Embryology Clinical Diseases and Stuff

Question 1

What is a herniated disc?

Answer 1

A herniated disc is when the nucleus pulposus (a remnant of the notochord) breaks through the anterior or posterior longitudinal ligament (typically posterior) and impinges on the spinal cord, creating pain.

Question 2

What is congenital scoliosis and what is it caused by?

Answer 2

Scoliosis is the abnormal lateral curvature of the spine that is the result of a) failure of somite formation or b) failure of somite segmentation.

Question 3

What is pectus carinatum?

Answer 3

Pectus carinatum is an overgrowth of cartilage causing the sternum to protrude outwards. It is the reciprocal of pectus excavatum, where the sternum pushes inward.

Question 4

What is pectus excavatum?

Answer 4

Pectus Excavatum is assumed to be caused by an overgrowth of costal cartilage that restricts the expansion of the ribs and pushes the sternum inwards.

Question 5

What is a sternal foramen?

Answer 5

A sternal foramen is in an ossification anomaly found in 4-10% of the population that may be mistake for a bullet wound or other sternal disease by CT. It is commonly found right about the heart and is not otherwise pathological.

Question 6

What is meromelia?

Answer 6

Meromelia is the partial arrest or failure of limb development.

Question 7

What is amelia?

Answer 7

Amelia is the complete arrest or failure of limb development

Question 8

WHat is phocomelia?

Answer 8

Phocomelia is when the feet and hands arise close to the trunk.

Question 9

What is mesolemia?

Answer 9

Mesolemia is a shortened limb where some part of the limb is shortened.

Question 10

What is radial club hand?

Answer 10

Radial club hand is due to the congenital absence or hypoplasia of the radial structures of the forearm and hand. Muscular structures and the radial nerve may also be hypoplastic or absent.

Question 11

What is polydactyly?

Answer 11

Polydactyly is a common phenomena where an extra digit is present. The extra digit is commonly medial or lateral, rather than central. In the foot, it is more frequently lateral.

The extra digit is often incompletely formed and useless.

Question 12

What does thalidomide do?

Answer 12

Thalidomise disrupts the Fgf4 signal from the AER to the progress zone. This “tricks” the area under the AER into thinking that it is a distal structure, thus, mitosis ceases.

Question 13

What is syndactyly?

Answer 13

Syndactyly is a failure of apoptosis of the AER at the distal ends that leads to webbed fingers or toes. It is more frequent between the medial digits (2/3 or 3/4)

Question 14

What is brachydactyly?

Answer 14

Brachydactyly is an uncommon abnormality manifested by shortened digits (reduction in the length of phalanges).

Question 15

What is cleft hand/foot?

Answer 15

Also known as Lobster-claw, Cleft hand/foot is the absence of one or more of the central digits of the hand/foot (i.e. 2, 3, or 4).

Question 16

What is sirenomelia?

Answer 16

Sirenomelia is when the lower limbs fail to separate, leading to mermaid-like appendages. Type 1 Sirenomelia is the least severe and just involves the skin. Type 7 Sirenomelia is the most severe and involves bony structures.

Question 17

What is achondroplasia?

Answer 17

Achondroplasia is the most prevalent form of dwarfism caused by a mutation on FGF-R3 that leads to pathological changes at the epiphyseal plate.

The zones of proliferation and hypertrophy are narrow and disorganized. This leads to the failure of proliferation and column formation of epiphyseal cartilage cells which impairs longitudinal growth of tubular bones)

Question 18

What is osteogenesis imperfecta?

Answer 18

Osteogenesis imperfecta, or Brittle Bone Disease, is a condition of bone fragility that predisposes the patient to fractures and deformities related to connective tissue abnormalities.

Question 19

What is talipes equinovarus?

Answer 19

Talipes equinovarus, or club foot, is when the sole of the foot is turned medially and the foot is inverted.

Question 20

What is flexible club foot?

Answer 20

Flexible club foot results from abnormal positioning or restricted movement of the lower limbs in utero. Feet are structurally normal and the abnormalities are corrected wither spontaneously or with braces.

Question 21

What is rigid club foot?

Answer 21

Rigid club foot is the abnormal development of the ankle and foot joints during the 6th and 7th week leading to bone deformities, particularly in the talus.