Title: LIF101 Anatomy
1LIF101Anatomy
- Lecture 11
- Muscles of the Arm and Hand
2Muscle Groups of the Upper Arm
- Abductor muscle of upper arm
- Deltoid
- Flexor muscle of upper arm
- Biceps brachii
- Extensor muscle of upper arm
- Triceps brachii
3Flexors
- Groups of muscles at the front (anterior) of arm
act as FLEXORS - Biceps are Flexor muscles of upper arm
- Ventral side
4Arm Movement
- ADDuctors draw limbs closer to the torso
- ABDuctors carry limbs out to the side
- ALIENS
5Extensors
- Work against the flexors (Antagonist)
- Posterior (back side) Straighten the joints
- Dorsal Side
6Deltoid
- Named for triangular shape (Greek delta ?)
- Origin lateral end of clavicle acromion process
and spine scapula - Insertion lateral humerus
7Deltoid
- Abducts humerus (raises arm)
- Rotates humerus in abducted position
- Anatomical landmark deltoid furrow
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10Flexor Muscles of Upper Arm
- Biceps brachii
- You can feel your biceps muscles move when you
turn a doorknob (rotate your forearm) - Attaches to scapula in two places (bi)
- Two heads
11Biceps Brachii
- Named for two divisions long head and short head
- Brach, Brachio Latin for arm
- Origin upper anterior of scapula
- Insertion proximal end of radius
12Biceps Brachii (Biceps)
- Flexes and supinates forearm
- Other features to know
- Bicipital tendon
- Bicipital aponeurosis
- Cubital fossa
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16Brachialis
- Directly beneath biceps
- Origin anterior humerus
- Insertion coranoid process of ulna
- Assists biceps in flexion of forearm
- Can be seen peeking out on either side of biceps
brachii.
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19Extensor Muscles of Upper Arm
- Triceps
- Roles
- Extends and
- Pronates
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21Triceps Brachii (Triceps)
- Named for three divisions lateral head, medial
head, long head - Originates at three places (three heads) one on
scapula and two on humerus - Insertion olecranon process of ulna (via
tendinous plate)
22Triceps Brachii (Triceps)
- All three heads together extend forearm (and
supinate it) - You can feel this muscle in motion when you push
or punch.
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25Forearm Muscles
- Divided into two main compartments
- Flexors/pronators (on ventral/palmar side)
- Extensors/supinators (on dorsal side)
- Functions rotate arm from palms up (supine)
position to palms down (pronate) position
26Forearm Muscles
- Some move wrist/hand others move fingers
- Body of muscles create fullness at proximal
forearm, then - Taper distally into long insertion tendons.
- Insertion tendons are anchored into place by the
annular ligament.
27Words Roots to Know
- Brachial, brachio, brachialis means upper arm
- Radial, radio, radialis means radial (thumb)
side of forearm - Ulnar, ulno, ulnaris means ulnar (pinky) side
of forearm - Digiti finger
28In General
- forearm muscles on the ventral side flex.
- forearm muscles on the dorsal side extend.
- forearm muscles on the radial side abduct.
- forearm muscles on the ulnar side adduct.
29General Areas of Origin
- The flexor/pronator group originates at or around
the medial epicondyle of the humerus. - The extensor/supinator group originates at or
around the lateral epicondyle of the humerus.
30Extensor/Supinator Muscles of Forearm(guess what
they do)
- Brachioradialis
- Extensor carpi radialis longus
- Extensor carpi radialis brevis
- Extensor digitorum
- Extensor digiti minimi
- Extensor carpi ulnaris
- Anconeus
31From Simblets Book
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34Extensor/Supinator Group The Radial Side
- Brachioradialis
- supinates forearm in extension
- pronates forearm in flexion
- Extensor carpi radialis longus
- extends and abducts wrist/hand
- sometimes blends with brachioradialis
- Extensor carpi radialis brevis
- extends and abducts wrist/hand
- shorter than E.C.R.L.
- not as superficial as E.C.R.L.
35Dorsal (Back) Side of Hand
- Extensor digitorum
- digitorum fingers
- extends fingers 25 (not thumb)
- also spreads fingers
- anatomical landmark tendons of extensor
digitorum on back of hand
36Extensor/Supinator Group The Rest
- Extensor digiti minimi
- Extends...well... you tell me!
- Very thin peeks out between the twins.
- Anconeus (ancon elbow)
- Helps extend forearm
- Triangular shape at proximal ulna does not have
long tendon like the others. - Ulnar crest separates flexor group from extensor
group
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42Flexor/Pronator Muscles of Forearm(in three
layers)
- Most superficial layer
- Flexor carpi ulnaris
- Flexor carpi radialis
- Palmaris longus
- Next layer
- Flexor digitorum superficialis
- Deepest layer
- Flexor digitorum profundus
43Flexor/Pronator Muscles of Forearm(Three muscles
on most superficial layer)
- Flexor carpi radialis
- pronates forearm flexes and abducts wrist and
hand - Flexor carpi ulnaris
- flexes and adducts wrist and hand
44Palmar aponeurosis
- palmar aponeurosis
- helps with (strengthens) grip
45Flexor/Pronator Muscles of Forearm(Next Two
Layers)
- Flexor digitorum superficialis
- Flexor digitorum profundus
- both flex hand and fingers (not thumb)
- superficialis more superficial
- profundus deeper flexes distal phalanges
- Biceps tendon separates flexors from extensors
46Its easy to tell one tendon from the other.
- Flexor carpi radialis tendon is closer to the
radial (thumb) side of the arm, as its name
implies. Once that's been established, one can
deduce that the other tendon is most likely that
of palmaris longus.
47The palmaris longus tendon is also more
superficial than the flexor carpi radialis tendon
because it runs outside the annular ligament.
- After surpassing the annular ligament, the
palmaris longus tendon inserts directly into the
palmar aponeurosis and tenses it to help
strengthen the grip.
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49The Ventral Forearm What are those Tendons?
- But the distal end of the ventral forearm does
have a few prominent surface landmarks. - I write "a few" instead of a specific number
because the number depends on the individual - Palmaris Longus is one of the tendons that's
often seen at this location is actually missing
in 12-15 of the human population!
- not less complicated than the dorsal side
- few of its muscles show clearly
- smooth and uncomplicated.
- "underbelly"-- paler and less hairy than its
dorsal counterpart - fewer hair follicles and less melanin production.
50In most cases, there are two fairly visible
tendons down the approximate center of the
ventral wrist.
- Degree of visibility also depends on genetics and
hand position - Those two tendons come from the palmaris longus
muscle and the flexor carpi radialis muscle. - How do we know this is the ventral side of the
forearm?
51Do you have a palmaris longus tendon?
- Make a claw fist to find out.
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57Muscles of the Hand
- Dorsal Interossei
- between metacarpals
- on dorsal side of hand
- abduct (spread) fingers
- First dorsal interosseus m. is surface landmark
- We also have palmar interossei
58Other Hand Structures
- Thenar muscles
- Hypothenar muscles
- Palmar aponeurosis
- Annular ligament
59Annular Ligament
- The annular ligament is a ring-like ligament
("annular" is Latin for "ring-like") that wraps
around the wrist like a bracelet and retains the
position of the tendons that run from the forearm
and into the hand.
60Other Hand Structures
- Anatomical snuffbox
- tendon of extensor pollicus longus (more dorsal)
- tendon of extensor pollicus brevis (more ventral)
61Assignments
- QUIZ Covers muscles of the arm and hand.