Week 1 Flashcards
What is fascia
Connective tissue containing varying amounts of fat that separate, support and interconnect organs and structures enable movement of one structure relative to another and allow the transit of vessels and nerves from one area to another
Superficial fascia
Subcutaneous connective tissue lying beneath and merging with the dermis . Attaches skin to rets of body
Categorised as fibrous fatty tissue and consists of various proportions of fibroblasts, aqueous matrix, elastin and collagen fibres and fat and immune cells
It allows movement of the skin over deeper areas of the body, acts as a conduit for vessels and nerves and serves as a metabolic reservoir
When is the only time the skin is separated from superficial fascia
When friction blisters of the skin develop, the inflammatory reaction of the friction burn leads to tissue fluid leaking out of the circulatory system and to separation of the skin from its superficial fascia. The skin over a blister soon dies because it is separated from its arterial supply
Deep fascia
The investing layer- most superficial, continuous throughout the body and wraps the body wall and limbs in a membrane of tough fibrous connective tissue that separates them from the skin and its attendant superficial fascia
Deep layer- inward continuations from the investing layer of deep fascia, in limbs deep fascia gives rise to intermuscular septa, interosseous membranes and periosteum. Lead to structural partitioning of a limb into distinct and separate muscular compartments
Muscular compartments
A typifying feature of muscles of a particular compartment is that they have common functions and share common innervation, arterial supply, venous drainage and lymphatics
If there’s a bleed or fluid accumulation within a muscular compartment of a limb this has the potential to escalate to a medical emergency within a short time this is the basis of compartment syndrome
Tendons
Dense regular connective tissue by consolidation of collagen fibres derived from the connective tissue envelopes that unsheathe the skeletal muscles
Act as sites of attachment of muscles to bone, bring about displacement of a bone about its joint
Axial skeleton
Skull, ribs and vertebrae
Appendicular skeleton
Upper limbs, lower limbs etc
Cartilage
Specialised type of hard connective tissue
Classified into hyaline, fibrous and elastic cartilage
Ligaments
Help to stabilise moveable joints
Dense regular connective tissue, tightly packed collagen bundles arranged in parallel so that they respond to mechanical stress from a single direction
Attach bones to bones
Bursae
Fluid filled sacs lined with a delicate smooth membrane, the synovial membrane, which is responsible for secreting synovial fluid
Found wherever tendons rub against bones, ligaments or other tendons and they allow skin to move easily over bony prominences
They’re completely sealed but in some places there’s communication between the bursal cavity and a synovial cavity
Fibrous joints
These occur when adjacent bones are connected by fibrous connective tissue. These are further divided into:
Sutures- which occur between most of the bones in the cranium
Syndesmoses- bones are more widely separated but are held together by either ligaments or wide sheets of connective tissue called interosseous membranes
In the jaws teeth are fit into the alveoli (bony sockets), the narrow fibrous joint between these and the roots of a tooth is called gomphosis
Cartilaginous joints
Bones are either connected through either hyaline cartilage or fibrocartilage
Primary cartilaginous joints (synchondroses) bones are united by hyaline cartilage, they occur primarily in bone growth, between the epiphysis and the diaphysis of long bones
Secondary cartilaginous joints (symphyses) are connected by fibrocartilage and tend to occur down the axis of the body they allow some restricted movement
Synovial joints
Allow for free movement between the bones and are the most common joints in the body
They consist of the articulating surfaces, a joint cavity between them and an articular capsule surrounding them
Articular cartilage comprises a special type of hyaline cartilage
Synovial joints are further classified in different groups depending on the shape of the adjacent bones and the angle they form
The shape will dictate the range of movement allowed
Agonist muscle
prime mover
The main muscle or muscle group directly responsible for a specific movement
Antagonist muscle
The muscle or muscle group that has the opposite action of a given agonist this helps the agonist perform its action
Synergists and fixators
Muscle/ muscle group which assists the agonist
These terms are sometimes used interchangeably but fixators have also a role in stabilising the joint whilst the agonist act
Isotonic contraction
Length of muscle changes, tension remains the same
The muscles can either lengthen( eccentric) or shorten (concentric)
Isometric contraction
The muscle is tense but maintains the same length
Why do ligaments and tendons heal slowly
They are poorly vascularised
What is a fascial compartment
A section within the body that contains muscles and nerves and is surrounded by deep fascia
Unipennate muscle
Fibres arranged obliquely to tendon only on one side
Feathered
E.g.extensor digitorum
Mulitpennate
Fibres diagonal multiple rows branching into one or more tendons
E.g deltoid muscle
Circular muscle
Concentrically arranged bundles of muscle fibres
E.g sphincters
Two-bellied muscle
Two separate muscle bellies united by an intermediate tendon
E.g. digastric muscle (located under the jaw)
E.g suspensory muscles of duodenum, omohyoid, occipitofrontalis
Convergent muscle
Broad origin, pointed insertion, lots of fibres one tendon
E.g pectoralis major
Fusiform muscle
Spindle shaped, tethered each end
E.g biceps
Bipennate muscle
Fibres both sides of tendon diagonal
E.g rectus femoris
Strap/flat muscle
Fibres parallel
E.g sartorius and sternocleidomastoid (strap)
E.g. anterolateral abdominal wall- external, internal oblique, transversus abdominis (flat)
Long bones
Longer than wide
Strength, structure, mobility
E.g femur
Short bones
As wide as long
Support, stability, little movement
E.g carpals
Flat bones
Thin, flat, thin layer of compact bone surrounding spongey bone, protection
E.g. ilium
Irregular bones
Any shape that dont fit
Various functions e.g protection of nervous tissue
E.g. vertebrae
Sesamoid bones
Usually short or irregular bones embedded in a tendon
E.g. patella
What makes joints stable
Ligaments
Relation between stability and mobility
Mobility relates to movement, stability relates to control, stability is defined as the ability to maintain control of joint movement or position
What is flexibility
The ability of a joint to move through an unrestricted, pain free range of motion
Anatomical range of movement in a joint or series of joints
Types of joints movements
Synarthroses- immovable
Amphiarthroses-slightly moveable e.g intervertebral disc
Diarthroses-freely moveable
Musculoskeletal system components
Skeleton: bone and cartilage
Muscles and tendons
Ligaments
Structure of skeletal muscle
Fascia around muscles
Muscle belly-wrapped in connective tissue- epimysium
Fascicle- perimysium
Muscle fibre- endomysium
Myofibrils
Myofilaments
Muscles are well supplied with nerves and blood vessels
Blood supply to muscles
Main artery (and accompanying veins and nerve) usually enters deep surface of muscle
Accessory arteries enter elsewhere
Blood vessels tend not to bridge between muscles (to avoid tearing)
‘Muscle pump’ acts on intramuscular veins with valves
Innervation of muscles
Most muscles in face, neck and limbs supplied by single nerve
Abdominal wall muscles supplied by multiple nerves
Nerves contains motor neurons and sensory neurons
Development of muscle
Skeletal muscle develops from the myotome of the somite
Somite is Split into sclerotome and dermomyotome
Myotome is a block of muscle supplied by one spinal nerve
Growth and repair of muscle
Prenatal muscle growth -almost exclusively growth in number of muscle fibres
Postnatal muscle growth- almost exclusively growth in size of muscle fibres- hypertrophy
Hypertrophy of muscles
Occurs when muscle stem cells (satellite cells) merge into muscle fibre, stimulated by:
-muscle overloading/resistance training
- protein ingestion
-various hormones e.g. IGF-I, growth hormone, testosterone
Muscle atrophy occurs with underuse, age, chronic inflammation, neuropathies
Function of muscles
Skeletal muscles attach to bones to produce movements
Fixed point of origin; mobile point of insertion
The force of the contracting muscle fibres is directed along the line of the tendon
Think about how the function of a muscle is linked to its shape and position
Strap muscles
Long and thin
Develop low forces but long range of contraction
Pennate muscles
Large number of fibres
Larger forces but shorter range of contraction
Spiral muscles
Cause rotation as they contract
Muscle attachments
Muscles attach usually to bone via:
Tendons- collagen- rich cords or straps
Aponeuroses- sheet like tendons
Fascia - dense connective tissue
Fleshy/direct (epimysium directly attaches to periosteum)
Bursae and tendon sheaths
Filled with synovial fluid
Bursae-pockets of synovial fluid between/under muscles or tendons, under ligaments, under skin
Sheaths- wrap around tendon,have synovial fluid, allow tendon to travel smoothly, movement
