term 2

msk 1.1

label the planes

what is this

name types of joints

what is this

rectus femoris

msk 1.2

what are these

what are these

what type of fracture is this

what type of fracture is this

what type of fracture is this

name each type of shape fragments of complete fractures

name each type of shape fragments of incomplete fractures

name each type of fracture displacement

Infection 1.1

name the shapes

name each condition

what is this and what is it caused by

infection 1.2

whats this caused by

what syndrome is this

what syndrome is this

name each

what is this

what is this

what is this

what is this

what is this

infection 2.1

what cell is this

msk 2.1

what does the bi-laminar embryonic disc convert to?

what are the 3 germ laters

somatic and splanchic layer of mesoderm

Somatic (parietal) layer forms:

• Body wall, Limb skeleton, Parietal layers of serous membranes (pericardium, pleura, peritoneum)

Splanchnic (visceral, inner) layer forms:

• Heart and blood vessels , smooth muscle/connective tissue of gut , Visceral layers of serous membranes

where do epiblast cells migrate through and form?

mesodermal fate of each

• axial mesoderm

• paraxial mesoderm

• intermediate mesoderm

• lateral plate mesoderm

what does the sclerotome differentiate into?

•Sclerotome is ventro-medial: differentiates into chondrocytes (cartilage cells).

• Contribute to the vertebrae, ribs, and axial skeleton

• • Skull bones • Ossicles of the middle ear • Rib cage and sternum • Vertebral column

what does dermamyotome become? explain

dermatome: differentiates dermis of the back skin

myotome: differentiates into skeletal muscle.

what is the function of somites?

define the segmental body plan of vertebrates.

• Give rise to Axial skeleton (vertebrae, ribs), Skeletal muscles, Dermis of the skin.

temporary structures.

whats a dermatome?

Dermatome: strip of skin supplied by a single spinal nerve

what is the clinical relevance of a dermatome?

Neurological examination to assess level of nerve root damage (radiculopathy).

What is the anteroposterior axis?

What is the proximodistal axis?

Thumb to little finger (digit 1 → digit 5)

Base of limb to fingertips/toe tips

what forms limb buds and when do they appear?

• upper limb buds

• lower limb buds

Q: What do neural crest cells contribute?

A: Schwann cells, sensory nerves, and melanocytes

whats aer and its function

Thickened ectoderm at the distal tip of the limb bud.
Maintains the progress zone(undifferentiated mesenchyme )and promotes limb outgrowth.

How does limb development proceed under AER control?

Proximal → distal.

What occurs during chondrification? when do chondrification centres appear

Formation of cartilage models of bones. late week 5

When does primary ossification begin?

week 7

What are the two primary muscle masses in each limb?

A: Flexor mass and extensor mass.

Q: What does the flexor mass form?
A: Flexor muscles (e.g., biceps).

Q: What does the extensor mass form?
A: Extensor muscles (e.g., triceps).

What remains cartilaginous at birth?

A: Epiphyses.

Where does primary ossification occur?

Diaphysis

Which structure controls proximal-distal limb growth?

: Apical ectodermal ridge (AER).

What separates the digits?

Apoptosis between digital rays.

Which limb rotates laterally?

Upper limb.

: Which limb rotates medially?

Lower limb

What is syndactyly?

What developmental process commonly fails in syndactyly?

What is polydactyly and what causes it?

Which gene is commonly mutated in synpolydactyly?

HOXD13

Which genetic pathways are commonly involved in limb malformations?

A: SHH signalling pathway and HOX genes

What is amelia?

What is meromelia?

a for all : Complete absence of one or more limbs.

m: Partial absence of one or more limbs

What was thalidomide originally used for?

Why is thalidomide important embryologically?

Q: What was thalidomide originally used for?
A: Morning sickness in pregnancy.

Q: Why is thalidomide important embryologically?
A: It is a potent teratogen causing limb defects.

What is phocomelia?

Hands or feet attached close to the trunk ("seal limbs").

Which limb defects are classically associated with thalidomide?

Phocomelia and amelia

What is the most common congenital anomaly of the hands and feet?

Polydactyly

msk 2.2

review not from last semester

What are the two functional(somatic) divisions of the PNS?

Sensory division and motor division.

How many pairs of cranial nerves are there?

How many pairs of spinal nerves are there?

12 pairs of cranial nerves

31 pairs of spinal nerves

Are most spinal nerves sensory, motor, or mixed?

whats the difference between afferent and efferent?

Q: Are most spinal nerves sensory, motor, or mixed?
A: Mixed.

Q: What does afferent mean?
A: Sensory information travelling toward the CNS.

• sensory info passes into posterior horn of sc

Q: What does efferent mean?
A: Motor information travelling away from the CNS.

• motor info passes into anterior horn of sc

***

epimere: muscles of back

hypomere: muscle of trunk and limbs

What is a neural level?

A segment of the nervous system connected to a specific body region.

each neural segment supply?
A: A specific sensory and motor territory.

Q: Why do dermatomes and myotomes retain segmental innervation?

Q: What determines adult sensory and motor nerve patterns?

Q: Why do dermatomes and myotomes retain segmental innervation?
A: They maintain the nerve supply of their original somite.

Q: What determines adult sensory and motor nerve patterns?
A: Embryonic somite segmentation.

At what vertebral level does the spinal cord end in adults?

L1

What is the cauda equina?

In anatomy, it refers to the collection of nerve roots at the lower end of the spinal cord

Why are dermatomes clinically useful?

They help identify spinal nerve/root lesions.

What happens when nerves enter the limb bud?

They form nerve plexuses.

Q: Why are plexuses important?
A: Damage to one spinal nerve does not completely paralyse the limb

Which plexus supplies the upper limb?

Brachial plexus

Which spinal nerve roots contribute to the brachial plexus?

C5–T1.

brachial plexus

Robert Taylor Drinks Cold Beer

limb nerve territories label

What does sensory loss in a peripheral nerve distribution suggest?

Peripheral nerve injury.

example of a peripheral nerve lesion?

carpal tunnel syndrome affecting the median nerve.

Which dermatome supplies the

• nipples

• xiphisternum

• umbilicus

• pubic region

What is an axial line?

Junction between two non-adjacent dermatomes.

dermatome revision