Lecture 11: MSK 2 Flashcards
What type of bone is the humerus?
Long bone
What are the distal articulations of the humerus?
Trochlea with the trochlear notch of the ulna (elbow joint)
Capitulum with the head of the radius
Indentations of humerus (anterior and posterior)
Anterior = Coronoid fossa (Ulna – Coronoid process)
Posterior = Olecranon fossa (Ulna - Olecranon process)
Where is the ulna on the forearm?
Medial
Little finger side
What bone is part of the “proper” elbow joint
Ulna
Distinguishing features of proximal head of ulna
Olecranon process
Trochlear notch
Coronoid process
Radial notch
See figure
Olecranon process
proximal end of ulna, shaped like wrench
Trochlear notch
Proximal end of ulna
Inner portion of wrench structure
Coronoid process
Proximal end of ulna
lower lip of wrench
Radial notch
Proximal end of ulna
faces laterally to accommodate radius
Distinguishing feature of distal end of ulna
Distal head = Styloid process
Which side of forearm is radius on?
Lateral
Thumb side
What does radius articulate with directly?
Carpal bones (wrist joint)
Proximal and distal ends of radius - features
Proximal: small rounded head
Distal: larger, ends as radial styloid process laterally
See figure
What do carpal bones allow?
Allow for mobility of the hand and opposition which is unique to the human species
Proximal row of carpals from lateral to medial
Scaphoid
Lunate
Triquetrum
Pisiform
See figure
Distal row of carpals from lateral to medial
Trapezium
Trapezoid
Capitate
Hamate
See figure
What do 5 metacarpals make up?
Palm of hand
Numbering of 5 metacarpals
Numbered 1 to 5 beginning with the thumb…the 5th metacarpal is on the ulnar side of the hand.
What type of bones are the metacarpals?
Long bones
Consist of a proximal base, shaft and distal head
What are the phalanges?
Fingers of the hand
How many phalanges per hand?
14
How many phalanges in thumb?
2
Proximal and distal
How many phalanges in each digit?
3
Proximal, middle and distal
How can you identify whether you are looking at anterior or posterior writs?
Anterior: can see hamate and pisoform
Posterior: do not see pisiform
What bones make up the elbow joint?
Humerus
Radius
Ulna
(mostly ulna and humerus)
What type of joint is the elbow joint?
Synovial joint
Hinge type
Movement of elbow joint
Flexion/Extension
What happens during elbow flexion
Trochlear notch of ulna articulates with the
trochlear surface of the humerus
Radial head glides on the capitulum of the
humerus.
What happens during elbow extension
Olecranon process of the ulna fits into the
olecranon fossa of the humerus (boney end-feel)
Carrying angle of forearm
Ulna naturally migrates laterally because trochlea is thicker medially
15 degree carrying angle (cubitus valgus) of forearm
Greater in females than males to accommodate for wider pelvic girdle
Where is the proximal radioulnar joint located?
Below elbow
Between proximal radius and ulna
Radioulnar joint type
Synovial joint
Pivot type
Movement of radioulnar joint
Pronation/Supination
Proximally radius and ulna are always side by side
Distally they cross each other when pronated
What is the wrist joint comprised of?
distal end of the radius and the proximal row of the carpal bones of the hand
Concave shape of the distal radius directly articulates with the convex shape of the scaphoid and lunate
How is the ulna separated from the carpals in the wrist joint?
fibro-cartilagenous disc
Ulna does not contribute to wrist joint
Wrist joint type
Synovial joint
Condyloid type
Movement of wrist
Flexion/Extension
Adduction/Abduction
(Ulnar/Radial Deviation)
See figure
What bones make up the Carp-metacarpal (CMC) joints
Distal row of the carpals & proximal base of the metacarpals
CMC joint type
Synovial joints
Condyloid type
Movements of CMC joints
Flexion/extension
Abduction/adduction
Ulnar/Radial deviation
Where is the 1st CMC joint
Thumb
Between the trapezium and the base of the first metacarpal.