EMBRYOLOGI SISTEM MUSKULOSKLETAL

dr. May Valzon

Sistem Skeletal

• Berkembang dari mesoderm paraxial, mesoderm lateral plate (somatic layer), neural crest(ektoderm)

• Mesoderm paraxial somitomers (somite)• Somite sclerotome dan dermomyotome• Minggu IV sclerotome menjadi mesencyme

fibroblasts, chondroblasts, or osteoblasts (bone-forming cells)

• bone-forming capacity sclerotome dan mesoderm lateral plate (somatic layer)

• Sclerotome sel-sel dinding anteromedial somite membentuk vertebra dan costa

• Dermomyotome sel-sel dinding posterolateral membentuk ekstrimitas dan otot dinding tubuh

• Neural crest mesencyme cranium dan ossa faciei

• Occipital somites and somitomeres basis cranii dan os occipitale

• Ada 2 macam proses penulangan (ossifikasi)– Intramemebranosa mesencyme langsung

menjadi tulang

– Endochondral mesencyme terlebih dahulu menjadi kartilago hyalin

Perkembangan Tengkorak

• Neurocranium (asal mesederm, kec. Os frontale)– Membranous neurocranium ossifikasi intramembranosa calvaria

– Cartilaginous neurocranium ossifikasi endochondral basis

• Viscerocranium (asal ectoderm)– Is formed mainly from the first two pharyngeal arches – Membranous viscerocranium dari Arcus pharyngealis I:

• Pars dorsalis(processus maxillaris) maxilla, the zygomatic bone, and part of the temporal bone

• Pars ventralis (process mandibularis) berisi kartilago Meckel mengalami ossifikasi intramembranosa menjadi mandibulae

– Cartilaginous neurocranium dari AP I dan II ossicula auditiva dan os hyoid

Ossifikasi intramembranosa diawali dengan pembentukan spikula

Asal embriyologi tulang tengkorak: biru (neural crest), merah (somit dan somitomeres)

Figure 9.4 Skull of a newborn, seen from above (A) and the right side (B). Note the anterior and posterior fontanelles and sutures. The posterior fontanelle closes about 3 months after birth; the anterior fontanelle closes about the middle of the second year. Many of the sutures disappear during adult life.

Korelasi klinis

• Craniofacial Defects and Skeletal Dysplasias

• Anencephaly

• Cranioschisis

• Dwarfism:– Achondroplasia (ACH)

– Thanatophoric dysplasia

– Hypochondroplasia

Craniosynostosis: scaphocephaly (A), acrocephaly, dan brachycephaly (B)

Achondroplasia (ACH)

Perkembangan Skeleton Axiale

• Vertebrae dan costa berkembang dari Sclerotome

• Sternum berkembang dari mesoderm dinding anterior tubuh

• Korelasi klinis: Vertebral Defects:

– Scoliosis

– Klippel-Feil sequence

– spina bifida

Perkembangan Skeleton Appedicular

• Pertengahan Minggu IV upper limb buds dan lower limb buds

• Mesencyme dari mesoderm dibungkus ektoderm • Minggu VI hand plates dan foot plates• Minggu VII segmentasi brachium – antebrachium

– manus ; femur – cruris – pedis• Minggu VIII segmentasi membentuk regio bahu, cubiti,

carpal• Ossifikasi endochondral dimulai pada akhir minggu VIII• Minggu XII muncul pusat ossifikasi primer• Pusat ossifikasi sekunder baru muncul setelah lahir

Limb Growth and Development

Korelasi klinis

• Bone Age USG usia kehamilan • Limb Defects 6 per 10 rb kelahiran

– Meromelia Phocomelia– Amelia – micromelia

• Penggunaan Thalidomide (1957 s.d 1962) Limb Defects • Periode sensitif Mg IV dan V• Kelaian jari: brachydactyly, syndactyly, polydactyly,

ectrodactyly• Cleft hand and foot (lobster claw deformity), Clubfoot • Amniotic bands• Congenital hip dislocation• deficiency of the radius

A. Amelia unilateral, B. Meromelia called phocomelia

A: Brachydactyly, B: Syndactyly, C: Polydactyly, D: Cleft foot, lobster claw deformity

OSSIFIKASI ENDOCHONDRAL PADA TULANG PANJANG

Ossifikasi Endochondral

• Pusat ossifikasi primer diaphysis

• Pusat ossifikasi sekunder epiphysial plate

Sistem Muscular

• Otot skelet Paraxial mesoderm

• Otot polos dan jantung splanchnic mesoderm

• Otot skelet dari dermomyuotome:

– ventrolateral edge or lip (VLL) (hypomeric, hypaxial) musculature

– dorsomedial edge or lip (DML) epimeric, epaxial musculature

Korelasi klinis

Poland anomalyPrune belly syndrome

MIOLOGI UMUM

• Ada 3 type Otot:

– Otot Skelet

– Otot Jantung

– Otot Halus

• Fungsi:

1.Alat gerak aktif

2.Penyokong statis

3.Memberi bentuk tubuh

4.Penyedia panas

Komponen Otot skelet

• Caput (bellies) a fleshy contractile portion

• Tendon dan aponeurosis a white non-contractile portion composed mainly of collagen bundles

• Otot skelet melekat ke: tulang, kartilago, ligamentum, atau kombinasi struktur tersebut, organ (contohnya?), membran mukosa (contohnya?), dan kulit (contohnya?)

• Otot skelet melekat melalui tendon atau aponeurosis

Penamaan Otot Skelet

• Berdasarkan fungsi contohnya? m. abductor digiti minimi

• Berdasarkan nama tulang tempat melekat m. sternocleidomastoid

• Berdasarkan bentuk dasar m. deltoideus

• Berdasrakn posisi (lat, med, ant, post), panjang (longus, brevis), ukuran (maximus, minimus), jumlah perlekatan (triceps, biceps)

Otot skelet berdasar bentuk:

– Pennatus = bulu: uni, bi, multi pinnatus

– Fusiform

– Flat

– Quadratus

– Convergent muscles

– Circular muscle

• Tipe otot skelet berdasarkan jenis serabutnya:

– Berdasarkan myoglobin: Otot merah vs Otot putih

– Berdasarkan frekwensi kontraksi: Fast twitch vs slow twitch

– Berdsarkan kedua hal tersebut :

1. slow oxidative fibers

2. fast oxidative-glycolytic fibers

3. fast glycolytic fibers

Slow Oxidative Fibers

• Diameter kecil• large amounts of myoglobin and many blood

capillaries, dark red in color• These slow-twitch• generate ATP mainly by aerobic cellular

respiration• fatigue-resistant fibers • are adapted formaintaining posture and for

aerobic, endurance-type activities such as running a marathon

Fast Oxidative–Glycolytic Fibers

• Diameter sedang

• contain large amounts of myoglobin and many blood capillaries, red

• contribute to activities such as walking and sprinting

• intracellular glycogen level is high

• Generated ATP from aerobic respiration and glycolysis

Fast Glycolytic Fiber

• largest in diameter most powerful contractions

• low myoglobin content, relatively few blood capillaries, few mitochondria, and appear white in color

• contain large amounts of glycogen and generate ATP mainly by glycolysis

• adapted for intense anaerobic movements of short duration lifting or throwing a ball

• fatigue quickly

Kontraksi otot

Tiga jenis kontraksi otot:

– Reflexive contraction

– Tonic contraction

– Phasic contraction:

Isometric contractions

Isotonic contractions

Concentric contraction

Eccentric contraction

Muscles serve specific functions in moving and positioning the body

• A prime mover or agonist

• Fixators

• Synergist

• Antagonist