Anatomy and Cell Biology 3319 Lecture 24: Muscles of the Upper Limb - The Shoulder and Arm
1 May 2018
School
Department
Professor
Lecture 024: Muscles of the Upper Limb - The Shoulder and Arm
Learning Objectives
● Review the movements of the upper limb
● Describe the bones of the forearm and hand
● Describe the 9 muscles that cross the shoulder joint and move the arm.
● Describe the attachments, functions and innervation of each muscle .
○ A) 2 posterior muscles: Latissimus Dorsi, Teres Major
○ B) 2 anterior muscles: Pectoralis Major, Coracobrachialis
○ C) Deltoid muscle
● Describe the ANTERIOR and POSTERIOR compartments of the arm and their muscular
components, actions and innervation.
● Review the Brachial Plexus and Nerve Branches
Movements of the arm at the shoulder joint
● FLEXION
○ Lifting the arm up (forwards)
● EXTENSION
○ Putting the arm down
● ADDUCTION
○ Putting the arm down horizontally
● ABDUCTION
○ Lifting the arm up horizontally
● MEDIAL ROTATION
○ Turn the palms down (from anatomical position)
● LATERAL ROTATION
○ Turning the palms up(to anatomical position)
● CIRCUMDUCTION
○ A conical movement (tip is at the shoulder)
○ Pinwheel motion
○ Combination of flexion, extension, adduction and abduction
Movements of the hand
● FLEXION
○ Making a fist
● EXTENSION
○ Making a palm
● ADDUCTION
○ Making the fingers touch
● ABDUCTION
○ Splay the fingers
Retraction of the Scapulae
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● Trapezius and rhomboids
work synergistically to produce
this movement
Bones of the Forearm
● Composed of 2 long bones
●Radius
○ More lateral
○Radius
notch/tuberosity
■ Attachment for
muscles
○ At the distal end, the
radius is a styloid
process
■ Will articulate
with 2 bones of
the hand
●Ulna
○ More medial
○Olecranon process
■ At the proximal
end
■ Tip of the elbow
○Trochlear notch
■ Slide around the trochlear of the humerus
● Articulates with
○ The humerus proximally (capitulum: radius, trochlea: ulna)
○ The bones of the wrist distally
○ Each other at the radioulnar joints (both proximal and distal ends)
■ Interconnected across their entire length by a flat ligament (interosseous
membrane)
■ The interosseous membrane divides the
forearm into an anterior compartment and a
posterior compartment
● Muscles of the different compartments
are innervated differently and function
differently
● Division is important!
●Colles fracture
○ Hairline fracture of the radius (pretty common)
Elbow Joint
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● Head of the radius articulates with the capitulum
● Proximal end of the ulna articulates with the
trochlear through the olecranon process
● Joint allows flexion and extension of the elbow
Positions of Radius and Ulna During Pronation
vs.Supination
● Can pronate the hand by movements of the bones
of the forearm
● Bones are parallel in the anatomical position
(supine position) and crossed in the prone
position
○ Radius cross in front of the ulna
Bones of the Hand
● Includes bones of the carpus (wrist), bones of the metacarpus (palm), and bones of the
phalanges (fingers)
●The true wrist
○ Two rows of 4 bones (8 carpal bones total)
■ Proximal row and distal row
○ Only the scaphoid and the lunate physically articulate with the distal end of the
radius to form the wrist joint
●Metacarpals
○ All 5 extend to the phalanges
○ Articulate with the phalanges forms the knuckles
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Lecture 024: muscles of the upper limb - the shoulder and arm. Review the brachial plexus and nerve branches. Movements of the arm at the shoulder joint. Turn the palms down (from anatomical position) A conical movement (tip is at the shoulder) Combination of flexion, extension, adduction and abduction. Trapezius and rhomboids work synergistically to produce this movement. At the distal end, the radius is a styloid process. Will articulate with 2 bones of the hand. Slide around the trochlear of the humerus. The humerus proximally (capitulum: radius, trochlea: ulna) Each other at the radioulnar joints (both proximal and distal ends) Interconnected across their entire length by a flat ligament (interosseous membrane) The interosseous membrane divides the forearm into an anterior compartment and a posterior compartment. Muscles of the different compartments are innervated differently and function differently. Hairline fracture of the radius (pretty common) Head of the radius articulates with the capitulum.
