Musculoskeletal System - Abnormalities

Introduction

Congenital dislocation hip

There are a large number of different musculoskeletal abnormalities affecting one or a combination of bone and muscle development in the skull, trunk and limbs. This page therefore can only broadly introduce the topic.

Musculoskeletal and limb disorders together form the largest group of congenital defects that occur in Australia. Some defects appear as obvious malformations, such as syndactyly and limb reductions. Other muscular defects only become obvious postnatally when the muscles are required to be used, those in highest use are respiratory (diaphragm, intercostals) and anti-gravity (those that hold you upright) muscles.

--Mark Hill 09:25, 14 April 2010 (EST) Page Template only - content from original UNSW Embryology site currently being edited and updated.

Australian Statistics

Textbooks

• The Developing Human: Clinically Oriented Embryology (8th Edition) by Keith L. Moore and T.V.N Persaud - Moore & Persaud Chapter 15 the skeletal system
• Larsen’s Human Embryology by GC. Schoenwolf, SB. Bleyl, PR. Brauer and PH. Francis-West - Chapter 11 Limb Dev (bone not well covered in this textbook)
• Before we Are Born (5th ed.) Moore and Persaud Chapter 16,17: p379-397, 399-405
• Essentials of Human Embryology Larson Chapter 11 p207-228

Developmental Dysplasia of the Hip

File:Congenital dislocation hip

Also called Congenital Hip Dislocation.

• Instability: 1:60 at birth; 1:240 at 1 wk: Dislocation untreated; 1:700
• congenital instability of hip, later dislocates by muscle pulls or gravity
• familial predisposition female predominance
• Growth of femoral head, acetabulum and innominate bone are delayed until the femoral head fits firmly into the acetabulum

Barlow test

(Barlow maneuver) A clinical term to describe a physical examination of the newborn for developmental dysplasia of the hip (DDH). The examiner adducts the hip (bringing the thigh towards the midline) while applying light pressure on the knee, directing the force posteriorly. A positive sign is the hip being dislocatable, if the hip can be popped out of socket with this test. This test is then combined with the Ortolani test (maneuver). The test is named after Thomas Barlow (1845 – 1945) a British royal physician.

Ortolani test

Ortolani maneuver) A clinical term to describe a physical examination of the newborn for developmental dysplasia of the hip (DDH). This is a test for posterior dislocation of the hip. Using the examiner's thumb, abduct the infant's leg, while using the examiner's index finger to place anterior pressure on the greater trochanter. A positive sign is a distinctive 'clunk' which can be heard and felt as the femoral head relocates anteriorly into the acetabulum, usually becomes negative after 2 months of age. This test is combined with the Barlow test (maneuver). Named after Marino Ortolani, the test developer in 1976.

Scoliosis

• assymetric growth impairment of vertebral bodies
• lateral deviation of spine (Lateral flexion, Forward flexion, Rotation of vertebral column on long axis)
• compensated by movement of vertebral column above and below affected region (producing a primary and two secondary curves)
• progresses rapidly in adolescence and becomes fixed once bone growth is completed.

Muscle Development

There can be abnormalities associated directly with muscle differentiation and function as well as those mediated indirectly by abnormalities of innervation or skeletal development and other associated systems.

Duchenne Muscular Dystrophy

The most common occuring in Boys and in Duchenne Muscular Dystrophy (DMD). This cause of the disease was discovered in 1988 as a mutation in dystrophin, a protein that lies under the muscle fiber membrane and maintains the cell's integrity. As skeletal muscles have little prenatal load or use it is not until postnatally that muscle wasting occurs, usually in the anti-gravity muscles first. This is a progressive disease usually detected between 3-5 years old.

• X-linked dystrophy
• large gene encoding cytoskeletal protein - Dystrophin
• progressive wasting of muscle, die late teens

Becker Muscular Dystrophy

A milder adult (30-40 years old) onset form of the disease Becker's Muscular Dystrophy (BMD) that involves mutations in the same dystrophin gene.

Autosomal Recessive Muscular Dystrophy

Dystroglycan, a protein that associates with both dystrophin and membrane molecules, is a candidate gene for the site of the mutation in autosomal recessive muscular dystrophies. A knockout mouse has been generated that has early developmental abnormalities.

Myotonic Dystrophy

An inherited disorder in which the muscles contract but have decreasing power to relax. With this condition, the muscles also become weak and waste away. The myotonic dystrophy gene, found on chromosome 19, codes for a protein kinase that is found in skeletal muscle, where it likely plays a regulatory role. The disease is "amplified" through generations probably by a similar GC expansion associated with Huntington disease.

Limb Abnormalities

Genetic

• Human Gene Mutations - mutation of any of the patterning genes will result in limb abnormalities (Will put Table on Web page mutations and terminology)

Type II syndactyly- HoxD13

Maternal

• thalidomide Phocomelia
• short ill-formed upper or lower limbs
• hyperthermia

References

Search PubMed

Search April 2010

• Musculoskeletal System Development - All (44637) Review (5065) Free Full Text (6601)
• Musculoskeletal Development - All (44637) Review (5065) Free Full Text (6601)

Search Pubmed: musculoskeletal system abnormalities

Additional Images

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  Adult axial skeleton

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  Adult appendicular skeleton

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  Bone structure

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  Developing vertebra

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  Endochondral bone

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  Fetal head lateral (12 weeks)

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  Fetal head medial (12 weeks)

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  Fetal head section (12 weeks)

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Cite this page: Hill, M.A. (2024, May 17) Embryology Musculoskeletal System - Abnormalities. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Musculoskeletal_System_-_Abnormalities

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