Flashcards in Axial Skeleton Deck (83):
What two parts can the skeleton be broken into?
Axial and appendicular
How many bones make up the axial skeleton?
What percent of the bones in the human body are in the axial skeleton?
What do the axial components include?
Skull - 22 bones
Bones associated with skull - 6 auditory ossicles, 1 hyoid bone
Vertebral column - 26
Thoracic cage - 24 ribs, 1 sternum
What is the function of the axial skeleton?
Create a framework that supports and protects organs
What are the two parts of the skull?
Cranium - containing the brain and face
Mandible - lower jaw
How many bones are in the skull?
22 bones. 8 from the cranium and 14 form the face.
What bones does the skull consist of?
What are the superficial facial bones?
How many bones make up the vertebrae?
24 movable bones or vertebrae, the sacrum and coccyx.
What separates the vertebrae?
What 5 parts describe the vertebral column?
7 cervical vertebrae
12 thoracic vertebrae
5 lumbar vertebrae
1 sacrum 5 fused bones
1 coccyx 4 fused bones
What does the spine transfer the weight to?
What regions of the spine have a lordosis curve?
Cervical and lumbar
What regions of the spine have a kyphosis curve?
Thoracic and sacrum
What is the side view of the spine?
Acceptable thoracic kyphosis angle is
thoracic kyphosis angle 20° to 40°
lumbar lordosis angle 30° to 50°
Cranial (cephalad) proximal
What does the spine start as during foetal development?
Cartilaginous model which ossifies into bone
What is the anterior element of the vertebrae?
What are the posterior elements of the vertebrae?
A vertebral or neural arch and articular processes
What is the function of the vertebral body?
To transfer load through the spinal column
What does the edge of the vertebral body contain?
Tiny holes through which blood vessels pass
What does the vertebral arch enclose?
The large vertebral foramen
What does the vertebral arch consist of?
Two pedicles and two laminae
What does each pedicle have on its inferior and superior borders?
A vertebral notch
What do the notches arranged together form?
What projects laterally from where the two pedicles and lamina unite?
What do the two lamina that meet in the midline posteriorly form?
The spinous process
How many articular surfaces does the neural arch have?
4. Two articulate with the vertebra above and two with the one below. They are often referred to as facet joints.
What do the articular processes do?
They interlock the vertebrae, preventing anterior displacement and restricts movement between the vertebrae
How is a vertebral body somewhat like an egg?
It has a dense bony cortex surrounding a spongy medulla.
What is the vertebral plateaux?
The flat surfaces of the superior and inferior aspects of the vertebral body
The periphery is raised to form a distinct rim called the?
Epiphyseal plate that becomes fused at 14-15 years old.
What causes Scheuerman's disease?
Abmormal ossification of the epiphyseal ring
What are the criss-crossing lines of the vertebral body called?
Trabeculae and they add strength
How many kg is required to crush a vertebral body?
What separates the vertebral bodies in the anterior column?
What is the joint between the vertebral bodies?
Symphysis and it's formed by two vertebral plateaux connected by a disc
What are the two parts of the intervertebral disc?
The nucleus pulposus and the annulus fibrosus
What is the nucleus pulposus?
A gelatinous substance containing 88% water that is strongly hydrophilic
What is the nucleus pulposus made up of chemically?
Mucopolysaccharide matrix containing protein bound chondroitin sulphate, hyaluronic acid and keratin sulphate
What is the nucleus pulposus comprised of?
Collagen fibres, cells resembling chondrocytes, connective tissue cells and very few clusters of mature cartilage.
Do blood vessels or nerves penetrate the nucleus?
Where does the nucleus rest?
On the centre of the vertebral plateau on an area covered by cartilage
What happens when a significant force is applied to the column?
Water contained within the gelatinous matrix of the nucleus escapes into the vertebral body through these pores.
What is the annulus fibrosus made up of?
Collagen fibres arranged in layers or lamellae whose construction can be likened to a cross-ply tyre.
What are the thicker outer layers of the lamellae anchored to the vertebral end plates by?
1mm thick layer of hyaline cartilage.
What does the strong woven structure of the annulus prevent?
A prolapse of the nucleus.
What is the spinal cord?
An elongated, almost cylindrical part of the central nervous system.
Where is the spinal cord suspended?
In the vertebral canal surrounded by 3 membranes called the meninges and cerebral spinal fluid CSF. From above, it is continuous with the medulla oblongata and runs from the upper border of the atlas to the lower border of the first lumbar vertebra
What does the spinal cord change into at the first lumber vertebrae?
The cauda equina.
What is the point called where the spinal cord finishes?
The filum terminale
How long is the spinal cord?
45cm long in an adult male and the thickness of the little finger
Where are the two enlarged areas of the spinal cord where the largest nerve roots exit?
C3-T2 and T9-T12
What is the spinal cord?
The nervous tissue link between the brain and the rest of the body
What two equal parts is the spinal cord divided into?
The anterior and posterior sections
What are the two parts divided by?
A shallow median fissure anteriorly adn by the posterior median sulcus posteriorly.
What are the three protective layers called that surround the spinal cord?
What is the outer layer of the meninges called?
What is the periosteum of the vertebrae called?
The epidural space
What is between the arachnoid and the pia mater?
The subarachnoid space which contains CSF.
What is CSF?
Cerebral spinal fluid formed in the choroid plexus of the brain.
Where does the fluid pass?
Through the fourth ventrical in the brain into the subarachnoid space around the brain and spinal cord.
What is the function of the CSF
Provides a cushion that helps protect the spinal cord and is involved in the exchange of nutrients and waste between the blood and the neurons of the spinal cord.
The layers of the spinal cord moving inward are...
Dura matter to
Pia mater to
White matter to
About how many ml of CSF is in the subarachnoid space?
What happens at each segment of the spinal cord?
A pair of nerves branch and exit the H shaped grey matter.
What does each nerve root have?
A ventral root and a dorsal root which meet shortly after leaving the spinal cord to form one nerve which is a mixture of motor and sensory fibres.
How many spinal nerves leave the vertebral canal via the intervertebral foramen?
How many nerves leave each section of the spine?
What do the ventral and dorsal nerve roots combine together to form?
The nerve proper
The nerve divides again into several branches called what?
What are plexuses?
The arrangement of ventral rami in to complex arrangements
What are the different plexuses?
Where does the spinal cord terminate?
How are reflexes used?
To judge the integrity of the sensory/motor nerve loop.
How does a clinician stimulate sensory nerves?
By striking an area of the body where the nerve is close to the surface. The impulse generated travels up the nerve as a sensory impulse through the spinal cord and back down the nerve as a motor impulse. Absence or change in reaction to the stimulus can be used to diagnose nerve disfunction.
What is the dorsal root of each spinal nerve connected to?
A specific region or segment of the body and supplies the sensory innervation to a segment of the skin known as a dermatome.