Bones Of Upper Limb Flashcards
Shoulder region
Deltoid, pectoral, scapular and lateral part of lateral cervical region
Four segments of upper limb
Shoulder
Arm
Forearm
Hand
Pectoral girdle
Bony ring, incomplete posteriorly, formed by scapulae and clavicles and completed anteriorly by manubrium of the sternum
Arm region
Between the shoulder and the elbow
Centered around humerus
Consists of anterior and posterior regions of the arm
Forearm region
Between elbow and wrist and contains ulna and radius
Consists of anterior and posterior regions of the forearm
Hand region
Distal to the forearm and contains the carpus, metacarpus and phalanges
Composed of the wrist, palm, dorsum of hand, and digits
Richly supplied with sensory endings for touch, pain and temperature
Superior appendicular skeleton
Pectoral girdle and bones of free part of upper limb
Articulates with axial skeleton only at sternoclavicular joint
Pectoral girdle is supported, stabilized and propelled by
Axio appendicular muscles
Which attach to the ribs, sternum and vertebrae of axial skeleton
Clavicle aka
Collar bone
Clavicle articulations
Sternal end with manubrium of sternum at sternoclavicular joint
A criminal end articulates with acromion of scapula at acromioclavicular joint
Structure of clavicle
Medial two thirds of shaft of clavicle are convex anteriorly
Lateral third is flattened and concave anteriorly
Functions or clavicle
Pivoting strut from whch scapula and free limb are suspended, keeping the free limb lateral to the thorax so that the arm has maximum freedom of motion
Fixing the strut in position, especially after it’s elevation enables elevation of the ribs for deep inspiration
Forms one of boundaries of cervical axillary canal, affording protection to neurovascular bundle supplying upper limb
Transmits shocks from the upper limb to the axial skeleton
Bony structure of clavicle
Designated as a long bone
Has no medullary cavity
Spongy bone with a shell of compact bone
Scapula general info
Shoulder blade
Triangular flat bone that lies on posterolateral aspect of the thorax, overlying the 2nd through 7th ribs
Detailed structure of scapula
Convex posterior surface, divided by spine of scapula into small supra spinous fossa and larger infra spinous fossa
Concave costal surface has large sub scapular fossa
Medial, lateral, and superior borders
Superior and inferior angles
Lateral border is thickest part
Head of the scapula: where glenoid cavity is, in superior lateral border
Neck of scapula: just medial to the head
Supra scapular notch: superior border of scapula is marked near the junction of its medial two thirds and lateral third by notch
Acromion: subcutaneous point of the shoulder
Glenoid cavity: superolaterally, lateral surface of head of scapula articulates with head of humerus. Shallow, concave, oval fossa, directed anterolaterally and slightly superiorly
Coracoid process: superior to glenoid cavity and projects anterolaterally
Humerus in general
Largest bone in upper limb
Articulates with scapula and ulna and radius
Proximal end of humerus
Head of humerus articulates with glenoid cavity of the scapula
Inter tubercular sulcus (bicipital groove) separates lesser tubercle from greater tubercle
Anatomical neck of humerus separates the head from tubercles
Distal to tubercles is narrow surgical neck of humerus
Shaft of humerus
Deltoid tuberosity: laterally
Radial groove: groove for radial nerve, spiral groove: posterior for radial nerve and profunda brachii artery
Inferior end of humoral shaft widens as sharp medial and lateral supra epicondylar ridges form and then end distally in the prominent medial epicondyle and lateral epicondyle
Distal end of the humerus
Trochlea, olecranon, capitulum, coronoid and radial fossae makes up condylar of humerus
Capitulum
Lateral articulation with the head of the radius
Trochlea
Medial for articulation with trochlear notch of the ulna
Coronoid fossa
Superior to the trochlea anteriorly
Receives coronoid process of ulna during full flexion of elbow
olecranon fossa
Posteriorly accomodates olecranon of the ulna during extension of elbow
Radial fossa
Superior to capitulum anteriorly
Accomodates edge of the head of the radius when the elbow is fully flexed
ulna general
stabilizing bone of the forearm
medial and longer of two forearm bones
proximal end of ulna
olecranon: posteriorly
coronoid process:anteriorly
together: form walls of trochlear notch which articulates with trochlea of humerus
inferior to coronoid process is tuberosity of the ulna
on lateral side of coronoid process is radial notch, which articulates with the head of the radius
distal to radial notche is supinator crest, and between it and the distal part of coronoidprocess is supinator fossa
shaft of ulna
thick proximally, but it tapers, diminishing in diameter distally
distal end of ulna
narrow
rounded head of ulna with small conical, ulnar styloid process
does not articulate directly with carpal bones
separated from carpals by a fibrocartilaginous articular disc
radius general
lateral, and shorter of two forearm bones
radius proximal end
cylindrical head, short neck and radial tuberosity (projection from medial surface)
head is concave for articulation with the capitulum of humerus. also articulates medially with the radial notch of the ulna
the neck of the radius is the narrw part betweenthe head and radial tuberosity
the radial tuberosity demarcates the proximal end from the shaft
the shaft of the radius
has a lateral convexity and gradually enlarges as it passes distally
distal radius
medial aspect of distal end of the radius forms ulnar notch, which accomodates head of ulna
lateral aspect terminates distally as the radial styloid process. larger than the ulnar styloid process and extends farther distally
dorsal tubercle of the radiuslies between two of the shallow grooves for passage of the tendons of the forearm musclesand serves as a trochlea for the tendon of the long extensor of the thumb
bones of wrist
lateral to medial, proximal then distal
scaphoid, lunate, triquetram, pisiform
trapezium, trapezoid, capitate, hamate
scaphoid
boat shaped bone that has a prominent scaphoid tubercle
lunate
moon shaped bone that is broader anteriorly than posteriorly
triquetram
a pyramidal bone on the medial aspect of the carpus
pisiform
a small, pea shaped bone that lies on the palmar surface of the triquetram
trapezium
a four sided bone on the lateral side of the carpus
trapezoid
a wedge shaped bone
capitate
the head shaped bone thsat is the largest bone in the carpus
hamate
a wedge shaped bone which has a hooked process (the hook of hamate) that extends anteriorly
metacarpus
forms the skeleton of the palm of the hand between the carpus and the phalanges
composed of five metacarpals
each consists of a base, shaft and head
proximal bases articulate with carpal bones and distal heads articulate with the proximal phalanges and form knuckles
1st metacarpal is thumb
phalanges`
each digit has three phalanges (proximal, middle, distal) except for the first (thumb has no middle)
each phalanxhas a base, shaft (body) and a head (distal)
distal phalanges are flattened and expanded at their distal ends
fracture of clavicle
weakest part at junction of middle and lateral thirds
SCM elevates medial fragment of bone
trapezius is unable to hold up lateral fragment b/c of weight of limb, shoulder drops
lateral fragment pulled medially by muscles that adduct arm like pectoralis major
ossification of clavicle
first long bone to ossify via intramembranous ossification, during fifth and sixth embryonic weeksfrom medial and lateral primary centers. ends of clavicle later pass through cartilaginous phase, form growth zones similar to those of other long bones
secondary ossification center appears at sternal end and forms scale like epiphysis that begins to fuse with diaphysis between 18 and 25 years of age, completly fused between 25 and 31 years of age
sometimes, fusion of two ossification centers fails to occur: defect: usually bilateral
fracture of scapula
usually result of severe trauma, usually accompanied by fractured ribs
require little treatment because scap is covered by muscle
most fractures involve acromion
fractures of humerus
fractures of surgical neck of humerus especially common in osteoporosis: fall on hand
transverse fractures on shaft of humerus: direct blow to the arm
supra-epicondylar fracture: distal partof humerus
nerves may be injured
surgical neck: axillary nerve
radial groove: radial nerve
distal humerus: median nerve
medial epicondyle: ulnar nerve
fractures of ulna and radius
direct injury usually produces transverse fractures at same level, often middle third of both bones
b/c of interosseus membrane, fracture of one bone is likely dislocation of nearest joint
fracture of distal radius is most common fracture in people> 50 years of age
Colles fracture: complete fracture of distal 2 cm of radius: forced dorsiflexion of hand:comminuted and displaced dorsally; ulnar styloid avulsed
fractures scaphoid
results from a fall on palm with hand abducted
across narrow part (waist) of scaphoid
pain primarily on lateral side of wrist, especially during dorsiflexion and abduction of hand
radiographs immediately may not show, but 10 to 14 days later will
avascular necrosis of proximal fragment of scaphoid may lead to DJD of wrist
fracture of hamate
non union of fractured bony parts because of traction produced by attached muscles
because ulnar nerve is close to hook of hamate, may be injured, causing decreased grip strength of hand
ulnar artery may also be damaged
severe crushing injuries of hand
multiple metacarpal fractures, resulting in instability of the hand
fracture of distal phalanx: usually comminuted with hematoma
fractures of proximal and middle phalanges: usually crushing or hyperextension injuries
