Bones of the Shoulder Girdle
 The shoulder girdle provides support and anchor for the humerus and anchors a variety of muscles.
It consists of the following bones: the clavicle and the scapula.
http://www.kettering.edu/visitors/story pics/shoulder-joint.jpg

The clavicle - description
 S –shaped bone
 Articulates medially with manubrium of sternum
 Articulates laterally with acromion of the scapula

The clavicle – what to know
 Superior surface
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Deltoid attachment
Trapezius attachment
 Inferior surface
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Acromial facet (lat)
Trapezoid ridge (a/i)
Conoid tubercle (p/i)
Subclavian groove
Costal pit (medial) http://www.sci.utah.edu/~simpson/documentation/projects/ annotation/webdocs/image_gal_files/miscellaneous/clavicl e.jpg

The clavicle – left from right
 Superior surface smooth
 Interior surface rough ( sub clavian groove)
 Lateral end flatter (art with scapula)
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Medial curve – posterior
Lateral curve – anterior

The scapula - description
 The body of the scapula is large and triangular
 Flat side is anterior side
(to slide over ribs)
 Articulates with the humerus at the glenoid fossa
 Articulates with the clavicle at the acromion http://www.kettering.edu/visitors
/storypics/shoulder-joint.jpg

The scapula – what to know
 Anterior/costal surface
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Body
3 borders
• Medial/vertebral
• Lateral/axillary
• superior
Coracoid process
(smaller, anterior)
Scapular notch
(superior)
Glenoid fossa http://www.alignmed.com/images/Scapula_1.jpg

The scapula – what to know
 Posterior/dorsal surface
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Scapular spine
3 borders
• Medial/vertebral
• Lateral/axillary
• Superior
Acromion process
(higher and wider)
Supraspinous and infraspinous processes http://content.answers.com/main/content/img/oxford/Oxford_Sports/01992108
96.scapula.1.jpg

The scapula – left from right
 Orient the spine posteriorly
 Put the point down
 Glenoid fossa is lateral

Bones of the thorax
 The thorax (or chest) is like a cage made of cartilage and bone. This cage protects the main organs of the circulatory and respiratory systems, and is the base to which the upper limbs are attached.
http://home.comcast.net/~wnor/thoraxbones.htm

The sternum - description
 Manubrium – widened superior portion
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Jugular notch at top, art. w/ BOTH clavicles, cartilage of BOTH 1 st ribs attach only at manubrium

The sternum - description
 Body – long medium width bone attach at inferior portion of manubrium, cartilage of ribs 3-7 attache to body of sternum
 Xiphoid process – small inferior portion of sternum
– attachment for abdomen muscles http://home.comcast.net/~wnor/thoraxbones.
htm

The sternum – what to know
 Manubrium
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Jugular notch
Clavicular notch
Costal notches
 Body of the sternum
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Costal notches
 Xiphoid process
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Can be fused to sternal body in some cases

The ribs - description
 24 total (though there may be variation in the number)
 Function – protect thoracic organs
 Each rib articulates with a thoracic vertebrae and has an extension of cartilage anteriorly
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Ribs 1-7 are true ribs (direct art. w/ sternum)
Ribs 8-10 are false ribs (indirect art.)
Ribs 11-12 are floating ribs (no art. w/ sternum)

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The ribs – what to know
Head – single or double facet
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Articulates with lateral vert body
 Neck
 Tubercle – single facet
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Articulates with transverse process of vert
(ribs 1-9/10)
 Shaft/body
 Angle
 Costal groove
 Sternal end
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Ribs 1-7 wide, 8-10 tapered, 11-12 flat

The ribs – how to sort
 Rib cage barrel-shaped
 Easiest to sort…
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1 st rib; short, flat, steep curve, long neck
Inner surface inferior
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11 th and 12 th ribs; fan-shaped head, no neck, tapered ends, 12 th VERY short
Inner surface superior

The ribs – sorting the rest
 Head shape changes to fan shaped
 Neck length shortens
 Curvature changes – but each rib conforms to the curvature of adjacent ribs

The ribs - sorting
 Figure 4.12b in book
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~ 1-4 long necks
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~ 5-9 double faceted head
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~ 7-9 wide head
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~ 9-12 no neck
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~ 11-12 no tubercle http://home.comcast.net/~wnor/thoraxbone s.htm

The ribs – left from right
 Head posterior – articulates with vertebrae
 Sternal end anterior
 Sharp ridge inferior

Skeletal anatomy of the arm
Comprised of 3 bones
Useful for
Humerus
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ALL useful for age/growth
Radius
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Handedness
Ulna
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Sex determination
? stature determination
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The humerus - description
 Longest, most robust bone of the arm
 Contains the Ball of the Ball and socket joint
 Articulations:
• Proximal – head of the humerus with the glenoid cavity of scapula
• Distal – radius and ulna with the capitulum and trochlea
(resp.)
 Shape = cylindrical shaft
• Round, articular proximal end
• Broad, flattened distal end

The humerus – What to know
 Proximal end:
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Head – points medially
Greater tubercle – anterolaterally
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Lesser tubercle – anterior
Neck – narrowest area
Deltoid tuberosity – lateral attach of deltoid m.
 Distal end:
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Medial and lateral epicondyle
(Med. Larger)
Fossas – named for what depression receives
• Olecranon – posterior
• Coronoid - anterior
Capitulum – rounded
• Art. w/ radial head
• Joint - rotation
Trochlea – large, spool-like
• Art. w/ ulna at olecranon process
• Joint – flexion/extension

Humerus – Right from left
 Orient humeral head superior (points medially)
 Make sure tubercles are anterior
 Make sure trochlea and capitulum are anterior and distal
 Olecranon fossa is posterior
 Larger of the 2 epicondyles is MEDIAL

The radius - description
 Lateral to the ulna, more robust
 Responsible for ROTATION

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The Radius
Shaft – teardrop X-section,
 broadens
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Round head proximally
Full-length interosseous ridge on medial surface
 Articulations
• Proximal - radial head with capitulum of humerus AND radial notch of ulna
• Distal - distal radial articular area with scaphoid and lunate AND ulnar notch of radius with distal ulna

The Radius – What to know
 Distal End:
 Proximal End:
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Head – art. at capit and radial notch
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Neck – narrow area
Radial tuberosity – anterio-medially orient. attach of biceps m.
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Styloid process – lateral
Ulnar notch – postero-medial area of art. w/ulna
Dorsal tubercle – posterior
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Distal articular area art. w/ scaphoid and lunate

Radius – Right from left
 Orient radial head superior
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Make sure the radial tuberosity, ulnar notch and interosseous crest are medial
(i.e. point toward the ulna and the interosseous space ….)
Dorsal tubercle is posterior (i.e. dorsal ….)
 Styloid process is lateral

The Ulna - description
 Medial to the radius, more slender; parallel to radius when arm supine
 Responsible for flexion/extension AND stability at elbow joint

The Ulna
 Articulations
• Proximal - Olecranon process with trochlea of humerus AND with radial head at radial notch of ulna
• Distal - Ulnar head art. w/ ulnar notch of radius; ?
Art. with lunate but separated by articular disk for
↑flexibility
 Shape = teardrop shaft
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Hook-shaped proximally
Narrow head distally

The Ulna – What to know
 Proximally:
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Olecranon process
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Semilunar notch
Coronoid process – anteri-medial
Radial notch – lateral art. w/ radial head
 Distally:
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Head – art. w/ radial ulnar notch
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Styloid process – medial

The Ulna – Right from left
 Orient the olecranon process superior and the semilunar notch is anterior
 Make sure the radial notch and the interosseous crest are lateral
 The head is distal
 The styloid process is medial