A&P Lab 2

organic components

- The organic component of the bone matrix is called osteoid. - It contains proteoglycans, glycoproteins and collagen fibers. - Without the organic components of the matrix, the bone would be very brittle and it would break if twisted or stretched. These organic molecules, especially the collagen fibers act like reinforcing metal rods in concrete (the concrete here being the mineral salts). They provide bone with great flexibility and tensile strength (resistance to being stretch or torn apart).

proximal end of humerus

(= the head) is shaped like a smooth round ball. Its fits into the glenoid cavity of the scapula. The shape of this shoulder joint allows the arm to hang freely on the side of the body and permits a high degree of flexibility but is not as strong as the hip joint. The head of the humerus is held against the scapula by strong fibrous ligaments connecting the two bones.

coxal bone

(= pelvic or innominate or hip bones). These articulate with the sacrum behind at the sacroiliac joint, and with each other in front at the pubic symphysis

Scapula

(= shoulder blade) posteriorly. The Scapula is a roughly triangular bone lying on the posterior aspect of the rib cage and tied in to the vertebral column and ribs by a complex system of muscles.

2 transverse processes

that extend lateraly on each side.

sternal and vertebral ends

Most ribs have a double articulation with the vertebral column. Facets on the head of the rib articulate with the bodies of thoracic vertebrae. A third facet is present on the tubercle of most ribs. This articulates with the transverse process of the vertebra.

Cannaliculi

Tiny canals going to all the lacunae filled with extracellular fluid and contain the fine cytoplasmic processes (=extensitons) of the osteocytes allow the osteocytes to be connected to each other by their very fine tentacle-like cytoplasmic processes

pectoral girdle

attache the upper limbs to the axial skeleton and provide insertion points for many muscles that move the upper limbs. The pectoral girdles are loosely attached to the axial skeleton and do NOT articulate with the vertebral column or with the ribs. Each pectoral girdle, right and left, consists of two bones: - a clavicle (= collar bone) anteriorly - and a scapula (= shoulder blade) posteriorly.

What are the two major sub divisions of the skeleton?

axial skeleton appendicular skeleton

a rib is made of

1. head 2. neck 3. shaft

clavicle

(= collar bone) anteriorly The clavicle is a horizontal strut which extends laterally from its articulation with the sternum to the shoulder where it articulates with the scapula. Its function is to brace the shoulder out from the midline, thus permitting great freedom of movement at this joint. Palpate this bone on your own body. Feel its movement at the joint with the sternum as you hunch or rotate your shoulder. Simulate activities such as swimming or playing tennis, and note the degree of movement at the shoulder.

First 7 pairs of ribs

(= true ribs) are joined directly to the sternum through costal cartilages.

Osteoblasts

(Osteo =bone; blast= germ) They are derived fom osteoprogenitor cells. Osteoblasts build bones: they are also found on the surfaces of bones and bone cavities containing blood vessels and bone marrow. There, they secrete the matrix.

osteoclasts

(Osteo =bone; clast= destroy) They are located on the surfaces of bones and bone cavities containing blood vessels and bone marrow. They destroy the matrix (the destruction of bone matrix is called bone resorption). This function of the osteoclasts is important in the development, growth, maintenance and repair of bone. Osteoclasts are quite different from the other types of bones cells. They have several nuclei and are believed to be differentiated monocytes.

Osteocytes

(Osteo =bone; cyte= cell) They make the majority of the bone cells and are found embedded in the bone matrix. Osteocytes derive from osteoblasts: osteoblasts are found on the surface of bones - as they secrete matrix, they surround themselves with the material and become "walled up" in the matrix - then, they stop secreting matrix and become osteocytes. Osteocytes do not secrete bone matrix: they only maintain the matrix surrounding them in good condition.

Endosteum

(Osteo =bone; endo= inside) it is an osteogenic membrane: a delicate connective membrane containing mainly osteocytes and osteoclasts. Endosteum covers all the bones' inner cavities that contain marrow and/or blood vessels.

Periosteum

(Osteo =bone; peri= around) covers and protects the outer surface of the bones that are not covered by cartilage.The periosteum is a double layered membrane is lining the outer surface of bones. It is made of a tough outer fibrous layer (in black) and a thin inner osteogenic layer (in orange).

osteoprogenitor

(Osteo =bone; pro= precursor; genitor= produce) They are indifferentiated cells that will undergo mitosis and develop into osteoblasts. They are found on the surfaces of bones and bone cavities containing blood vessels and bone marrow.

bone tissue

*Hard* tissue that *supports and protects* softer tissues and organs. -Marrow produces RBC -Connective Tissue are made of a hard calcified matrix, and of osteocytes scattered in the matrix.

What are the classifications of bones?

- long bones, - short bones, - flat bones, - irregular bones

How can bones be classified?

- of their shape - and of the presence or not of a large cavity devoided of bone tissue right in the center of the bone.

organic and inorganic components of bone tissue

- organic components: the cells and the organic part of the matrix - inorganic components: inorganic part of the matrix: the calcium salt

1 spinous process

- that extend posteriorly. You can feel them when you run your fingers on your own spine on your back.

What are the two layers of the periosteum?

-the outer fibrous layer, a dense irregular connective tissue proper, is the protective layer; - the inner layer is delicate. It is the osteogenic layer (Osteo =bone; genic= beginning) and contains mainly osteoblasts (bone forming cells) and osteoclasts (destroyers of bone).

functions of bone

1. Support 2. Protection 3. Assist in movement 4. Site of blood cells production 5. Mineral homeostasis 6. Storage of energy

ribs

12 pairs of ribs on the skeleton. posterior side of the thorax: All articulate with the thoracic vertebrae anterior side of the thorax: The first 7 pairs (= true ribs) are joined directly to the sternum through costal cartilages. The costal cartilages of ribs 8, 9 and l0 (= false ribs) are attached to the costal cartilage of the rib immediately above. Ribs ll and l2 (= floating ribs) are not attached anteriorly.

facial bones

14 bones which support the face, bear the teeth, give protection to special sense organs (eye, nose) and provide attachment for muscles that move the jaw.

How many bones are in the human body?

206 bones

what separates the vertebrae?

24 vertebrae are separated by pads of fibrocartilage, intervertebral disks, that cushion the vertebrae and absorb shocks

cranium

8 bones which enclose and protect the brain

obturator foramen

A large opening, the obturator foramen is formed between the ischium and pubis below the acetabulum. Its chief function is to lighten the weight of the pelvis.

head of femur

A large rounded articular surface which covers the head of the femur fits into the socket formed by the acetabulum (in the pelvis). The head is united to the shaft at an angle by the neck. This is a frequent fracture site in the elderly.

scapular spine

A strong, more or less horizontal ridge extends across its posterior surface

leg vs arm function

Although the basic plan of the leg skeleton is very similar to that of the arm, there are important differences related to function. The main functions of the leg are weight bearing and propulsion of the body. Its bones are generally longer and stronger than those of the arm, and there is less flexibility in most of the joints.

glenoid cavity

Below the acromion is a shallow depression, the glenoid cavity which has a smooth surface for articulation with the humerus.

epiphyseal line

Between epiphysis and diaphysis, there is the epiphyseal line. This is a left over of the epiphyseal plate, a thin plate of hyaline cartilage separating the epiphyses from the diaphysis. The epiphyseal plate exists only in young growing long bones and aloows them to grow in length.

what can we say about bone cells because they are connective tissue?

Bone tissues are connective tissues: that means that bones cells are scattered in the matrix, far apart from each others.

What are the membranes of the bone tissue? what do they do? what do they contain?

Both external and internal bone surfaces are covered with membranes: - the periosteum and the endosteum Both membranes contain osteoblasts and osteoclasts and thus are involved in bone growth, bone repair and maintenance.

Atlas

C1 Clues to look for: 1. a round hole on the transverse processes = transverse foramen (clue to identify any cervical vertebrae). 2. no body (clue to recognise C1). This vertebra looks like a nice little ring. The first vertebra is articulated with the skull and thus it is also called Atlas by analogie to the mythological Atlas that carried the world on his shoulder. The superior articular facets are wide and articulate with the occipital condyles of the skull.

cervical vertebrae

C1-C7

axis

C2 Clues to look for: 1. a round hole on the transverse processes = transverse foramen (clue to identify any cervical vertebrae). 2. a little head on the top (clue to recognise C2). This is the odontoid process (= dens). It acts as pivot for the rotation of Atlas (=C1) and allow you to rotate your head from one side to another as in gesturing "NO".

C3-C7

Clues to look for: 1. round hole on the transverse processes (= transverse foramen) (clue to identify any cervical vertebrae); the vertebral blood vessels pass there to irrigate the brain. 2. presence of a body (clue to recognise C3-C7).

Sacrum

Clues to look for: 1. it is big, triangular. It is made of 5 fused vertebrae. 2. it contains 8 see-through holes passages for nerves and blood vessels. The anterior openings are called anterior (= ventral; = pelvic) sacral foramina and the posterior openings are called posterior (= dorsal) sacral foramina.

Coccyx

Clues to look for: 1. it is small, triangular. It is made of 4 (or in some case 3 or 4) fused vertebrae.

how do we classify bone tissue as compact or spongy?

Depending of the size, shape and distribution of the cavities, the bone tissues will be categorized as compact or spongy.

cartilaginous intervertebral disc

From the first vertebra to the sacrum , adjacent vertebrae are separated from each other by a cartilaginous intervertebral disc located between their bodies. These discs form strong joints. Because they are slightly elastic, they permit movements (the vertebral column is not a rigid rod) and they absorb vertical shocks.

how are the pectoral and pelvic girdles

Functional differences between the two pairs of limbs reflect differences in their structure and in their attachment to the appendicular skeleton.The forelimbs (arms) in man are not needed for locomotion, and hence are freed for manipulating the external environment and tools. The pectoral girdle is anchored to the appendicular skeleton only at the joint between the clavicle and sternum. This form of attachment is both weak and unstable but allows great flexibility and freedom of movement in the upper limb.In contrast the attachment of the pelvic girdle to the sacrum is strong and stable. Balance and weight transfer are enhanced by the V shaped wedge of the sacrum fitting into the more or less rigid pelvis.

central canal

Haversian canal Running through the core of an osteons and along its axis contains blood vessels and nerves.

Pelvic Girdle vs Pectoral Girdle

In contrast to the pectoral girdle which allows the upper limb a high degree of mobility, the pelvic girdle is secured to the axial skeleton by some of the strongest ligaments in the body and its sockets which articulate with the thigh bones are deep, cuplike and heavily reinforced by ligaments. This explains why we cannot move our arms and legs with the same degree of freedom.

irregular bones

Irregular bones are all the weird-shaped bones that do not belong in any other category. They do not have any cavity similar to the medullary cavity of the long bones. Irregular bones are made mostly of spongy bone tissue enclosed by a thin crust of compact bone tissue.

lumbar vertebrae

L1-L5 Clues to look for: 1. a short and stubby spinous process that projects directly posteriorly 2. the body is massive.

intervertebral foramen

Lateral openings exist between adjacent vertebrae through which the spinal nerves exit from the vertebral canal.

articulation between scapula and the vertebral column and between the scapula and the thoracic cage

Note that there is NO articulation between the scapula and the vertebral column or between the scapula and the thoracic cage.

articular portion of the epiphysis

On its outer surface, the articular portion of the epiphysis is coated with hyaline cartilage.

Illium

On the ilium locate the iliac crest, the bony ridge palpable when you place your hands on your hips. Note the large and rather rough surface for articulation with the sacrum (sacroiliac joint).

bone tissue types

Osteocytes and matrix can arrange themselves in two very different patterns to form compact bone tissue or spongy bone tissue .

T/F Osteocytes secrete bone matrix

Osteocytes do not secrete bone matrix: they only maintain the matrix surrounding them in good condition.

Bone Membranes

Other types of bones cells are found on the bone membranes lining up the outer surface of the bones as well as the bone cavities containing blood vessels and bone marrow.

rib or clavicle

Please do not mistake the clavicle for a rib.- Ribs are shape like "C" (one curvature only)- Clavicle are shaped like "S" (two curvatures)

prominent projection of the femur

Prominent projections at the proximal end of the femur (greater and lesser trochanters) serve as points of attachment for several large muscles of the buttocks and thighs; to those at the distal end (lateral and medial epicondyles) are attached the strong ligaments that bind the knee joint together.

floating ribs

Ribs ll and l2 (= floating ribs) are not attached anteriorly.

thoracic vertebrae

T1-T12 Clues to look for: 1. a long spinous process that goes down 2. two articular surfaces up and down on each lateral sides of the body. They are the costal demifacets and articulate with the heads of the ribs. All thoracic vertebrae, except the last two bear facets on their transverse processes. These facets articulate with the tubercles of the ribs.

foot

The Bones of the Foot consist of 7 tarsal bones in the posterior and middle portions of the foot, and 5 metatarsals and 14 phalanges in the anterior portion.

thigh

The Femur is the sole bone of the thigh. It is the largest and longest bone in the body. It articulates proximally with the pelvis and distally with the tibia of the leg.

Humerus

The Humerus is the sole bone of the arm.It is the longest and largest bone of the upper limb. It articulates proximally with the scapula and distally with both the radius and the ulna

kneecap

The Patella or kneecap is a small bone which forms in the tendon of the large flexor muscle on the anterior surface of the thigh where it crosses the knee joint to insert on the tibia. It functions to protect the joint, and to strengthen and improve the leverage of the tendon. Note the twin articular surfaces (= facets) on its posterior aspect. These slide on the distal end of the femur. It does NOT articulate with the tibia or the fibula.

Radius

The Radius is the shorter bone of the forearm, and lies on the lateral (thumb) side. The lozenge shaped head has a smooth circular band running around it. This is the surface for articulation with the ulna. As the hand is pronated (turned palm down), the proximal end of the radius rotates, and the distal end pivots around the ulna. Observe this movement in your own arm as you change the position of the hand. The radius articulates with the capitulum of the humerus.

leg

The Tibia and Fibula are the two bones in the leg. The more massive tibia lies medial to the slender fibula. Only the tibia articulates with the femur at the knee. Both bones participate in the ankle joint and articulate with the talus. . The tibia and the fibula articulate also with each other proximally and distally at the tibiofibular joints. They are also connected throughout their entire lenght by an interosseous membrane (a tough, flexible fibrous membrane).

ulana

The Ulna is the longer of the two bones in the forearm. Its proximal end looks like a hook: identify the 2 proeminent processes, the olecranon process and the coronoid process separated by a deep concavity: the trochlear notch. This concavity articulates with the trochlea of the humerus and allows only flexion and extension of the forearm. The Olecranon process forms your elbow. Palpate the olecranon process at your elbow and trace the course of the ulna to the wrist.

distal end of humerus

The articular surface at the distal end of the humerus is complex. The three fossae (depressions) on either side of the distal end (coronoid, olecranon and radial) accommodate projections on the ulna and radius when the elbow is flexed or extended.The pulley-shaped trochlea articulates with the ulna and the ball-shaped capitulum articulates with the radius.

What makes up the axial skeleton? what does it support?

The bones of the axial skeleton are the bones that form the axis of the body: they are - the bones of the skull (including the auditory ossicles and the hyoid bone), - the bones of the thorax (the ribs and the breastbone) - the bones of the vertebral column. The axial skeleton supports the head, the neck and the trunk and protects the brain, the spinal cord and the organs in the thorax (lungs, heart, big blood vessels).

osteons

The bulk of the compact bone tissue is made of these cylindrical units they are made of arranged in circles and concentric layers of bone matrix (= concentric lamellae )

carpus

The carpus (wrist) consists of 8 carpal bones arranged in two rows of 4. These bones are small and irregular in shape. They articulate with each other, with the radius proximally, and with the metacarpals distally.

compact bone tissue is made of

The compact bone tissue is made mostly of bone matrix deposited in layers 3-7 micrometers thick. These layers of bone matrix are called lamellae The bulk of the compact bone tissue is made of cylindrical units: the osteons

false ribs

The costal cartilages of ribs 8, 9 and l0 are attached to the costal cartilage of the rib immediately above.

radius and wrist

The distal end of the radius articulates with the carpal bones of the wrist and with the ulna.

ankle joint

The distal ends of the tibia and fibula together form a flat topped arch which encloses the talus (one of the tarsal bones) so as to permit free movement in one plane (dorsiflexion and plantar flexion), but limited movement from side to side (inversion and eversion). Distal projections on the medial side of the tibia and the lateral side of the fibula help to stabilize the joint and form the prominent projections palpable on either side of the ankle (medial and lateral malleoli).

ends of the femurs

The ends of both femurs are farther apart from the midline of the body at the hip than at the knee. The long shafts do not go down straight but angles medially as they descend toward the knee. This allows the knee joint to be closer to the body's center of gravity and provide for a better balance

distal end of femur

The expanded distal end of the femur has an irregular articular surface. Its lateral and medial condyles both articulate with the tibia of the leg (NOT with the fibula). Between these anteriorly is the smooth articular surface for the patella (= patellar surface).

Fibula

The fibula does not reach the femur but articulates with the tibia at both its proximal and distal ends. Movement between these bones is limited. Compare with the upper limb. Its lower end is the distal malleolus that forms the big lateral ankle bulge.

form of the pelvis

The form of the pelvis reflects the functions of the lower limbs. Note the triangular shape of the sacrum which is wedged between the pelvic bones, thus transmitting weight from the vertebral column laterally to the head of the femur. The latter bone articulates with the pelvis in a deep cup shaped socket, the acetabulum. This cup faces down and forward. Its superior and posterior walls are stronger and heavier than those on the opposite sides, reinforcing the joint for the transmission of weight (from above) and for the propulsive thrust of the legs in walking (from in front).

skeletal system

The framework of bones and cartilage that provides support, protects our organs and allows us to move consists of several types of connective tissue: cartilage, bone, red and yellow bone marrow, the periosteum, and the endosteum

types of lamellae in compact bone

The lamellae of compact bone are disposed in three different patterns 1. the concentric lamellae 2. the interstitial lamellae 3. the circumferential lamellae

pubis

The main feature of the pubis is the articular surface of the pubic symphysis

metatarsals and phalanges

The metatarsals and phalanges are similar to corresponding bones in the hand in number and position.

pelvic girdle

The pelvic girdle attaches the lower limbs to the axial skeleton, transmits the weight of the upper body to the lower limbs, and supports the visceral organs of the pelvic cavity.

what bones make up the pelvic girdle

The pelvic girdle consists of the two coxal bones (= pelvic or innominate or hip bones). These articulate with the sacrum behind at the sacroiliac joint, and with each other in front at the pubic symphysis. Together with the sacrum the pelvic bones enclose a cavity, the pelvis, through which pass the terminal portions of both the digestive and the urinogenital systems.

How is the periosteum attached, supplied, etc?

The periosteum is anchored to the bone with strands of collagen fibers (=Sharpey's fibers) that extend from its fibrous layer into the bone matrix.The periosteum is supplied with nerve, blood and lymphatic vessels that penetrate into the bones.The outer periosteum has to be tough because it is subjected to a lot of pulling: it is connected to tendons, ligaments and the fibrous layer of the articular capsule in synovial joints.

Phalanges

The phalanges are the bones of the digits. There are 3 bones in each of the fingers, and two in the thumb. The terminal phalanx in each digit is spade shaped, providing a broad base to support the soft tissue of the finger tips.

Acromion

The scapular spine terminates laterally in a prominent projection, the acromion which articulates with the clavicle. Palpate the scapular spine on a friend's back, and locate the joint between the acromion and the clavicle.

shape of the pelvis and sexual differences

The shape of the pelvis shows distinct sexual differences.In general the female pelvis is lighter, shallower and wider than that of the male, and the pelvic outlet is larger, and oval rather than heart shaped. There are also sexual differences in the shape of the sacrum: in the female it is wider and shorter.

coracoid

The short hook like process medial to the glenoid fossa is the coracoid. It is firmly anchored to the clavicle by ligaments and serves as an important base for the attachment of muscles of the arm.

forearm

The skeleton of the forearm is formed by two parallel long bones: the ulna and the radius.Their proximal articulation is with the humerus and their distal articulation is with the bones of the wrist.The radius and the ulna articulate also with each other proximally and distally at the radioulnar joints. They are also connected throughout their entire lenght by an interosseous membrane (a tough, flexible fibrous membrane).

tarsal bones

The tarsal bones, often called 'ankle bones', articulate with the bones of the leg and form the skeleton of the heel and mid portion of the foot. Identify the talus with its articular surface and the large calcaneus which projects backwards to form the heel.

Thoraccic cage

The thorax (ribs and sternum), together with the thoracic vertebrae, form the thoracic cage. This structure encloses and protects the heart and lungs, and supports the shoulder girdle. The respiratory muscles are attached to it, and it forms a rigid box within which the lungs are inflated.

tibia

The tibia is the shin bone. It may be palpated throughout its length on the front of the leg from the knee to the medial side of the ankle.It transmits the weight of the body to the foot. Examine its proximal end, and note two nearly separate, shallow, smooth depressions (= medial and lateral condyles) which articulate with the femur. Just distal to these on the anterior surface is a low vertical ridge (= tibial tuberosity) to which the strong ligament of the patella attaches.Note also the inferior projection, the medial malleolus that forms the inner bulge of the ankle and articulates with the talus.

ulna and the wrist

The ulna approaches the wrist on the side of the little finger. Distally, the ulna does not articulate with the wrist directly, but it does articulate with the radius.

What are the types of vertebrae?

The vertebral column is composed of 33 vertebrae:- 7 cervical vertebrae: C1 - C7- 12 thoracic vertebrae: T1 - T12- 5 lumbar vertebrae: L1 - L5- 5 fused vertebrae: the sacrum- 4 fused vertebrae: the coccyx.

upper limbs

There are 30 bones in each forelimb distributed as follows: - upper arm: humerus (1) - forearm: radius (1) and ulna (1) - wrist: carpals (8) - palm: metacarpals (5) - digits (= thumb and fingers): phalanges (s. phalanx) (14)

lower limbs

There are 30 bones in each hind limb distributed as follows:- thigh: femur (1)- knee: patella (1)- leg: tibia (1) and fibula (1)- ankle: tarsals (7)- foot: metatarsals (5)- digits: phalanges (14)

Metacarpals

There are 5 metacarpals supporting the palm, one associated with each digit. The four associated with the fingers articulate proximally with each other as well as with the carpal bones.

sacral hiatus

There is a gap in the middle of the posterior part of the arch of the 5th sacral vertebrae. This means that there is an entrance to the vertebral canal. This entrance is called the sacral hiatus. Epidural anesthesia are injected in the sacral hiatus or in the posterior sacral foramina.

inorganic components of the matrix

They are mineral salts, mainly Hydroxyapatite (a cristallized form of tricalcium phosphate), some calcium carbonate, and small amount of magnesium hydroxide, fluoride and sulfate. - They give the bone its characteristic that makes it unique among all the other tissues: an exceptional HARDNESS which allows it to resist compression.- -Mineral salts are abundants: they make 65% of the bone mass and nearly 2/3 of the matrix.

perforating canals

Volkmann's canals lie perpendicular to the haversian canals. Perforating canals connect blood vessels and nerves of the central canals with those outside the bone and with those inside the medullary cavity and inside the cavities of the spongy bone tissue

What allows us to balance on two feet?

We stand and move about on two legs, and our hands and arms are free for other activities. Being bipedal, however, creates problems with respect to balance. The weight of the body must remain centered over the feet, or we fall over. The double S curve of the human vertebral column does just this, and reduces the muscle action required to maintain balance to a minimum. These curvatures also increase the strength, resilience and flexibility of the spine, making it function like a spring rather than as a rod. At birth the vertebral column is arched as in quadrupeds. At approximately the third month after birth, when the infant begins to hold its head erect, the cervical curve develops. Later, when the child sits up, stands and walks, the lumbar curve develops.

dry bones

all the organic matter is gone. Only the calcified matrix (the bone stuff) is left.

sesamoid bones

are a special brand of short bones: they are embedded within a tendon and act to alter its direction of pull. They differ in size, shape and quantity from an individual to another.

spongy bone

cancellous bone consists of an irregular latticework of thin blades of bone called trabeculae. The spaces between the trabeculae contain blood vessels and red marrow which produces blood cells. The spaces between the trabeculae can be seen with naked eye and give spongy bone tissue its "spongy" look.

curves of the vertebral column

cervical, thoracic, lumbar, sacral

appendicular skeleton

consisting of the limb bones and the girdles which anchor the limbs to the axial skeleton. Most ribs have a double articulation with the vertebral column. Facets on the head of the rib articulate with the bodies of thoracic vertebrae. A third facet is present on the tubercle of most ribs. This articulates with the transverse process of the vertebra.

axial skeleton

consisting of the skull, vertebral column, ribs and sternum;

skull

consists of 29 bones. These may be considered in 3 functional groups: 1. cranium 2. facial bones 3. others

short bones

cubelike. They do not have any cavity similar to the medullary cavity of the long bones. Short bones are made mostly of spongy bone tissue, but their outer parts are made of a thin crust of compact bone tissue.

posterior sacral foramina

dorsal rami of sacral spinal nerves emerge here

epiphyses

expanded ends of bones that form joints with adjacent bones covered by a thin layer of compact tissue. Their interior contains spongy bones and red marrow.

vertebral column function

extends from the skull to the pelvis and forms the major axial support of the body. It functions to support the head, trunk and arms, and to transmit the weight of these parts to the legs through the pelvic girdle. Additionally, it surrounds and protects the fragile spinal cords while allowing the spinal nerves to issue from the cord via opening between adjacent vertebrae.

fine cytoplasmic processes

extensions of the osteocytes in the canaliculi

yellow marrow

fat

the interstitial lamellae

fill the spaces between osteons

Diaphysis

has a thick wall made of compact tissue surrounding a central cavity (= medullary cavity) containing yellow marrow (=fat).

endosteum

is colored in green. It is lining the outside of the trabeculae and the wall of the Haversian and Volkmann's canals.

vertebral column physiology

is far from being a rigid supporting rod: 24 single bones (vertebrae) and 2 composite, or fused, bones (the sacrum and coccyx) are connected in such a way as to provide a flexible curved structure.

sacral canal

is the sacral part of the vertebral canal.

ischium

is the strongest component of the pelvic bone. Note the large ischial tuberosity on which the weight of the body rests when sitting, thus resting the legs.

neck of the rib

it is a constricted portion between the head and the shaft. It contains a knoblike structure (= the tubercle) on its posterior surface near its junction with the shaft,

head of the rib

it is a projection at the posterior end of the rib and it joints with the thoracic vertebrae,

arch of vertebrae

it is attached to the posterior part of the body. Arch and posterior part of the body form a ring that surrounds and protects the spinal cord. The space (between the body and the arch) that contains the spinal cord is called the vertebral foramen. The vertebral foramina of all the vertebrae of the vertebral column form the vertebral canal.

shaft of the rib

it makes most of the rib.

lacunae

little chambers osteocytes lie in

In the child the pelvic girdle consists of 3 pairs of

of separate bones, a superior element (the ilium) and two inferior elements, the ischium posteriorly and the pubis anteriorly. All three bones meet within the acetabulum. These bones fuse during adolescence to form the single coxal bone on either side characteristic of the adult.

spongy bone tissue

one that looks like swiss cheese or like a sponge (the cheese stuff and sponge stuff being the bone stuff) located inside bones. does not contain osteons. It consists of layers of bone matrix (= lamellae M) arranged in an irregular latticework of thin plates of bone called trabeculae. The spaces within the trabeculae are filled with red bone marrow and blood vessels. These blood vessels are connected to blood vessels found in the Volkman's and haversian canals.

compact bone

one that looks more dense, more compact It makes the outer part of bones. consists of precise arrangements of microscopic cylindrical structures called osteons. The matrix and osteocytes of osteon are laid down in concentric rings around a central (Haversian) canal that contains blood vessels and nerve. If you look at compact bone tissue with naked eye, it look very dense: you cannot see any cavities in it.

anterior sacral foramina

openings on the anterior side of the sacrum

Sternum

or breast bone is divided into 3 portions: the superior manubrium, the middle body and the inferior xiphoid process. The articular surface (= clavicular notch) for the clavicle (collar bone) is located laterally on its superior edge. The first 7 ribs articulate with the sternum through costal cartilages

Types of bone cells

osteoprogenitaors,osteocytes, osteoblasts, osteoclasts

flat bones

platelike. They are thin and do not have any cavity similar to the medullary cavity of the long bone the outer part of a flat bone is made of a layer of spongy bone tissue sandwiched between two layers of compact bone tissue.

olecranon process

projection at the upper end of the ulna that forms the bony point of the elbow

concentric lamellae

re arranged concentrically around longitudinal vascular channels to form the osteons (= cylindrical units of the compact bone tissue H); they have been colored to differentiate them easily from the two other types of lamellae.

connective tissue proper loose reticular

red marrow

thorax

ribs and sternum

circumferential lamellae

run around the circumference of the bone. The inner circumferential lamellae are located on the inner side of the compact bone tissue and the outer circumferential lamellae are located on the outside.

Sharpey's fiber

secure periosteum to underlying bone strands of collage fibers

Lacunae

small cavities in bone that contain osteocytes

What coves a long bone?

the long bone is entirely covered by the periosteum except where the articular cartilage coats the epiphysis.The endosteum covers the surface of the medullary cavity, the trabeculae of the spongy bone tissue and covers the wall of the various canals that pass through the compact bone.

other bones in the skull

the single hyoid bone which supports the larynx (voice box), and 3 pairs of ear ossicles in the middle ear which transmit sound waves to the inner ear.

long bone

their length is superior to their width consist of a shaft (= diaphysis) and two expanded ends (= epiphysis, plural: epiphyses) that articulate with other bones.

Seven processes

they arise from the arch 2 transverse, 1 spinous, 4 articular (2 superior articular processes and 2 inferior articular processes)

2 inferior articular processes

they extend downward and articulate with the vertebra immediately inferior to them.

2 superior articular processes

they extend upward and articulate with the vertebra immediately superior to them.

body of vertebrae

thick disc-shaped anterior part of the vertebra. It is the weight bearing part of the vertebra. As you go down the vertebral column, the body of the vertebrae will get thicker because the weight that those vertebrae have to bear increases.

T/F Bone tissue differs from all other connective tissues

true bc of inorganic and organic compounds Roughly, the matrix is about 20% water, 20% protein and 60% mineral salts.

lateral metacarpals

which is associated with the thumb, is more freely movable and articulates only with the carpus. Free movement at this joint permits opposition of the thumb and fingers so that objects may be grasped in the hand.