1.2.2 Makeup of Muscle & 1.2.5 Joints in Motion

Muscle>Fasicle>Muscle Fiber>Myofibril
Epimysium covers muscle, Perimysium covers fasicle, Endomysium covers muscle fibers.

6 Muscle Rules

1. Muscles must have at least 2 attachments and must cross at least one joint

2. Muscles always “pull” and get shorter

3. The attachment that moves is known as the insertion; the attachment that remains stationary is known as the origin

4. Muscles that decrease the angle between ventral surfaces of the body are known as flexors; Muscles that increase the angle are known as extensors

5. Muscles work in opposing pairs

6. Muscle striations point towards the attachments and show the direction of the pull.

Sprains, Strains, Tears

• Sprain: injury to ligament (connects bone to bone) due to overstretching

• Strain: injury to tendon/muscle due to overstretching

• Tear: serious injury when ligament/tendon is torn apart

7 classification categories of muscle names 

1. Shape (for ex., trapezius)

2. Size (for ex., gluteus maximus)

3. Location (for ex., frontalis)

4. Direction of fibers (for ex., Obicularis Oculi)

5. Action (for ex., Flexor Carpi Ulnaris)

6. Origin+Insertion (for ex., Brachioradialis)  

7. Number of attachment points (for ex., Biceps Brachii)

Types of Joints

• Fibrous Joints: Fixed/immobile joint. Mostly made of cartilage

• Cartilaginous Joints: Joint with some motion. Made of hyaline cartilage

• Synovial Joints: Most common joint. Movable joint with fluid in between bones.

Types of Synovial Joints

1. Hinge Joint: Bends/straightens. Flexion/extension

2. Saddle Joint: Back and Forth, side to ride, no rotation

3. Ball and Socket Joint: Forwards/backwards, sideways, with rotation

4. Condyloid Joint: Up/down and side to side

5. Plane Joint: Gliding motion between 2 flat/slightly curved bones

6. Pivot Joint: Limited rotation around an axis

Types of Range of Motion Movements

• Rotation: turns on a single axis

• Circumduction: circular motion (makes a cone)

• Elevation: moves up

• Depression: moves down

• Flexion: decrease angle (bending)

• Extension: increase angle (straighten)

• Abduction: moves away from midline

• Adduction: moves towards the midline 

• Plantar flexion: toes down

• Dorsiflexion: toes up

Types of Cartilage

• Articular (Hyaline): Cushion joints, protect bone, supports weight. Found on ends of bone condyles

• Elastic: Provides structural support. Found in the ear, nose, and epiglottis

• Fibrocartilage: For shock absorption. Found in between vertebrae and in pelvis.

Cartilage is a flexible connective tissue that provides shape and support to various body parts and cushions bones (allowing for movement and flexibility).