Cervical Vertebrae. Seven vertebrae (C 1 -C 7 ) are the smallest, lightest vertebrae C1 & C2 are atypical C 3 -C 7 are typical

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1 Cervical Vertebrae Seven vertebrae (C 1 -C 7 ) are the smallest, lightest vertebrae C1 & C2 are atypical C 3 -C 7 are typical Oval body & wider side to side short spinous processes (except C7) and is bifid (split at its tip) vertebral foramina is large and triangular Each transverse process contains a transverse foramen thru which the vertebral arteries pass to service the brain C7 spinous process is larger and not bifid C7 vertebra prominens (can be seen thru the skin) is the landmark for counting.

2 Cervical Vertebrae Table 7.2.2

3 Cervical Vertebrae: The Atlas (C 1 ) No intervertebral disc between C1 &C2 The atlas has no body and no spinous process It consists of anterior and posterior arches, and two lateral masses Each lateral mass has articular facets on both its superior and inferior surfaces The superior surfaces of lateral masses articulate with the occipital condyles The inferior surfaces articulate with the Axis (C2)

4 Cervical Vertebrae: The Atlas (C1) Figure 7.16a, b

5 Cervical Vertebrae: The Axis (C 2 ) The axis has a body, spine, and vertebral arches as do other cervical vertebrae Unique to the axis is the dens, or odontoid process, which projects superiorly from the body and is cradled in the anterior arch of the atlas The dens fuses w/ axis during embryonic development the axis is held in place by the transverse ligament of the atlas at the atlas anterior arch (see next slide) The dens is a pivot for the rotation of the atlas

6 Cervical Vertebrae: The Atlas (C 2 ) Figure 7.17a

7 Regional Characteristics of Vertebrae Table 7.2.1

8 Regional Characteristics of Vertebrae Table 7.2.2

9 Thoracic Vertebrae There are twelve vertebrae (T 1 -T 12 ) all of which articulate with ribs T1 is similar to C7 in structure T12 is similar to L1 in structure Increase in size from T1 to T12

10 Thoracic Vertebrae: Unique Characteristics Body is heart-shaped. Two small facets on each side of body Superior costal facet Inferior costal facet Receive the heads of the ribs T10-T12 possess only a single costal facet The vertebral foramen is circular The spinouse process is long and points downward The transverse processes have facets (transverse costal facets) that articulate with the tubercles of the ribs The superior and inferior articular facts lie in a frontal plane not allowing flexion/extension but do allow rotation

11 Lumbar Vertebrae The five lumbar vertebrae (L 1 -L 5 ) are located in the small of the back and have an enhanced weight-bearing function Unique characteristics: Pedicles & laminae are shorter & thicker than other vertebrae Spinous processes are short and flat and hatchet shaped (seen when you bend over) attahcment site for muscles Vertebral foramen is triangular Orientation fo facets differ from other types: They lock the lumbar vertebrae together and provide stability by preventing rotation of the lumbar spine

12 Lumbar Vertebrae Figure 7.17c

13 Sacrum Sacrum Consists of five fused vertebrae (S 1 -S 5 ), which shape the posterior wall of the pelvis It articulates with L 5 superiorly, with the auricular surfaces of the hip bones laterally forming the sacroiliac joints, and with the coccyx inferiorly Major markings include: the sacral promontory which bulges anteriorly into the pelvic cavity transverse ridges that mark lines of fusion The anterior sacral foramina that transmits blood vessels and sacral spinal nerves Median sacral crest Posterior sacral foramina Lateral sacral crests sacral canal: the continuation of the vertebral canal Sacral hiatus: failure of fusion of the 5 th laminae

14 Coccyx Coccyx (Tailbone) The coccyx is made up of four (in some cases three to five) fused vertebrae that articulate superiorly with the sacrum Muscle attachment to 9 muscles used for various movements including excretion

15 Bony Thorax (Thoracic Cage) The thoracic cage is composed of the thoracic vertebrae dorsally, the ribs laterally, and the sternum and costal cartilages anteriorly The costal cartilage secures the ribs to the sternum

16 Bony Thorax (Thoracic Cage) Functions Forms a protective cage around the heart, lungs, and great blood vessels Supports the shoulder girdles and upper limbs Provides attachment for many neck, back, chest, and shoulder muscles Uses intercostal muscles to lift and depress the thorax during breathing

17 Bony Thorax (Thoracic Cage) Figure 7.19a

18 Bony Thorax (Thoracic Cage) Figure 7.19b

19 Sternum (Breastbone) A dagger-shaped, flat bone that lies in the anterior midline of the thorax Results from the fusion of three bones the superior manubrium, the body, and the inferior xiphoid process

20 Sternum (Breastbone) Manubrium: Body: Articulates via clavicular notches with clavilcles laterally Articulates with the first 2 rib pairs Articulates with cartilage of the 2 nd -7 th ribs Xiphoid process: Articulates with the sternal body and attachment point for some abdominal muscles

21 Sternum (Breastbone) Anatomical landmarks: CAN PALPATE ALL OF EM jugular (suprasternal) notch: Superior border of the maubrium In line with T2-T3 intersection Point where left common carotid artery splits from the aorta sternal angle: Hinge Allows sternal body to move forward upon inhalation Inline with T4-T5 intersection Inline with 2 nd pair of ribs xiphisternal joint: Lies opposite T9

22 Ribs Figure 7.19a

23 Ribs There are twelve pair of ribs forming the flaring sides of the thoracic cage All ribs attach posteriorly to the thoracic vertebrae The superior 7 pair (true, or vertebrosternal ribs) attach directly to the sternum via costal cartilages Ribs 8-10 (false, or vertebrochondral ribs) attach indirectly to the sternum via costal cartilage (or not at all) Costal margin: inferior margin of the rib cage Each joins the costal cartilage immediately above it Formed b y costal cartilage of ribs 7-10 Ribs (floating, or vertebral ribs) have no anterior attachment

24 mmmmm.ribs The typical rib is a bowed flat bone The bulk of the rib is the shaft Superior border is smooth Inferior border is sharp, thin and has a costal groove on its inner face that lodges the intercostal nerves and blood vessels The neck is the constricted portion beyond the head The head is the posterior most end and articulates with the vertebral bodies by 2 facets: i) joins the body of the same-numbered thoracic vertebra ii) joins the body of the vertebra immediately superior Tubercle: articulates with the costal facet of the transverse process of the same numbered thoracic vertebrae

25 Structure of a Typical True Rib Bowed, flat bone consisting of a head, neck, tubercle, and shaft Figure 7.20a

26 Structure of a Typical True Rib Bowed, flat bone consisting of a head, neck, tubercle, and shaft Figure 7.20b

27 Appendicular Skeleton The appendicular skeleton is made up of the bones of the limbs and their girdles Pectoral girdles attach the upper limbs to the body trunk Pelvic girdle secures the lower limbs

28 Pectoral Girdles (Shoulder Girdles) Figure 7.22a

29 Pectoral Girdles (Shoulder Girdles) The pectoral girdles consist of: Clavicle anteriorly & scapula posteriorly Anteriorly, the medial end of each clavicle joins the sternum The distal ends of the clavicle meet the scapulae laterally The scapulae are attached to the thorax & vertebral column by muscles The clavicle and scapula are light weight and very mobile However, there is a price to pay greater mobility means poor stability often resulted in a painful dislocated shoulder

30 Clavicles (Collarbones) Figure 7.22b, c

31 Clavicles (Collarbones) The acromial (lateral) end articulates with the scapula, and the sternal (medial) end articulates with the sternum The superior surface is smooth while the inferior surface is ridged and grooved by ligaments Provide attachment points for numerous muscles, and act as braces to hold the scapulae and arms out laterally away from the body The clavicles transmit compression force from the upper limbs to the axial skeleton

32 Scapulae (Shoulder Blades) Figure 7.22d

33 Scapulae (Shoulder Blades) Triangular, flat bones lying on the dorsal surface of the rib cage, between the 2 nd and 7 th ribs Scapulae have three borders: Superior: shortest, sharpest Medial (vertebral): paralles the vertebral column Lateral (axillary): abuts the armpit and ends superiorly in the glenoid cavity which articulates with the humerus Scapulae have three angles: Superior angle: superior scapular border meets the medial border Lateral angle: superior scapular border meets the lateral border Inferior angle: medial & lateral borders meet Moves extensively with arm raising

34 Scapulae (Shoulder Blades) The posterior surface of the scapula has a prominent spine (palpate) The spine terminates laterally at the acromion The acromion articulates with the acromial end of the clavicle forming the acromioclavicular joint The coracoid process anchors the biceps The suprascapoid notch allows a passage way for nerves The infraspinous, supraspinous, subscapular fossae are sites for muscle attachment (later this semester)

35 Scapulae (Shoulder Blades) Figure 7.22e

36 Scapulae (Shoulder Blades) Figure 7.22f

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