunchback
Injury to Bones
A break in a bone will stimulate injured osteocytes to proliferate. They then secrete large quantities of matrix to form new bone. In addition, other types of bone cells called osteoclasts are present in almost all cavities of bone. They are derived from immune system cells and are responsible for the reabsorption of bone. These are large cells that remove bone from the inner side during remodeling, such as when a bone is broken.
Examples of Long Bones
Examples of obvious long bones are the clavicle, humerus, radius, ulna, femur, tibia and fibula. Not so obvious are those short versions of a long bone, the metacarpals of the hand, the metatarsals of the foot and the phalanges of the fingers and toes
Irregular Bones
Irregular bones are bones of a very peculiar and different or irregular shape. They consist of spongy bone enclosed by thin layers of compact bone. Examples of irregular bones are the vertebrae and the ossicles of the ears
Movement
It assists in body movement by providing attachments for muscles that pull on the bones that act as levers.
Mineral Storage
It is a storage area for mineral salts, especially phosphorus and calcium, and fats.
Blood Cell Formation
It manufactures blood cells. This process is called hematopoiesis and occurs chiefly in red bone marrow
Protection
It protects vital organs of the body such as the brain, spinal cord, the heart and lungs, and it protects other soft tissues of the body.
Support
It supports and stabilizes surrounding tissues such as muscles, blood vessels, nerves, fat and skin.
First Anatomist
Leonardo da Vinci (1452-1519), the famous Italian Renaissance artist and scientist, is credited as the first anatomist to correctly illustrate the skeleton with its 206 bones.
Ligaments
Ligaments are tough connective tissue structures that attach bones to bones like the ligament that attaches the head of the femur to the acetabulum of the pelvic bone in the hip joint
Long Bones
Long bones are bones whose length exceeds their width and consist of a diaphysis or shaft composed mainly of compact bone, a metaphysis or flared portion at each end of the diaphysis consisting mainly of cancellous or spongy bone, and two extremities, each called an epiphysis, separated from the metaphysis by the epiphyseal line where longitudinal growth of the bone occurs
_____ bones are enclosed in a tendon and fascial tissue
Sesamoid
Sesamoid Bones
Sesamoid bones are small rounded bones. These bones are enclosed in a tendon and fascial tissue and are located adjacent to joints. They assist in the functioning of muscles. The kneecap, or patella, is the largest of the sesamoid bones. Some of the bones of the wrist and ankle could also be classified as sesamoid bones as well as short bones.
Short Bones
Short bones are not merely shorter versions of long bones. They lack a long axis. They have a somewhat irregular shape. They consist of a thin layer of compact tissue over a majority of spongy or cancellous bone. Examples of short bones of the body are the carpal bones of the wrist and the tarsal bones of the foot
Types of Ossification
There are two types of ossification (the formation of bone by osteoblasts). Both types of ossification result in compact and cancellous bone: 1.Intramembranous Ossification 2.Endochondral Ossification
Muscular System
Through their tendons, muscles pull on bones, bringing about movement. Calcium from bones is necessary for muscle contraction to occur.
Yellow Bone Marrow
Yellow bone marrow is connective tissue consisting chiefly of fat cells. It is found primarily in the shafts of long bones within the medullary cavity, the central area of the bone shaft. Yellow bone marrow extends into the osteons or haversian systems, replacing red bone marrow when it becomes depleted.
Suture
articulation in which the bones are united by a thin layer of fibrous tissue. a narrow junction often found between two bones like the sutures of the skull bones.
Correct calcium ion concentration in blood and bone is maintained by _____, which stores calcium, and _____, which releases it
calcitonin, parathormone
Volkmann's/perforating canals
canals that run horizontally to the Haversian canals
Osteoblasts invade _____ and begin the process of ossification
cartilage
Osteoblasts
cells involved in the formation of bony tissue
Medullary cavity
center of the shaft of long bone filled with yellow bone marrow
An osteon, also called the _____ _____, allows for the effective metabolism of bone cells
haversian canal
Cardiovascular System
1.Blood cells transport oxygen and nutrients to bone cells and take away carbon dioxide and waste products. 2.Calcium from bones is necessary for blood clotting and normal heart functions
Reproductive System
1.Bones are a source of calcium during breastfeeding. 2.The pelvis aids in supporting the uterus and developing fetus during pregnancy in the female
Digestive System
1.Calcium, necessary for bone matrix development, is absorbed in the intestine from our daily food intake. 2.Excess calcium can be eliminated via the bowels
Respiratory System
1.Oxygen is brought into the body via the respiratory system and transported by the blood to bone cells for biochemical respiration. 2.The ribs along with the intercostal muscles and diaphragm bring about breathing
There are two types of bone marrow:
1.Red Bone Marrow 2.Yellow Bone Marrow
Lymphatic System
1.Red bone marrow produces lymphocytes, which function in our immune response
The skeleton has five general functions:
1.Support 2.Movement 3.Protection 4.Mineral Storage 5.Blood Cell Formation
Nervous System
1.The cranial bones protect the brain, and the vertebrae and intervertebral disks protect the spinal cord. 2.Receptors for pain monitor trauma to bones. 3.Calcium from bones is necessary for nerve transmission.
Endocrine System
1.The hormone calcitonin causes calcium to be stored in bones. 2.The hormone parathormone causes calcium to be released from bones. 3.Growth hormone from the anterior pituitary gland effects bone development
Urinary System
1.The kidneys help regulate blood calcium levels. 2.Excess calcium can also be eliminated via the kidneys
Integumentary System
1.Vitamin D is produced in the skin by UV light. 2.It enhances the absorption of calcium in bones for bone and tooth formation
Associated with the bones are:
1.cartilage 2.tendons 3.ligaments
Deposition of Bone
Bone develops from spindle-shaped cells called osteoblasts that develop from undifferentiated bone cells called osteoprogenitor cells. These osteoblasts are formed beneath the fibrovascular membrane that covers a bone called the periosteum. These osteoblasts are also found in the endosteum, which lines the bone marrow or medullary cavity
Volkmann's or Perforating Canals
Canals running horizontally to the haversian (central) canals, also containing blood vessels, are called Volkmann's or perforating canals. It is tissue fluid that circulates through all these canals and bathes the osteocyte, bringing in oxygen and food and carrying away waste products and carbon dioxide, keeping the osteocytes alive and healthy.
Cancellous Bone
Cancellous or spongy bone is located at the ends of long bones and forms the center of all other bones. It consists of a meshwork of interconnecting sections of bone called trabeculae (trah-BEK-you-lee), creating the spongelike appearance of cancellous bone. The trabeculae give strength to the bone without the added weight of being solid. Each trabecula consists of several lamellae with osteocytes between the lamellae just as in compact bone. The spaces between the trabeculae are filled with bone marrow. Nutrients exit blood vessels in the marrow and pass by diffusion through the canaliculi of the lamellae to the osteocytes in the lacunae
_____ bone is dense and strong, whereas _____ bone is spongy
Compact, cancellous
Growth of Bones
Deposition of bone is controlled by the amount of strain or pressure on the bone. The more strain, the greater the deposition of bone. The heel bone, or calcaneus, is a large strong bone because it receives the weight of the body when walking. Bones (and muscles) in casts will waste away or atrophy, whereas continued and excessive strain via exercise will cause the bone and muscles to grow thick and strong. This is the reason children are told to run and play to develop strong bones during their formative years. When a cast is removed, the patient participates in physical therapy to build up the bone (and muscles) that became weak while in the cast
Flat Bones
Flat bones are thin bones found whenever there is a need for extensive muscle attachment or protection for soft or vital parts of the body. These bones, usually curved, consist of two flat plates of compact bone tissue enclosing a layer of cancellous bones. Examples of flat bones are the sternum, ribs, scapula, parts of the pelvic bones and some of the bones of the skull
Maintaining Bone
In a healthy body, a balance must exist between the amount of calcium stored in the bones, the calcium in the blood and the excess calcium excreted by the kidneys and via the digestive system. The proper calcium ion concentration in the blood and bones is controlled by the endocrine system. Two hormones, calcitonin and parathormone, control the calcium concentration in our bodies. Calcitonin causes calcium to be stored in the bones; parathormone causes it to be released into the bloodstream
Location of Red Bone Marrow
In an adult, the ribs, vertebrae, sternum and bones of the pelvis all contain red bone marrow in their cancellous tissue. These bones produce blood cells in adults. Red bone marrow within the ends of the humerus or upper arm and the femur or thigh is plentiful at birth but gradually decreases in amount as we age
Intramembranous Ossification
The first type is intramembranous ossification, in which dense connective tissue membranes are replaced by deposits of inorganic calcium salts, thus forming bone. The membrane itself will eventually become the periosteum of the mature bone. Underneath the periosteum will be compact bone with an inner core of spongy or cancellous bone. Only the bones of the cranium or skull form by this process. Because complete ossification in this way does not occur until a few months after birth, one can feel these membranes on the top of a baby's skull as the soft spot or fontanelle . This allows the baby's skull to give slightly as it moves through the birth canal.
Medullary (Interior of the Shaft)
The interior of the shaft is the medullary cavity filled with yellow bone marrow. The extremities or the epiphyses of the long bone have a thin covering of compact tissue overlying a majority of cancellous tissue, which usually contains red marrow
Red Bone Marrow
The many spaces within cancellous bone are filled with red bone marrow. This marrow is richly supplied with blood and consists of blood cells and their precursors. The function of red bone marrow is hematopoiesis, or the formation of red and white blood cells and blood platelets. Therefore, blood cells in all stages of development will be found in red bone marrow. We shall discuss in more detail the different stages of blood cell development in Chapter 13
Endochondral Ossification
The other bones of the body are formed by the second process called endochondral ossification. This is the process in which cartilage is the environment in which the bone cells develop (endo = inside, chondro = cartilage). As the organic matrix becomes synthesized, the osteoblast becomes completely surrounded by the bone matrix and the osteoblast becomes a mature bone cell or osteocyte
Diaphysis (Shaft)
The shaft consists mainly of compact bone. It is thickest toward the middle of the bone because strain on the bone is greatest at that point. The strength of a long bone is also ensured by the slight curvature of the shaft, a good engineering design to distribute weight
Composition of the Skeleton
The skeletal system includes all the bones of the body and their associated cartilage, tendons and ligaments. Despite the appearance of the bones, they are indeed composed of living tissue. The hard, "dead" stonelike appearance of bones is due to mineral salts like calcium phosphate embedded in the inorganic matrix of the bone tissue.
Strength and Elasticity of Bone
The strong protein matrix is responsible for a bone's resilience or "elasticity" when tension is applied to the bone so that it gives a little under pressure. The mineral salts deposited into this protein matrix are responsible for the strength of the bone so that it does not get crushed when pressure is applied to the bone
Sinus/antrum
a cavity within a bone
Haversian/central canals
a feature of compact bone containing capillaries, also called central canals
Endosteum
a fibrovascular membrane that lines the medullary cavity of a long bone
Line
a less prominent ridge of bone than a crest
Cartilage
a type of specialized connective tissue. is the environment in which bone develops in a fetus. It is also found at the ends of certain bones and in joints in adults, providing a smooth surface for adjacent bones to move against each other
There are two types of bone tissue:
compact or dense bone, and cancellous or spongy bone. In both types of tissue, the osteocytes are the same, but the arrangement of how the blood supply reaches the bone cells is different. The two types of tissue have different functions. Compact bone is dense and strong, whereas cancellous bone has many open spaces, giving it a spongy appearance. It is in these spaces that bone marrow can be found.
Ligament
connective tissue that attaches bone to bone
Tendons
dense connective tissue that attaches muscle to bone. Tendons are similar structures that attach muscle to bone
Long bones consist of a _____ (or shaft), _____ (or flared portion) and a(n) _____ (or extremity).
diaphysis, metaphysis, epiphysis
The replacement of cartilaginous structures with bone is called:
endochondral ossification
The _____ is the membrane that lines the medullary cavity
endosteum
Trabeculae
fibrous connective tissue; extension of the capsule of a lymph node
Periosteum
fibrovascular membrane that covers a bone
Metaphysis
flared portion at each end of a long bone composed of cancellous or spongy bone
Intramembranous ossification
formation of bone by a process in which dense connective tissue membranes are replaced by deposits of inorganic calcium salts
Ossification
formation of bone by osteoblasts
Cancellous or spongy bone
forms the inner spongy tissue underneath compact bone
Compact or dense bone
forms the outer layer of bone and is very dense
Red bone marrow
found within cancellous bone; makes blood cells
Epiphyseal line
place where longitudinal growth of bone takes place
Condyle
rounded prominence found at the point of articulation with another bone. a rounded or knuckle-like prominence usually found at the point of articulation with another bone such as the lateral and medial condyle of the femur