PNB 2264 Lecture Notes - Lecture 3: Biceps, Radial Tuberosity, Olecranon
Differentiating Right and Left Bones
Bones of forearm: radius and ulna
Radius bone markings
● Head (disc-shaped, circular, articulates with capitulum of humerus)
● Neck Radial tuberosity (anterior, attachment for biceps brachii muscle)
● Styloid process (lines up with thumb)
Ulna bone markings
● Trochlear notch (U-shaped, articulates with trochlea of humerus)
● Olecranon (bump of elbow)
● Styloid process (lines up with pinky-finger)
Radius → circular head/disk shape
● Articulates with capitulum of humerus
● Radial tuberosity → attachment point of biceps brachii muscle
Ulna → U shape
● Articulates with chockliar of humerus
● Olecranon process = bump of elbow
Ulna and Radius = have styline process
● Thin, pointed feature
● Palpate wrist = feel styline processes
● Ulna = pinky finger
● Radius = side of thumb
Right or left?
● Radius
○ Compare with own body → anatomical position
○ Make sure palm is facing forward
○ Place head of radius at your elbow
○ Face the radial tuberosity anterior
○ Styline process lines up with thumb or right hand = right radius
● Ulna
○ Start at anatomical position
○ Palm facing up
○ Place notch at elbow
○ Line up styloid process with pinky → pinky of right hand = right ulna
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Document Summary
Head (disc-shaped, circular, articulates with capitulum of humerus) Neck radial tuberosity (anterior, attachment for biceps brachii muscle) Trochlear notch (u-shaped, articulates with trochlea of humerus) Radial tuberosity attachment point of biceps brachii muscle. Compare with own body anatomical position. Place head of radius at your elbow. Styline process lines up with thumb or right hand = right radius. Line up styloid process with pinky pinky of right hand = right ulna. Greater tubercle - important sites of muscle assertion. Surgical neck - interface between head and shaft. Acromian - process that articulates the acromial end of clavicle. Infraspinous fossa - site of origin of shoulder muscle. Glenohumeral joint = head of humerus + glenoid fossa of scapula. Rotator cuff = greater tubercle + supraspinous fossa + infraspinous. All of the muscles on rotator cuff insert all muscles of the humerus. Muscles of rotator cuff are imp to stability.