Chapter 8 - Skeletal: Appendicular System Flashcards
What are the bones of the appendicular skeletal system?
The bones that make up the upper and lower limbs
Bones of the two girdles that attach the limbs to the axial system
How does the appendicular skeletal system contribute to homeostasis?
By providing attachment points and leverage for muscles, (aids in body movement)
Support and protection for internal organs
Storing and releasing calcium
What does the pectoral girdle consist of?
A clavicle and a scapula
What is the clavicle? What does it articulate with?
“Collarbone” - Anterior bone
Articulates with the manubrium of the sternum and the scapula
What does the scapula articulate with?
Clavicle and the humerus
How are the pectoral girdles held in place?
By a large group of muscles that extend from the vertebral column and ribs to the scapula
* do not articulate with the vertebral column
What is the function of the pectoral girdle?
Attach the bones of the upper limbs to the axial skeletal system
What is the medial end of the clavicle called?
Sternal end
Rounded, and articulates with the manubrium of the sternum
What is the lateral end of the clavicle called?
Acromial end
Broad, flat, articulates with the acromion of the scapula
What is the conoid tubercle?
Inferior surface of the lateral end of the clavicle is the point of attachment for the conoid ligament
Attaches the scapula to the clavicle
What is the impression for the costcoclavicular ligament?
Inferior surface of the medial end of the clavicle
Point of attachment for the costcoclavicular ligament
Attaches the clavicle to the first rib
What joints are formed by the articulation of the clavicle with other bones?
Sternoclavicular - sternum and clavicle
Acromioclavicular - scapula and clavicle
What joints are formed by the articulation of the scapula with other bones?
Acromioclavicular - scapula and clavicle
Glenohumeral - scapula and humerus
What is the scapula?
The shoulder blade
Large, triangular, flat bone situated in the superior part of the posterior thorax between the levels of the 2nd and 7th rib
What is the glenoid cavity?
Shallow depression that accepts the head of the humerus
Forms the glenohumeral joint
How many bones are in each upper limb?
30 bones in three locations 1. Humerus in the arm 2. Ulna and radius in the forearm 3. 8 carpals in the wrist 5 metacarpals in the palm 14 phalanges
What does each upper limb include?
Humerus Ulna Radius Carpals Metacarpals Phalanges
What is the humerus?
Arm bone
Longest and largest bone of the upper limb
What does the humerus articulate with?
Proximally with the scapula and distally with the ulna and radius
What does the proximal end of the humerus feature?
A rounded head that articulates with the glenoid cavity of the scapula to form the glenohumeral joint
What is the former site of the the epiphyseal growth plate on adult humerus?
Anatomical neck, distal to the head
Visible as an oblique groove
What is the capitulum?
Distal end of the humerus
Rounded knob, articulates with the head of the radius
What is the radial fossa?
Anterior depression above the capitulum
Articulates with the head of the radius when the forearm is flexed
What is the surgical neck?
A constriction of the humerus, where the head tapers to the shaft
What is the ulna?
Located on the medial aspect of the forearm
Longer than the radius
(Little finger side)
What is the olecranon?
At the proximal end of the ulna
Forms the prominence of the elbow
What is the radius?
Smaller bone of the forearm
Located on the lateral aspect of the forearm
(Thumb side)
What is the elbow joint?
Where the ulna and radius articulate with the humerus
Head of radius + capitulum of humerus
Trochlear notch of ulna + trochlea of humerus
How do the ulna and radius connect with each other?
At three places:
- Broad, flat fibrous connective tissue called interosseous membrane, between the two shafts of the bones
- Head of radius + ulna radial notch (proximally)
- Head of ulna + ulnar notch of the radius (distally)
What is the carpus?
Proximal region of the hand
Consists of 8 small bones joined to one another by ligaments
What are intercarpal joints?
Articulations among carpal bones
How are carpals arranged?
In two transverse rows of 4 bones each
What is the mnemonic for the carpal bones?
Stop letting those people touch the cadavers hand
Scaphoid, lunate, triquetrum, pisiform, trapezium, trapezoid, capitate, harnate
What are the 4 carpal bones in the proximal row?
- Scaphoid
- Lunate
- Triquetrum
- Pisiform
What are the 4 carpal bones of the distal row?
- Trapezium
- Trapezoid
- Capitate
- Harnate
Which is the largest carpal bone?
- Capitate
Which carpal is most likely to break?
Scaphoid (70% of the time)
What forms the carpal tunnel?
Pisiform and hamate on the ulnar side
Scaphoid and trapezium on the radial side
What passes through the carpal tunnel?
Long flexor tendons of thumb and digits
Median nerve
What are the metacarpals?
Intermediate region of the hand
Consists of 5 bones
What does each metacarpal bone consist of?
Proximal base
Intermediate shaft
Distal head
How are the metacarpals named?
1-5
Starting with the thumb (1) through to pinky (5)
What forms the carpometacarpal joint?
Proximal bases articulate with the distal row of carpal bones
What forms the metacarpophalangeal joint?
Distal head articulate with proximal phalanges
What are commonly called the knuckles?
Heads of the metacarpals
What are the phalanges?
Bones of the digits
Make up the distal part of the hand
14 bones
How are the phalanges named?
1-5
Thumb (1), pinky (5)
What does each phalanx consist of?
Proximal base
Intermediate shaft
Distal head
What is different about the thumb?
Has two phalanges instead of three
Has no MIDDLE phalanx
What are the three rows of phalanges called?
- Proximal row (first row) - articulates with metacarpals & second row
- Second row (middle row) - articulates with proximal row & distal row
- Third row (distal row)
What does the pelvic girdle consist of?
Two hip bones (coxal or pelvic bones or os coxa)
What is the public symphysis?
Where the hip bones unite anteriorly
Where do the hip bones join posteriorly?
At the sacroiliac joints
What is the bony pelvis?
The compete ring
Hip bones, pubic symphysis, sacrum
What is the function of the bony pelvis?
Provides a strong and stable support for the vertebral column and pelvic and lower abdominal organs
Also connects the bones of the lower limbs to the axial skeleton
What do the hip bones of a newborn consist of?
Three bones separated by cartilage
- Superior ilium
- Inferior and anterior pubis
- Inferior and posterior ischium
Which part of the hip bone articulates with the femur?
The femur articulates with the acetabulum of the hip bone
Which part of the hip bone articulates with the sacrum?
The sacrum articulates with the auricular surface of the hip bone
What is the ilium?
The largest of the three components of the hip bone
Composed of a superior ala and inferior body
What passes through the greater sciatic notch?
Sciatic nerve
Longest nerve in the body
Just below the posterior inferior iliac spine
What is the ischium?
The inferior, posterior portion of the hip bone
Composed of superior body and inferior ramus
What is the ramus?
Portion of the ischium that fuses with the pubis
What are the features of the ischium?
Prominent ischial spine
Lesser sciatic notch
Rough and thickened ischial tuberosity
What is the obturator foramen? Where is it located?
Largest foramen in the skeleton
Blood vessels and nerves pass through it, it is nearly completely closed by the fibrous obturator membrane
Located in the ischium, together, the ramus and pubis surround it
What is the pubis?
Pubic bone
Anterior and inferior part of the hip bone
What makes up the pubis?
Superior ramus
Inferior ramus
Body
What changes the gait of a pregnant woman?
Altered center of gravity
Increased flexibility of the pubic symphysis
What is the acetabulum?
A deep fossa formed by the ilium, ischium, and pubis
Functions as a socket that accepts the rounded head of the femur
What forms the hip (coxal) joint?
Together the acteabulum and the femoral head
How is the bony pelvis divided?
Into superior and inferior parts
By a boundary called the pelvic brim or inlet
How would you trace the pelvic brim?
Beginning posteriorly:
At the sacral promontory of the sacrum, trace laterally and inferiorly along the arcuate lines of the ilium
Continue inferiorly along the pectineal lines of the pubis
Finally, trace anteriorly along the public crest to the superior portion of the pubic symphysis
What defines the “false” pelvis?
The portion of the bony pelvis superior to the pelvic brim
Also called the greater pelvis
What defines the “true” pelvis?
The portion of the bony pelvis inferior to the pelvic brim
Also called the lesser pelvis
What are the components of the true pelvis?
Inlet
Outlet
Cavity
What is the pelvic inlet?
The superior opening of the true pelvis
What is the pelvic outlet?
The inferior opening of the true pelvis
What is contained in the true pelvis?
Surround the pelvic cavity
Contains the rectum, urinary bladder, vagina and cervix in females and the prostate in males
What is the pelvic axis?
An imaginary line that curves through the true pelvis from the central point of the plane of the pelvic inlet to the central point of the plane of the pelvic outlet
Why is the pelvic axis important during childbirth?
It is the route taken by the baby’s head as it descends through the pelvis
How is a male’s pelvis different from a female’s?
Males are heavier and larger
Female is wider and shallower - more space in the true pelvis
How many bones are in a lower limb extremity?
30 bones, in four locations
Describe the four locations of bones in a lower limb extremity.
- Femur in the thigh
- The patella (kneecap)
- Tibia and fibula in the leg
- 7 tarsals in the tarsus
5 metatarsals in the metatarsus
14 phalanges in the digits of the foot
What is the femur?
The thigh bone
Longest, heaviest and strongest bone in the body
What does the proximal end of the femur articulate with?
Acteabulum of the hip bone
What does the distal end of the femur articulate with?
The tibia and patella
What is the difference between an epicondyle and a condyle?
A condyle is a smooth prominence in a bone where it forms a joint with another bone
An epicondyle is a protuberance above the condyle of a bone to which ligaments or tendons are attached
What is the result of the angle of the body shaft of the femur?
Angles medially
Therefore, the knees are closer together than the hip joints
What is the fovea capitis?
The head of the femur has a small central depression
The ligament of the head of the femur connects the fovea capitis of the femur to the acetabulum of the hip bone
What does a “broken hip” typically refer to?
A break in the neck of the femur
What is the greater trochanter?
A projection from the junction of the neck and shaft that serve as an attachment point for tendons of some thigh and buttock muscles
Lateral side
Superior
What is the lesser trochanter?
A projection from the junction of the neck and shaft that serve as an attachment point for tendons of some thigh and buttock muscles
Medial side
Inferior
What is the landmark commonly used to locate the site for intramuscular injections into the lateral surface of the thigh?
The greater trochanter
Why is the angle of convergence of the femurs greater in females than males?
Greater in females b/c the female pelvis is broader
What is the name of the roughened projection that is a site of attachment for the adductor Magnus muscle?
Adductor tubercle
Superior to the medial epicondyle
What is the patella?
The kneecap
A small, triangular bone
Where is the patella located?
Anterior to the knee joint
What is the proximal portion of the patella called?
The base
What is the distal portion of the patella called?
The apex
What is the function of the patella?
Increases the leverage of the tendon of the quadriceps femoris muscle
Maintains the position of the tendon when then knee is bent
Protects the knee joint
The patella is classified as which type of bone, why?
Sesamoid
B/c it develops in a tendon
Where is the patellofemoral joint?
Between the posterior surface of the patella and the patellar surface of the femur
What is the most common problem runner’s face?
Patellofemoral syndrome
“Runner’s knee”
Normal tracking does not occur
What is the tibia?
Shin bone
The larger, medial, weight-bearing bone of the leg
What does the tibia articulate with?
Femur and fibula proximally
Fibula and talus distally
How are the fibula and tibia connected?
By interosseous membrane
What is at the proximal end of the tibia?
A lateral condyle and a medial condyle
What do the medial condyle and lateral condyle of the tibia articulate with? And what do they form?
The condyles of the femur
Form the tibiofemoral joint
What tibia structure articulates with the talus of the ankle?
Medial malleolus
Which long bone is most likely to break?
The tibia
What is the fibula?
Parallel and lateral to the tibia
Considerably smaller
* does not articulate with the femur but does help stabilize the ankle joint
What does the head of the fibula (proximal end) articulate with?
What joint does it form?
Inferior surface of the lateral condyle of the tibia (below the level of the knee joint)
Proximal tibiofibular joint
Which bone do we most often do a bone graft from? Why?
Fibula - b/c the tibia is the weight bearing bone and even after a bone graft has been performed on the fibula, walking, running and jumping can still occur
What is the tarus?
The ankle
The proximal region of the foot and consists of 7 tarsal bones
Name the 7 tarsal bones.
- Talus - ankle bone
- Calcaneus - heel
- Navicular
- Third (lateral) cuneiform
- Second (intermediate) cuneiform
- First (medial) cuneiform
- Cuboid
What is the mnemonic for remembering the 7 tarsal bones?
Tall centres never take shots from corners Talus Calcaneus Navicular Third cuneiform Second cuneiform First cuneiform Cuboid
What is the only tarsal bone that articulates with the tibia and fibula?
What is the joint called?
Talus - The most superior tarsal bone
Talocrural joint
What are the joints between tarsal bones called?
Intertarsal joints
During walking, how is weight distributed throughout the tarsals?
The talus transmits 1/2 of the body weight to the calcaneus, the other half to the other tarsal bones
What are the metatarsal bones?
Bones in the intermediate region of the foot
Consist of 5 metatarsal bones
Numbered 1-5 from medial to lateral
What does each metatarsal consist of?
Proximal base
Intermediate shaft
Distal head
What do the metatarsals articulate with proximally?
The 1,2,3 cuneiform bones and the cuboid bone to form the tarsometatarsal joints
What do the metatarsals articulate with distally?
The proximal row of the phalanges to form the metatarsophalangeal joints
What are phalanges and how are they numbered?
Toes
Numbered 1-5 starting with the big toe
What does each phalanx consist of?
Proximal base
Intermediate shaft
Distal head
What is different about the big toe compared to the other 4 toes?
Big toe only has two heavy phalanges
Other 4 toes have three (proximal, middle and distal)
What are the joints inbetween the phalanges called? (Toes)
Interphalangeal joints?
What is the function of the foot arches?
Enable the foot to support the weight of the body
Provide ideal distribution of the body weight over the soft and hard tissue of the foot
Provide leverage while walking
How many arches are in the foot?
2
What are the names of the arches in the foot?
Longitudinal arch
Transverse arch
Describe the longitudinal arch.
Has two parts - medial and lateral
Forms an arch from the anterior to the posterior part of the foot
Describe the medial part of the longitudinal arch of the foot.
Originates at the calcaneus, rises to the talus, and descends through the navicular, three cuneiforms, and the heads of the three medial metatarsals
Describe the lateral part of the longitudinal arch of the foot.
Originates at the calcaneus, rises to the cuboid and descends to the heads of the two lateral metatarsals
Where is the transverse arch of the foot located?
Between the medial and lateral aspects of the foot
How is the transverse arch formed?
Formed by the navicular, three cuneiforms, and the bases of the five metatarsals
How much weight does the ball of the foot carry? The heel?
Ball - 40%
Heel - 60%
What structural feature of the arches allows them to absorb shocks?
Because the arches are not rigid, they yield when weight is applied and spring back when weight is lifted, allowing them to absorb the shock of walking
How does most skeletal tissue arise?
From mesenchymal cells (connective tissue cells derived from mesoderm)
How does most of the skeleton of the skull arise?
From ectoderm
During skull development, what are the two major portions?
- Neurocranium - forms the bones of the skull, mesodermal in origin
- Viscerocranium - forms the bones of the face, ectodermal in origin
The neurocranium is divided into two parts, what are they?
- Cartilaginous neurocranium
2. Membranous neurocranium
How does Cartilaginous neurocranium develop, what part does it form?
Consists of hyaline cartilage developed from mesenchyme, undergoes endochondral ossification
Forms the bones at the base of the skull
How does Membranous neurocranium develop, what part does it form?
Consists of mesenchyme and undergoes intramembranous ossification
Forms the flat bones that make up the roof and sides of the skull
What separates the flat bones of the skull during fetal life and infancy?
Fontanels - membrane filled spaces
The viscerocranium is divided into two parts, what are they?
- Cartilaginous viscerocranium
2. Membranous viscerocranium
How does cartilaginous viscerocranium develop and what parts does it form?
Derived from cartilage of the first two pharyngeal (brachial) arches
Endochondral ossification of these cartilages forms the ear bones and the hyoid bone
How does membranous viscerocranium develop and what parts does it form?
Derived from mesenchyme in the first pharyngeal arch and then undergoes intramembranous ossification
Forms the facial bones
What is the notochord?
A solid cylinder of mesodermal cells that stimulates the mesenchymal cells to form the vertebral bodies, costal ribs centres and vertebral arch centres
Which of the three basic embryonic tissues - ectoderm, mesoderm, and endoderm - gives rise to most of the skeletal system?
Most of the skeletal system arises from embryonic mesoderm
What are upper limb buds?
During the 4th week of fertilization, the upper limbs appear as small elevations at the sides of the trunk
What are lower limb buds?
About 2 days after the upper limb buds appear, the lower limbs appear
What happens to the limb buds as they develop?
They constrict around the middle portion, to produce hand plates and foot plates
They represent the beginnings of the hands and feet