A&P 7: 206 Bones Flashcards
Skeleton (skeletal system)
composed of bones, cartilages, joints, and ligaments; accounts for about 20% of body mass; bones make up most of it
Axial skeleton
structured from 80 bones segregated into 3 major regions: the skull, vertebral column, and thoracic cage; forms the longitudinal axis of the body, supports the head, neck, and trunk, & protects the brain, spinal cord, and the organs in the thorax
Skull
body’s most complex bony structure; formed by cranial and facial bones, 22 in all
Cranium
cranial bones; enclose and protect the fragile brain and furnish attachment sites for head and neck muscles
Sutures
except for the mandible, all bones of the adult skull are firmly united by these interlocking joints, the lines of which have a saw-toothed/serrated appearance
Cranial vault
AKA the calvaria; forms the superior, lateral, and posterior aspects of the skull, as well as the forehead
Cranial base
forms the skull’s inferior aspects
Frontal bone
shell-shaped; forms the anterior cranium; articulates posteriorly with the paired parietal bones via the prominent coronal suture
Supraorbital margins
the frontal squamous region ends inferiorly at these thickened superior margins of the orbits that lie under the eyebrows
Anterior cranial fossa
the frontal bone extends posteriorly from the supraorbital margins, forming the superior wall of the orbits and most of this, which supports the frontal lobes of the brain
Supraorbital foramen (notch)
each supraorbital margin is pierced by this, which allows the supraorbital artery and nerve to pass to the forehead
Glabella
smooth portion of the frontal bone between the orbits
Frontal sinuses
the areas lateral to the glabella are riddled internally with these spaces
Parietal bones
2 large, curved rectangular bones that form most of the superior and lateral aspects of the skull, hence forming the bulk of the cranial vault
Coronal suture
where the parietal bones meet the frontal bone anteriorly
Sagittal suture
where the parietal bones meet superiorly at the cranial midline
Lambdoid suture
where the parietal bones meet the occipital bone posteriorly
Squamous suture
one on each side, where a parietal and temporal bone meet on the lateral aspect of the skull
Occipital bone
forms most of the skull’s posterior wall and base; articulates anteriorly with the paired parietal and temporal bones via the lambdoid and occipitomastoid sutures; the basilar part of this bone also joins with the sphenoid bone in the cranial base
Posterior cranial fossa
internally, the occipital bone forms the walls of this depression, which supports the cerebellum of the brain
Foramen magnum
in the base of the occipital bone is this large hole though which the inferior part of the brain connects with the spinal cord; flanked laterally by 2 occipital condyles
Occipital condyles
rockerlike; articulate with the 1st vertebra of the spinal column in a way that permits a nodding (“yes”) motion of the head
Hypoglossal canal
hidden medially and superiorly to each occipital condyle is this canal through which a cranial nerve (XII) passes
External occipital protuberance
just superior to the foramen magnum is this median protrusion; you can feel this knoblike projection just below the most bulging part of your posterior skull
Temporal bones
2 bones that lie inferior to the parietal bones and meet them at the squamous sutures; form the inferolateral apsects of the skull and parts of the cranial base
Squamous part
flaring part of the temporal bone that abuts the squamous suture
Zygomatic process
barlike part of the temporal bone that meets the zygomatic bone of the face anteriorly
Zygomatic arch
squamous part of the temporal bone + zygomatic process, which you can feel as the projection of your cheek; AKA cheekbone
Mandibular fossa
small, oval depression on the inferior surface of the zygomatic process that receives the condylar process of the mandible, forming the freely movable temporomandibular joint
Tympanic part
part of the temporal bone surrounding the external acoustic meatus (external ear canal), through which sound enters the ear
Petrous part
thick part of the temporal bone that houses the middle and internal ear cavities, which contain sensory receptors for hearing and balance
Middle cranial fossa
together, the sphenoid bone and the petrous portions of the temporal bones construct this depression, which supports the temporal lobes of the brain
Jugular foramen
opening at the junction of the occipital and petrous temporal bones that allows passage of the internal jugular vein and 3 cranial nerves (IX, X, & XI)
Cranial canal
just anterior to the jugular foramen; transmits the internal carotid artery into the cranial cavity
Foramen lacerum
jagged opening between the petrous temporal bone and the sphenoid bone; almost completely covered by cartilage in a living person
Internal acoustic meatus
positioned superolateral to the jugular foramen; transmits cranial nerves VII & VIII
Mastoid process
conspicuous feature of the petrous part of the temporal bone; acts as an anchoring site for some neck muscles
Styloid process
needle-like attachment point for several tongue and neck muscles and for a ligament that secures the hyoid bone of the neck to the skull
Stylomastoid foramen
between the styloid and mastoid processes, allows cranial nerve VII (the facial nerve) to leave the skull
Mastoid air cells
the mastoid process is full of these air cavities; their position adjacent to the middle ear cavity puts them at risk for infections
Sphenoid bone
bat-shaped bone that spans the width of the middle cranial fossa; considered the keystone of the cranium because it forms a central wedge that articulates with all other cranial bones
Body (of the sphenoid)
contains the paired sphenoidal sinuses
Sphenoidal sinuses
paired cavities within the body of the sphenoid
Sella turcica
“Turk’s saddle”; superior surface of the body of the sphenoid bears this saddle-shaped prominence
Hypophyseal fossa
the seat of the sella turcica; forms a snug enclosure for the pituitary gland (hypophysis)
Greater wings
project laterally from the sphenoid body, forming parts of (1) the middle cranial fossa, (2) the posterior walls of the orbits, & (3) the external wall of the skull, where they are seen as flag-shaped, bony areas medial to the zygomatic arch
Lesser wings
hornlike parts of the sphenoid the form part of the floor of the anterior cranial fossa and part of the medial walls of the orbits
Pterygoid processes
trough-shaped parts of the sphenoid that project inferiorly from the junction of the body and the greater wings; anchor the pterygoid muscles, which are important in chewing
Optic canals
openings lying anterior to the sella turcica; allow the optic nerves (cranial nerves II) to pass to the eyes
Superior orbital fissure
long slit between the greater and lesser wings of the sphenoid; allows cranial nerves that control eye movements (III, IV, VI) to enter the orbit
Foramen rotundum
provides passageway for branch of cranial nerve V (the maxillary nerve) to reach the face; medial part of the greater wing and is usually oval
Foramen ovale
provides passageway for branch of cranial nerve V (the mandibular nerve) to reach the face; large, oval opening posterior to the foramen rotundum
Foramen spinosum
posterolateral to the foramen ovale is this small opening which transmits the middle meningeal artery, which serves the internal faces of some cranial bones
Ethmoid bones
delicate bone with a complex shape; lies between the sphenoid and the nasal bones of the face; it is the most deeply situated bone of the skull; forms most of the bony area between the nasal cavity and the orbits
Cribriform plates
superior surface of the ethmoid is formed by these paired horizontal plates, which help form the roof of the nasal cavities and the floor of the anterior cranial fossa; the plates are punctured by tiny holes that allow the filaments of the olfactory nerves to pass from the smell receptors in the nasal cavities to the brain
Crista galli
projecting superiorly between the cribriform plates is this triangular process that looks like a “rooster’s comb”; the outermost covering of the brain (dura mater) attaches to this and helps secure the brain in the cranial cavity
Perpendicular plate
part of the ethmoid bone that projects inferiorly in the median plane and forms the superior part of the nasal septum, which divides the nasal cavity into right and left halves
Lateral mass
flanking the perpendicular plate on each side is this, which is riddled with sinuses
Ethmoidal air cells
sinuses of the lateral mass; flanks the perpendicular plate
Superior & middle nasal conchae
extending medially from the lateral masses, these delicately coiled parts are named after conch shells; they protrude into the nasal avity
Orbital plates
the lateral surfaces of the ethmoid’s lateral masses are called this because they contribute to the medial walls of the orbits
Sutural bones
tiny, irregularly shaped bones or bone clusters that occur within sutures, most often in the lambdoid suture
Mandible
u-shaped lower jawbone; largest, strongest bone of the face; has a body (chin) and 2 upright rami (branches); each ramus meets the body posteriorly at a mandibular angle
Mandibular angle
each ramus of the mandible meets the body posteriorly here
Mandibular notch
at the superior margin of each ramus are 2 processes separated by this u-shaped cut-out
Coronoid process
an anterior part of the mandible which serves as an insertion point for the large temporalis muscle that elevates the lower jaw during chewing
Condylar process
a posterior part of the mandible that articulates with the mandibular fossa of the temporal bone, forming the temporomandibular joint of the same side
Body (mandible)
part of the mandible that anchors the lower teeth
Alveolar processes (mandible)
superior border of the mandibular body containing the sockets in which the teeth are embedded
Mandibular symphysis
in the midline of the mandibular body is this slight ridge, indicating where the 2 mandibular bones fused during infancy
Mandibular foramina
large opening on the medial surface of each ramus of the mandible that permits the nerves responsible for tooth sensation to pass to the teeth in the lower jaw; dentists inject lidocaine here to prevent pain while working on the lower teeth
Mental foramina
openings on the lateral aspects of the mandibular body; allow blood vessels and nerves to pass to the skin of the chin and lower lip
Maxillary bones (maxillae)
bones fused medially that form the upper jaw and the central portion of the facial skeleton; all bones except the mandible articulate with these bones, hence they are considered the keystone bones of the facial skeleton
Alveolar processes (maxillae)
parts of the maxillae that carry the upper teeth
Anterior nasal spine
just inferior to the nose, the maxillae meet medially, forming this pointed part at their junction
Palatine processes
parts of the maxillae that project posteriorly from the alveolar processes and fuse medially at the intermaxillary suture, forming the anterior 2/3 of the hard palate (bony roof of the mouth)
Incisive fossa
just posterior to the teeth is a midline foramen called this, which serves as a passageway for blood vessels and nerves
Frontal processes
extend superiorly to the frontal bone, forming part of the lateral aspects of the bridge of the nose
Maxillary sinuses
the regions that flank the nasal cavity laterally contain these cavities, the largest of the paranasal sinuses; extend from the orbits to the roots of the upper teeth
Zygomatic processes
laterally, the maxillae articulate with the zygomatic bones via these parts
Inferior orbital fissure
located deep within the orbit at the junction of the maxilla with the greater wing of the sphenoid; permits the zygomatic nerve, the maxillary nerve (a branch of cranial nerve V), and blood vessels to pass to the face
Infraorbital foramen
just below the eye socket on each side is this opening that allows the infraorbital nerve (a continuation of the maxillary nerve) and artery to reach the face
Zygomatic bones
irregularly shaped bones commonly called the cheekbones; articulate with the zygomatic processes of the temporal bones posteriorly, the zygomatic processes of the frontal bone superiorly, and with the zygomatic processes of the maxillae anteriorly; form the prominence of the cheeks and part of the inferolateral margins of the orbits
Nasal bones
thin, basically rectangular bones fused medially, forming the bridge of the nose; articulate with the frontal bone superiorly, the maxillary bones laterally, and the perpendicular plate of the ethmoid bone posteriorly; inferiorly they attach to the cartilages that form most of the skeleton of the external nose
Lacrimal bones
delicate, fingernail-shaped bones that contribute to the medial walls of each orbit; articulate with the frontal bone superiorly, the ethmoid bone posteriorly, and the maxillae anteriorly; each one contains a deep groove the helps form a lacrimal fossa
Lacrimal fossa
depression/groove in the lacrimal bones that houses the lacrimal sac, part of the passageway that allows tears to drain from the eye surface into the nasal cavity
Palatine bone
each L-shaped bone is fashioned from 2 bony plates, the horizontal and the perpendicular; has 3 important articular processes - the pyramidal, sphenoidal, and orbital
Horizontal plates
joined at the medial palatine suture, complete the posterior portion of the hard palate
Perpendicular (vertical) plates
superiorly projecting plates that form part of the posterolateral walls of the nasal cavity and a small part of the orbits
Vomer
slender, plow-shaped bone that lies in the nasal cavity where it forms part of the nasal septum
Inferior nasal conchae
paried, thin, curved bones in the nasal cavity; project medially from the lateral walls of the nasal cavity, just inferior to the middle nasal conchae of the ethmoid bone; largest of the 3 pairs of conchae; form part of the lateral walls of the nasal cavity
Orbits
cone-shaped bony cavities in which the eyes are firmly encased and cushioned by fatty tissue
Nasal cavity
constructed of bone and hyaline cartilage; roof formed by the cribriform plates of the ethmoid; lateral walls are largely shaped by the superior and middle conchae of the ethmoid bone, the perpendicular plates of the palatine bones, and the inferior nasal conchae; depressions under cover of the conchae on the lateral walls = meatuses (=passage; superior, middle, and inferior); floor formed by the palatine processes of the maxillae and the palatine bones; divided into left and right parts by the nasal septum
Paranasal sinuses
sinuses of 5 of the skull bones (frontal, sphenoid, ethmoid, and paired maxillary); lined with mucosa, filled with air; cluster around the nasal cavity; lighten the skull and enhance the resonance of the voice
Hyoid bone
lies just inferior to the mandible in the anterior neck; unique bone - only bone in the body that does not articulate directly with any other bone; anchored by the narrow stylohyoid ligaments to the styloid processes of the temporal bones; horseshoe shaped, with a body and 2 pairs of horns (cornua), this bone acts as a movable base for the tongue; body and greater horns are attachment points for neck muscles that raise and lower the larynx during swallowing and speech
Vertebral column
spine; spinal column; consists of 26 irregular bones connected in such a way that a flexible, curved structure results; serves as the axial support of the trunk; extends from the skull to the pelvis, where it transmits the weight of the trunk to the lower limbs; surrounds and protects the delicate spinal cord and provides attachment points for the ribs and for the muscles of the back and neck
Vertebrae
in the fetus and infant, the vertebral column consists of 33 separate bones called this; inferiorly, 9 of these eventually fuse to form 2 composite bones, the sacrum and the tiny coccyx; remaining 24 persist as individual ____ separated by intervertebral discs
Cervical vertebrae
7 vertebrae of the neck
Thoracic vertebrae
12 bones of the thorax
Lumbar vertebrae
5 supporting bones of the lower back
Sacrum
inferior to the lumbar vertebrae is this bone, which articulates with the hip bones of the pelvis
Coccyx
terminus of the vertebral column
Cervical and lumbar curvatures
concave posteriorly
Thoracic and sacral curvatures
convex posteriorly
Anterior & posterior longitudinal ligaments
major supporting ligaments of the spine; run as continuous bands down the front and back surfaces of the vertebrae from the neck to the sacrum; broad one prevents hyperextension of the spine (strongly attached to both the bony vertebrae and the discs); narrow, weak one prevents hyperflexion of the spine (attaches only to the discs)
Ligamentum flavum
connects adjacent vertebrae, contains elastic connective tissue and is especially strong; stretches as we bend forward and then recoils when we resume an erect posture
Intervertebral disc
cushionlike pad composed of 2 parts - inner, gelantinous nucleus pulposus & the anulus fibrosus
Nucleus pulposus
inner gelatinous part of an intervertebral disc; acts like a rubber ball, giving the disc its elasticity and compressibility
Anulus fibrosus
surrounds the nucleus pulposus; strong collar composed of collagen fibers superficially and fibrocartilage internally; limits the expansion of the nucleus pulposus when the spine is compressed; also binds successive vertebrae together, withstands twisting forces, and resists tension in the spine
Herniated (prolapsed) disc
“slipped disc”; usually involves rupture of the anulus fibrosus followed by protusion of the spongy nucleus pulposus through the anulus
Body (centrum)
anterior part of a vertebra; weight-bearing region
Vertebral arch
posterior part of a vertebra
Vertebral foramen
together, the body and vertebral arch enclose this opening
Vertebral canal
successive vertebral foramina of the articulated vertebrae form this canal through which the spinal cord passes
Pedicles
short, bony pillars projecting posteriorly from the vertebral body; form the sides of the vertebral arch
Laminae
flattened plates that fuse in the median plane & complete the vertebral arch posteriorly
Intervertebral foramina
the pedicles have notches on their superior and inferior borders, providing these lateral openings between adjacent vertebrae; spinal nerves issuing from the spinal cord pass through these foramina
Spinous process
1 of 7 processes that project from the vertebral arch; a median posterior projection arising at the junction of the 2 laminae
Transverse process
2 of 7 processes that project from the vertebral arch; extends laterally from each side of the vetebral arch
Superior & Inferior articular processes
4 of 7 processes that project from the vertebral arch; paired processes that protrude superiorly and inferiorly from the pedicle-lamina junctions; smooth joint surfaces of these processes = facets, which are covered in hyaline cartilage
Transverse foramen
each transverse process contains this opening through which the vertebral arteries pass to service the brain
Vertebra prominens
because its spinous process is palpable through the skin, C7 can be used as a landmark for counting the vertebrae and is called this
Atlas
C1; has no body and no spinous process; essentially a ring of bone consisting of anterior and posterior arches and a lateral mass on each side; each lateral mass has articular facets on both its superior and inferior surfaces; superior articular facets receive the occipital condyles of the skull and thus carry it; joint that allows you to nod “yes”
Axis
C2; has a body and other typical vertebral processes, but not as specialized as the atlas; only unusual feature is the knoblike dens
Dens
knoblike feature of the axis, projecting superiorly from its body; actually the “missing” part of the atlas, which fuses with the axis during embryonic development; acts as a pivot for the rotation of the atlas; joint that allows you to indicate “no”
Superior articular processes of the sacrum
articulates superiorly with L5 and inferiorly with the coccyx
Auricular surfaces
laterally, the sacrum articulates via these surfaces with the 2 hip bones
Sacroiliac joints
laterally, the sacrum articulates via its auricular surfaces with the 2 hip bones to form these joints of the pelvis
Sacral promontory
“high point of the sea”; anterosuperior margin of the 1st sacral vertebra, bulges anteriorly into the pelvic cavity; body’s center of gravity lies about 1cm posterior to this landmark
Transverse ridges
4 ridges cross the anterior aspect of the sacrum, marking the lines of fusion of the sacral vertebrae
Anterior sacral foramina
lie at the lateral ends of the transverse ridges and transmit blood vessels and anterior rami of the sacral spinal nerves
Alae
regions lateral to the anterior sacral foramina expand superiorly as these winglike parts
Median sacral crest
in its posterior midline, the sacral surface is roughened by these fused spinous processes of the sacral vertebrae
Posterior sacral foramina
median sacral crest is flanked laterally by these openings, which transmit the posterior rami of the sacral nerves and then the lateral sacral crests
Lateral sacral crests
remnants of the transverse processes of S1-S5
Sacral canal
the vertebral canal continues inside the sacrum as this
Sacral hiatus
enlarged external opening at the inferior end of the sacral canal due to the lamnae of the 5th and sometimes 4th sacral vertebrae failing to fuse medially
Thoracic cage
AKA bony thorax; thorax = chest; its bony underpinnings are called this
Sternum
breastbone; lies in the anterior midline of the thorax; vaguely resembles a dagger; flat bone approximately 6 inches long (15cm), resulting from the fusion of 3 bones - manubrium, body, & xiphoid process
Clavicular notches
manubrium articulates via these with the clavicle bones laterally (as wells as the 1st 2 pairs of ribs)
Jugular (suprasternal) notch
easily palpated, central indentation in the superior border of the manubrium
Sternal angle
felt as a horizontal ridge across the front of the sternum, where the manubrium joins the sternal body; this cartilaginous joint acts like a hinge, allowing the sternal body to swing anteriorly when we inhale; handy reference point for finding the 2nd rib & thus for counting the ribs during a physical exam and for listening to sounds made by specific heart valves
Xiphisternal joint
point where the sternal body and xiphoid process fuse; lies at the level of the 9th thoracic vertebra
Ribs
12 pairs of these form the flaring sides of the thoracic cage; all of these attach posteriorly to the thoracic vertebrae (bodies and transverse processes) & curve inferiorly toward the anterior body surface
True (vertebrosternal) ribs
superior 7 rib pairs, attach directly to the sternum by individual costal cartilages (bars of hyaline cartilage)
False ribs
remaining 5 pairs of ribs; either attach indirectly to the sternum or lack a sternal attachment
Vertebrochondral ribs
rib pairs 8-10, which attach to the sternum indirectly, each joining the costal cartilage immediately above it
Costal margin
inferior margin of the rib cage, formed by the costal cartilages of ribs 7-10
Vertebral (floating) ribs
rib pairs 11 & 12; have no anterior attachments; their costal cartilages lie embedded in the muscles of the lateral body wall
Appendicular skeleton
bones of the limbs and their girdles; appended to the axial skeleton that forms the longitudinal axis of the body
Pectoral (shoulder) girdle
consists of the clavicle anteriorly and the scapula posteriorly; paired ones of these and their associated muscles form your shoulders; attach the upper limbs to the axial skeleton and provide attachment points for many of the muscles that move the upper limbs
Clavicles
“little keys”; collarbones; slender, S-shaped bones that can be felt along their entire course as they extend horizontally across the superior thorax
Sternal end
each clavicle is cone shaped at its medial ___ ___, which attaches to the sternal manubrium
Acromial end
each clavicle is flattened at its lateral end, called this; articulates with the scapula
Scapulae
shoulder blades; thin, triangular flat bones; name is derived from a word meaning “spade” or “shovel”, for ancient cultures made spades from the shoulder blades of animals
Glenoid cavity
the thick lateral (axillary) border of the scapula abuts the armpit and ends superiorly in this small, shallow fossa; articulates with the humerus, forming the shoulder joint
Spine (of the scapula)
posterior surface of the scapula bears a prominent ____ that is easily felt through the skin; ends laterally in an enlarged, roughened triangular projection (acromion)
Acromion
spine of the scapula ends laterally in this enlarged, roughened, triangular projection; articulates with the acromial end of the clavicle, forming the acromioclavicular joint
Acromioclavicular joint
acromion of the scapula articulates with the acromial end of the clavicle, forming this joint
Coracoid process
projects anteriorly from the superior scapular border; looks like a bent finger or beak; helps anchor the biceps muscles of the arm
Suprascapular notch
coracoid process is bounded by this nerve passage medially
Humerus
sole bone of the arm; typical long bone; largest, longest bone of the upper limb; articulates with the scapula at the shoulder and with the radius and ulna (forearm bones) at the elbow
Head (humerus)
at the proximal end of the humerus is its smooth, hemispherical ___, which fits into the glenoid cavity of the scapula in a manner that allows the arm to hang freely at one’s side
Anatomical neck
immediately inferior to the head of the humerus is this slight constriction
Greater tubercle
inferior to the anatomical neck of the humerus; 1 of 2 sites of attachment of the rotator cuff muscles
Lesser tubercle
inferior to the anatomical neck of the humerus, more medial than the greater tubercle; 1 of 2 sites of attachment of the rotator cuff muscles
Intertubercular sulcus
AKA bicipital groove; separates the greater and lesser tubercles of the humerus
Surgical neck
just distal to the tubercles of the humerus; named because it is the most frequently fractured part of the humerus
Deltoid tuberosity
about midway down the shaft on its lateral side is this V-shaped, roughened attachment site for the deltoid muscle of the shoulder
Radial groove
runs obliquely down the posterior aspect of the shaft of the humerus, marking the course of the radial nerve, and important nerve of the upper limb
Trochlea
1 of 2 condyles at the distal end of the humerus, which looks like an hourglass tipped on its side; articulates with the ulna
Capitulum
1 of 2 condyles at the distal end of the humerus; lateral, ball-like; articulates with the radius
Medial & Lateral Epicondyles
trochlea and capitulum are flanked by these muscle attachment sites
Medial & Lateral Supracondylar ridges
directly above the medial/lateral epicondyles; ulnar nerve (runs behind the medial epicondyle) is responsible for the tingling in your “funny bone”
Coronoid fossa
superior to the trochlea on the anterior surface; with the olecranon fossa, allow the ulna to move freely when the elbow is flexed and extended
Olecranon fossa
posterior surface of the trochlea; with the coronoid fossa, allow the ulna to move freely when the elbow is flexed and extended
Radial fossa
small, lateral to the coronoid fossa; receives the head of the radius when the elbow is flexed
Radioulnar joints
the radius and ulna articulate with each other both proximally and distally at these small joints
Interosseous membrane
radius and ulna are connected along their entire length by this flat, flexible ligament
Ulna
“elbow”; slightly longer than the radius; main responsibility = forming the elbow joint with the humerus
Olecranon & coronoid processes
2 prominent processes of the ulna that grip the trochlea of the humerus, forming a hinge joint that allows the forearm to be bent upon the arm (flexed), then straightened again (extended)
Trochlear notch
separates the olecarnon and coronoid processes of the ulna
Radial notch
on the lateral side of the coronoid process is this small depression, where the ulna articulates with the head of the radius
Head (ulna)
distally, the ulnar shaft narrows and ends in this knoblike part
Ulnar styloid process
medial to the head of the ulna, from which a ligament runs to the wrist
Radius
“rod”; bone that is thin at its proximal end and wide distally (opposite of ulna)
Head (radius)
shaped somewhat like the head of a nail; superior surface is concave; articulates with the capitulum of the humerus; medially, this part articulates with the radial notch of the ulna
Radial tuberosity
just inferior to the head of the radius; anchors the biceps muscle of the arm
Ulnar notch
distally, where the radius is expanded, it has a medial ___ ____, which articulates with the ulna
Radial styloid process
anchoring site for ligaments that run to the wrist
Carpals
8, marble-size short bones, closely united by ligaments; gliding movements occur between these bones - makes carpus as a whole quite flexible
Scaphoid
“boat-shaped” carpal in the proximal row (lateral to medial)
Lunate
“moon-like” carpal in the proximal row (lateral to medial)
Triquetrum
“triangular” carpal in the proximal row (lateral to medial)
Pisoform
“pea-shaped” carpal in the proximal row (lateral to medial); does not participate in forming the wrist joint
Trapezium
“little table” carpal in the distal row (lateral to medial)
Trapezoid
“four-sided” carpal in the distal row (lateral to medial)
Capitate
“head-shaped” carpal in the distal row (lateral to medial)
Hamate
“hooked” carpal in the distal row (lateral to medial)
Metacarpals
5 of these bones radiate from the wrist like spokes to form the metacarpus (palm of the hand)
Bases (of the metacarpals)
articulate with the carpals proximally and with each other medially and laterally
Heads (of the metacarpals)
bulbous tops of the metacarpals that articulate with the proximal phalanges of the fingers; when you clench your fist, these = knuckles
Fingers (digits)
numbered 1-5 beginning with the thumb
Pollex
thumb
Phalanges (of the hand)
finger bones; each hand contains 14 miniature long bones called this; 3 in each finger (distal, middle, and proximal) except the thumb, which has 2 (distal & proximal)
Pelvic (hip) girdle
attaches the lower limbs to the axial skeleton; transmits the full weight of the upper body to the lower limbs; supports the visceral organs of the pelvis; secured to the axial skeleton by some of the strongest ligaments in the body
Os coxae
hip bones; AKA coxal bone (hip); each hip bone unites with its partner anteriorly and with the sacrum posteriorly
Acetabulum
at the point of fusion of the ilium, ischium, and pubis is this deep hemispherical socket
Ilium
“flank”; a large flaring bone that forms the superior region of a coxal bone; consists of a body and a superior winglike portion called the ala
Ala
superior winglike portion of the ilium
Iliac crests
when you rest your hands on your hips, you are resting them on these thickened superior margins of the alae, to which many muscles attach
Anterior superior iliac spine
each iliac crest ends anteriorly in this blunt part
Posterior superior iliac spine
each iliac crest ends posteriorly in this sharp part
Greater sciatic notch
just inferior to the posterior inferior iliac spine, the ilium indents deeply to form this notch, through which the thick cordlike sciatic nerve passes to enter the thigh
Gluteal surface
the broad, posterolateral surface of the ilium; crossed by 3 ridges
Posterior, anterior, and inferior gluteal lines
3 ridges on the ilium to which the gluteal muscles attach
Iliac fossa
the medial surface of the iliac ala exhibits this concavity
Auricular surface
posterior to the iliac fossa, this roughened, ear-shaped surface articulates with the same-named surface of the sacrum, forming the sacroiliac joint; weight of the body is transmitted from the spine to the pelvis through the sacroiliac joints
Arcuate line
running inferiorly and anteriorly from the auricular surface is this robust ridge; helps define the pelvic brim, the superior margin of the true pelvis
Ischium
forms the posteroinferior part of the hip bone; roughly L- or arc-shaped, it has a thicker, superior body adjoining the ilium, and a thinner, inferior ramus
Ischial spine
part of the ischium projecting medially into the pelvic cavity; serves as a point of attachment of the sacrospinous ligament running from the sacrum
Lesser sciatic notch
just inferior to the ischial spine; a number of nerves and blood vessels pass through this notch to supply the anogenital area
Ischial tuberosity
the inferior surface of the ischial body is rough and grossly thickened as this tuberosity; when we site, our weight is borne entirely by these, which are the strongest parts of the hip bones
Pubis
AKA pubic bone; forms the anterior portion of the hip bone; V-shaped with superior and inferior pubic rami issuing from its flattened medial body
Pubic crest
the anterior border of the pubis is thickened to form this crest
Pubic tubercle
at the lateral end of the pubic crest is this tubercle, one of the attachments for the inguinal ligament
Obturator foramen
as the 2 rami of the pubis run laterally to join with the body and ramus of the ischium, they define this large opening in the hip bone, in which a few blood vessels and nerves pass
Pubic symphysis
the bodies of the 2 pubic bones are joined by this fibrocartilage disc, forming the midline joint
Pubic arch
AKA subpubic angle; inferior to the pubic symphysis, the inferior pubic rami angle laterally, forming this inverted, V-shaped arch/angle; the acuteness of this angle helps differentiate the male and female pelves
Pelvis
the deep, basinlike structure formed by the hip bones, sacrum, and coccyx; AKA bony pelvis
Pelvic brim
separates the false (greater) pelvis and the true (lesser) pelvis; a continuous oval ridge that runs from the pubic crest through the arcuate line and sacral promontory
False pelvis
portion of the pelvis superior to the pelvic brim; bounded by the alae of the ilia laterally and the lumbar vertebrae posteriorly; really = part of the abdomen and helps support the abdominal viscera; does not restrict childbirth in any way
True pelvis
region inferior to the pelvic brim that is almost entirely surrounded by bone; forms a deep bowl containing the pelvic organs; dimensions (particularly those of its inlet and outlet) are critical to the uncomplicated delivery of a baby and are carefully measured by an OB
Pelvic inlet
AKA pelvic brim; widest dimension is from right to left along the frontal plane
Pelvic outlet
inferior margin of the true pelvis; bounded anteriorly by the pubic arch, laterally by the ischia, and posteriorly by the sacrum and coccyx
Femur
single bone of the thigh; largest, longest, strongest bone in the body; clothed in bulky muscles, prevents palpation
Head (femur)
ball-like top of the femur; has a small central pit (fovea capitis)
Fovea capitis
small central pit in the head of the femur
Greater & lesser trochanters
at the junction of the shaft and neck of the femur are these lateral trochanters; attachment sites for thigh and buttock muscles
Intertrochanteric line
connects the 2 trochanters of the femur anteriorly
Intertrochanteric crest
connects the 2 trochanters of the femur posteriorly (prominent)
Gluteal tuberosity
inferior to the intertrochanteric crest on the posterior shaft of the femur; blends into a long vertical ridge (linea aspera)
Linea aspera
long vertical ridge on the femur
Medial & lateral supracondylar lines
distally, the linear aspera diverges, forming these lines; sites of muscle attachment
Lateral & medial condyles (femur)
articulate with the tibia
Medial & lateral epicondyles (femur)
sites of muscle attachment which flank the condyles superiorly
Adductor tubercle
on the superior part of the medial epicondyle is this bump
Patellar surface
smooth surface between the condyles on the anterior femoral surface; articulates with the patella
Intercondylar fossa
between the condyles on the posterior aspect of the femur is this deep, U-shaped fossa
Patella
“small pan”; triangular sesamoid bone enclosed in the quadriceps tendon that secures the anterior thigh muscles to the tibia; protects the knee joint anteriorly and improves the leverage of thigh muscles acting across the knee
Tibia
shinbone; receives the weight of the body from the femur; transmits it to the foot; second only to the femur in size and strength
Medial & lateral condyles (tibia)
at the broad proximal end of the tibia are these concave condyles, which look like 2 huge checkers lying side by side
Intercondylar eminence
irregular projections that separates the medial and lateral condyles of the tibia
Tibial tuberosity
just inferior to the condyles, the tibia’s anterior surface displays this rough tuberosity, to which the patellar ligament attaches
Anterior border (of the tibia)
sharp border of the tibia; not covered by muscles; can be felt just deep to the skin along their entire length
Medial malleolus
“little hammer”; forms the medial bulge of the ankle
Fibular notch
on the lateral surface of the tibia; participates in the inferior tibiofibular joint
Fibula
“pin”; sticklike bone with slightly expanded ends; articulates proximally and distally with the lateral aspects of the tibia
Head (fibula)
proximal end of the fibula
Lateral malleolus
distal end of the fibula; forms the conspicuous lateral ankle bulge and articulates with the talus
Tarsus
made up of 7 bones called tarsals that form the posterior half of the foot; corresponds to the carpus of the hand; body weight is carried primarily by the 2 largest, most posterior of these
Talus
1 of the largest, most posterior tarsals; “ankle”; articulates with the tibia and fibula superiorly and the strong calcaneus
Calcaneus
“heel bone”; carries the talus on its superior surface; Achilles (calcaneal) tendon of the calf muscles attaches to the posterior surface of this
Calcaneal tuberosity
part of the calcaneus that touches the ground
Sustentaculum tali
the shelflike projection of the calcaneus that supports part of the talus; AKA talar shelf
Cuboid
lateral tarsal bone
Navicular
medial tarsal bone
Medial, intermediate, and lateral cuneiform bones
anterior tarsal bones
Metatarsus
consists of 4 small, long bones called metatarsals; numbered I-V beginning on the medial (great toe) side of the foot
Hallux
great toe; has only 2 phalanges (proximal and distal)
Medial longitudinal arch
arch of the foot that curves well above the ground, leaves no print; talus is the keystone of this arch (originates at the calcaneus, rises toward the talus, and then descends to the 3 medial metatarsals)
Lateral longitudinal arch
very low arch of the foot; elevates the lateral part of the foot just enough to redistribute some of the weight to the calcaneus and the head of the 5th metatarsal (to the ends of the arch); cuboid is the keystone bone of this arch
Transverse arch
2 longitudinal arches serve as pillars for this arch, which runs obliquely from one side of the foot to the other, following the lines of the joints between the tarsals and metatarsals
Fontanelles
unossified remants of fibrous membranes that make up the skull bones at birth; allow the infant’s head to be compressed slightly during birth and accommodate brain growth in the fetus and infant; “little fountain” in which a baby’s pulse can be felt; AKA soft spots
Primary curvatures
thoracic and sacral curvatures; convex posteriorly; well-developed at birth
Secondary curvatures
cervical and lumbar; convex anteriorly; associated with a child’s development
