Lecture 4

Muscle origin

the place where the muscle begins the more fixed and proximal attachment

What are the 2 types of attachments of skeletal muscles?

1) Origin 2) Insertion

Types of fascia

1. Superficial Fascia ■ Is a loose connective tissue membrane between the dermis and the deep (investing) fascia and has a fatty superficial layer (fat, cutaneous vessels, nerves, lymphatics, and glands) and a membranous deep layer. 2. Deep Fascia ■ Is a sheet of fibrous tissue that invests the muscles and helps support them by serving as an elastic sheath or stocking. ■ Provides origins or insertions for muscles, forms fibrous sheaths or retinacula for tendons.

What are the muscular actions?

1.Prime-mover 2. Antagonist 3. Fixator 4. Synergist

Muscles with fibers parallel to line of pull

A Strap-like. B- Fusiform C- Quadrilateral

Antagonist

A character or force in conflict with the main character It is the muscle which opposes the prime-mover e.g. triceps muscle is the antagonist of biceps in flexion of elbow.

Muscles with fibers oblique to line of pull

A- Pinnate: 1- Unipinnate. 2- Bipinnate. 3- Multipinnate. 4- Circumpinnate. B- Non pinnate 1- Triangular 2- Circular

Structures associated with skeletal muscles

A. Tendons B. Ligaments C. Aponeuroses D. Retinaculum E. Fascia

Tendons

Are fibrous cord -like bands of dense connective tissue that connect muscles to bones or cartilage. ■ Are supplied by sensory fibers extending from muscle nerves that make proprioception

aponeurosis

Fibrous or membranous sheet connecting a muscle and the part it moves

Muscle insertion

Location where the muscle ends; the portion away from the body's midline which is the more movable and distal attachment Attachment of voluntary muscles through a medium of fibrous tissue in the form of cord- like tendon or wide sheet of fascia called aponeurosis, as in external and internal oblique aponeurosis.

Proprioception sensation

Sensation of the position perception of joint and muscle movement, body position in space, activity and passive movement

Skeletal muscle

Stripped or voluntary A muscle that is attached to the bones of the skeleton and provides the force that moves the bones.

Smooth muscle

Unstripped Involuntary muscle found inside many internal organs of the body

Cardiac muscle fibers

contractile cells of the heart like stripped muscle fibers but branching. These are involuntary in action. All muscles are derived form mesodermal layer of embryonic disc

Synergist

muscle that aids a prime mover in a movement and helps prevent rotation Aid the action of prime mover& concentrate the action of a prime-mover over the others.

Prime-mover

muscle with the major responsibility for a certain movement It is the primary muscle that start a movement e.g. biceps muscle is the prime-mover of flexion of elbow.

What are the 3 types muscles?

skeletal, smooth, cardiac

Fixator

stabilizes the origin of a prime mover They are muscles which fix the origin of a prime-mover to perform better action. e.g. muscles of clavicle and scapula in movements of upper limb to fix these two bones.

Muscles

tissues or fibers that cause movement of body parts and organs

Skeletal muscle forms

• It depends on direction of muscle fibers to line of pull (imaginary line from origin to insertion). 1- Muscles with fibers parallel to line of pull: 2- Muscles with fibers oblique to line of pull

Ligaments

■ Are fibrous bands that connect bones to bones usually around a joint or cartilage or are folds of peritoneum serving to support visceral structures.

Aponeuroses

■ Are flat fibrous sheets or expanded broad tendons that are found in some muscles and serve as the means of origin or insertion of a flat muscle.

Retinaculum

■ Is a fibrous band that holds a structure in place in the region of joints.

Fascia

■ Is a fibrous sheet that envelops the body under the skin and invests the muscles