The Notion Of Cavities, Bony Spaces, Compartments And Their Neuronal Innervation

Question 1

What is bone?

Answer 1

• it is a living tissue of the body that forms the skeleton of the body
• it is constituted from dense connective tissue and thus made from: cells (secretion), fibres (connective tissue), matrix (ground substance)

Question 2

What are the 2 forms of bone?

Answer 2

Compact bone
- solid mass of dense connective tissue
Cancellous bone
- branching network of trabeculated dense connective tissue

Question 3

What are the 5 classes of bone?

Answer 3

• Flat
• Short
• long
• irregular
• sesamoid

Question 4

What is seen in the cross section of flat bones?

Answer 4

• Tri-laminar:
• Compact bone (outer table)
• trabecular bone (diploe) - contains bone marrow
• compact bone (inner table)
• Inner and outer tables are lined with periosteum
  Flat bones are considered strong and protective due to 3 layers of bone and 2 layers of compact

Question 5

what are flat bones used for?

Answer 5

trapping bone marrow

Question 6

what is a long bone?

Answer 6

a bone that is longer than it is wide and had a marrow cavity in the middle (excluding clavicle which has no cavity and so a modified long bone)

Question 7

What are the 2 surfaces of a long bone?

Answer 7

(due to a marrow cavity)

• inner surface - lines the marrow cavity
• outer surface - forms the outer margin of the bone

Question 8

what are the 2 surfaces of the long bone lined by?

Answer 8

• periosteum - lines the outer surface

- endosteum - lines the inner surface

Question 9

what is the importance of periosteum?

Answer 9

• generates cells known as osteoblasts (osteoclasts & osteocytes)
• rich blood supply that nourishes bone
• maintains bone in healthy state
• repairs bone in case of fractures
• rich innervation from sensory nerves of somatic nervous system for pain sensation from bone

Question 10

what is the gross structure of the periosteum (or endosteum)?

Answer 10

• fibrous layer (outer)
• cellular later (inner)
• collagen fibres of the periosteum are continuous with those of bone, adjacent joint capsule, tendon and ligaments

Question 11

what is the lining of cartilage called?

Answer 11

• soft tissue known as perichondrium

Question 12

what are the components of cartilage?

Answer 12

• periochondrium
• mesenchyme cell (chondroblast)
• extracellular matrix containing chondroytes (which are within lacuna), proteoglycans, collagen and hyaluronic acid)
• periochondrium

Question 13

what is the gross structure of perichondium?

Answer 13

• fibrous layer (outer) - maintained by fibrocytes

- cellular layer (inner) - chondrogenic layer which generates cartilage itself (chondrocytes)

Question 14

what is a bony space?

Answer 14

Surfaces of bones onto which muscles, tendons, ligaments and soft tissues attach
Can be sites for pathologies

Question 15

what are fossae?

Answer 15

superficial ditches on surfaces - used as support or receive another bone

Question 16

what are para nasal sinuses?

Answer 16

• series of strategically organised, hollow spaces of cavities within bones of the head

Question 17

what characteristics do paranasal sinuses have?

Answer 17

• open into nasal cavity
• are lined by:
  : periosteum (like any bone)
  : secretory epithelium (pseudo-stratified columnar epithelium (ciliated with goblet cells for blood supply)) - thin membrane that is continuous and so same as nasal cavity

Question 18

how is epithelium lining of paranasal sinuses innervanted?

Answer 18

@ somatic sensory
- derived from sensory division of trigeminal nerve
- sensations are somatic and therefore we are consciously aware
- pain, temperature, irritation etc.
@ autonomic parasympathetic innervation
- efferent division of ANS
- increase secretions from nasal cavity and paranasal sinuses
- commonly derived from the autonomic division of CN VII (greater petrosal branch of this)

Question 19

what is the structure of muscles of body wall (generic overview)?

Answer 19

• muscle fibres lie in different slopes of obliquity
• intermediate layer is reinforced with bony condensation (ribs) to a cranio-caudal extent
• outmost layer passes outside ribs
• innermost layer passes inside ribs
• all three layers are inner ages segmentally by anterior primary rami

Question 20

what are the tissue layers of the anterior abdominal wall?

Answer 20

SUPERFICIAL ==> DEEP

• skin edge
• camper fascia (superficial fatty layer of subcutaneous tissue)
• scarpa fascia (deep membranous layer of subcutaneous tissue)
• investing fascia - superficial
• external oblique
• investing fascia - intermediate
• internal oblique
• investing fascia - deep
• transversus abdominis
• endoabdominal (transversalis) fascia
• extraperitoneal fat
• parietal peritoneum

Question 21

why is it difficult to work out boundaries of major cavities?

Answer 21

they all continue onto one another

Question 22

Structure of tissues in cranial cavity

Answer 22

• Skull
• Dura
• Arachnoid
• Pia mater
• Brain tissue

Question 23

what is the cranial cavity?

Answer 23

• has a closed box like compartment of the head created from sutures between bones of the cranium
• special lining by 3 layers of connective tissue deep in the internal layer of the periosteum - meninges
• meninges receive somatic sensory innervation from the sensory division of the trigeminal nerve (headache)

Question 24

what are the main sub-compartments the meninges separate the intracranial compartment into?

Answer 24

• supra-tentorial compartment

- infra-tentorial compartment

Question 25

what is the structure of tissues in the thoracic cavity?

Answer 25

• chest wall
• parietal pleura
• pleural cavity
• visceral pleura
• lung

Question 26

what lines the abdominopelvic cavity?

Answer 26

periotneum

Question 27

what is the abdomen divided into?

Answer 27

• intra-peritoneal zone (or just peritoneal)

- extraperiotenal zone (retro peritoneal zone)

Question 28

what is the intra peritoneal zone divided into?

Answer 28

greater sac

lesse sac

Question 29

what are important anatomical pouches (slide 35)

Answer 29

?