Anatomy & Physiology I

SELECTED BONES AND MARKINGS

Prof. Atsma/Summer 2004

Introduction: Following are tables which describe selected bones and their most important markings. Find and be able to identify these bones/markings on the bones provided in your laboratory or the ALC.

Part 1

AXIAL SKELETON

Skull

Bone

Markings

1. FRONTAL - "forehead" bone extending from the superior eye sockets to the top of the skull

Frontal sinus* - located within the central, anterior portion area

Supraorbital foramen - small holes just above the eye sockets

2. PARIETAL - two large bones that make up most of the top and sides of the skull

NA

3. TEMPORAL - inferior to the parietals; partially covered by the ears; also curves under the earlobe area; described as having a squamous (flat) region and a petrous (irregular) region.

Zygomatic process - slender portion extending anterior (together with the slender portion of the zygomatic = zygomatic arch)

Mandibular fossa - small depressions where the mandible attaches

External auditory meatus - the canal for the passage of sound vibrations through each temporal bone to the middle ear

Mastoid process - the large, blunt projections pointing inferiorly

Mastoid sinus * - hollow area in the mastoid portion

Styloid process - the 'needle-like' projections on the underside of the temporal bones

4. OCCIPITAL - posterior/inferior part of the skull/braincase.

Foramen magnum - large hole in the inferior portion of the occipital for the passage of the spinal cord

Occipital condyles - the two mostly lateral bumps around the foramen magnum

External occipital protuberance and crest - small posteriorly pointing bump and ridge; nicknamed the occipital bun by anthropologists after the old hairstyle.

*Internal and only visible on cut/disarticulated skulls

Skull (continued)

Bone

Markings

5. ZYGOMATIC - the "cheekbones;" the processes of the zygomatic and temporal bones meet to form the "zygomatic arch"

 

NA

6. MAXILLA - "upper jaw bone;" also extends upward to form part of the eye socket and nasal cavities; curves into the roof of the mouth

Palatine (horizontal) process - the anterior 3/4 of the "hard palate"

Infraorbital foramen - two small holes under each eye socket

Alveoli - small sacs for the roots of each tooth

Maxillary sinus* - located laterally within the maxilla

7. PALATINE - this small, separate bone finishes the last 1/4 of the "hard palate"; really a pair of fused bones, as are many of the bones of the face.

NA

8. MANDIBLE - "lower jaw bone"

Body - the horseshoe-shaped, anterior 3/4 of the mandible where the teeth attach

Mental foramen - two small holes near the front of the mandible for the passage of nerves/ blood vessels

Ramus - the posterior 1/4 of the mandible that curves upward from the body

Condyloid process - (A.K.A. mandibular condyle) the blunt, rounded processes that fit into the mandibular fossae of the temporal bones

Coronoid process - the more pointed projections anterior to the condyloid processes

Alveoli - small sacs/sockets for the roots of each tooth

9. LACRIMAL - small rectangular bones barely inside the medial portion of the eye socket; surrounds the lacrimal canals (the holes found medially/inferiorly in the eye socket)

 

*Internal and only visible on cut/disarticulated skulls

Skull (continued)

Bone

Markings

10. NASAL - two fused bones make up the bony 'bridge' of the nose

NA

11. ETHMOID - very irregular bone that forms the roof of the nasal cavity and a small part of the floor of the brain case

Superior and middle conchae - paired curved, feathery bones inside the nasal cavity (the superior cannot be seen except in sagittal cuts of the skull)

Perpendicular plate - plate-like bone making up the superior part of the nasal septum (attaches to the vomer to form the bony nasal septum)

Cribriform plate - flat upper portion of the ethmoid making up a small portion of the floor of the anterior brain case; dotted with small "pin holes" called olfactory foramina (for olfactory nerve fibers)

Crista galli - small "shark fin-like" projection in the middle of the cribriform plate; separates the two olfactory bulbs which send nerve endings through the olfactory foramina.

Ethmoid sinuses* - the irregular folds of the ethmoid are mostly hollow and contain the ethmoid sinuses; visible mainly in damaged "real" bones and diagrams

12. INFERIOR CONCHA - paired curved, feathery bones inside the nasal cavity (the most inferior of the three pairs of conchae)

NA

13. SPHENOID - A "bat" or "butterfly shaped" bone that extends through the skull behind the eyes from temple to temple

Sella turcica - small depression on the back of the butterfly in which the pituitary gland is found (translates to "Turkish saddle")

Pterygoid process - "legs" of the bat/butterfly that extend to the maxilla/palatine bones

Greater wings - large lateral projections that run along the posterior of the eye sockets and end at the area commonly referred to as the "temples"

- Lesser wings - small flat area immediately anterior to the sella turcica

Sphenoidal sinus* - located within the central portion of the sphenoid

*Internal and only visible on cut/disarticulated skulls

Skull (continued)

Bone

Markings

14. VOMER - plate-like bone making up the inferior part of the bony nasal septum

 

 

15. SUTURES - Jagged, immovable joints connecting major skull bones.

Frontal (coronal) - along the frontal plane; posterior border of frontal bone

Sagittal - along the sagittal plane; separates the two parietal bones

Lambdoidal - horseshoe-shaped posterior suture; forms most of the border of the occipital bone, largely separating it from the parietal bones

Squamosal - curves around the upper flat ("squamous") portion of the temporal bones

 

 

16. WORMIAN BONES - (A.K.A. sutural bones) small bones trapped within the sutures

NA

17. HYOID BONE - Single small bone in the neck; not attached to any other bone; anchors some muscles of the mouth/throat

NA

18. EAR OSSICLES - Tiny, specialized bones found between the auditory meatus and the mastoid sinus

Malleus - "hammer"

Incus - "anvil"

Stapes - "stirrup"

*Internal and only visible on cut/disarticulated skulls


VERTEBRAL COLUMN

Bone

Markings

1. "GENERALIZED" VERTEBRA

Body - solid, mostly rounded mass

Transverse process - slender wings that extend laterally

Spinous process - posterior pointing process; may be sharp or blunt

Pedicle - slender connection between body and transverse process

Lamina - slender connection between transverse and spinous processes

Vertebral foramen - opening encircled by all of the above leaving space for the spinal cord and its surrounding tissues

Intervertebral foramina - lateral spaces between vertebrae for the passage of the spinal nerves

Intervertebral discs - fibrocartilaginous discs composing amphiarthrotic joints between bodies of vertebrae

2. CERVICAL - First curved region with 7 vertebrae; proportionally small body

Atlas ("C-1") - ringlike without a body; "yes bone"

Axis ("C-2") - has a second body which actually belongs to the atlas (the dens); "no bone"

Dens (aka odontoid process) - "tooth-like" projection of the axis

Transverse foramina - small holes in transverse processes found only in cervical vertebrae

3. THORACIC - Second curved region with 12 vertebrae; long, thin spinous processes; proportionally intermediate body

Facets - flat surface (for attachment of ribs) on body and transverse process; one pair is found on the transverse processes, the other on the body near the pedicles.

4. LUMBAR - Third curved region with 5 vertebrae; blunt, square spinous processes; proportionally large body

NA

 

Vertebral Column (continued)

Bone

Markings

5. SACRAL (OR "SACRUM") - Slightly curved, shield-like region of fused vertebrae that closes the posterior portion of the pelvis

Sacral foramina - holes for passage of nerves from in between the fused vertebrae

Sacral canal - equivalent to vertebral foramina; longitudinal tunnel for the inferior portion of the spinal cord in the fetus (contains sacral nerves called the cauda equina in adults)

6. COCCYX - several very small vertebrae; vestigial tailbone

NA


Other Bones of the Axial Skeleton

Bone

Markings

1. STERNUM - long flat bone in the middle anterior thoracic area

 

Manubrium - almost square top portion

Body - long middle portion

Xiphoid process - small, sharp inferior portion

2. RIBS - Twelve pairs of long curved bones between vertebrae and sternum; "true ribs" attached to sternum by costal cartilage; "false ribs" attached to sternum indirectly by cartilage of rib of it, and "floating ribs" (last two pair that do not attach to the sternum)

Head - slightly thicker portion attached to the vertebrae

Neck - below head

Tubercle - bump below neck

Shaft - long and uniform in thickness between tubercle and costal cartilage

 

Part 2

APPENDICULAR SKELETON

Shoulder and Arm

Bone

Markings

1. CLAVICLE - "S" curved "collar bone"

NA

2. SCAPULA - flat "shoulder blade" bone

Spine of scapula (aka spinous process) - long raised ridge running from side to side on upper, posterior portion of the bone

Acromion process - lateral flattened extension of the spinous process

Coracoid process - thin, pointed lateral projection

Glenoid cavity (fossa) - (very) shallow depression for the joint made with the humerus

3. HUMERUS - upper arm bone

Head - rounded, medial part of the proximal epiphysis

Anatomical neck - (very) shallow groove directly below the rounded head

Surgical neck - the start of the diaphysis where proximal fractures are more likely to occur

Greater and lesser tubercles - small bumps facing anterior; the greater tubercle is superior to the lesser (not necessarily significantly larger)

Deltoid tuberosity - raised area about 1/3 of the way down the lateral humerus

Capitulum - rounded distal projection

Trochlea - half rounded/half flattened and sharp distal projection; may be thought of as resembling a pizza cutter or pulley.

Medial and lateral epicondyles - somewhat pointed lateral projections above the capitulum and trochlea

Coronoid fossa - shallow anterior depression for the coronoid process of the ulna

Olecranon fossa - deeper posterior depression for the olecranon process of the ulna

 

Shoulder and Arm (continued)

Bone

Markings

4. ULNA - the medial bone of the forearm; runs from elbow toward pinky

 

 

 

Olecranon process - the large bony, posterior/superior projection of the elbow

Coronoid process - the more pointed, slender anterior projection of the proximal ulna; think of the points of a crown/'coronation'

Trochlear notch - (formerly studied as part of the greater semilunar notch) "C-shaped" notch on the anterior surfaces of the two previous processes

Radial notch (aka Radio-ulnar joint) - small smooth area on the side of the coronoid process where the head of the radius attaches

Styloid process - somewhat pointed distal projection

5. RADIUS - the lateral bone of the forearm that ends at the wrist on the thumb side

 

Head - round but flat-topped proximal epiphysis

Neck - area under head

Radial tuberosity - bump below the neck

Styloid process - somewhat pointed distal projection

6. CARPALS - small "short" bones in the wrist

NA

7. METACARPALS - small "long" bones found in the "palm" of the hand

 

 

8. PHALANGES - finger bones; three per finger, two per thumb

NA


Pelvis and Leg

Bone

Markings

9. OS COXA (A.K.A. INNOMINATE OR COXAL BONES) - each forms one side and half of the front of the pelvis

 

Acetabulum - deep lateral fossa for head of the femur; divided like a pie into three imaginary pieces by the bones marked '**' below

ILIUM** - from the upper third of the acetabulum to the top of the os coxa; makes the upper 2/3 of the coxal bone

Iliac crest - thickened upper ridge of ilium

Iliac spines - two points facing anterior/two facing posterior (and somewhat medially); superior spines are at opposite ends of the crest; the inferior spines are about one inch below (and again on opposite sides).

Sacroiliac joint - irregular posterior/medial surface of the ilium where the sacrum attaches to close the posterior of the pelvis

- ISCHIUM** - thicker posterior/inferior portion of the coxal bone

- Ischial tuberosity - the thick, main body of the ischium

- Ischial Spine - one fairly large posteriorly pointing spine

PUBIS** - thinner anterior inferior portion of the coxal bone; the two pubic bones close the pelvis at the front via the pubic symphysis

Ramus of ischium/ramus of pubis - angled extensions of the ischium/ pubis that meet to form a slender bridge at bottom of coxal bone

Obturator foramen - large inferior hole

10. FEMUR - "thigh bone"

Head - obvious rounded projection

Neck - long thin extension connecting the head to the shaft

Greater and lesser trochanters - large bumps between neck and thin portion of the diaphysis; the greater trochanter is superior (and usually larger); the lesser trochanter is posterior/medial and usually smaller

Linea aspera - posterior longitudinal ridge along the diaphysis

Medial and lateral condyles - the two large, rounded, distal projections; since the head always points medially, the condyle on the same side as the head is the medial condyle

 

Pelvis and Leg (continued)

Bone

Markings

11. PATELLA - Sesamoid bones formed in the patellar tendon; anterior bone associated with the knee joint

NA

12. TIBIA - Large, medial lower leg bone

Medial and lateral condyles - the large flat-topped bumps at the proximal end; the one on the same side as the medial malleolus (see below) must be the medial condyle

Tibial tuberosity - anterior facing bump between the two condyles

Medial malleolus - somewhat pointed posterior projection only on the medial side

Anterior crest - raised ridge on the anterior diaphysis; fairly sharp wedge shape should indicate why hitting your "shin" is so painful

13. FIBULA - Slender, lateral lower leg bone

Head - shorter, more rounded proximal epiphysis

Lateral malleolus - somewhat longer, more pointed distal epiphysis

Note: The medial malleolus of the tibia and the lateral malleolus of the fibula form the two bulges commonly referred to as the "ankle bones." They form the sides of an arch over the talus (see below).

14. TARSALS - Small "ankle bones;" two are much larger than the rest

Talus - large, topmost tarsal connected to the tibia and fibula

Calcaneus - large "heel bone"

15. METATARSALS - slender, small, long bones that comprise most of the arch and "balls" of the feet

NA

16. PHALANGES - "toe bones;" like the fingers, each toe has three segments, the "great toe" has two (like the thumb)

NA

Prof. Atsma/Summer 2004

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