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The Skeletal System
The Skeletal SystemThe Skeletal System Parts of the skeletal system
Bones (skeleton) – 20% of your body mass
Joints – junction of 2 or more bones
Cartilages - connective tissue
Ligaments – fasten bone to bone
Divided into two divisions
Axial skeleton – skull, spine and thorax
Appendicular skeleton – limbs & girdles
5 Functions of Bones5 Functions of Bones
Support of the body
Protection of soft organs
Movement due to attached skeletal muscles
Storage – Ca & P also K, Na, S, Mg, and Cu as well as adipose tissue
Blood cell formation - hematopoiesis
Bones of the Human BodyBones of the Human Body
The skeleton has 206 bones
Two basic types of bone tissue
Compact bone
Dense
Homogeneous
Spongy bone
Small needle-like pieces of bone
Many open spaces
Figure 5.2b
4 Classifications of Bones 4 Classifications of Bones Long bones
Typically longer than wide
Have a shaft with heads at both ends
Contain mostly compact bone
• Examples: Femur, humerus, bones of fingers
Classification of BonesClassification of Bones
Short bones
Generally cube-shape
Contain mostly spongy bone
Examples: Carpals, tarsals
Classification of BonesClassification of Bones
Flat bones
Thin and flattened
Usually curved
Thin layers of compact bone around a layer of spongy bone
Examples: Skull, ribs, sternum
Classification of BonesClassification of Bones
Irregular bones
Irregular shape
Do not fit into other bone classification categories
Example: Vertebrae and hip
Gross Anatomy of a Long BoneGross Anatomy of a Long Bone Diaphysis
Shaft – surrounds the medullary cavity
Composed of compact bone
Epiphysis
Ends of the bone
Composed mostly of spongy bone
Bulbous shape provides space for muscle attachment.
Figure 5.2a
Medullary cavity
Center of long bones
Contains yellow marrow (mostly fat) in adults
Contains red marrow (for blood cell formation) in infants
Figure 5.2a
Gross Anatomy of a Long BoneGross Anatomy of a Long Bone
• Epiphysis Line
• Found in adult bones
• Thin line of bony tissue spanning the epiphysis
• Epiphyseal plate
• Cartilage in young bone between the diaphysis and the epiphysis for long bone lengthening
• AKA : Growth Plate
Gross Anatomy of a Long BoneGross Anatomy of a Long Bone
Periosteum
Outside covering of the diaphysis
Contains nerves, blood vessels, lymph vessels
Fibrous connective tissue membrane contains osteoblasts
Sharpey’s fibers
Secure periosteum to underlying bone
Figure 5.2c
• Arteries - Supply bone cells with nutrients
Gross Anatomy of a Long BoneGross Anatomy of a Long Bone
Endosteum
Membrane in medullary cavity
Contains osteoclasts and osteoblasts
Figure 5.2c
• Arteries - Supply bone cells with nutrients
Gross Anatomy of a Long BoneGross Anatomy of a Long Bone
Slide 5.8a
Articular cartilage
Covers the external surface of the epiphyses
Made of hyaline cartilage
Decreases friction at joint surfaces
Figure 5.2a
Gross Anatomy of a Long BoneGross Anatomy of a Long Bone
• Hematopoiesis – blood cell formation
• Occurs in red marrow cavities of spongy bone
• Red Marrow Cavities
• Newborn
• Medullary cavity and all cavities of spongy bone contain red bone marrow.
• Most Adults
• Confined to the cavities of spongy bone of flat bones and medullary cavity of some long bones
Gross Anatomy of a Long BoneGross Anatomy of a Long Bone
Bone MarkingsBone Markings Table Table 5.15.1
Surface features of bones
Sites of attachments for muscles, tendons, and ligaments
Passages for nerves and blood vessels
Categories of bone markings
Projections and processes – grow out from the bone surface
Depressions or cavities – indentations
• On a separate sheet of paper and with a group, examine a collection of bones and determine their type (long, short, flat, irregular), their location, and name any bone markings.
• Make a data table and describe each bone.
Bone MarkingsBone Markings Table Table 5.15.1
Bone Type Location Markings
• What do you remember about this picture?
• What makes it a connective tissue?
Microscopic Anatomy of BoneMicroscopic Anatomy of Bone
Microscopic Anatomy of BoneMicroscopic Anatomy of Bone Bone consists of a few different types of cells
Osteoblasts – bone building
Osteocytes – mature bone cells
Osteoclasts – bone destroying
Microscopic Anatomy of BoneMicroscopic Anatomy of Bone Osteoblasts – bone building
Found in periosteum and endosteum
Secrete matrix
Microscopic Anatomy of BoneMicroscopic Anatomy of Bone Osteocytes – mature bone cells
Osteoblasts that have become trapped in lacunae
Maintain the bone tissue
Microscopic Anatomy of BoneMicroscopic Anatomy of Bone Osteoclasts – bone destroying
Giant cells that participate in bone resorption
Mainly found in endosteum
Microscopic Anatomy of BoneMicroscopic Anatomy of Bone Bone also is made up of a hard matrix
Organic Component: collagen fibers and other organic materials
Inorganic component: 2 salts: calcium phosphate and calcium hydroxide form hydroxyapatite.
Microscopic Anatomy of BoneMicroscopic Anatomy of Bone The tissue consists of many units working together
Osteon (Haversian System)
A unit of microscopic bone; concentric circle & matrix rings
Microscopic Anatomy of BoneMicroscopic Anatomy of Bone Osteon (Haversian System)
Cells = osteocytes
Matrix = lamellae
Microscopic Anatomy of BoneMicroscopic Anatomy of Bone Each Osteon contains:
Central (Haversian) canal
Opening in the center of the osteon
Carries blood vessels and nerves
Microscopic Anatomy of BoneMicroscopic Anatomy of Bone Each Osteon contains:
Lacunae
Cavities containing bone cells (osteocytes)
Arranged in concentric rings
Lamellae
Rings around the central canal
All collagen fibers run in the same direction
Figure 5.3
Microscopic Anatomy of BoneMicroscopic Anatomy of Bone
Each Osteon contains:
Canaliculi
Tiny canals
Radiate from the central canal to lacunae
Form a transport system
Microscopic Anatomy of BoneMicroscopic Anatomy of Bone Each Osteon contains:
Volkmann’s canal
Canal perpendicular to the central canal
Connect blood vessels and nerves of periosteum to Haversian canal
• Make a concept map of the microscopic structure and anatomy of a long bone. Each section should be connected with a phrase. For example, osteon = contains osteocytes and lacunae
Microscopic Anatomy of BoneMicroscopic Anatomy of Bone
Osteon
Osteocytes Lamellae
Contains cells and matrix
Changes in the Human SkeletonChanges in the Human Skeleton
In embryos, the skeleton is primarily hyaline cartilage
During development, much of this cartilage is replaced by bone
Cartilage remains in isolated areas
Bridge of the nose
Parts of ribs
Joints
Bone GrowthBone Growth
Epiphyseal plates allow for growth of long bone during childhood
New cartilage is continuously formed
Older cartilage becomes ossified
Cartilage is broken down
Bone replaces cartilage
Hormonal Effects on Bone
• Growth hormone, produced by the pituitary gland, and thyroxine, produced by the thyroid gland, stimulate bone growth.
• GH stimulates protein synthesis and cell growth throughout the body.
• Thyroxine stimulates cell metabolism and increases the rate of osteoblast activity.
Hormonal Effects on Bone
• At puberty, the rising levels of sex hormones (estrogens in females and androgens in males) cause osteoblasts to produce bone faster than the epiphyseal cartilage can divide. This causes the characteristic growth spurt as well as the ultimate closure of the epiphyseal plate.
• Estrogens cause faster closure of the epiphyseal growth plate than do androgens.
• Estrogen also acts to stimulate osteoblast activity.
Hormonal Effects on Bone
• Parathyroid hormone and calcitonin are 2 hormones that antagonistically maintain blood [Ca2+] at homeostatic levels.
• Since the skeleton is the body’s major calcium reservoir, the activity of these 2 hormones affects bone resorption and deposition.
Growth in Bone Length
• Epiphyseal cartilage (close to the epiphysis) of the epiphyseal plate divides to create more cartilage, while the diaphyseal cartilage (close to the diaphysis) of the epiphyseal plate is transformed into bone. This increases the length of the shaft.
•As a result osteoblasts begin producing bone faster than the rate of epiphyseal cartilage expansion. Thus the bone grows while the epiphyseal plate gets narrower and narrower and ultimately disappears. A remnant (epiphyseal line) is visible on X-rays (do you see them in the adjacent femur, tibia, and fibula?)
At puberty, growth in bone length is increased dramatically by the combined activities of growth hormone, thyroid hormone, and the sex hormones.
Bone FracturesBone Fractures
A break in a bone
Types of bone fractures
Closed (simple) fracture – break that does not penetrate the skin
Open (compound) fracture – broken bone penetrates through the skin
Bone fractures are treated by reduction and immobilization
Realignment of the bone
Common Types of FracturesCommon Types of Fractures
Repair of Bone FracturesRepair of Bone Fractures
Hematoma (blood-filled swelling) is formed
Break is splinted by fibrocartilage to form a callus
Fibrocartilage callus is replaced by a bony callus
Bony callus is remodeled to form a permanent patch
Stages in the Healing of a Bone Stages in the Healing of a Bone FractureFracture
Figure 5.5
Fracture Repair
• Step 1:
A. Immediately after the fracture, extensive bleeding occurs. Over a period of several hours, a large blood clot, or fracture hematoma, develops.
B. Bone cells at the site become deprived of nutrients and die. The site becomes swollen, painful, and inflamed.
• Step 2:A. Granulation tissue is formed as the hematoma is
infiltrated by capillaries and macrophages, which begin to clean up the debris.
B. Some fibroblasts produce collagen fibers that span the break , while others differentiate into chondroblasts and begin secreting cartilage matrix.
C. Osteoblasts begin forming spongy bone.
D. This entire structure is known as a fibrocartilaginous callus and it splints the broken bone.
• Step 3:
A. Bone trabeculae increase in number and convert the fibrocartilaginous callus into a bony callus of spongy bone. Typically takes about 6-8 weeks for this to occur.
Fracture Repair
• Step 4:A. During the next several months, the bony callus is continually
remodeled. B. Osteoclasts work to remove the temporary supportive structures
while osteoblasts rebuild the compact bone and reconstruct the bone so it returns to its original shape/structure.
What kind of fracture is this?It’s kind of tough to tell, but this is a _ _ _ _ _ _ fracture.
AXIAL SKELETONAXIAL SKELETON
• Forms the longitudinal part of the body
• 80 bones; Divided into three regions
1. Skull
2. Vertebral column
3. Bony thorax
• Protect brain, spinal cord, and organs within the thorax
The Axial SkeletonThe Axial Skeleton
The Skull
THE SKULL
• 22 bones
• Divided into Cranial & Facial bones:
• Cranial- Attachment for head muscles and protect brain
• Facial- form framework for the face
• 1. hold eyes forward
• 2. provide cavities for special sense organs (taste and smell)
• 3. secure teeth
• 4. anchor the facial muscles
Bones of the Cranium
The Skull – Cranium Bones• Frontal bone
• Parietal bones
• Meet in the midline of the skull at the sagittal suture
• Occipital Bone
• Foramen magnum “large hole”
• Occipital condyle on either side of foramen articulates with 1st vertebrae- lets nod !
Frontal View
Frontal
Frontal View
Parietal
Frontal View
Temporal
Frontal View
Nasal
Frontal View
Vomer
Frontal View
Zygomatic
Frontal View
Maxilla
Frontal View
Mandible
Frontal View
FrontalParietal
Temporal
Zygomatic
Nasal
Vomer
Maxilla
Mandible
Frontal View
The Skull - Cranium Bones• Temporal bones = “time”
• External Auditory Meatus – canal that lead to the eardrums and middle ear.
• Mastoid process- anchoring site for neck muscles, lump behind ear, less prominent in females than males
• Styloid process- attachment for muscles in neck and ligaments
• Zygomatic Process- attachment site for some muscles of the neck
• Jugular Foramen – allows jugular vein to pass through; which drains the brain
• Carotid Canal – through which internal carotid artery runs, supply blood to the brain.
The Skull - Cranium Bones• Sphenoid-
• looks like a bat, butterfly; inside of the skull
• Foramen Ovale – allows fibers of cranial nerve V to pass to the chewing muscles of the lower mandible.
• Air cavities that fill the sphenoid bone are called sphenoid sinuses
Lateral View
Frontal
Lateral View
Parietal
Lateral View
Temporal
Lateral View
Nasal
Lateral View
Zygomatic
Lateral View
Maxilla
Lateral View
Mandible
Lateral View
Sphenoid
Lateral View
Occipital
Lateral View
Mastoid Process
Lateral View
External Auditory Meatus
Lateral View
Frontal
Nasal
ZygomaticMaxilla
Mandible
Parietal
Sphenoid
Temporal
Occipital
External Auditory Meatus
Mastoid Process
Lateral View
The Skull
• Most bones are flat bones
• Contain interlocking joints called SUTURES
• There are 4 types of sutures:
1. Coronal - frontal bone meets parietal
2. Sagittal- parietal bones are paired, separated
3. Squamous-parietal bone meets temporal bone
4. lambdoidal -parietal bones meet occipital bone
Sutures
Sagittal
Sutures
Frontal(Coronal)
Sutures
Squamous
Sutures
Lambdoid
Sutures
Frontal(Coronal)
Sagittal
Squamous
Lambdoid
Sutures
FACIAL BONES• 14 bones form the lower front of the skull and provide
the framework for most of the face.
• 12 of those bones are paired; Mandible & Vomer are single
1. Mandible - strongest, largest bone in the face (lower jaw)
2. Maxillae - upper jaw
3. Palatine bones – form posterior part of the hard palate.
4. Zygomatic bones = cheekbones
FACIAL BONES FACIAL BONES (Continued) (Continued)
6. Nasal bones - fused medially, form bridge of nose
• Lower part of nose is made of cartilage
7. Lacrimal bones
• very small within orbit (eye-socket)
8. Hyoid
• Only bone in the entire body that does not articulate to another bone
• Not really part of the skull, but is closely related to the mandible and the skull.
• Serves as movable base for the tongue
• Attachment point for several muscles in the neck, elevates larynx during speech and swallowing
• Anchored by ligaments attached to styloid processes of temporal bones
Bones of the SkullBones of the Skull
Slide 5.22Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 5.11
Human Skull, Superior ViewHuman Skull, Superior View
Slide 5.23Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 5.8
Human Skull, Inferior ViewHuman Skull, Inferior View
Slide 5.24Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 5.9
Pasanasal Sinuses• Clustered around nasal cavity
• Lighten the skull & Enhance resonance of voice
• Air enters sinuses from nasal cavity; mucous from sinuses drips to nasal cavity
VERETBRAL COLUMN• AKA the spine
• 70 cm= 28 inches long in average adult
• 26 irregular bones connected so the flexible, curved spine is formed
• Extends from the skull to pelvis
• Spinal cord runs through the central canal
• Attachment points for ribs and muscles
• 33 in fetus and infant- 9 fuse to form sacrum and coccyx
• Remaining 24 act as separate vertebrae with connective tissue discs in between each
• Ligaments and trunk muscles hold column in place
• Intervertebral discs- cushion-like pads- shock
Vertebral Column • 5 major divisions:
• 7 cervical
• 12 thoracic (1 per each pair of ribs)
• 5 lumbar
• sacrum, coccyx (tiny)
• about 5% of otherwise normal people have variations in numbers of thoracic and lumbar vertebrae (cervical # is constant)
Abnormal Spinal Curvatures• Scoliosis- abnormal lateral
curvature
• Result from abnormal vertebral structure or disease involving muscle paralysis, uneven pull of muscles on spine
• kyfosis- hunchback-
• dorsally exaggerated curvature of thoracic vertebrae- osteomalacia, rickets
• lordosis- exaggerated lumbar curvature (temporary in prgnant or obese- trying to correct center of gravity
Structure of Vertebrae• Body or Centrum – weight
bearing
• Vertebral arch
• Vertebral foramen – canal through which spinal cord passes
• Spinous process
• Superior and Inferior Articular processes – all vertebrae to form joints
• Intervertebral foramina- notched in pedicles of vertebrae to allow space btw vertebrae (from side view)- allows nerves from spinal cord to pass through
APPENDICULAR SKELETON• Appendages hang
from pectoral and pelvic girdles
• Upper and lower limbs differ in their functions and mobility, they have the same structural plan- 3 major segments connected by freely movable joints
Atlas – (C1)has no body or spinous process; supports the head; allows the rocking motion of the occipital condyles; allows you to say ‘yes’
Regional Characteristics of VertebraeRegional Characteristics of Vertebrae
Axis- (C2) has a special knoblike feature called the dens; provides a pivot for rotation of the first cervical vertebra and the head; allows you to say ‘no’
Regional Characteristics of VertebraeRegional Characteristics of Vertebrae
The Bony ThoraxThe Bony Thorax
Slide 5.31a
“The Chest” forms a cage to protect major organs
Heart and lungs
Looks like an inverted cone
Composed of three parts
Sternum
Thoracic vertebrae
12 ribsFigure 5.19a
The Bony ThoraxThe Bony Thorax
Slide 5.31b
Sternum (breastbone)
Manubrium
Body
Xiphoid process
Ribs (12)
All 12 attach posteriorly to the thoracic vertebra
1-7 = true ribs; attach directly to sternum by costal cartilages
8-12 = false ribs
8-10 attach indirectly to sternum
11 and 12 = floating ribs
Thoracic vertebrae (T1- T12)
Figure 5.19a
The Bony ThoraxThe Bony Thorax
Slide 5.31a
Intercostal spaces are filled with muscles that aid in breathing
Figure 5.19a
Pectoral (shoulder girdle)• 2 Main Bones- clavicle and scapula
• medial ends of each clavicle join sternum
• distal ends meet scapula
• does not quite make a “belt”- scapula only attaches to the thorax and vertebral column by muscles
• pectoral girdle attach upper limbs to axial skeleton and insertion points for muscles
• girdles are very light, allow flexibility and mobility not seen elsewhere in body
Pectoral (shoulder girdle)
Reasons upper appendages have flexibility and mobility not seen elsewhere in the body:
1. the only point of attachment of pectoral girdles to axial skeleton is at sternoclavicular joints
2. looseness of scapular attachments allows scapula to move rather freely; can be moved side to side, elevated, depressed
3. socket of shoulder is shallow, small, and poorly reinforced- good for flexibility, bad for stability- shoulder dislocations are fairly common
Pectoral (Shoulder) GirdlePectoral (Shoulder) Girdle Composed of two bones
Clavicle (collarbone)
Scapula (shoulder blade)
These bones are very light and allow, the upper limb to have exceptionally free movement
Shoulder girdle is very light and unstable
Clavicle is the only part of the girdle that attaches to the axial skeleton
Socket of shoulder is shallow and poorly reinforced by ligaments
Good for flexibility; bad for stability
Shoulder dislocations are common
Scapula- shoulder blades
• triangular, located btw ribs 2 and 7
• superior border is the shortest
• medial border parallels the spinal column
• lateral border abuts the armpit (axillary border)
• glenoid cavity- small, shallow cavity- articulates with the humerus of the arm
• *relatively unstable shoulder joint
• anterior surface fairly featureless
• posterior- spine- ends laterally in enlarged projection called acromion
• acromion articulates with acromial end of clavicle to form acromioclavicular joint
• projection anterior from superior border is the coracoid process- beaklike, like a bent little finger- coracoid helps anchor biceps
• suprascapular notch- a nerve passgeway
Scapula (shoulder blade)Scapula (shoulder blade)
Connects the clavicle and humerus
Lie on the dorsal surface of the rib cage over ribs 2-7
Flat bone, roughly triangular in shape
Attached to the thorax and vertebral column only by muscles
Scapular Bone MarkingsScapular Bone Markings Glenoid cavity
Shallow, articular surface that articulates with the head of the humerus forming the shoulder joint
Acromion
Articulates with the clavicle to form the acromioclavicular joint
Forms the summit of the shoulder
Coracoid process
Small, hook-like structure on the lateral edge of the superior portion of the scapula
Assists in stabilizing shoulder joint and anchors biceps
Spine
Raised region on the posterior side for attachment of trapezius
Clavicle (collar bone)Clavicle (collar bone)
Extend horizontally across the superior thorax
Functions as an anchor for muscles and ligaments and acts as a brace
Articulates with the scapula (acromion) at the acromioclavicular joint
Articulates with the manubrium (sternum) on the medial (sternal) end
Clavicles- collarbones
• rounded on sternal end- attaches to manubrium
• flat on acormial end- attaches to acromion of scapula
• resist compression poorly- use outstretch arms to break a fall, clavicles break
• sensitive to muscle pull, become larger and stronger in people who do a lot of manual labor involving shoulder and arm muscles
Arm• Upper arm- humerus
• articulates with scapula and radius and ulna
• Proximal end- smooth head, fits into glenoid cavityanatomical neck- slight constriction
• greater and lesser tubercles- muscle attachment points
• intertubercular groove- serves as a guide for tendon of biceps
The Upper Limb
Pectoral girdle (Shoulder)
Humerus (Arm)
Radius and Ulna (Forearm)
Carpals, metacarpals, phalanges (Hand)
Bones of the Upper LimbBones of the Upper Limb
Arm Bone Markings
•surgical neck- most frequently fractured portion of the humerus•medial and lateral epicondyles•trochlea- medial- articulates with ulna•capitulum- lateral, ball like- articulates with radiusulnar nerve runs behind medial epicondyle, it’s responsible for tingling sensation when you hit you elbowcoranoid fossa- anteriorolecranon fossa- posterior- allow unla to rotate freely
Forearm- Ulna & Radius
• Articulate with each other proximally and distally at radioulnar joints
• in anatomical position- radius lateral
• palm faces back- pronation- radius and ulna form an X
Forearm• ulna- slightly longer, primarily
responsible for forming elbow joint
• coranoid and olecranon processes fit into fossa of humerus (grip the trochlea)
• olecranon locks into olecranon fossa to prevent hyperextension
• radius- styloid process
• major contributor to the wrist
HAND- carpals, metacarpals, phalanges
• Carpals- bones of wrist
• 8, marble sized short bones
• Arranged into 2 irregular rows
• Metacarpals- bones of palm
• 5- numbered 1-5 from thumb to pinkie
• heads of metacarpals are knuckles
• phalanges- bones of fingers
• each hand has 14 phalanges
• except for thumb, each finger has 3 bones
• distal, middle, and proximal phalanges
• (thumb has no middle)
• proximal articulate with the heads of metacarpals
The Hand (27 bones)The Hand (27 bones)
Carpals – wrist (8)
Arranged in two rows of four
Articulate with the radius to form the radiocarpal joint
Articulate with each other and united by ligaments
Metacarpals – palm (5)
When you clinch your fist the heads are your “knuckles”
Articulates between each phalanx called metacarpophalangeal joints
Phalanges (phalanx bones) – fingers (14)
Each finger has 3 bones (distal, middle, and proximal) except for the thumb that has 2 bones
Articulates between each phalanx called interphalangeal joints
Pelvic Girdle• attaches lower limbs to axial
skeleton and supports visceral organs of pelvic cavity
• pelvic girdle secured to axial skeleton by some of the strongest ligaments in the body
• sockets are deep and cuplike
• pelvic girdle made up of 2 coxal (hip) bones
• each unites anteriorly (with each other) and posteriorly (with sacrum)
• pelvis= both coxal bones plus sacrum and coccyx
Pelvic Girdle• during childhood, 3 separate bones- ilium, ischium, and pubis
• these fuse firmly by adulthood
• point where the three fuse is a deep socket called acetabulum- vinegar cup- acetabulum articulates with the head of the femur
• ilium= hands on hip bone
• sacroiliac joint
• ischium- the sitting down bone
• pubis- bladder rests upon it
• obturator foramen- blood vessels and nerves pass through
• pubic symphysis- fibrocartilage
• pubic arch- sharpness helps us determine male or female
Bony PelvisBony Pelvis
Both hip (coxal) bones, sacrum and coccyx
Pelvic Girdle (Hip)Pelvic Girdle (Hip) Functions
Connects the vertebral column to the femurs Bear the full weight of the upper body when
sitting and standing Transfer the weight from the axial skeleton to
the lower limbs Provides attachments for powerful muscles,
ligaments and tendons which makes it the most stable joint but lacks mobility
Protects some of the urinary, reproductive and digestive organs
Coxal BonesCoxal Bones
Ilium (hands on hip) Uppermost and largest bone of the pelvis Large flaring bones that forms the superior region Anteriorly it joins the pubis Inferiorly it joins the ischium Extends upward from the acetabulum
Coxal BonesCoxal Bones
Ischium (sit down bone) Lower, back portion of the hip bone Proceeds downward from the acetabulum
below the ilium and behind the pubis Expands into a large tuberosity and
curves forward and forms the top of the obturator foramen
Coxal BonesCoxal Bones
Pubis (bladder rests on it) Anterior portion of the hip bone Extends medially and inferiorly from the acetabulum Articulates with the opposite side at the pubic symphysis Forms the front of the pelvis and supports the organs
Pelvic Girdle Bone MarkingsPelvic Girdle Bone Markings Acetabulum
All three bones fuse together to form a deep socket
Located on the lateral surface of the bone
Articulates with the head of the femur for the hip joint
Iliac crest Superior border of the wing
of ilium Attachment for many muscles
Ischial tuberosity Inferior surface of ischium Weight is placed on this
projection when sitting down Attachment site for a massive
ligament and muscles Orbturator foramen
Hole created by the ischium and pubis bones through which nerves and muscles pass
Pelvic Girdle Bone MarkingsPelvic Girdle Bone Markings Pubic symphysis
Pubis bones articulate together by a fibrocartilage disc
Pubic arch Inferior to the joint is
an inverted V-arch Sharpness
determines male versus female
True pelvis (lesser pelvis) Inferior region
surrounded by bone False pelvis
(greater pelvis) Superior, expanded
portion of the cavity
Gender Differences of the PelvisGender Differences of the Pelvis Female pelvis is modified for
childbearing
1.Wider, shallower, lighter and rounder
2.Tilted forward
3.True pelvis defines the birth canal
4.True pelvis and false pelvis are wider in females
5.Pubic arch more than 90 degrees in females
FEMUR• Femur
• head, fovea capitis
• patella
Femur (Thigh)Femur (Thigh) Largest and longest bone in the body
Length is ¼ of a person’s height
It can support up to 30 times the weight of an adult
Articulates with hip proximally and tibia distally
Patella
Kneecap
Bone enclosed in the quadriceps tendon that secures the thigh muscles to the tibia
Femur Bone MarkingsFemur Bone Markings Head
Articulates with coxal bone at acetabulum
Greater and lesser trochanter
Sites of attachment for thigh and buttocks muscles
Gluteal tuberosity
Lateral ridge that runs vertically upward to the base of the greater trochanter
Attachment site for gluteus maximus
Lateral and Medial condyle
Distal projections that articulate with the tibia
TIBIA & FIBULA
• Tibia- shin bone
• medial malleolus
• Fibula- little white bone
• lateral malleolus
Tibia and Fibula (Lower leg)Tibia and Fibula (Lower leg)
Located from the ankle to the knee
Both ends of the two bones articulate at tibiofibular joint
Bones are connected by an interosseous membrane
Tibia (Shinbone)Tibia (Shinbone) Receives the weight of the body and the
bigger of the two
Second largest bone in the body
Articulates with the femur superiorly, the fibula laterally and with the talus (ankle) inferiorly
Tibia Bone MarkingsTibia Bone Markings Tibial tuberosity
Crest to which the patellar ligament attaches from the patella and the quadriceps muscle
Medial malleolus
Medial surface of the distal tibia
Articulates with the talus bone to form the ankle joint
Fibula Fibula
Located on the lateral side of the tibia
Stick-like bone with expanded ends
Articulates with the tibia on both ends
Does not articulate with the femur
Fibula Bone Marking: lateral malleolus
Distal end of the fibula that articulates with talus
Causes the ankle to bulge laterally
Attachment site for ligament s
METATARSALS & TARSALS
• Foot is composed of tarsals, metatarsals and phalanges.
• Supports weight & serves as lever
• Calcaneus and Talus are the two bones that support most of the body’s weight
• Metatarsals form sole
• 14 phalanges form toes; distal, middle & proximal
Sesmoid bone
The Foot (26 bones)The Foot (26 bones) Functions
Supports body weight
Acts as a level to propel the body forward in locomotion
Adapts to uneven ground
Ankle and Foot (26 bones)Ankle and Foot (26 bones) Tarsals (7) – ankle
Posterior half of the foot
Forms the arches of the foot which serves as a shock absorber
Body weight is carried by two large bones – talus and calcaneus
Talus (ankle bone)
Articulates with tibia and fibula
Calcaneus (heel bone)
Attachment site for Achilles tendon
Metatarsals (5) – sole
Phalanges – toes (14)
Each toe has 3 bones (distal, middle, and proximal) except for the big toe which has 2
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