myotome

1. The segment of a somite in a vertebrate embryo that differentiates into skeletal muscle.
2. A muscle or group of muscles derived from one somite and innervated by a single segment of a spinal nerve.

1. The segment of a somite in a vertebrate embryo that differentiates into skeletal muscle. Also called muscle plate.
2. A muscle or group of muscles derived from one somite and innervated by a single segment of a spinal nerve.
3. A knife for dividing muscle.

1. an instrument for dividing muscles.
2. the muscle plate or portion of a somite that develops into voluntary muscle.
3. a group of muscles innervated from a single spinal nerve.

Myotome
Scheme showing the manner in which each vertebral centrum is developed from portions of two adjacent segments. (Myotome labeled in upper right.)
Transverse section of a human embryo of the third week to show the differentiation of the primitive segment. ao. Aorta. m.p. Muscle-plate. n.c. Neural canal. sc. Sclerotome. s.p. cutis-plate. ("Muscle-plate" is an older term for "myotome.")
Gray's	subject #17 80
Carnegie stage	13/14
Precursor	somite
Gives rise to	muscle

In vertebrate embryonic development, a myotome is a group of tissues formed from somites that develop into the body wall muscle.

Each myotome divides into a dorsal epaxial part and a ventral hypaxial part.

The epaxial muscle mass loses its segmental character to form the extensor muscles of the neck and trunk.

The myoblasts from the hypaxial division form the muscles of the thoracic and anterior abdominal walls.

The term "myotome" is also used to describe the muscles served by a single nerve root.^[1] It is the motor equivalent of a dermatome.

See also

Dermatome (Anatomy)

References

1. ^ myotome at eMedicine Dictionary

External links

• Embryology at UNSW Notes/skmus7
• Embryology at UNSW Notes/week3_6
• mslimb-009 — Embryology at UNC

v • d • e Developmental biology > Human embryogenesis (development of embryo) and development of fetus First three weeks Week 1 Fertilization · Egg activation · Zygote · Cleavage · Morula · Blastula (Blastomere) · Blastocyst · Inner cell mass Week 2 (Bilaminar) Hypoblast · Epiblast Week 3 (Trilaminar) Germ layers Archenteron/Primitive streak (Primitive pit, Primitive knot/Blastopore, Primitive groove) · Gastrula/Gastrulation · Regional specification Ectoderm Surface ectoderm · Neuroectoderm · Somatopleure · Neurulation · Neural crest Endoderm Splanchnopleure Mesoderm Chorda- · Paraxial (Somite/Somitomere/Sclerotome/Myotome/Dermatome) · Intermediate · Lateral plate (Intraembryonic coelom, Splanchnopleure/Somatopleure) Extraembryonic/ uterus Trophoblast (Cytotrophoblast, Syncytiotrophoblast) Blastocoele · Yolk sack/exocoelomic cavity · Heuser's membrane · Extraembryonic coelom · Vitelline duct Umbilical cord (Umbilical artery, Umbilical vein, Wharton's jelly) · Allantois Placenta · Decidua (Decidual cells) · Chorionic villi/Intervillous space · Gestational sac (Amnion/Amniotic sac/Amniotic cavity, Chorion) Histogenesis Programmed cell death (Apoptosis) · Stem cells · Germ line development Organogenesis Limb development: Limb bud · Apical ectodermal ridge/AER other structures: Eye development · Cutaneous structure development · Heart development · Development of the urinary and reproductive organs (Some dates are approximate—see Carnegie stages and a timeline.)

This developmental biology article is a stub. You can help Wikipedia by expanding it.

This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)