Prof. mamoun KremliDR: Gehan Mohamed

Recognize some Limb Anomalies Amelia, Meromelia, Hemimelia Polydactyly Syndactyly Amniotic band syndrome

Discuss Etiology

Melia: from Greek: ”Limb”

Amelia: GK, A: Lack of..Meromelia: Gk, meros: “part”: lack of

part Phocomelia:Gk, Phoco: “Seal”: like limb

of Seal Hemimelia: GK, Hemi: “Half”: lack of half

of limb

Limbs arise from small limb buds Upper limb bud appear after 26 days Lower limb bud appear after 28 days.

Somatic lateral mesoderm →limb buds (mesodermal core + ectodermal cap) → elongated & fragmented → 3 portions

Wk 6

Terminal portions of limb buds form hand & foot plates

Digital rays in distal ends form fingers & toes (wk 8) (apoptosis of tissues in between)

Limb anomalies Are-prevented: Amelia-Interrupted: Meromelia. Phocomelia,

Hemimelia

Very early in the developing embryo: Between 24-36 days following fertilization

Absence of one or more limbs

Absence of one or more limbs

A. Environmental Factors1. Teratogenic drugs

▪ e.g. Thalidiomide (was introduced as analgesic drug )

2. Maternal Factors - Diabetes mellitus3. Vascular accidents in uterus

B. Genetics – 20%1. Mutations in genes

Partial absence of a limb or limbs

Extremities resemble those of a seal.Typically, hands and feet are present

(may be normal or abnormal), but the intervening arms and legs are absent

Poly: many, dactyl: digit (finger/toe)Presence of more than normal number

of fingers or toes Rudimentary finger or toe, or Fully developed extra digit(s)

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Most common congenital malformation of limbs

Incidence: 1 in 2000-3000

10-40 % are familial

Non hereditary non syndromic

Few reports association with maternal smoking

This type of mild syndactyly is found occasionally on the physical examination.

This is usually an isolated finding, and in this location, has no impact on function.

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Watson S Arch Dis Child 2000;83:10-17Copyright © BMJ Publishing Group Ltd & Royal College of Paediatrics and Child Health. All rights reserved.

Hand with transverse deficiency at the metacarpal level.

At a different planeAt 90o to other fingersOpposition motion

50% of hand function

Watson S Arch Dis Child 2000;83:10-17Copyright © BMJ Publishing Group Ltd & Royal College of Paediatrics and Child Health. All rights reserved.

Pollicization of the index finger to make a thumb

Father Child after surgery

Watson S Arch Dis Child 2000;83:10-17

Copyright © BMJ Publishing Group Ltd & Royal College of Paediatrics and Child Health. All rights reserved.

Hand with thumb and aplastic fingers.

The constriction of appendages by amniotic bands may result in: Restrictions of the growth around the digits, arms

and legs Constriction rings around the digits, arms and legs

the bands will partially constrict the blood flow in the affected appendage causing a deep groove in the baby's skin

Swelling of the extremities distal to the point of constriction (congenital lymphedema)

Amputation of digits, arms and legs (congenital amputation)

After surgery

Before surgery

Partial fibular hemimelia

Short leg

Which is worse?Why?

Which is worse?Why?

Which bone is more important for knee and ankle joint surfaces?

Many congenital anomaliesNomenclature:

Amelia Phocomelia, meromelia Hemimelia Polydatyly, Syndactyly Amniotic band syndrome

Importance of thumb 50% of hand function

Tibial hemimelia Vs. Fibular hemimelia

Causes od anomalies: Teratogenic Drugs Uterine problems

▪ Blood supply (vascular accidents) Maternal factors

▪ Disease: Diabetes▪ Smoking, Alcohol

Hereditary