7.1 Bones of the Limbs Flashcards
- What is an example of a disease where one tissue type turns into another?
Fibrodysplasia ossificans progressive, this is where a mutation in the gene that controls bone growth results in the uncontrolled bone growth after injury, resulting in an extra heterotropic skeleton. Body eventually becomes fused and movement near impossible, attempts to remove abnormal growth just triggered repair mechanisms an caused more abnormal growth.
How many bones are there in the human skeleton?
206, but this number can vary due to variable numbers of sesamoid bones and coccygeal vertebrae (and other small bones). Homeotic bones may increase number of ribs or alter digits.
What makes up the axial skeleton?
- Cranium
- Vertebral column
- Ribs and sternum
What makes up the appendicular skeleton?
- Pectoral girdle
- Upper limb bones
- Pelvic girdle
- Lower limb bones
What are the functions of the skeleton?
- Movement and muscle attachment
- Protection of soft tissues
- Calcium storage (variable and vital - through negative feedback system using hormones from the thyroid and parathyroid)
- Resistance to forces (incl gravity)
- Haematopoiesis (blood cell production in red blood cell marrow)
What are the main constituents of bone?
Collagen and calcium hydroxyapatite - they balance strength and weight of the skeleton
How can collagen be removed from bones and what is the effect of this?
Collagen can be removed through heat treatment (denatures the protein), causes bone to become very brittle and hard, so shatters easily.
How can calcium hydroxyapatite be removed from bones and what is the effect of this?
Calcium hydroxyapatite can be removed through treatment with acid, leaving the collagen intact. Bone loses its rigidity and strength, so becomes extremely flexible.
What is the function of collagen in bones?
Organic component
- Increases flexibility
- Some elasticity
(- Is the most common protein in the body and bones)
What is the function of calcium hydroxyapatite in bones?
Inorganic component (along with calcium carbonate and magnesium carbonate)
- Mainly calcium phosphate
- Crystals impregnate collagen matrix
- Provides hardness and rigidity
How is bone a composite material?
Because it is made up of multiple components
What are the two histological types of bone?
- Woven (immature)
- Lamellar (mature)
Where is woven bone seen?
- Development/immature bones
- Fracture repair
- Pathology (excess seen in some tumours)
Temporary type of bone, will be made into lamellar
What is considered to be lamellar bone?
- Compact bone
- Spongy bone
- MATURE BONE
Permanent bone, made up of lots of layers
What are the different morphological classifications (shapes) of bones, with examples?
- Flat (e.g. parietal)
- Short (e.g. carpals)
- Long (e.g. femur)
- Sesamoid (e.g. patella)
- Irregular (e.g. vertebrae)
What are diaphyses?
Primary ossification centres of bones, will usually make up the main body (e.g. shaft of femur).
Will contain more compact or cortical bone and possibly yellow marrow.
What are epiphyses?
Areas of secondary ossification/growth plate, at the ends/extensions of bones.
Will be made up of mostly spongy bone, collagen running in different directions allowing the bone to be able to withstand high tensile stress.
What is the metaphysis?
This is the region adjacent to the growth/epiphyseal plate during development, will ossify and connect the diaphysis to the epiphysis.
Often where the bones ‘flare’.
What is endochondral ossification?
Endo = in, chondral = cartilage, ossification = turn into bone
This is where hyaline cartilage is converted into bone during osteogenesis in embryonic development.
What is the benefit of secondary ossification centres?
Allows long bones to grow along with the person - birth would be extremely difficult if bones were always full size.
What is intramembranous ossification and where does it occur?
This is where fibrous membranes are converted straight into bone, with no intermediate steps. Occurs in the flat bones of the skull and irregular ones such as the mandible - the head is relatively full-sized at birth.
What are the primary ossification sites in a 12 week old foetus?
- Frontal bone of skull
- Parietal bone of skull
- Occipital bone of skull
- Mandible
- Clavicle
- Scapula
- Radius
- Ulna
- Humerus
- Femur
- Tibia
- Ribs
- Spinal vertebra
- Ilium
(In areas where bones WILL be - for example, in the wrist - no bone will currently exist but their ‘ghosts’ of deposited cartilage will in a similar shape)
- What effect could dislocations or fractures along growth plates in children have?
Disruption of growth, resulting in uneven development of bone and even necrosis if blood supply is compromised
Go revise the spine flashcards
Do it!
What are features of the sternum?
Aka the breastbone
- Formed of three main parts, manubrium, body and xiphoid process (top -> bottom)
- Suprasternal notch on manubrium, aka jugular notch, is at the level of the T2 vertebrae
- Sternal angle/manubriosternal joint is lower than the T4 vertebrae
- Xiphoid process is at the level of T9 or T10
How are ribs 1-7 attached anteriorly and what is their simple classification?
To the sternum via costal cartilage, ‘vertebrosternal’
How are ribs 8-10 attached anteriorly and what is their simple classification?
Through costal cartilage attaching to the rib above, ‘vertebrocostal’
How are ribs 11-12 attached anteriorly and what is their simple classification?
No anterior attachment, ‘floating’
What are the bones of the upper limb?
Humerus, radius and ulna
- What are cervical ribs?
Congenital abnormality where a rib emerges from above the normal ‘first rib’ from the C7 vertebrae, may present as chest pain
What does the pectoral girdle enable?
A wide range of movement, unlike the fused bones of the pelvic girdle. This is partly due to the shallow shoulder joint, so has a relatively high risk of dislocation.
Compare the pectoral and pelvic girdles.
- Pelvic has far less movement, as deeper socket and fused bones - pectoral girdle has far more mobile joints, allowing for greater range of movement and a shallow socket
- Pelvic is inherently more stable because of the deeper socket, the shallow shoulder joint of the pectoral girdle makes this joint far more prone to dislocation.
What is a unique feature of the forearm?
The bones are capable of pronation and supination, adding dexterity - the lower limb is unable to do this
What is a unique feature of the hand?
Specialised thumb joint allows opposition which increases manual dexterity
What makes up the arm?
The shoulder to the elbow/upper arm in layman’s terms
What makes up the forearm?
The elbow to the wrist
What are the three types of bones in the hand and wrist?
Carpals, metacarpels and phalanges
What are the 8 carpals?
Proximal row, lateral to medial (from anatomical position) - Scaphoid - Lunate - Triquetrum - Pisiform Distal row, lateral to medial - Trapezium - Trapezoid - Capitate - Hamate
What makes up the pectoral girdle?
Clavicle and scapula
What joints are within the pectoral girdle?
- Sternoclavicular joint (only one between the upper limb and the axial skeleton)
- Acromioclavicular joint (AC, acromion process is on the scapula)
- Coracoclavicular joint (coracoid process is on the scapula also)
- Where do fractures frequently occur on the clavicle?
In the middle third/shaft of the bone
How does the clavicle appear from a superior view?
Convex medially (near joint with manubrium) and concave laterally (near joint with acromion)
What are different features present on the scapula?
- Acromion process (joint with clavicle, palpable above shoulder)
- Coracoid process (joint with clavicle, palpable below lateral clavicle)
- Subscapular fossa (where subscapularis sits)
- Supraspinous fossa (where supraspinatus sits, above spine of scap)
- Spine of scapula (posterior projection of bone)
- Infraspinous fossa (where infraspinatus and teres minor sit, below spine of scap)
- Glenoid fossa (distal fossa, where humerus articulates, has fibrous labrum)
What is a fossa?
An indentation or depression into the bone
What is a condyle?
Round prominence at the end of a bone, most likely to be part of a joint
What is an epicondyle?
A rounded projection near that of a condyle (medial and lateral condyles seen on the humerus)
What is an eminence of bone?
A small bump
What is a prominence of bone?
A large bump
What is a tubercle or tuberosity?
A projection or bump with a roughened surface that often allows for the attachment of muscles. Tubercles are often smaller.
What is a ramus of bone? (Also seen in the nervous system)
Extension of bone (seen in the mandible)
What is a facet?
A small, flattened articular surface
What is a line on a bone?
A long, often roughened, thin projection
What is the spine of a bone?
A relatively long projection or bump seen on a bone
What are ridges or crests on bones?
Long, narrow lines
What is a malleolus?
Bony prominence on each side of the ankle (medial and lateral, lateral is formed by the fibula, medial by the tibia)
What is a trochanter?
A region on the femur where muscles attach - can be the greater, lesser or third trochanter.
What is the humeral head?
A secondary ossification centre of the humerus, this is where the humerus articulates with the scapula at the glenoid fossa
What is the anatomical neck of the humerus?
Where the head of the humerus meets the main body of the bone
What is the surgical neck of the humerus?
A common site of fracture in the proximal end of the humerus
Where do the rotator cuff muscles attach?
To the greater and lesser tuberosities of the humeral head
Greater: Supraspinatus, infraspinatus, Teres minor
Lesser: Subscapularis
What is the deltoid tuberosity?
Where the deltoid muscle attaches/inserts into the humerus
Where are the medial and lateral epicondyles palpable?
On either side of the elbow (rounded sticky-out bits)
Where does the radial head articulate with the humerus and with what?
At the capitulum (and radial fossa) of the humerus, with the radial head
Where does the ulnar head articulate with the humerus and with what?
At the ‘ulnar notch’ (olecranon fossa, trochlea and coronoid fossa)
Where do the biceps attach?
To the radial tuberosity
Where does brachialis attach?
To the ulnar tuberosity
Where does the triceps attach?
To the olecranon
What are the processes at the distal end of the radius and the ulna called?
Styloid processes, articulate with the wrist/carpal bones
Where does the radial head articulate with the ulna, and with what ligament?
With the radial notch on the ulnar, is held in place by the anular ligament at the proximal radio-ulnar joint
What happens during pronation and supination?
The radius rotates around the ulna - during pronation, the distal radius rotates medially, crossing over the ulna anteriorly
Where does the head of the ulna articulate with the radius?
With the ulnar notch of the radius
What separates the ulna from the carpals?
Articular disc of the ulna
- What can happen if the scaphoid becomes fractured?
A fall on to the hand can fracture the scaphoid, this may cause damage to the radial artery (main blood supply to the hand) which runs solely from the distal to the proximal scaphoid. A fracture may result in avascular necrosis of the proximal portion of the scaphoid.
Pain or tenderness in the anatomical snuffbox may be an indicator of a scaphoid fracture
What are the joints between the carpal and the metacarpal bones?
Carpometacarpel joints
What are the joints between the metacarpals and the phalanges?
Metacarpophalangeal joints (layman’s terms: knuckles)
What are the metacarpals?
The long bones between the fingers and the wrist
What are the phalanges?
There are distal, medial and proximal phalanges that make up the bones in our fingers and toes
What are the joints between the proximal and medial phalanges?
Proximal interphalangeal joint (PIP)
What are the joints between the medial and distal phalanges?
Distal interphalangeal joint (DIP)
What stabilises the pelvic girdle?
Strong joints between the sacrum, ilium and two pubic bones
What is the bicondylar angle of the femur?
The ‘carrying’ angle - ensures that the centre of gravity is maintained over the knees to optimise the efficiency of bipedal locomotion without excessive reduction of pelvic width.
What are the bones that make up the pelvis?
The ilium, ischium and the pubis (x2 for all) and also the sacrum make up the pelvis
What reinforces the knee joint?
Internal ligaments (when bearing body weight), see joints flashcards
How do the leg bones interact?
They don’t revolve around each other like the arm bones, the fibula doesn’t form part of the knee joint
What is the thigh region of the lower limb?
From the hip to the knee
What is the leg region of the lower limb?
From the knee to the ankle
What are the prominences on the ilium?
- Anterior Superior Iliac Spine (ASIS)*
- Iliac crest *
- Posterior Superior Iliac Spine (PSIS)*
- Anterior Inferior Iliac Spine (AIIS)
- Greater sciatic notch (where the sciatic nerve passes through)
- externally palpable surfaces
What are the prominences on the ischium?
- Ischial spine
- Ischial tuberosity *
- externally palpable surfaces
What are the prominences on the pubis?
Pubic tubercle*
- externally palpable surfaces
What is the acetabulum?
Where the ilium, ischium and pubis meet, and where the femur articulates with the hip bone
What attaches at the greater trochanter? What is it?
Gluteus medius and minimus
A larger prominence on the femoral neck
What attaches at the lesser trochanter? What is it?
Powerful hip flexor (iliopsoas)
A smaller prominence on the femoral neck
What is the linea aspera and what attaches there?
‘Rough line’, muscles for adduction attach here
- What can happen if an intra-capsular fracture of the femoral neck occurs?
The blood supply to the femoral head may become compromised leading to avascular necrosis (death of bone tissue because the bone is no longer requiring nutrients) and potential sepsis if left untreated
What processes are on the end of the femur?
The medial and lateral condyles
What are the three articulations within the knee?
2x femoral-tibial, 1x femoral-patellar
Is the fibula part of the knee joint?
No
What bones are involved in the knee joint?
The femur, the tibia and the patella
What processes are on the proximal head of the tibia?
The medial and lateral tibial condyles
What lies between the tibial condyles?
The intercondylar eminence
What is the shin bone?
The tibia (you can palpate the medial border)
What is the interosseous membrane?
A fibrous sheet between bones that also acts as a muscle attachment point
What bone makes the medial malleolus?
The tibia
What bone makes the lateral malleolus?
The fibula
What bone does the tibia and fibula articulate with?
The talus of the tarsal bones
What are the tarsal bones?
Posterior to anterior
- Calcaneus
- Talus
- Navicular (supposedly boat shaped, medial)
- Cuboid (supposedly cuboid, lateral)
- Cuneiform bones (medial, intermediate and lateral)
How many phalanges are there in the hallux and pollux?
Hallux: big toe
Pollux: thumb
2 bones in each
What is the second digit an axis of?
An axis of abduction and adduction
What is important about the calcaneus?
The large bony prominence of the heel, and where the Achilles tendon inserts
What is the tuberosity of the 5th metatarsal prone to?
Avulsion fracture - where a fragment of bone tears away from the main mass of bone as a result of physical fracture following excess inversion of the foot
What are the metatarsals?
The long bones of the foot between the tarsals and the phalanges
