Axial Skeleton/Skull Flashcards
Parts of the Rib Cage
Sternum, Ribs
Parts of Sternum/breastbone
Manubrium, Body, Xiphoid process
1.) Supra-sternal Notch
2.) Lateral Manubrium
3.) Inferior Manubrium
Superior part of manubrium that articulates with the clavicle.
articulates with first rib
Articulates with the body of the sternum
Sternal Angle/ Angle of Louis
Lies at the junction between the manubrium and body of the sternum
where the second rib attaches, and is opposite the intervertebral disc 4T and 5T.
How many ribs and where do they articulate.
12 pairs
most articulate to the thoracic vertebrate posteriorly and to the sternum anteriorly
True Ribs (1-7)
Connect directly to the sternum by their own cartilage
False ribs (8-10)
attach to cartilage of true ribs rather than the sternum directly
Floating ribs (11-12)
They do not attach to the sternum.
“Typical” rib parts (3-9)
Head, Neck, Body
Head of rib
wedge shape, two articular facets. Inferior facet articulates with he corresponding vertebra, while the superior vertebra above
neck of rib
connects head to body
where connects to the body, there is a rough tubercle which articulates with the corresponding vertebra
body/shaft of rib
flat and curved
contains the costal/subcostal groove
Costal groove: for neurovascular supply of the thorax
atypical Ribs (1,2, 11,12)
First rib: Shortest and flattened with greatest curvature
Head has single
articular facet for T1 vertebral body,
upper surface contains two shallow grooves separated (for Subclavian artery and vein)
Hyoid bone
The hyoid bone is in the neck and is held in place on the C3 vertebra by muscles and
ligaments.
function: stabilize the larynx and serves as an attachment site for the tongue and pharyngeal
muscles
Vertebral Column
7C, 12T,5L, 5S 3-4 Co
Function: solid, protective,
flexible tube maintains posture, and supports the weight of the head and body.
mobility: The cervical,
thoracic, and lumbar vertebrae are mobile, while the sacral and coccygeal are fused.
Vertebral body
Located anteriorly and serves as the main weight-bearing element of the
vertebra
Transverse Process
laterally projecting processes that extend from the junction of the
pedicle and lamina.
Spinous process
posteriorly projecting tip of the vertebral arch that is easily palpated
through the skin
Pedicles
region of the vertebral arch that connects the transverse process to the vertebral
body.
Laminae
region of the vertebral arch that connects the spinous process to the transverse process.
The Vertebral Arch
Consists of paired pedicles and laminae.
Superior articular process inferior articular process.
Articular surfaces that project superiorly and inferiorly from the vertebral arch
They articulate with adjacent vertebrae, forming facet (zygapophyseal)
synovial joints.
Vertebral foramen and the vertebral canal
Formed by the vertebral arch and vertebral body, contains the spinal cord.
vertebral canal: The stacked vertebral foramina of the entire vertebral column
Intervertebral (neural) Foramina
bilateral openings between every pair of adjacent
vertebrae where the spinal nerves communicate between the spinal cord and body tissues.
Intervertebral disc
function: cartilage shock absorber between adjacent vertebra bodies
made of:
1.) annulus Fibrosis: tough fibrocartilaginous outer ring
2.) Nucleus Pulposus: gelatinous core
Cervical/neck vertebrae (7)
- Located in the neck
- Transverse Foramina: transport the vertebral arteries and veins to and from the posterior region of the brain (N.B., vessels pass through all cervical transverse foramina except C7).
- spinous processes of the cervical vertebrae are often bifid or forked.
- Cervical (C1)/ atlas: articulates with the occipital bone and “holds” the weight of the skull.
- Cervical (C2)/axis: =articulation with the atlas, via the dens (odontoid process), enables rotation of the skull. In other words, the skull rotates because of the dens, hence the name “axis.”
- cervical (C7) vertebral prominens: The most prominent spinous process at the base of the neck.
Thoracic vertebrae (12)
- Located in the thoracic region.
- Transverse process: contains 12 Costal facets are present for articulation with the 12 pairs of ribs.
- spinous processes are thin and point inferiorly.
Lumbar vertebrae (5)
- Located in the lower back.
- Mammillary process: is a posterior projection arising from the superior articular process
- Spinous processes are thick and point posteriorly.
- Their Vertebral bodies are large and blocklike.
Sacrum (5 fused vertebrae)
- Located between os coxae.
- Sacral foramina: Spinal nerves traverse the sacral foramina that flank the vertebral bodies.
- Sacroilliac joint: The lateral surfaces of the sacrum articulate with the ilium of the os coxae to form sacroiliac joints.
- Sacral canal is located posterior to the body.
- Sacral Promontory: sharp anterior projection from the superior surface of the first sacral vertebral body.
- Sacral Hiatus: inverted U-shaped gap in the inferior part of the vertebral canal.
Coccyx (3 to 4):
- Located below the sacrum, the coccyx is also called the “tailbone.”
- Commonly fuse together to form a single small triangular bone that articulates at its base with the lower end of the Sacrum
Clinical Correlates
The sacrum may consist of six vertebrae due to due to the incorporation of:
a.) first coccygeal vertebra into the sacrum, l
b.) Sacralization of the L5: last lumbar vertebra fused to S1; normal anomaly
Rarely, there may be a reduction in sacral vertebrae
a.) Lumbarization of the S1: normal anomaly called Lumbarization of the S1.
The bodies of the sacral vertebrae usually do not unite with each other until about 20 years old; the central area of the body and the intervertebral discs may remain unossified well into middle age.
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